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

2. 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

3. Why study carbon?

4. 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.

5. 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 – ha
Aspect – North
Elevation – 750 to 1250 m
Slope – moderate to steep

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

7. Methods: data collection

8. Methods: data analysis
Aboveground biomass
AGTB = * 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]

9. 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

10. 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

11. Results
Pure Pinus forest
Pure Quercus forest

12. 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

13. Results

14. Results

15. 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.

16. 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

17. Thank you!

18. References
Pine forest (photo in the title slide) – Flickr
Quercus tree (photo in the title slide) – Wikimedia (
Global temperature anomaly Vs atmospheric carbon dioxide concentration (graph) – 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.