Presentation on theme: "Age, growth patterns, spacing, and land use history of an Eastern White pine (Pinus strobus) population in Range Pond State Park, Poland, Maine. Cara Howieson,"— Presentation transcript:
Age, growth patterns, spacing, and land use history of an Eastern White pine (Pinus strobus) population in Range Pond State Park, Poland, Maine. Cara Howieson, Erika Cyr, Jessica Otis, and Aurora Dibner- Bio 270- Bates College Abstract We characterized the age, growth patterns and spacing of a population of Eastern White pines (Pinus strobus) in Range Pond State Park, Poland Maine. Using transect survey techniques the age, diameter at breast height (1.37m), height, nearest neighbor distances, the lengths of three internodes at breast height and above, and species composition in our sample were measured. Two major age groups were identified by frequency analysis (42-53 years and years old). The population consisted of tall, thin trees with minimal foliage. The White pines exhibited similarity in size, spacing, and growth patterns despite differences in age. Aerial photographs from 1949 and 1964 revealed that the year old White pines initially grew under a canopy of large trees which probably caused growth suppression. This population of large canopy trees was later cut. We believe that the similarity in growth morphology resulted from growth and recruitment under an established overstory. Introduction White pines are early invaders of gaps in forests following disturbances due to their ability to occupy a wide range of soil, moisture, and lighting conditions. These conditions influence the growth and aging patterns of White pines. White pines grow on nearly all soil types except poorly drained soil where White pines occur only as individuals or small groups. On disturbed sites with sandy loams or silty loams White pine grows well and with little hardwood competition (Abrams 2001). White pines are only moderately shade tolerant; White pines that are not in crowded conditions and have plenty of light may grow up to cm in height and produce many heavily foliated lateral branches. White pines, in crowded, low light environments, exhibit increased primary growth relative to secondary growth resulting in tall, thin morphology or growth form (Bormann 1965). White pines self-prune, a process that occurs when the lower branches die back due to poor light availability. Self pruning results in live foliage being limited to the crown of the tree (Lancaster and Leak, 1978). White pines are an early to middle successional species, which rapidly colonize land following disturbances such as agricultural abandonment, fire, and blow-downs. The White pine age structure established after a large-scale disturbance generally has a narrow age range due to rapid recruitment. (Abrams 2001). We investigated the age, size and spacing of a White pine population in Range Pond State Park, Poland, Maine, to characterize the population and infer the abiotic and biotic factors that have influenced its development. Methods Site Description The study site is a mixed species, secondary (?) growth forest on the northeastern border of Range Pond State Park in Poland, Maine (Fig. 1) located at latitude N and longitude W. The soil of this flat terrain is categorized as Adams Series, loamy sand characterized by low natural fertility, and poor moisture-retention. The Eastern White pine is the dominant species at Range Pond State Park and constitutes 67% of the living stand, while the Red Maple and Red Oak constitute 19% and 8% of the population, respectively. Approximately 40-60% of standing pine stems are dead trees, most of which are in the understory. Sampling Plan Six transects of unspecified length were set up parallel to Plains Road. All trees of at least 3 cm stem diameter which fell within one meter to either side of the transect lines were included until 20 White pine had been sampled on each transect. Characteristics measured on each White pine: Stem height (m) and internode distances to describe primary growth characteristics Diameter Breast Height (cm) to describe secondary growth characteristics Age (yrs.) was measured from core samples Whorl counts were measured to describe age characteristics Nearest Neighbor Distances (m) for White pines or hardwoods was measured to describe the effects of spatial distribution on growth Conclusions The age and species composition of the stand are consistent with typical New England early successional, pine-dominated forests. The existence of canopies for part or all of the lives of the White pines at this site likely explains the similar growth patterns of all age groups. Natural thinning related to population density, the ice storm of 1998, drought in the early 1970s, and poor soil quality probably all contributed to the high mortality of White pines in the stand. Acknowledgements Many thanks to all of the students in the 2003 Bio 270 class for braving the snow and inclement weather. Thanks also to Sharon Kinsman for her ongoing guidance and support. Kathy Claerr, thank you for your help in species identification. A very special thanks to Greg Anderson for all of his time, advice, and technological support. Thanks to Mike Buffo, Katie Whorf and Julia Briedis for your assistance. We gratefully acknowledge the State of Maine Department of Conservation, Bureau of Parks and Lands, for allowing access to Range Pond State Park. The USDA Service Office in Lewiston provided access to their collection of aerial photos for which we are most grateful. Land use history Growth patterns Size, Age, and Spacing Finished at last! Figure 1. Location of the study site in Range Pond State Park in Poland, Maine. Figure 3. The age structure of the White pine population contains three major age groups: the first established from 1939 to 1947, the second group established from and the last mature pines recruited in the late sixties. Following strong establishment from 1939 to 1959 recruitment drops off and stops by X value = bin center. N=114 trees. Figure 2. The White pines exhibited relatively uniform height structure (even-sized) across all ages. We estimated the canopy consisting of trees that were 16m tall. N=115 trees. Figure 6. Aerial photos of the area around the study site from A) 1949 and B) 1964 show that a mature stand of trees on the site were harvested between 1949 and The yellow triangle marks trees that were not cut and acted as a size reference for changes in the stand near them. The red rectangle marks the actual study area. A B Figure 5. In the year old and year old age clusters, there is a similar pattern of primary and secondary growth consistent with our field observations. N=119 trees. Figure 4. Comparison of mean (± 1 SD) age, size, and spacing characteristics of the YO and YO White pine age groups. N = 105 trees except NND for which N = 102 trees. Nearest neighbor distances to White pines (live or dead) from sampled White pines were used to calculate the Holgate Coefficient of Spatial Dispersion (Zar ) which indicated that White pines are distributed randomly. Literature Cited Abrams, M Eastern White Pine Versatility in the Presettlement Forest. BioScience 51(11): Bormann, F.H Changes in the growth pattern of white pine trees undergoing suppression. Ecology 46(3): Brower, J.E. and J.H Zar Field and Laboratory Methods for General Ecology. 2 nd ed. Wm. C. Brown Publishers, Dubuque, IA. 226p. Lancaster, K.F. and Leak, W.B A silvicultural guide for white pine in the northeast. For. Serv. Gen. Tech. Rept. NE-41, 13 p.