Which forest type sequesters higher carbon in biomass – Pinus roxburghii or Quercus glauca Aditya Acharya School of forest sciences, UEF 10.10.2018

Introduction Carbon sequestration – capturing of the carbon dioxide from the atmosphere Carbon stock – quantity of carbon in a carbon pool Carbon pool – a reservoir that accumulates or release carbon

Why study carbon?

Why forest carbon then? Objective Sixty percent of the world’s terrestrial carbon is in forest vegetation and soils (Winjum et al., 1992). Forests act as sink as well as source of carbon dioxide. Carbon sequestration capacity varies according to species, age, location etc. Quantification of vegetation carbon stock helps to understand their role in the climate change mitigation Objective The objective of the study is to compare the amount of biomass carbon sequestered by two different forest types (species) growing in their natural habitat, with an aim to see which forest type has higher contribution to mitigation of climate change.

Study area Pinus roxburghii forest Area – 35.25 ha Aspect – North east Elevation – 750 to 1400 m Slope – moderate to steep Quercus glauca forest Area – 20.28 ha Aspect – North Elevation – 750 to 1250 m Slope – moderate to steep

Methods: data collection Sampling – Simple random Sampling intensity – 1%

Methods: data collection

Methods: data analysis Aboveground biomass AGTB = 0.0509 * density * D2 * H (Chave et al., 2005). Where, AGTB = above-ground tree biomass [kg]; D = tree diameter at breast height [cm]; H = tree height [m]. log (AGSB) = a + b log (D) AGSB = above ground sapling biomass [kg] a and b = species specific constants; dimensionless D = over bark diameter of the sapling [cm]

Methods: data analysis Aboveground biomass 𝐋𝐇𝐆= W𝑠𝑢𝑏𝑠𝑎𝑚𝑝𝑙𝑒 𝑑𝑟𝑦 𝑊 𝑠𝑢𝑏𝑠𝑎𝑚𝑝𝑙𝑒 𝑤𝑒𝑡 ∗𝑊 f𝑖𝑒𝑙𝑑 Where, LHG = biomass of leaf litter, herbs and grasses [gm/m2] Wfield = weight of the fresh sampled LHGs within plot of 1m2 [gm] Wsubsample, dry = weight of oven dry sub sample taken to the lab [gm] Wsubsample, wet = weight of the fresh sub sample of LHGs taken to the lab [gm] Total aboveground biomass = AGTB+AGSB+LHG

Methods: data analysis Belowground biomass 20% of the total aboveground biomass, assuming root-to-shoot ratio of 1:5, recommended by MacDicken(1997). Total biomass = Total aboveground biomass + Total belowground biomass Biomass stock densities are converted to carbon stock densities using the IPCC (2006) default carbon fraction of 0.47

Results Pure Pinus forest Pure Quercus forest

Results Pine Forest Quercus Forest Tree density (per ha) 613 927 Max. dbh (cm) 43 50.9 Min. dbh (cm) 4.1 2.5 Average dbh (cm) 20.1 18.7 Max. height (m) 22 25 Min. height (m) 2 Average height (m) 9.7 9.2 Sapling density (per ha) 3600 10400 7.6 4.8 1.6 1.1 3.6 3.3 3 4.5 1.5 2.2

Results

Results

Conclusion Recommendation Quercus glauca sequesters greater amount of carbon than Pinus roxburghii in the study area Recommendation Regeneration of Quercus should be promoted than Pinus from the carbon sequestration point of view, keeping in mind the locality factors.

Limitations Measurement of root biomass was not taken but calculated using conversion factors Biomass of deadwood and shrubs was not calculated separately The human pressure on both of the forests was assumed to be exactly similar

Thank you! aditya@uef.fi

References Pine forest (photo in the title slide) – Flickr (https://www.flickr.com/photos/89139703@N00/3928282490) Quercus tree (photo in the title slide) – Wikimedia (https://commons.wikimedia.org/wiki/File:Quercus_glauca_kz02.jpg) Global temperature anomaly Vs atmospheric carbon dioxide concentration (graph) – http://www.falw.vu/~gwerf/climate.html, assessed on Feb 02, 2016) *Disclaimer – it was a part of my BSc thesis (2016) conducted under the supervision of Mr. Bishnu Hari Wagle, Lecturer, Tribhuvan University, Institute of Forestry, Pokhara, Nepal.