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PENGELOLAAN RUANG TERBUKA HIJAU KOTA smno2ub.ac.id2014
Cities, 21 (4): 311– (4 Green-space preservation and allocation for sustainable greening of compact cities C.Y Jim Including greenery in human settlements is a tradition deeply rooted in antiquity, with diverse expressions. Realization of the green city ideal has changed with prevailing social–economic–political regimes and landscape styles. Variations in land use and development mode have generated green spaces of different geometry, distribution and composition. The compact city incurs inherent physical and institutional obstacles, restricting the quantity and quality of amenity vegetation. Recent research findings in arboriculture, urban forestry, urban ecology, urban planning and urban geography suggest alternative strategies for both existing and new green sites. A multidisciplinary interpretation distils relevant principles and practices to facilitate greening in packed neighborhoods and overcome major constraints. Measures are proposed to guard green spaces from intrusion, intensification and infilling to preserve both sites and conditions for plants, wildlife and ecological functions. New developments and redevelopments, with suitable encouragement and incentives, can earmark enough new green areas with appropriate location and design. Natural enclaves, especially woodlands, with high biodiversity and complex biomass should be incorporated into the future built environment. Partnership among government, developers and citizens should nurture the community’s determination and capability to augment greening. A coordinating body to mobilize initiatives and efforts could gel disparate stakeholders and bring concerted actions.
. Landscape and Urban Planning, 79 (3–4): 240– (3–4 Using GIS and landscape metrics in the hedonic price modeling of the amenity value of urban green space: A case study in Jinan City, China Fanhua Kong aFanhua Kong a,,, Haiwei Yin b, Nobukazu Nakagoshi Haiwei Yin b Urban green spaces have important amenity values that include provision of leisure opportunities and aesthetic enjoyment. However, most of these values lack a market price. Consequently, they are usually ignored or underestimated by urban planning policy-makers, with the result that remnant urban green spaces are being gradually encroached upon by urban sprawl. As a result, quantitative information regarding the implicit, non-market price benefits from urban green space is urgently required. Properties bought and sold on the market are compound commodities that embody amenity values and people are willing to pay to live in the proximity of local amenity environment. Thus hedonic models, which use such properties as proxies, can often be employed to quantify environmental amenities. In China, residential housing reform (in place since 1998) has terminated the traditional residential welfare system, and made it possible to quantify the monetary value of green space amenities based on hedonic pricing models. This study was conducted in Jinan City, and will help address the previous absence of the application of hedonic price models to the valuation of urban green space amenities in mainland China. GIS and landscape metrics were used in determining hedonic price model variables. As expected, the results proved that the hedonic pricing model performed well using this approach, and accordingly it was further improved. Results also confirmed the positive amenity impact of proximate urban green spaces on house prices, and highlighted the preferences of homeowners in Jinan City. Green space amenity variables that were statistically significant at the 5% level included the size–distance index of scenery forest, accessibility to park and plaza green space types, and the percentage of urban green space. In addition, land-use patch richness, the location sector and the education environment also proved to be highly significant variables. The results of the study should provide insights to policy- makers involved in urban planning.
Morancho, A.B A hedonic valuation of urban green areas. Landscape and Urban Planning, 66 (1): 35–41. Morancho (2003) analyzed the link between housing prices and urban green areas endowments using the hedonic technique as methodological approach. Together with the conventional variables used to explain housing prices, three environmental variables are considered: the existence of views of a park or a public garden, the distance from the dwelling to its nearest green area and the size of that open space. The sample is made up of 810 observations gathered from the city of Castellón (Spain). Results show housing size to be the most relevant variable on price. As far as the hedonic variables are concerned, there is an inverse relationship between the selling price of the dwelling and its distance from a green urban area.
Chinese Geographical Science, 21 (4): Urban green space planning based on computational fluid dynamics model and landscape ecology principle: A case study of Liaoyang City, Northeast China Yuan ZhouYuan Zhou, Tiemao Shi, Yuanman Hu, Chang Gao, Miao Liu, Shilei Fu, Shizhe Wang Tiemao ShiYuanman HuChang GaoMiao LiuShilei Fu As a result of environmental degradation, urban green space has become a key issue for urban sustainable development. This paper takes Liaoyang City in Northeast China as an example to develop green space planning using the computational fluid dynamics (CFD) model, landscape ecological principles and Geographical Information System (GIS). Based on the influencing factors of topography, building density and orientation, Shou Mountain, Longding Mountain and the Taizi River were selected as the urban ventilation paths to promote wind and oxygen circulation. Oxygen concentration around the green spaces gradually decreased with wind speed increase and wind direction change. There were obvious negative correlation relationships between the oxygen dispersion concentration and urban layout factors such as the building plot ratio and building density. Comparison with the field measurements found that there was significant correlation relationship between simulated oxygen concentration and field measurements (R 2 = , p < 0.001), moreover, simulation precision was higher than 92%, which indicated CFD model was effective for urban oxygen concentration simulation. Only less than 10% areas in Liaoyang City proper needed more green space urgently to improve oxygen concentration, mainly concentrated in Baitai and west Wensheng districts. Based on landscape ecology principle, green space planning at different spatial scales were proposed to create a green space network system for Liaoyang City, including features such as green wedges, green belts and parks. Totally, about 2012 ha of green space need to be constructed as oxygen sources and ventilation paths. Compared with the current green space pattern, proposed green space planning could improve oxygen concentration obviously. The CFD model and research results in this paper could provide an effective way and theory support for sustainable development of urban green space.
Landscape and Urban Planning, 72 (4): 325– (4 Comprehensive concept planning of urban greening based on ecological principles: a case study in Beijing, China. Feng Li aFeng Li a,, Rusong Wang a,,, Juergen Paulussen a, Xusheng Liu Rusong Wang aJuergen Paulussen a Greenspace is an important part of complex urban ecosystems and provides significant ecosystem services. It benefits urban communities environmentally, esthetically, recreationally and economically. Beijing Province is in north of China, and has a total area of 16,807.8 km 2 and a population of about 13.8 million. This paper aims to develop a comprehensive conceptual framework for urban greening of Beijing Province based on landscape ecological principles. It attempts to answer how to establish an urban greening plan at the regional, city and neighborhood levels to achieve long-term sustainability. At the regional level, a big natural and semi-natural forest area in the northwest and an ecological buffer belt in the southeast are planned to protect the environmental quality of Beijing and provide habitats for wildlife. At the city level, a green network system of green wedges, parks and green corridors has been proposed. This green network helps to limit future urban expansion, improve urban environmental quality and serve as habitats and migration routes for wildlife. At the neighborhood level, green extensions and connections of riverside greenway, road greenway, parks and vertical greening permeate into the built-up areas. They provide open space close to residential areas and offer places for recreation. This three-level green system constitutes an integrated ecological network for urban sustainable development of Beijing. For future development of Beijing, urban parks, forestry, agriculture, water and infrastructure should be planned and designed in an integrated way. After this greenspace plan is legislated and completely realized, Beijing will develop an interconnected and integrated network of urban greenspaces. It has the prospect of achieving the aim of “Green Olympic City 2008” and the long-term goal of developing Beijing towards an “Eco-City”.
Habitat International, 34 (2): 244– (2 Public green space inequality in small towns in South Africa M. Matthew McConnachieM. Matthew McConnachie, Charlie M. Shackleton The distribution of public green space within towns is frequently uneven, and influenced by attributes such as its location relative to the commercial core, as well as the ethnicity and relative wealth and education of the residents. Yet most studies are from large cities in developed countries. In contrast, this study reports on the distribution of public green space across 9 small towns in a developing country, namely South Africa, which offers a unique case study because of its former racially defined settlement patterns. We do so using GIS analysis of aerial photographs focusing on 3 types of suburbs in each town, defined on the basis of wealth as well as race-based history under the previous apartheid regime. The more affluent suburbs, inhabited mainly by whites, have the lowest density of housing and the highest area of green space per capita. Proportionally, they have a similar area under public green space as to the previously racially defined townships, but because of the lower housing density, they have a greater area per person. The newly built low-cost housing areas (termed RDP suburbs), occupied largely by poor black South Africans, are poorly endowed with public green space, and fare worse than the other 2 suburb types on all attributes measured. This needs to be addressed in further low-cost housing developments.
Robitu, M., M.Musy, C. Inard dan D. Groleau Modeling the influence of vegetation and water pond on urban microclimate. Solar Energy, 80 (4): 435–447. The beneficial influence of trees and water ponds on summer comfort in urban spaces was studied experimentally in situ and in wind tunnels but the modeling needs further development to become effective in practical applications (Robitu et al., 2006). The numerical approach is based on coupling the CFD model of airflow, in which the influence of trees is considered as source terms, and the radiation exchange, completed with thermal conduction. The CFD, radiation and thermal conduction models use the same discretization grid at their common boundaries. The model was used to estimate the influence of trees and water ponds in a real town square. Comparison of results between two situations, with and without vegetation and water pond, indicate that surface temperatures are reduced in presence of trees and the comfort is improved.
. Urban Forestry & Urban Greening, 7 (1): 25–40.7 (1 Application of land suitability analysis and landscape ecology to urban greenspace planning in Hanoi, Vietnam. Pham Duc UyPham Duc Uy, Nobukazu Nakagoshi Urban green spaces, an important component of urban ecosystems, provide many environmental and social services that contribute to the quality of life in cities. One of the key tasks of planners is how to optimize the benefits of urban green spaces. This study introduces a program for developing green spaces in urban areas through (1) land suitability analysis based on GIS; (2) quantifying green areas based on the ecological factor threshold method to maintain ecological balance; and (3) applying landscape-ecology principles in organizing green spaces in urban areas. A case study was made for Hanoi, Vietnam and its results show that most of the planned green spaces in the 2020 Hanoi Master Plan are suitable for development. However, the recommended 18 m 2 green area per capita seems not to be enough to maintain ecological balance and organization of the green spaces in the 2020 plan seems to lack a theoretical basis, or a holistic framework, at different scales. From this perspective, we propose that Hanoi should set aside an extra green area from 6842 to 10,228 ha, and that the 2020 Hanoi green structure plan at regional, city and neighborhood scales includes three green wedges, one green belt, various parks and other green ways to create a green network ecologically more effective than the sum of the individual green spaces. This green structure and the combined data approaches used here will form a base for building a garden city or an eco-city in the future.
Building and Environment, 45 (8): 1880– (8 A simple method for designation of urban ventilation corridors and its application to urban heat island analysis. Man Sing WongMan Sing Wong, Janet E. Nichol,, Pui Hang To, Jingzhi Wang Janet E. NicholPui Hang To This paper describes urban wind ventilation mapping, using the concept of “building frontal area index”, and uses the Kowloon peninsula of Hong Kong as an example of a dense, sub-tropical urban environment where ventilation is critical for human health. The frontal area index is calculated for uniform 100 m grid cells, based on three dimensional buildings in each cell, for eight different wind directions. The frontal area index is then correlated with a land use map, and the results indicate that high density commercial and industrial areas with large building footprints had higher values than other urban land use types. Using the map of frontal area index, the main ventilation pathways across the urban area are located using least cost path analysis in a raster GIS. Field measurements of urban winds confirmed the significance and functionality of these modelled ventilation paths. Comparison of the pathways with a map of the urban heat island suggests that ventilation is a key parameter in mitigating heat island formation in the study area. Planning and environmental authorities may use the derived frontal area index and ventilation maps as objective measures of environmental quality within a city, especially when temperatures in the inner city are a major concern.
Landscape and Urban Planning, 100 (3): 268– (3 Spatial–temporal dynamics of urban green space in response to rapid urbanization and greening policies Xiaolu Zhou Xiaolu Zhou,,, Yi-Chen Wang Rapid urbanization has caused many environmental impacts associated with the reduction of green space. Having realized the important role of green space in urban ecosystems, many local governments in China have set out a series of policies to introduce green elements into urban areas. Insights into how urban green space changes in response to urbanization and greening policies are essential for guiding sustainable urban development. This paper employed integrated approaches to characterize the changing patterns and intensities of green space in Kunming, China from 1992 to Spatial variations of green space pattern were derived through concentric and directional landscape analyses integrated with landscape metrics. Change intensities of the two time periods from 1992 to 2000 and from 2000 to 2009 were calculated for the study area as a whole, the concentric belts, and the directional transects to examine the variation of the green space change rate in the city. Results revealed that both rapid urbanization and greening policies accounted for the process of green space change. Among the green space land use types, agriculture land was largely encroached and fragmented by urban sprawl, especially in the outer belts of the city. Forest land was also impacted but encountered a relatively moderate loss rate compared to agriculture land. Conversely, greening policies contributed to the recovery of grass land in the last decade. The study demonstrated the usefulness of the concentric and directional landscape analyses in characterizing the spatial– temporal variations of urban green space in cities with a concentric development form.
Semenzato,P., T. Sievänen, E.S. de Oliveira, A.L. Soares dan R. Spaeth Natural Elements and Physical Activity in Urban Green Space Planning and Design. Forests, Trees and Human Health, 2011, pp While studies on physical activity behavior are widely available, research on physical activity environments is relatively new, particularly when related to ‘natural’ environments. Semenzato et al. (2011) described planning issues and design elements that can influence the use of urban green areas for physical activity are discussed. Availability, features, conditions, safety, aesthetics and climatic comfort are the main characteristics of urban green areas considered in the discussion, particularly in relation to natural elements. In the first part of the chapter the current literature presenting scientific evidence is examined. Once this evidence is discussed examples of best practices and significant planning and design solutions concerning the most relevant attributes of the green spaces are presented.
. Journal of Forestry Research, 20 (1): Analysis of problems in urban green space system planning in China Xiao-Jun Wang This paper discusses the major problems in urban green space system (UGSS) planning at both general and special planning levels in China. At general planning level, the problems of the UGSS are mainly from the ignorance in the characteristics of urban nature spaces and the limitation factors of the urban planning system. Great importance is attached to the green spaces in the built area of city, but the green spaces in surrounding areas of the city is unnoticed. Furthermore, because the area of UGSS planning is strictly limited by the administrative zoning, the green space system loses its integrity and rationality in spatial patterns. The schedules of urban development planning mismatched the paces and progresses of the ecological restoration cycles. At special plan level, the problem of the UGSS in China is that the green spaces quantity was over emphasized but the rationality of their layouts is neglected.. Meanwhile, the requirement of the spatial structures and the green spaces layouts to balance between the urban development and the natural ecological environments is often ignored. With regard to the layouts in the UGSS planning practices, the existing problems are the compromising to the existing land-uses, the ‘filling in’ approach to plan green spaces and an over-emphasis on the layout patterns.
Wang Xiao-jun Type, quantity and layout of urban peripheral green space. Journal of Forestry Research, 12 (1): Urban peripheral green space (UPGS) plays more and more important role in sustaining urban physical and ecological environments. Wang Xiao-jun (2001) proposed a preliminary classification of UPGS was presented for seven types and quantity index of UPGS was discussed tentatively. The quantity and layout problems in urban peripheral green space, and the several principles were mainly discussed in urban ventilation and sanitation, recreational opportunity and landscape ecological structure.
Ecology, Planning, and Management of Urban Forests, 2008, pp Benefits of Urban Green Space for Improving Urban Climate Volker HeidtVolker Heidt, Marco Neef Urban settlements transform the natural environment so greatly that people tend to see the city only as an employment site, and economic and cultural center. Thus a growing number of people prefer to reside in greener suburbs or rural areas. This results in increased automobile commuter traffic, accompanied by traffic jams, accidents, stress, and ever more damage to the environment. Concepts of sustainable development or the ecological city represent strategies for changing these negative trends. The purpose for doing so is principally the well-being of a city’s residents. Often this entails bringing more of the natural environment back into the city, because urban green space fulfills several critical functions in an urban context that benefit people’s quality of life. There is a broad consensus about the importance, and therefore the value, of urban green space in cities as currently constructed, in addition to its value in planning ecological cities. Steadily growing traffic and urban heat not only damage the environment, but also incur social and economic costs. As we explain further, we can save costs even by making small changes to existing situations. Furthermore, we maintain and show that an integrated approach is needed for designing and maintaining urban green space. The main thesis of this chapter, therefore, is as follows: To provide sufficient quality of life in high-density cities, it is important to maintain and restore an urban green space system; moreover, urban green space and a comfortable urban climate also produce social and economic benefits.
. Urban Ecosystems, 16 (2): Analyzing the pattern and connectivity of urban green spaces: A case study of Izmir, Turkey Şerif Hepcan The primary concerns in this study were to quantify the connectivity and green space pattern using landscape metrics (PLAND, NP, AREA_MN and CONNECT) in the central districts of the city of Izmir. The primary research materials included thirteen 1:25,000 scale standard topographical maps and IKONOS satellite image with 1 m resolution. The PLAND scores revealed that while the urban fabric occupied almost 26 % of the study area, the urban green spaces covered only 1.45 %. This was also the lowest score in proportion to the areas of other land-use/cover classes. Furthermore, the results of NP and MPS indicated that the configuration of urban green spaces was very patchy and highly fragmented. Likewise, using CONNECT, the overall connectivity score of urban green spaces was 0.12, which was the lowest score of all areas measured the metrics. The Güzelbahçe district seemed to hold the most promise for connectivity, with a CONNECT score of On the other hand, the Bornova district presented the least promising case in terms of connectivity, with a score of In the study area, the correlations between the size of the districts/built-up areas and the CONNECT scores of the urban green spaces were found to be “non-significant” (P < 0.01). The ultimate goals were to increase the amount of systematically planned urban green spaces and set up a green infrastructure in Izmir. In the case of Izmir, a master planning approach, which uses a systematic and comprehensive method to guide urban green spaces, is necessary to develop planning and design strategies for fully functional and multi-purpose urban green space systems.
. Landscape and Ecological Engineering, November 2007, Volume 3, Issue 2, pp Issue 2 Analyzing urban green space pattern and eco-network in Hanoi, Vietnam Pham Duc UyPham Duc Uy, Nobukazu Nakagoshi In Hanoi, the capital city of Vietnam, there has recently been a growing awareness about the roles and benefits of greening in urbanized areas. As a result, planners and decision-makers propose a combination of water bodies and green areas, using cultural as well as historic values, in a strategic concept for city planning in Hanoi. This study aims at quantifying the landscape patterns and ecological processes or clearly linking pattern to process to identify green space changes and their driving forces, based on gradient analysis combined with landscape metrics, GIS support, and FRAGSTATS 3.3, from 1996 to The results of gradient analysis taken four directions show that green spaces have been become more fragmented in this period, especially in the south and west directions. These changes could be caused by land use change, economic growth, population increase, urbanization, and weakness in planning and managing the urban development. From this context, graph theory was also applied to find any eco-networking, by mitigating the fragmentation and enhancing the green space connectivity, as a biodiversity conservation strategy for the city. Analyzing the green network based on graph theory indicates that among six different network scenarios which were produced from several models (Traveling Salesman, Paul Revere, Least Cost to User), network F with 37 links, and gamma (0.07), beta (0.62), cost ratio (0.606), circuitry (0.098) and connectivity (0.398) is the best option for ecological restoration in the Hanoi city. This will be a basis for the 2020 Green Space Planning in Hanoi.
Landscape and Urban Planning, 78 (3): 147– (3 Spatial-temporal gradient analysis of urban green spaces in Jinan, China Fanhua Kong Fanhua Kong,, Nobukazu Nakagoshi In China, rapid urbanization has profoundly transformed the spatial pattern of urban land use, including urban green spaces. The government plans to optimize green spaces to integrate with urban development; this requires an understanding of the process of green space change. Quantification of green space patterns is a prerequisite to understanding green space changes, and is essential for monitoring and assessing green space functions. This paper presents a new method for quantifying and capturing changes in green space patterns, through a case study of Jinan City, China, during 1989–2004. Supported by GIS and remote sensing, the method comprises quantification of local area green spaces by the “moving window” technique (using FRAGSTATS), and a gradient analysis involving sampling from the urban center to the fringe. Results demonstrate that the significantly altered green space pattern could be quantified using landscape metrics in each local area. Gradient analysis undertaken in eight directions from the urban center reflects the changes in and effects of urbanization, and the implementation of government policy. In comparison with quantifying metrics in entire landscapes, this method more effectively links patterns and processes, and can establish an important basis for subsequent analysis of ecological and socioeconomic functions of green spaces.
Linehan, J., M. Gross dan J.Finn Greenway planning: developing a landscape ecological network approach. Landscape and Urban Planning, 33 (1–3): 179–193. Greenway planning has steadily grown in popularity in the planning and design professions as an efficient and socially desirable approach to open space planning. Linehan, Gross dan Finn (1995) presented a theoretical and methodological approach to greenway planning that accounts for regional biodiversity and systematizes the selection of greenway links. The approach is based on the premise that a network of wildlife reserves and corridors should serve as the skeletal framework of a comprehensive greenway system. This approach was derived from the knowledge bases of landscape ecology, conservation biology, network theory, and landscape planning.
. Landscape Ecology, 2006, Volume 21, Issue 5, pp Issue 5 Impacts of road corridors on urban landscape pattern: a gradient analysis with changing grain size in Shanghai, China. Ming ZhuMing Zhu, Jiangang Xu, Nan Jiang, Jianlong Li, Yamin Fan Jiangang XuNan JiangJianlong Li. Urbanization is one of the most important driving forces for land use and land cover change. Quantifying urban landscape pattern and its change is fundamental for monitoring and assessing ecological and socioeconomic consequences of urbanization. As the largest city in the country, Shanghai is now the fastest growing city in China. Using land use data set of 2002 and combining gradient analysis with landscape metrics, we analyzed landscape pattern of Shanghai with increasing grain size to study the impacts of road corridors on urban landscape pattern. Landscape metrics were computed along a 51×9 km 2 transect cutting across Shanghai with a moving window. The results showed that the urban landscape pattern of Shanghai was greatly changed when road corridors were merged with urban patches and the variation of patch density would alter when grain size changed. As a linear land use type, road corridors exhibited a different spatial signature comparing with other land use types and distinctive behavior with increasing grain size. Merging road and urban patches resulted in a sharp reduction in patch density, mainly caused by segmentation of roads corridors. The results suggested that grain size around 7.5 m might be optimal for urban landscape analysis. Landscape patch density is significantly correlated with road percent coverage and the most important effect of road corridors in urban landscape is increased habitat fragmentation.
Irvine, K.N., R. A. Fuller, P. D.Wright, J. Tratalos, S. R. Payne, P. H. Warren, K. J. Lomas, K.J.Gaston Ecological and Psychological Value of Urban Green Space. Dimensions of the Sustainable City, 2 (..): In urban environments, perhaps more so than in any other setting, people and nature must coexist in close, and sometimes uncomfortable, proximity. With half of the world’s human population living in cities and a continued decline of biodiversity in the wider landscape, urban nature plays an increasingly important role in creating cities that are both ecologically and socially sustainable (Irvine et al., 2010). However, understanding the value of urban green spaces as a resource requires an integration of several, rarely overlapping, approaches to evaluating and managing these places.
Barradas, V.L Energy balance and transpiration in an urban tree hedgerow in Mexico City. Urban Ecosystems, 4 (1): A series of sap flow (transpiration, TRP) and energy balance components measurements were carried out in a representative tree hedgerow of Fraxinus uhdei in Mexico City (19° 19' N, 99° 11' W, 2250 m ASL) (Barradas, 2000). Measurements of sap flow in the trunks of the trees was selected as an alternative tool instead of eddy covariance or Bowen ratio-energy balance methods in order to determine the energy balance components of the tree canopy. These measurements were made in October (end of the rainy season) and December (dry season) in 1997, from 8:00 to 17:00 LST. TRP showed a unimodal pattern during the day. Mean daily transpiration was higher at the end of the rainy season (1506 g m −2 d −1 ) than in the begining of the dry season (972 g m −2 d −1 ) with maxima rates of and g m −2 s −1, respectively. During the rainy season net radiation (Q N ) was mainly dissipated by latent (Q E ) and sensible (Q H ) heat, 60 and 34 %, respectively. Latent heat increased in the day up to 184 W m −2. Q N was dissipated by Q H and Q E by 75 and 25%, respectively, and Q H had a maximum hourly value of 298 W m −2 during the day (8:00-17:00 LST) in the dry season. Seasonal differences in Q E and Q H were probably due to differences of water availability. Heat storage of the tree hedgerow canopy was found to be a negligible component of the energy balance in both seasons. Actual transpiration of the system was always lower than transpiration at equilibrium. This was probably due to a low water availability in the substratum, a high atmospheric evaporative demand and an effective stomatal control. Because the tree hedgerow was completely surrounded by paved areas and wind was coming from a drier side, it is possible that transpiration rates were affected by advection probably supressing TRP.
. Environmental Management, 2009, Volume 44, Issue 4, pp Issue 4 Transpiration and Root Development of Urban Trees in Structural Soil Stormwater Reservoirs J. BartensJ. Bartens, S.D. Day, J. R. Harris, T.M. Wynn, J.E. Dove S.D. DayJ. R. HarrisT.M. Wynn Stormwater management that relies on ecosystem processes, such as tree canopy interception and rhizosphere biology, can be difficult to achieve in built environments because urban land is costly and urban soil inhospitable to vegetation. Yet such systems offer a potentially valuable tool for achieving both sustainable urban forests and stormwater management. We evaluated tree water uptake and root distribution in a novel stormwater mitigation facility that integrates trees directly into detention reservoirs under pavement. The system relies on structural soils: highly porous engineered mixes designed to support tree root growth and pavement. To evaluate tree performance under the peculiar conditions of such a stormwater detention reservoir (i.e., periodically inundated), we grew green ash (Fraxinus pennsylvanica Marsh.) and swamp white oak (Quercus bicolor Willd.) in either CUSoil or a Carolina Stalite-based mix subjected to three simulated below-system infiltration rates for two growing seasons. Infiltration rate affected both transpiration and rooting depth. In a factorial experiment with ash, rooting depth always increased with infiltration rate for Stalite, but this relation was less consistent for CUSoil. Slow-drainage rates reduced transpiration and restricted rooting depth for both species and soils, and trunk growth was restricted for oak, which grew the most in moderate infiltration. Transpiration rates under slow infiltration were 55% (oak) and 70% (ash) of the most rapidly transpiring treatment (moderate for oak and rapid for ash). We conclude this system is feasible and provides another tool to address runoff that integrates the function of urban green spaces with other urban needs.
. Can Urban Tree Roots Improve Infiltration through Compacted Subsoils for Stormwater Management?. JEQ, 37 (6): Julia Bartens af, Susan D. Day *b, J. Roger Harris c, Joseph E. Dove d and Theresa M. Wynn Global land use patterns and increasing pressures on water resources demand creative urban stormwater management. Strategies encouraging infiltration can enhance groundwater recharge and water quality. Urban subsoils are often relatively impermeable, and the construction of many stormwater detention best management practices (D-BMPs) exacerbates this condition. Root paths can act as conduits for water, but this function has not been demonstrated for stormwater BMPs where standing water and dense subsoils create a unique environment. We examined whether tree roots can penetrate compacted subsoils and increase infiltration rates in the context of a novel infiltration BMP (I-BMP). Black oak (Quercus velutina Lam.) and red maple (Acer rubrum L.) trees, and an unplanted control, were installed in cylindrical planting sleeves surrounded by clay loam soil at two compaction levels (bulk density = 1.3 or 1.6 g cm −3 ) in irrigated containers. Roots of both species penetrated the more compacted soil, increasing infiltration rates by an average of 153%. Similarly, green ash (Fraxinus pennsylvanica Marsh.) trees were grown in CUSoil (Amereq Corp., New York) separated from compacted clay loam subsoil (1.6 g cm −3 ) by a geotextile. A drain hole at mid depth in the CUSoil layer mimicked the overflow drain in a stormwater I-BMP thus allowing water to pool above the subsoil. Roots penetrated the geotextile and subsoil and increased average infiltration rate 27-fold compared to unplanted controls. Although high water tables may limit tree rooting depth, some species may be effective tools for increasing water infiltration and enhancing groundwater recharge in this and other I-BMPs (e.g., raingardens and bioswales).
Environmental Management, 38 (3): Perception and Attitude of Residents Toward Urban Green Spaces in Guangzhou (China) C. Y. JimC. Y. Jim, Wendy Y. Chen Fast economic and social changes in recent years in China have brought massive expansion, redevelopment, and restructuring of cities. These changes offer cities the opportunity to improve environmental quality through urban green spaces (UGSs) and to address the challenges of meeting community aspirations. This study explored peoples’ minds concerning UGSs in Guangzhou city in south China in relation to the following: (1) knowledge and perception of 25 ecosystem services and 8 negative impacts; (2) attitude toward site condition and management; (3) expectation of landscape design; and (4) preference ranking of venues. A questionnaire was designed to solicit opinions from 340 respondents randomly chosen from residents living in the study area. The results indicated widespread recognition of ecosystem services and strong support of UGS programs. Negative responses were weakly expressed. Amelioration of urban microclimate and environmental quality were emphasized. Environmental functions stressed in publicity programs, together with aggravating environmental problems in the city, tended to focus respondents’ attention on UGS benefits. Wildlife habitat, species conservation and other natural ecosystem services drew limited concerns. Awareness of economic benefits was very low. Visual-landscape contributions with strong preference for naturalistic design and recreational benefits were highlighted. Compared with other countries, Guangzhou residents were characterized by visual–scenic–recreation orientation and pragmatic–utilitarian perception of UGSs, reflecting underlying differences in the understanding of inherent ecosystem services of green spaces. Relevant UGS policies and practices could adopt the approaches of market survey, citizen participation, and precision planning in order to meet increasingly mature and refined demands. Citizens’ understanding of high-order ecosystem services could be enhanced to encourage appreciation of nature and their associated benefits.
Nowak, D.J Institutionalizing urban forestry as a “biotechnology” to improve environmental quality. Urban Forestry & Urban Greening, 5 (2): 93–100. Urban forests can provide multiple environmental benefits. As urban areas expand, the role of urban vegetation in improving environmental quality will increase in importance. Quantification of these benefits has revealed that urban forests can significantly improve air quality (Nowak, 2006). As a result, national air quality regulations are now willing to potentially credit tree planting as means to improve air quality. Similarly, quantification of other environmental benefits of urban trees (e.g., water quality improvement, carbon sequestration) could provide for urban vegetation to be incorporated in other programs/regulations designed to improve environmental quality.
Urban Forestry & Urban Greening, 2 (2): 101–114.2 (2 Selection of trees for urban forestry in the Nordic countries Arne Sæbø aArne Sæbø a,,, Thorarinn Benedikz b, Thomas B. Randrup Thorarinn Benedikz b Trees in the urban environment are subjected to a number of stresses which are very different from those suffered by trees in typical rural conditions. The stresses listed in this paper should be a basis for the selection criteria used in urban tree improvement programs. The basic properties of trees are climatic adaptation, disease resistance and a large phenotypic plasticity. Properties related to the urban situation are related to stresses caused by social factors, the restrictive soil volume and crown space, soil pollution, air pollution, de-icing salt, wind and drought. In addition, aesthetic factors, growth form and growth potential and resistance to breakage of limbs are important selection criteria. The priority ranking of the selection criteria depends on the environment wherein the plants are to be used. The need to broaden the range of species and cultivars planted in Nordic cities should have high priority, and selection programs should, therefore, include new species of urban trees. A practical selection should be made within the four major Nordic climatic regions, which are the northern maritime, northern continental, southern maritime and southern continental regions. The establishment of broad co-operation in the selection of plant materials for urban uses is discussed.
Journal of Forestry Research, 14 (3): Status of urban vegetation in Guangzhou City Guan Dong-shengGuan Dong-sheng, Chen Yu-juan According to a survey for the urban vegetation of Guangzhou, urban vegetation has a significantly difference from natural vegetation because of intense human impacts. The research was conducted in a synthetic survey for soil, species diversity, roadside trees and ecological function of urban vegetation in Guangzhou City. The results showed that: (1) soil densities of urban roadside and park forests were higher than mean density of natural forest soil. The pH values of soil in urban roadside were higher too, and the content of organic matter and the concentration of nitrogen were lower. (2) Species diversity of urban vegetation was lower. The most number of species was only 16 species in tree layers of urban forest. (3) Tree growth was limited by narrow space in high-density urban area, where the trees with defects and disorders were common. (4) Comparing with mature natural forests, the productivity of urban vegetation was lower. The effect of urban vegetation on balance of carbon and oxygen were influenced by the low primary production of urban vegetation. Therefore, the growth condition for urban vegetation should be improved. Biodiversity, primary production and ecological function should be increased for urban vegetation in order to improve urban eco-environment.
Beckett,K.P., P.H.F. Smith dan G. Taylor Urban woodlands: their role in reducing the effects of particulate pollution. Environmental Pollution, 99 (3): 347–360. In recent years a substantial research effort has focused on the links between particulate air pollution and poor health. As a result the PM 10 value has been set as a measure of such pollutants which can directly cause illness (Beckett, Smith dan Taylor, 1998). Due to their large leaf areas relative to the ground on which they stand and the physical properties of their surfaces, trees can act as biological filters, removing large numbers of airborne particles and hence improving the quality of air in polluted environments. The role of vegetation and urban woodlands in reducing the effects of particulate pollution is reviewed here. The improvement of urban air quality achieved by establishing more trees in towns and cities is also illustrated.
Chi Yung Jim Tree–Habitat Relationships in Urban Hong Kong. Environmental Conservation / Volume 19 / Issue 03 / Autumn 1992 pp Environmental Conservation Trees, as welcome and necessary components of Nature and functional landscape elements in cities, provide a worth-while theme for applied ecological study. Of the different approaches, the micro-scale evaluations of tree—habitat interactions can throw light on practical tree management. The roadside trees in Hong Kong, generally dwelling in a stressful physical and physiological environment, have been surveyed in detail in the field with regard to species composition, tree structure, tree defects, and habitat characteristics. Despite a diversified floristic composition, the street-tree population is dominated by a small number of common species, of which 12 have been chosen for in-depth evaluations. The recent emphasis on exotic and fast-growing species with limited final dimensions will modify the treescape in the long run. Many existing large specimens have been sacrificed to urban redevelopments. The differential performance of different species with reference to the occurrence of defects has been interpreted. Almost all the trees are inflicted by some structural or physiological problems, and large trees are practically collectors of diverse maladies. The urban tree habitats of Hong Kong are characterized by gravely cramped and stressful conditions from the soil-level upwards and especially as regards headroom. Tree-habitat correlations and associations suggest a need to plant rapid-growing, tall but narrow-canopied species that are able to resist a maximum proportion of the inevitable tree defects and diseases. The shortage of good-quality habitats with space for tree-growth, and the accompanying unfavourable ecological niches, are crucial factors for tree existence. The prospects of street trees in the long-term urban planning and upgrading for environmental quality, with special reference to the provision and preservation of proper habitats, are elaborated, with Hong Kong as a practical example.
Alvey, A.A Promoting and preserving biodiversity in the urban forest. Urban Forestry & Urban Greening, 5 (4): 195–201. Efforts at mitigating global biodiversity loss have often focused on preserving large, intact natural habitats. However, preserving biodiversity should also be an important goal in the urban environment, especially in highly urbanized areas where little natural habitat remains. Increasingly, research at the city/county scale as well as at the landscape scale reveals that urban areas can contain relatively high levels of biodiversity (Alvey, 2006). Important percentages of species found in the surrounding natural habitat, including endangered species, have been found in the urban forest. This contribution concisely highlights some examples of urban biodiversity research from various areas of the world. Key issues involved in understanding the patterns and processes that affect urban biodiversity, such as the urban–rural gradient and biotic homogenization, are addressed. The potential for urban areas to harbor considerable amounts of biodiversity needs to be recognized by city planners and urban foresters so that management practices that preserve and promote that diversity can be pursued. Management options should focus on increasing biodiversity in all aspects of the urban forest, from street trees to urban parks and woodlots.
Escobedo,F.J., J.E. Wagner, D.J. Nowak, C. Luz De la Maza, M. Rodriguez dan D.E. Crane, Analyzing the cost effectiveness of Santiago, Chile's policy of using urban forests to improve air quality. Journal of Environmental Management, 86 (1): 148–157. Santiago, Chile has the distinction of having among the worst urban air pollution problems in Latin America. As part of an atmospheric pollution reduction plan, the Santiago Regional Metropolitan government defined an environmental policy goal of using urban forests to remove particulate matter less than 10 μm (PM 10 ) in the Gran Santiago area. Escobedo et al. (2008) used cost effectiveness, or the process of establishing costs and selecting least cost alternatives for obtaining a defined policy goal of PM 10 removal, to analyze this policy goal. The PM 10 removal by Santiago's urban forests based on socioeconomic strata and using field and real-time pollution and climate data via a dry deposition urban forest effects model. Municipal urban forest management costs were estimated using management cost surveys and Chilean Ministry of Planning and Cooperation documents. The managing municipal urban forests (trees, shrubs, and grass whose management is under the jurisdiction of Santiago's 36 municipalities) to remove PM 10 was a cost-effective policy for abating PM 10 based on criteria set by the World Bank. The cost effectiveness of managing municipal urban forests and street trees to other control policies (e.g. alternative fuels) to abate PM 10 in Santiago and determined that municipal urban forest management efficiency was similar to these other air quality improvement measures.
Nielsen,A.B. dan F. Møller Is coppice a potential for urban forestry? The social perspective. Urban Forestry & Urban Greening, 7 (2): 129–138. After years of decline and neglect, low woodland types based on coppice management experience renewed interest. Substantial research has demonstrated the potentials of coppice for biomass production and for nature conservation, and coppices are increasingly being suggested for urban situations (Nielsen dan Møller, 2008). The understanding of the more social aspects of coppice woodlands in modern urban situations is limited. This contribution classifies coppice management systems as a basis for identification of social aspects of coppices and their potential use in contemporary urban forestry. Based on this classification, the social perspectives and potential niches for urban coppices are discussed, while lines of research are suggested which will support the development of a thorough and up-to-date knowledge base, against which the social merits of urban coppice woodlands can be critically evaluated.
Randrup,T.B. dan B.Persson Public green spaces in the Nordic countries: Development of a new strategic management regime. Urban Forestry & Urban Greening, 8 (1): 31–40. Park authorities in the Nordic countries were studied for the first time in a combined survey (Randrup dan Persson, 2009). Major similarities were found between countries, but also interesting differences. These differences are believed to be essential in understanding how to share experiences between the countries. The need for strategic green space management (SGSM), which operates on three levels within the organisation; operations, tactics, and policies. A theoretical description of SGSM is presented for future consideration and inspiration in practice as well as in research.
. Urban Forestry & Urban Greening, 3 (2): 65–78.3 (2 The urban forest in Beijing and its role in air pollution reduction Jun Yang aJun Yang a,,, Joe McBride a, Jinxing Zhou b, Zhenyuan Sun Joe McBride aJinxing Zhou b Tree planting has been proposed by the municipal government as a measure to alleviate air pollution in Beijing, the capital of China. This study examines that proposal. It is based on the analyses of satellite images and field surveys to establish the characteristics of current urban forest in the central part of Beijing. The influence of the urban forest on air quality was studied using the Urban Forest Effects Model. The results show that there are 2.4 million trees in the central part of Beijing. The diameter distribution of the trees is skewed toward small diameters. The urban forest is dominated by a few species. The condition of trees in the central part of Beijing is not ideal; about 29% of trees were classified as being in poor condition. The trees in the central part of Beijing removed tons of pollutants from the air in The air pollutant that was most reduced was PM 10 (particulate matters with an aerodynamic diameter smaller than 10 μm), the reduction amounted to 772 tons. The carbon dioxide (CO 2 ) stored in biomass form by the urban forest amounted to about 0.2 million tons. Future research directions to improve our understanding of the role of individual tree species in air pollution reduction are discussed.
. Journal of Environmental Psychology, 11 (3): 201– (3 Stress recovery during exposure to natural and urban environments. R.S. UlrichR.S. Ulrich., R. F. Simons, B.D. Losito, E.Fiorito, M.A. Miles, M. Zelson R. F. SimonsB.D. LositoE.FioritoM.A. MilesM. Zelson Different conceptual perspectives converge to predict that if individuals are stressed, an encounter with most unthreatening natural environments will have a stress reducing or restorative influence, whereas many urban environments will hamper recuperation. Hypotheses regarding emotional, attentional and physiological aspects of stress reducing influences of nature are derived from a psycho-evolutionary theory. To investigate these hypotheses, 120 subjects first viewed a stressful movie, and then were exposed to color/sound videotapes of one of six different natural and urban settings. Data concerning stress recovery during the environmental presentations were obtained from self-ratings of affective states and a battery of physiological measures: heart period, muscle tension, skin conductance and pulse transit time, a non-invasive measure that correlates with systolic blood pressure. Findings from the physiological and verbal measures converged to indicate that recovery was faster and more complete when subjects were exposed to natural rather than urban environments. The pattern of physiological findings raised the possibility that responses to nature had a salient parasympathetic nervous system component; however, there was no evidence of pronounced parasympathetic involvement in responses to the urban settings. There were directional differences in cardiac responses to the natural vs urban settings, suggesting that attention/intake was higher during the natural exposures. However, both the stressor film and the nature settings elicited high levels of involuntary or automatic attention, which contradicts the notion that restorative influences of nature stem from involuntary attention or fascination. Findings were consistent with the predictions of the psycho-evolutionary theory that restorative influences of nature involve a shift towards a more positively-toned emotional state, positive changes in physiological activity levels, and that these changes are accompanied by sustained attention/intake. Content differences in terms of natural vs human-made properties appeared decisive in accounting for the differences in recuperation and perceptual intake.
Urban Forestry & Urban Greening, 2 (2): 115–124.2 (2 Tree protection legislation in European cities Ariane Schmied a Ariane Schmied a, Werner Pillmann In this study, a survey on regulations and legal requirements concerning tree protection in European cities has been elaborated. It is designed as an information source for decision support in legal development, city planning and nature conservation. The survey is based on questionnaires on the one hand and on laws, ordinances and regulations on the other. Out of the 34 cities which were contacted or for which legal documents were found on the Internet, 25 (74%) have laws protecting trees in public and/or private areas. Against the background of rising ecological awareness, most of the laws were adopted from the 1970s onward. In most cases the protection of a tree is regulated by means of the circumference or the diameter of the stem, while sometimes the height of the tree is the criterion on which protection depends. In other cases, protection is granted if a tree is growing in a protected area or if the tree is submitted to a “Tree Preservation Order”. In all 25 cities the felling of protected trees is subjected to an official authorisation. In many laws interdictions concerning trees are listed. Most frequently, it is prohibited to cut down, to remove, to fell, to damage, to destroy, to modify, and to prune protected trees, and to enhance their decay. A law concerning tree protection seems to make sense, if it can be implemented in a non- bureaucratic, professional and efficient way, respecting the protection and conservation of nature. It should be structured simply and equitably, and its administration and implementation should be simple and efficient.
Urban Forestry & Urban Greening, 9 (2): 93–100.9 (2 Social interactions in urban parks: Stimulating social cohesion? Karin Peters Karin Peters,,, Birgit Elands, Arjen Buijs Birgit Elands People from all ethnic backgrounds spend some of their leisure time in green areas. This study found that urban parks are more inclusive green places than non-urban green areas, and that urban parks can promote social cohesion. The objective of the research was to establish the extent to which urban parks facilitate social cohesion and how social interaction and place attachment can contribute to such cohesion. Quantitative research (a survey) and qualitative research (observations and interviews) carried out in five urban parks in the Netherlands revealed that there are many similarities in the ways that ethnic groups use urban parks and in the meanings of such parks to these groups. Urban parks are sites where different ethnic groups mingle and where informal and cursory interactions can stimulate social cohesion. Furthermore, being involved and concerned with parks can facilitate attachment to these places. Urban parks can provide a vital locality where everyday experiences are shared and negotiated with a variety of people. The design of a park, its location and people's image of the park in combination with the cultural characteristics of various ethnic groups inform the opportunities for intercultural interactions.
. Urban Forestry & Urban Greening, 7 (2): 129–138.7 (2 Is coppice a potential for urban forestry? The social perspective Anders Busse NielsenAnders Busse Nielsen, and F. Møller After years of decline and neglect, low woodland types based on coppice management experience renewed interest. Substantial research has demonstrated the potentials of coppice for biomass production and for nature conservation, and coppices are increasingly being suggested for urban situations. Yet, our understanding of the more social aspects of coppice woodlands in modern urban situations is limited. Against this background, this contribution classifies coppice management systems as a basis for identification of social aspects of coppices and their potential use in contemporary urban forestry. Based on this classification, the social perspectives and potential niches for urban coppices are discussed, while lines of research are suggested which will support the development of a thorough and up-to-date knowledge base, against which the social merits of urban coppice woodlands can be critically evaluated.
Konijnendijk, C.C A decade of urban forestry in Europe. Forest Policy and Economics, 5 (2): 173–186. Major changes in society have led to a call for structural changes in forestry, also in Europe. Urbanisation as one of the major driving forces has had a clear impact on European forestry. One of the new approaches emerging in response is the concept of urban forestry (Konijnendijk, 2003). It was developed in North America during the 1960s as innovative approach to managing natural resources in urban environments. Aimed at the integrated planning and management of all tree-based resources in cities and towns, the concept found broad support in North America after initial resistance from both foresters and urban green professionals. Similar resistance was met in Europe, and here it took until the early 1990s before the concept of urban forestry found broader acceptance and support. Since then, a European urban forestry research community has emerged, as have policies, programmes and higher education incorporating elements of urban forestry. Urban forest resources in Europe might be small in relative terms compared to other natural resources. They do, however, cover millions of hectares of land and provide multiple, highly demanded goods and services. Forestry can benefit from urban forestry experiences and innovations, for example in terms of better meeting the expectations and demands of urban society. Urban forestry, on the other hand, is firmly rooted in some of the basic concepts of traditional forestry, such as sustained yield.
Keeling, R.F Measuring correlations between atmospheric oxygen and carbon dioxide mole fractions: A preliminary study in urban air. Journal of Atmospheric Chemistry, 7(2): Keeling (1988) monitored the O 2 and CO 2 mole fraction of the air on 25 and 26 October 1986 in Cambridge, Massachusetts. The O 2 concentrations were detected from changes in the relative refractivity of dried air between two lines of 198 Hg at and Å using dual-wavelength interferometry. Changes in oxygen mole fraction were resolved with two-minute time resolution to a precision of ±2.0 ppm. Changes in O 2 were shown to be strongly anticorrelated with changes in CO 2 as expected for combustion processes.
Chinese Geographical Science, 20 (2): A new carbon and oxygen balance model based on ecological service of urban vegetation Kai YinKai Yin, Qianjun Zhao, Xuanqi Li, Shenghui Cui, Lizhong Hua, Tao Lin Qianjun ZhaoXuanqi LiShenghui CuiLizhong Hua The application of human induced oxygen consumption and carbon emission theory in urban region was summed up and on this base a new model of urban carbon and oxygen balance (UCOB) was constructed by calculating the carbon and oxygen fluxes. The purpose was to highlight the role of vegetation in urban ecosystems and evaluate the effects of various human activities on urban annual oxygen consumption and carbon emission. Hopefully, the model would be helpful in theory to keep the regional balance of carbon and oxygen, and provide guidance and support for urban vegetation planning in the future. To test the UCOB model, the Jimei District of Xiamen City, Fujian Province, China, a very typical urban region, was selected as a case study. The results turn out that Jimei’s vegetation service in oxygen emission and carbon sequestration could not meet the demand of the urban population, and more than times of vegetation area should be added to meet the whole oxygen consumption in Jimei while 9.60 times of vegetation area are needed to meet the carbon sequestration targets. The results show that the new UCOB model is of a great potential to be applied to quantitative planning of urban vegetation and regional eco-compensation mechanisms.
Churkina, G Modeling the carbon cycle of urban systems. Ecological Modelling, 216 (2): 107–113. Although more than 80% of carbon dioxide emissions originate in urban areas, the role of human settlements in the biosphere evolution and in global carbon cycling remains largely neglected (Churkina, 2008). Understanding the relationships between the form and pattern of urban development and the carbon cycle is however crucial for estimating future trajectories of greenhouse gas concentrations in the atmosphere and can facilitate mitigation of climate change. Churkina (2008) reviewed state-of-the-art in modeling of urban carbon cycle, started with the properties of urban ecosystems from the ecosystem theory point of view. The key elements of an urban system and to which degree they are represented in the existing models. The necessity of including biophysical as well as human related carbon fluxes in an urban carbon cycle model and necessity of collecting relevant data.
Seasonal and annual variations in the photosynthetic productivity and carbon balance of a central Siberian pine forest. Tellus Series B, 54 (5): … Jon Lloyd, Olga Shibistova, Daniil Zolotoukhine, Olaf Kolle, Almut Arneth, Christian Wirth, Julie M. Styles, N. M. Tchebakova, E.-Detlef Schulze We present a first analysis of data (June 1998 to December 2000) from the long-term eddy covariance site established in a Pinus sylvestris stand near Zotino in central Siberia as part of the EUROSIBERIAN CARBONFLUX project. As well as examining seasonal patterns in net ecosystem exchange (N E ), daily, seasonal and annual estimates of the canopy photosynthesis (or gross primary productivity, G P ) were obtained using N E and ecosystem respiration measurements. Although the forest was a small (but significant) source of CO 2 throughout the snow season (typically mid- October to early May) there was a rapid commencement of photosynthetic capacity shortly following the commencement of above-zero air temperatures in spring: in 1999 the forest went from a quiescent state to significant photosynthetic activity in only a few days. Nevertheless, canopy photosynthetic capacity was observed to continue to increase slowly throughout the summer months for both 1999 and 2000, reaching a maximum capacity in early August. During September there was a marked decline in canopy photosynthesis which was only partially attributable to less favourable environmental conditions. This suggests a reduction in canopy photosynthetic capacity in autumn, perhaps associated with the cold hardening process. For individual time periods the canopy photosynthetic rate was mostly dependent upon incoming photon irradiance. However, reductions in both canopy conductance and overall photosynthetic rate in response to high canopy-to-air vapour differences were clearly evident on hot dry days. The relationship between canopy conductance and photosynthesis was examined using Cowan's notion of optimality in which stomata serve to maximise the marginal evaporative cost of plant carbon gain. The associated Lagrangian multiplier (λ) was surprisingly constant throughout the growing season. Somewhat remarkably, however, its value was markedly different between years, being 416 mol mol −1 in 1999 but 815 mol mol −1 in Overall the forest was a substantial sink for CO 2 in both 1999 and 2000: around 13 mol C m −2 a −1. Data from this experiment, when combined with estimates of net primary productivity from biomass sampling suggest that about 20% of this sink was associated with increasing plant biomass and about 80% with an increase in the litter and soil organic carbon pools. This high implied rate of carbon accumulation in the litter soil organic matter pool seems unsustainable in the long term and is hard to explain on the basis of current knowledge.
Ecological Economics, 60 (3): 2007, Pages 533–54260 (3 An environmental accounting framework applied to green space ecosystem planning for small towns in China as a case study Lingxian Zhang a Lingxian Zhang a, Qing Liu b, Nigel W. Hall c, Zetian Fu Qing Liu bNigel W. Hall c The paper presents a method that addresses the problem of the amount of green space required for the environment areas of lower biodiversity by the ecological element threshold method. The original habitat had been highly disturbed by human activities in most developing countries. Taking the population carrying capacity, the balance of carbon–oxygen, and the supply–demand equilibrium of water resource as a group of conjugate restriction factors of green space planning, it quantifies the total amount of green space required to keep the ecological system in balance for the town of Shaliuhe, Hebei Province as the case study. The results show that the main restrictive factor at Shaliuhe town is the imbalance between the supply and demand for the water resource, 89.34% of which is used in agriculture. Therefore, the effects of various ecological improvements are calculated for the years 2005, 2010 and This case study could be used as a model for the planning of other towns on the northeast China plain to improve the environment, ecology and sustainability. Similarly, the Chinese scenario might provide a useable reference to other developing countries.
Urban EcosystemsUrban Ecosystems, 2014, 17 (2): Pervious and impervious pavement reduce production and decrease lifespan of fine roots of mature Sweetgum trees. A. VolderA. Volder, B.Viswanathan, W. T..Watson B.ViswanathanW. T..Watson Root zones of mature Sweetgum paved with either pervious or impervious concrete after 15– 18 years of tree growth exhibited much reduced standing fine root length compared to unpaved plots 3 years after pavement installation. The objective of this paper was to determine whether these observed reductions in standing root length were due to reduced root production rates or due to enhanced root mortality rates in response to the presence of either pavement. We measured both fine root production and root death over a 15-month period using biweekly nondestructive observations of the root zones at four depths. In addition, we used proportional hazards analysis to determine how the presence of pavement affected chances of root mortality. We found that new root production was more negatively affected by the presence of either pavement than root mortality while chances of root mortality were increased by the presence of pavement, leading to much reduced standing net root length in paved plots at any given time. Surprisingly, even though root production and mortality were strongly altered by pavement, there was no significant effect on tree diameter growth. These results suggest that while Sweetgum root dynamics are negatively affected by pavement, there is enough plasticity within this species to adapt to altered root zone dynamics without affecting aboveground growth.
Balakina, J.N., O.V. Makarova, V.V. Bondarenko, L.J. Koudstaal, E.J. Ros, A.J. Koolen, W.K.P. van Loon Simulation of oxygen regime of tree substrates. Urban Forestry & Urban Greening, 4 (1): 23–35. The oxygen regime of urban tree-growing sites may be sub-optimal for tree growth and the related ornamental value of trees. Problems may especially occur in situations where the substrate is covered by pavement and/or where the water table is very shallow. The stability (oxygen consumption rate) of the organic components of the substrate (peat, green waste compost, etc.) and the design of the growing site also play an important role. The oxygen regime of a number of designs (wide strip of substrate; narrow strip; wide strip with multiple aeration pipes; narrow strip with one aeration pipe) was simulated for a range of substrates with the computer program “Matlab, pde toolbox”. Balakina, et al. (2005) computed equilibrium distributions of oxygen in the substrates from gas diffusion coefficients of the different parts of the growing site constructions and from the specific oxygen consumption rate of the substrate. The simulation results were compared with measurements on an experimental substrate strip. In can be shown the importance of organic matter stability and growing site design. On wide strips the presence of aeration pipes may be very advantageous, or even necessary.
. Plant and Soil, 227 (1-2): On the assessment of root and soil respiration for soils of different textures: interactions with soil moisture contents and soil CO2 concentrations T.J. BoumaT.J. Bouma and D.R. Bryla Estimates of root and soil respiration are becoming increasingly important in agricultural and ecological research, but there is little understanding how soil texture and water content may affect these estimates. We examined the effects of soil texture on (i) estimated rates of root and soil respiration and (ii) soil CO 2 concentrations, during cycles of soil wetting and drying in the citrus rootstock, Volkamer lemon (Citrus volkameriana Tan. and Pasq.). Plants were grown in soil columns filled with three different soil mixtures varying in their sand, silt and clay content. Root and soil respiration rates, soil water content, plant water uptake and soil CO 2 concentrations were measured and dynamic relationships among these variables were developed for each soil texture treatment. We found that although the different soil textures differed in their plant-soil water relations characteristics, plant growth was only slightly affected. Root and soil respiration rates were similar under most soil moisture conditions for soils varying widely in percentages of sand, silt and clay. Only following irrigation did CO 2 efflux from the soil surface vary among soils. That is, efflux of CO 2 from the soil surface was much more restricted after watering (therefore rendering any respiration measurements inaccurate) in finer textured soils than in sandy soils because of reduced porosity in the finer textured soils. Accordingly, CO 2 reached and maintained the highest concentrations in finer textured soils (> 40 mmol CO 2 mol −1 ). This study revealed that changes in soil moisture can affect interpretations of root and soil measurements based on CO 2 efflux, particularly in fine textured soils. The implications of the present findings for field soil CO 2 flux measurements are discussed.
Burton,A.J., G.P. Zogg, K.S. Pregitzer dan D.R. Zak Effect of measurement CO 2 concentration on sugar maple root respiration. Tree Physiol., 17 (7): Accurate estimates of root respiration are crucial to predicting belowground C cycling in forest ecosystems. Inhibition of respiration has been reported as a short-term response of plant tissue to elevated measurement [CO 2 ]. Burton et al. (1997) sought to determine if measurement [CO 2 ] affected root respiration in samples from mature sugar maple (Acer saccharum Marsh.) forests and to assess possible errors associated with root respiration measurements made at [CO 2 ]s lower than that typical of the soil atmosphere. Root respiration was measured as both CO 2 production and O 2 consumption on excised fine roots (≤ 1.0 mm) at [CO 2 ]s ranging from 350 to > 20,000 μl l −1. Root respiration was significantly affected by the [CO 2 ] at which measurements were made for both CO 2 production and O 2 consumption. Root respiration was most sensitive to [CO 2 ] near and below normal soil concentrations (< 1500 μl l −1 ). Respiration rates changed little at [CO 2 ]s above 3000 μl l −1 and were essentially constant above 6000 μl l −1 CO 2. These findings call into question estimates of root respiration made at or near atmospheric [CO 2 ], suggesting that they overestimate actual rates in the soil. The sugar maple root respiration at atmospheric [CO 2 ] (350 μl l −1 ) is about 139% of that at soil [CO 2 ]. Although the causal mechanism remains unknown, the increase in root respiration at low measurement [CO 2 ] is significant and should be accounted for when estimating or modeling root respiration. Until the direct effect of [CO 2 ] on root respiration is fully understood, we recommend making measurements at a [CO 2 ] representative of, or higher than, soil [CO 2 ]. In all cases, the [CO 2 ] at which measurements are made and the [CO 2 ] typical of the soil atmosphere should be reported.
. Carbon and oxygen isotope ratios of ecosystem respiration along an Oregon conifer transect: preliminary observations based on small-flask sampling. Tree Physiol (1998) 18 (8-9): J. R. EhleringerJ. R. Ehleringer and C. S. Cook Isotope ratio analyses of atmospheric CO 2 at natural abundance have significant potential for contributing to our understanding of photosynthetic and respiration processes in forest ecosystems. Recent advances in isotope ratio mass spectrometry allow for rapid, on-line analysis of small volumes of CO 2 in air, and open new research opportunities at the ecophysiological, whole-organism, and atmospheric levels. Among the immediate applications are the carbon and oxygen isotope ratio analyses of carbon dioxide in atmospheric air. Routine analysis of carbon dioxide in air volumes of approximately 50–300 μl is accomplished by linking a commercially available, trace gas condenser and gas chromatograph to an isotope ratio mass spectrometer operated in continuous-flow mode. Samples collected in the field are stored in either gas-tight syringes or 100-ml flasks. The small sample volume required makes it possible to subsample the air in flasks for CO 2 and then to sample the remaining air volume for the analysis of the isotopic composition of either methane or nitrous oxide. Reliable δ 13 C and δ 18 O values can be obtained from samples collected and stored for 1–3 days. Longer-term storage, on the order of weeks, is possible for δ 13 C measurements without drift in the isotope ratio signal, and should also be possible for δ 18 O measurements. When linked with an infrared gas analyzer, pump and flask sampling system, it is feasible to sample CO 2 extensively in remote forest locations. The air-sampling system was used to measure the isotope ratios of atmospheric CO 2 and to conduct a regression analysis of the relationship between these two parameters. From the regression, we calculated the δ 13 C of ecosystem respiration of four coniferous ecosystems along a precipitation gradient in central Oregon. The ecosystems along the coast-to-interior Oregon (OTTER) gradient are dominated by spruce–hemlock forests at the wet, coastal sites (> 200 cm precipitation annually) to juniper woodlands (20 cm precipitation) at the interior, dry end of the transect. The δ 13 C values of ecosystem respiration along this transect differed by only 1.3‰ (range of –25.2 to –23.9‰) during August at the peak of the summer drought. Following autumn rains in September, the δ 13 C of ecosystem respiration in the four stands decreased; overall the difference in the carbon isotope ratio of ecosystem respiration among sites increased to 3.9‰ (–26.8 to –22.9‰).
Yan-Shih Lin, B.E. Medlyn, and D.S. Ellsworth Temperature responses of leaf net photosynthesis: the role of component processes. Tree Physiol, 32 (2): The response of photosynthesis to temperature is a central facet of plant response to climate. Such responses have been found to be highly variable among species and among studies. Understanding this variability is key when trying to predict the effects of rising global temperatures on plant productivity. There are three major factors affecting the response of leaf net photosynthesis to temperature (A n –T): (i) photosynthetic biochemistry, (ii) respiration and (iii) vapour pressure deficit (D) and stomatal sensitivity to vapour pressure deficit during measurements. The overall goal of our study was to quantify the relative contribution of each of these factors in determining the response of A n to temperature. We first conducted a sensitivity analysis with a coupled photosynthesis–stomatal (A n –g s ) model, using ranges for parameters of each factor taken from the literature, and quantified how these parameters affected the A n –T response. Second, we applied the A n –g s model to two example sets of field data, which had different optimum temperatures (T opt ) of A n, to analyse which factors were most important in causing the difference. We found that each of the three factors could have an equally large effect on T opt of A n. In our comparison between two field datasets, the major cause for the difference in T opt was not the biochemical component, but rather the differences in respiratory components and in D conditions during measurements. We concluded that shifts in A n –T responses are not always driven by acclimation of photosynthetic biochemistry, but can result from other factors. The D conditions during measurements and stomatal responses to D also need to be quantified if we are to better understand and predict shifts in A n –T with climate.
Clint J. Springer, E. H. DeLucia, and R.B. Thomas Relationships between net photosynthesis and foliar nitrogen concentrations in a loblolly pine forest ecosystem grown in elevated atmospheric carbon dioxide. Tree Physiol, 25 (4): We examined the effects of elevated carbon dioxide concentration ([CO 2 ]) on the relationship between light-saturated net photosynthesis (A sat ) and area-based foliar nitrogen (N) concentration (N a ) in the canopy of the Duke Forest FACE experiment. Measurements of A sat and N a were made on two tree species growing in the forest overstory and four tree species growing in the forest understory, in ambient and elevated [CO 2 ] FACE rings, during early and late summer of 1999, 2001 and 2002, corresponding to years three, five and six of CO 2 treatment. When measured at the growth [CO 2 ], net photosynthetic rates of each species examined in the forest overstory and understory were stimulated by elevated [CO 2 ] at each measurement date. We found no effect of elevated [CO 2 ] on N a in any of the species. The slope of the A sat —N relationship was 81% greater in elevated [CO 2 ] than in ambient [CO 2 ] when averaged across all sample dates, reflecting a differential CO 2 effect on photosynthesis at the top and bottom of the canopy. We compared A sat —N relationships in trees grown in ambient and elevated [CO 2 ] at two common CO 2 concentrations, during late summer 2001 and both early and late 2002, to determine if the stimulatory effect of elevated [CO 2 ] on photosynthesis diminishes over time. At all three sample times, neither the slopes nor the y-intercepts of the A sat —N relationships of trees grown in ambient or elevated [CO 2 ] differed when measured at common CO 2 concentrations, indicating that the responses of photosynthesis to long-term elevated [CO 2 ] did not differ from the responses to a short-term increase in [CO 2 ]. This finding, together with the observation that N a was unaffected by growth in elevated [CO 2 ], indicates that these overstory and understory trees growing at the Duke Forest FACE experiment continue to show a strong stimulation of photosynthesis by elevated [CO 2 ].
R. O. Teskey, H. L. Gholz, and W. P. Cropper, Jr Influence of climate and fertilization on net photosynthesis of mature slash pine. Tree Physiol, 14 (11): Net photosynthesis was measured under field conditions in 23-year-old slash pine (Pinus elliottii Engelm. var. elliottii) trees to determine how it was affected by fertilization and climate. There was only a small decrease in rates of net photosynthesis from late summer through winter demonstrating that appreciable carbon gain occurs throughout the year in slash pine. Although fertilization substantially increased leaf area and aboveground biomass, it only slightly increased the rate of net photosynthesis. Simultaneous measurements of gas exchange in fertilized and unfertilized (control) plots allowed the detection of a small, but statistically significant difference in average net photosynthesis of 0.14 μmol m −2 s −1. Irradiance, and to a lesser extent air temperature, were the environmental factors that exerted the most control on net photosynthesis. The highest rates of net photosynthesis occurred between air temperatures of 25 and 35 °C. Because air temperatures were within this range for 46% of all daylight hours during the year, air temperature was not often a significant limitation. Soil and atmospheric water deficits had less effect on photosynthesis than irradiance or air temperature. Although the depth to the water table changed during the year from 10 to 160 cm, predawn and midday xylem pressure potentials only changed slightly throughout the year. Predawn values ranged from –0.63 to –0.88 MPa in the control plot and from –0.51 to –0.87 MPa in the fertilized plot and were not correlated with water table depth. There was no correlation between xylem pressure potentials and net photosynthesis, presumably because water uptake was adequate. Although vapor pressure deficits reached 3.5 kPa during the summer, they had little effect on net photosynthesis. Over a vapor pressure deficit range from 1.0 to 3.0 kPa, net photosynthesis only decreased 21%. No differences in responses to these environmental factors could be attributed to fertilization.
Kundu, S. K. dan P. M. A. Tigerstedt Variation in net photosynthesis, stomatal characteristics, leaf area and whole-plant phytomass production among ten provenances of neem (Azadirachta indica). Tree Physiol., 19 (1): Variation in net photosynthesis, CO 2 exchange parameters, stomatal characteristics, leaf area and seedling dry weight were investigated among 10 provenances of neem (Azadirachta indica A. Juss.) (Kundu dan Tigerstedt, 1999). Significant provenance variation was established for net photosynthesis (8.14 to μmol m −2 s −1 ), stomatal conductance (0.37 to 0.59 mol m −2 s −1 ), stomatal density (145 to 204 mm −2 ), and total guard cell length (2681 to 3873 μm). Net photosynthesis was positively correlated with whole-plant dry weight and leaf area. Stomatal density was positively correlated with net photosynthesis, whole-plant dry weight, and leaf area. Total guard cell length was positively correlated with all of these traits. Information on six traits was used in a cluster analysis to construct a dendrogram to assess phenetic relationships among the provenances. With a few exceptions, the dendrogram revealed three major clusters grouped according to rainfall distribution. The whole plant phytomass production of neem seedlings was associated with photosynthesis and stomatal characteristics during the early stages of growth.
. Thijs L. Pons and Rob A. M. Welschen Midday depression of net photosynthesis in the tropical rainforest tree Eperua grandiflora: contributions of stomatal and internal conductances, respiration and Rubisco functioning. Tree Physiol., 23 (14): High midday temperatures can depress net photosynthesis. We investigated possible mechanisms underlying this phenomenon in leaves of Eperua grandiflora (Aubl.) Benth. saplings. This tropical tree establishes in small gaps in the rainforest canopy where direct sunlight can raise midday temperatures markedly. We simulated this microclimate in a growth chamber by varying air temperature between 28 and 38 °C at constant vapor pressure. A decrease in stomatal conductance in response to an increase in leaf-to-air vapor pressure difference (ΔW) caused by an increase in leaf temperature (T leaf ) was the principal reason for the decrease in net photosynthesis between 28 and 33 °C. Net photosynthesis decreased further between 33 and 38 °C. Direct effects on mesophyll functioning and indirect effects through ΔW were of similar magnitude in this temperature range. Mitochondrial respiration during photosynthesis was insensitive to T leaf over the investigated temperature range; it thus did not contribute to midday depression of net photosynthesis. Internal conductance for CO 2 diffusion in the leaf, estimated by combined gas exchange and chlorophyll fluorescence measurements, decreased slightly with increasing T leaf. However, the decrease in photosynthetic rate with increasing T leaf was larger and thus the difference in CO 2 partial pressure between the substomatal cavity and chloroplast was smaller, leading to the conclusion that this factor was not causally involved in midday depression. Carboxylation capacity inferred from the CO 2 response of photosynthesis increased between 28 and 33 °C, but remained unchanged between 33 and 38 °C. Increased oxygenation of ribulose-1,5-bisphosphate relative to its carboxylation and the concomitant increase in photorespiration with increasing T leaf were thus not compensated by an increase in carboxylation capacity over the higher temperature range. This was the principal reason for the negative effect of high midday temperatures on mesophyll functioning.
. Pierre Y. Bernier, F. Raulier, P. Stenberg, and Chhun-Huor Ung Importance of needle age and shoot structure on canopy net photosynthesis of balsam fir (Abies balsamea): a spatially inexplicit modeling analysis. Tree Physiol., 21 (12-13): We have developed a spatially inexplicit model of canopy photosynthesis for balsam fir (Abies balsamea(L.) Mill.) that accounts for key processes of light–shoot interaction including irradiance interception by the shoot, spatial aggregation of shoots into branches and crowns, the differential propagation of diffuse and direct light within the canopy, and an ideal representation of penumbra. Also accounted for in the model are the effects of the average radiative climate and shoot age on needle retention, light interception, and photosynthetic capacity. We used reduced versions of this model to quantify the effects of simplifying canopy representation on modeled canopy net photosynthesis. Simplifications explored were the omission of direct beam transformation into penumbral light and the use of different constant shoot properties throughout the canopy. The model was parameterized for a relatively dense balsam fir stand (leaf area index of 5.8) north of Québec City, Canada, and run using hourly meteorological data obtained at the site. The overall performance of the complete model was satisfactory, with maximum values of canopy net photosynthesis of 23 μmol (m 2 ground) −1 s −1 (83 mmol m −2 h −1 ), and a near-saturation of the canopy at a photosynthetically active radiation photon flux density of about 750 μmol m −2 s −1 (2.7 mol m −2 h −1 ). The omission of penumbral effects through the use of unattenuated direct (beam) radiation at all layers of the canopy, as used for broad-leaved species, reduced canopy net photosynthesis by 3.7%. Analysis of the results show that the small impact of penumbra on canopy net photosynthesis stems from the high proportion of diffuse radiation (73%) estimated from our meteorological data set; single-hour results under clear sky conditions approach theoretical bias values of about 30%. Use of mean shoot photosynthetic, light capture and light transmission properties throughout the canopy biased canopy net photosynthesis by less than 3%. However, simulations carried out based on properties of 1-year-old shoots throughout the canopy overestimated canopy net photosynthesis by 9%. Use of the shoot as our smallest functional unit was a potential source of bias because the differential absorption of direct and diffuse radiation within the shoot could not be factored into the model. Other sources of potential bias are discussed.
. Stephen B. Horsley and K.W. Gottschalk Leaf area and net photosynthesis during development of Prunus serotina seedlings. Tree Physiol., 12 (1): We used the plastochron index to study the relationship between plant age, leaf age and development, and net photosynthesis of black cherry (Prunus serotina Ehrh.) seedlings. Leaf area and net photosynthesis were measured on all leaves ≥ 75 mm of plants ranging in age from 7 to 20 plastochrons. Effects of plant developmental stage on leaf area and net photosynthesis were evaluated for leaves of differing age (horizontal series), leaves on plants of constant age (vertical series), and leaves of constant age (oblique series). Regression techniques were used to estimate leaf area from leaf blade dimensions. The best equations for predicting leaf area had R 2 values of 0.991–0.992 and used linear or logarithmic functions of both leaf length and width. Suitable, but less precise, equations with R 2 values of 0.946–0.962 were developed from either leaf length or leaf width. Leaf area development in black cherry seedlings was similar to that in other indeterminate species. Leaves of young plants reached full expansion at a lower leaf plastochron age than leaves of older plants. Maximum net photosynthesis per unit leaf area occurred 2–3 plastochrons before full leaf expansion. There was strong ontogenetic drift in net photosynthesis with leaf age; net photosynthesis decreased as plant age increased in leaves of the same plastochron age. Plots of the oblique series were particularly useful in providing information about interaction effects.
Teskey, R.O., J. A. Fites, L. J. Samuelson dan B. C. Bongarten Stomatal and nonstomatal limitations to net photosynthesis in Pinus taeda L. under different environmental conditions. Tree Physiol., 2 (1-2-3): Net photosynthesis, transpiration and stomatal conductance of two-year-old Pinus taeda L. seedlings were compared under various environmental conditions. Teskey, et al. (1986) examined seedlings responses to air temperature, irradiance, ambient CO 2 concentration, absolute humidity deficit and xylem pressure potential. The seedlings exhibited little response to a wide range of absolute humidity deficits (7 to 16 g m −3 ) and temperatures (20 to 35 °C), but were sensitive to changes in water deficit, irradiance and CO 2 concentration. Net photosynthesis and stomatal conductance were linearly related under all of the environmental conditions measured. However, the gas phase limitation to photosynthesis was generally small (20 to 30%). The stomatal response was closely coupled to changes in photosynthesis, internal limitations, rather than the rate of gaseous diffusion of CO 2, were primarily responsible for limiting photosynthesis.
Jeffrey D. Herrick and Richard B. Thomas Leaf senescence and late-season net photosynthesis of sun and shade leaves of overstory sweetgum (Liquidambar styraciflua) grown in elevated and ambient carbon dioxide concentrations. Tree Physiol., 23 (2): We examined the effects of elevated CO 2 concentration ([CO 2 ]) on leaf demography, late-season photosynthesis and leaf N resorption of overstory sweetgum (Liquidambar styraciflua L.) trees in the Duke Forest Free Air CO 2 Enrichment (FACE) experiment. Sun and shade leaves were subdivided into early leaves (formed in the overwintering bud) and late leaves (formed during the growing season). Overall, we found that leaf-level net photosynthetic rates were enhanced by atmospheric CO 2 enrichment throughout the season until early November; however, sun leaves showed a greater response to atmospheric CO 2 enrichment than shade leaves. Elevated [CO 2 ] did not affect leaf longevity, emergence date or abscission date of sun leaves or shade leaves. Leaf number and leaf area per shoot were unaffected by CO 2 treatment. A simple shoot photosynthesis model indicated that elevated [CO 2 ] stimulated photosynthesis by 60% in sun shoots, but by only 3% in shade shoots. Whole-shoot photosynthetic rate was more than 12 times greater in sun shoots than in shade shoots. In senescent leaves, elevated [CO 2 ] did not affect residual leaf nitrogen, and nitrogen resorption was largely unaffected by atmospheric CO 2 enrichment, except for a small decrease in shade leaves. Overall, elevated [CO 2 ] had little effect on the number of leaves per shoot at any time during the season and, therefore, did not change seasonal carbon gain by extending or shortening the growing season. Stimulation of carbon gain by atmospheric CO 2 enrichment in sweetgum trees growing in the Duke Forest FACE experiment was the result of a strong stimulation of photosynthesis throughout the growing season.
Day, M.E Influence of temperature and leaf-to-air vapor pressure deficit on net photosynthesis and stomatal conductance in red spruce (Picea rubens). Tree Physiol., 20 (1): The roles of temperature (T) and leaf-to-air vapor pressure deficit (VPD) in regulating net photosynthesis (A net ) and stomatal conductance (G s ) of red spruce (Picea rubens Sarg.) were investigated in a field study and in a controlled environment experiment (Day, 2000 ). Both A net and G s exhibited a relatively flat response to temperatures between 16 and 32 °C. Temperatures between 32 and 36 °C markedly decreased both A net and G s. Vapor pressure deficits above 2 kPa had significant effects on both A net and G s. The influence of VPD on A net and G s fit a linear response model and did not interact significantly with T effects.
. P. Harley, A. Guenther, and P. Zimmerman Effects of light, temperature and canopy position on net photosynthesis and isoprene emission from sweetgum (Liquidambar styraciflua) leaves. Tree Physiol., 16 (1-2): In June 1993, net photosynthetic rates, stomatal conductance and isoprene emission rates of sweetgum leaves (Liquidambar styraciflua L.) were measured at the top of the forest canopy (sun leaves) and within the canopy at a height of 8–10 m above ground level (shade leaves). Large differences in net photosynthetic rates and stomatal conductance were found between sun and shade leaves. Mean rates of isoprene emission, expressed on a leaf area basis, were significantly lower in shade leaves than in sun leaves (4.1 versus 17.1 nmol m −2 s −1 ); however, because specific leaf area of sun leaves was lower than that of shade leaves ( versus m 2 g −1 ), the difference between sun and shade leaves was less, though still significant, when isoprene emissions were expressed on a dry mass basis (45.5 versus 29.0 μg C g −1 h −1 ). Saturation of both net photosynthesis and isoprene emission occurred at lower PPFDs in shade leaves than in sun leaves. The effect of leaf temperature on isoprene emissions also differed between sun and shade leaves. Sun leaves lost a significantly greater percentage of fixed carbon as isoprene than shade leaves. The leaf-level physiological measurements were used to derive parameters for a canopy-level isoprene flux model. The importance of incorporating differences between sun- and shade-leaf properties into existing models is discussed.
. Yoshiyuki Miyazawa and Kihachiro Kikuzawa Physiological basis of seasonal trend in leaf photosynthesis of five evergreen broad-leaved species in a temperate deciduous forest Tree Physiol (2006) 26 (2): he physiological basis of photosynthesis during winter was investigated in saplings of five evergreen broad-leaved species (Camellia japonica L., Cleyera japonica Thunb., Photinia glabra (Thunb.) Maxim., Castanopsis cuspidata (Thunb.) Schottky and Quercus glauca Thunb.) co-occurring under deciduous canopy trees in a temperate forest. We focused on temperature dependence of photosynthetic rate and capacity as important physiological parameters that determine light-saturated rates of net photosynthesis at low temperatures during winter. Under controlled temperature conditions, maximum rates of ribulose bisphosphate carboxylation and electron transport (V cmax and J max, respectively) increased exponentially with increasing leaf temperature. The temperature dependence of photosynthetic rate did not differ among species. In the field, photosynthetic capacity, determined as V cmax and J max at a common temperature of 25 °C (V cmax (25) and J max (25) ), increased until autumn and then decreased in species- specific patterns. Values of V cmax (25) and J max (25) differed among species during winter. There was a positive correlation of V cmax (25) with area-based nitrogen concentration among leaves during winter in Camellia and Photinia. Interspecific differences in V cmax (25) were responsible for interspecific differences in light-saturated rates of net photosynthesis during winter.
Radoglou, K. dan R.O. Teskey Changes in rates of photosynthesis and respiration during needle development of loblolly pine. Tree Physiol, 17 (7): Net photosynthetic rates of developing foliage and one-year-old foliage of loblolly pine (Pinus taeda L.) were measured under field conditions (Radoglou dan Teskey, 1997). In the subsequent year, net photosynthesis and dark respiration rates of current-year and one-year-old foliage were measured under controlled environmental conditions. Loblolly pine foliage grows slowly, reaching its final size 3.5 to 4 months after bud burst. Positive rates of net photosynthesis were recorded when the foliage was 13 and 18% of final length, in the controlled-environment and field study, respectively. However, because of high rates of dark respiration during the initial growth period, a positive diurnal carbon balance did not occur until foliage was about a third of final length (40 days after bud burst). Two months after bud burst, when foliage was about 55% of final length, its photosynthetic capacity exceeded that of one year old foliage. The highest rates of net photosynthesis were achieved when foliage was more than 90% fully expanded.
Koch, G.W., J.S. Amthor dan M. L. Goulden Diurnal patterns of leaf photosynthesis, conductance and water potential at the top of a lowland rain forest canopy in Cameroon: measurements from the Radeau des Cimes. Tree Physiol, 14 (4): Koch, Amthor dan Goulden (1994) measured diurnal patterns of leaf conductance, net photosynthesis and water potential of five tree species were measured at the top of the canopy in a tropical lowland rain forest in southwestern Cameroon. Access to the 40 m canopy was by a large canopy-supported raft, the Radeau des Cimes. The measurements were made under ambient conditions, but the raft altered the local energy balance at times, resulting in elevated leaf temperatures. Leaf water potential was equal to or greater than the gravitational potential at 40 m in the early morning, falling to values as low as –3.0 MPa near midday. Net photosynthesis and conductance were typically highest during midmorning, with values of about 10–12 μmol CO 2 m −2 s −1 and 0.2–0.3 mol H 2 O m −2 s −1, respectively. Leaf conductance and net photosynthesis commonly declined through midday with occasional recovery late in the day. Photosynthesis was negatively related to leaf temperature above midday air temperature maxima. These patterns were similar to those observed in other seasonally droughted evergreen communities, such as Mediterranean-climate shrubs, and indicate that environmental factors may cause stomatal closure and limit photosynthesis in tropical rain forests during the midday period.
M. E. Jach and R. Ceulemans Effects of season, needle age and elevated atmospheric CO 2 on photosynthesis in Scots pine (Pinus sylvestris) Tree Physiol (2000) 20 (3): Five-year-old Scots pine (Pinus sylvestrisL.) seedlings were grown in open-top chambers at ambient and elevated (ambient μmol mol −1 ) CO 2 concentrations. Net photosynthesis (A), specific leaf area (SLA) and concentrations of nitrogen (N), carbon (C), soluble sugars, starch and chlorophyll were measured in current-year and 1-year-old needles during the second year of CO 2 enrichment. The elevated CO 2 treatment stimulated photosynthetic rates when measured at the growth CO 2 concentration, but decreased photosynthetic capacity compared with the ambient CO 2 treatment. Acclimation to elevated CO 2 involved decreases in carboxylation efficiency and RuBP regeneration capacity. Compared with the ambient CO 2 treatment, elevated CO 2 reduced light-saturated photosynthesis (when measured at 350 μmol mol −1 in both treatments) by 18 and 23% (averaged over the growing season) in current-year and 1-year-old needles, respectively. We observed significant interactive effects of CO 2 treatment, needle age and time during the growing season on photosynthesis. Large seasonal variations in photosynthetic parameters were attributed to changes in needle chemistry, needle structure and feedbacks governed by whole-plant growth dynamics. Down-regulation of photosynthesis was probably a result of reduced N concentration on an area basis, although a downward shift in the relationship between photosynthetic parameters and N was also observed.
. Does growth temperature affect the temperature responses of photosynthesis and internal conductance to CO 2 ? A test with Eucalyptus regnans Tree Physiol (2008) 28 (1): Internal conductance to CO 2 transfer from intercellular spaces to chloroplasts (g i ) poses a major limitation to photosynthesis, but only three studies have investigated the temperature dependance of g i. The aim of this study was to determine whether acclimation to 15 versus 30 °C affects the temperature response of photosynthesis and g i in seedlings of the evergreen tree species Eucalyptus regnans F. Muell. Six-month-old seedlings were acclimated to 15 or 30 °C for 6 weeks before g i was estimated by simultaneous measurements of gas exchange and chlorophyll fluorescence (variable J method). There was little evidence for acclimation of photosynthesis to growth temperature. In seedlings acclimated to either 15 or 30 °C, the maximum rate of net photosynthesis peaked at around 30 or 35 °C. Such lack of temperature acclimation may be related to the constant day and night temperature acclimation regime, which differed from most other studies in which night temperatures were lower than day temperatures. Internal conductance averaged 0.25 mol m −2 s −1 at 25 °C and increased threefold from 10 to 35 °C. There was some evidence that g i was greater in seedlings acclimated to 15 than to 30 °C, which resulted in seedlings acclimated to 15 °C having, if anything, a smaller relative limitation due to g i than seedlings acclimated to 30 °C. Stomatal limitations were also smaller in seedlings acclimated to 15 °C than in seedlings acclimated to 30 °C. Based on chloroplast CO 2 concentration, neither maximum rates of carboxylation nor RuBP-limited rate of electron transport peaked between 10 and 35 °C. Both were described well by an Arrhenius function and had similar activation energies (57–70 kJ mol −1 ). These findings confirm previous studies showing g i to be positively related to measurement temperature.
Figueroa,J.A., H.M. Cabrera, C. Queirolo dan L.F. Hinojosa Variability of water relations and photosynthesis in Eucryphia cordifolia Cav. (Cunoniaceae) over the range of its latitudinal and altitudinal distribution in Chile. Tree Physiol., 30 (5): Figueroa et al. (2010) during the summer of the year 2008 investigated variation in leaf water and photosynthetic characteristics of Eucryphia cordifolia Cav. (Cunoniaceae) along its broad latitudinal distribution in central south Chile (36° to 42° S). The latitudinal variation in water potential (Ψ w ), water potential at saturation (Ψπ sat ), water potential at the turgor lost point (Ψπ tlp ), stomatal density of the leaves, leaf nitrogen concentrations and photosynthetic light response were studied in eight populations. The populations located in the northern region of the distribution of E. cordifolia had the lowest leaf water potential. Osmotic potential at full turgor was highest in the two southernmost populations and gradually decreased towards the northernmost points. Similarly, osmotic potential at zero turgor was the lowest in the northern population. The symplastic water content was lower in the two southernmost populations. The highest net photosynthesis rate was recorded for plants in the populations of intermediate distributions, and it was dependent on the precipitation and temperature gradient. The northern populations, which are subject to the lowest precipitations, showed the lowest stomatal densities, which were tightly linked with stomatal conductance variation. Therefore, the variability of A max was independent of stomatal density and conductance, so that the northern populations, subject to environments with less water availability, presented higher photosynthetic water use efficiency. The leaf water relations, stomatal characteristics and photosynthetic rates of the leaf would vary along its latitudinal gradient, helping to explain the ability of E. cordifolia trees to inhabit a broad latitudinal and altitudinal range throughout the central south Chile.