Estimation of Stem Carbon Stock of Selected Eucalyptus grandis Plantations in Up Country Sri Lanka

Abstract

Plantation forestry plays an important role in mitigating global warming and climate change
by sequestering carbon dioxide in their biomass. Eucalyptus grandis is an important timber
species in plantation forestry in Sri Lanka. The objectives of the present study were to
estimate the stem carbon stock, the total amount of atmospheric carbon dioxide sequestered
in stems and the monetary value of carbon sequestered in stems of selected E. grandis
plantations in upcountry Sri Lanka. Four study sites were selected from Kandapola,
Bogawanthalawa, Haputhale and Pinnawala to represent upcountry, intermediate zone and
wet zone where E. grandis is confined to. Each plantation was divided into three strata and
0.05 ha circular sample plot was laid out in each stratum. Each individual in the plot was
measured for total tree height and diameter at breast height (dbh). The carbon content of each
E. grandis stem of individuals in the plantations was calculated using a constructed model to
predict stem carbon of E. grandis, in which the explanatory variables are total tree height and
dbh. Thereby total stem carbon stock of each plantation was estimated. Total amount of
atmospheric carbon dioxide sequestered in all the E. grandis stems of each plantation and
monetary value of carbon sequestered in each stem were thereby calculated for each
plantation. The lowest value of estimated amount of carbon sequestered in E. grandis stems
per hectare was observed in Kandapola plantation (28.176 t/ha) while the highest value was
observed in Pinnawala plantation (504.095 t/ha). The highest value of estimated total stem
carbon stock of a plantation was observed in Bogawanthalawa plantation (17,390.669 t). For
estimated amount of atmospheric carbon dioxide sequestered in E. grandis stems, the lowest
value was observed in Kandapola plantation (103.405 t/ha) while the highest value was
observed in Pinnawala plantation (1,850.027 t/ha). The highest value of estimated total
amount of atmospheric carbon dioxide sequestered in the stems of a plantation was observed
in Bogawanthalawa plantation (63,823.757 t). When considering the monetary value of
carbon stock in E. grandis stems, the lowest estimated value was observed in Kandapola
plantation (3,803.72 Rs./ha) while the highest value was observed in Pinnawala plantation
(68,052.76 Rs./ha). When considering plantation wise carbon stock, the highest value of
estimated monetary value was observed in Bogawanthalawa plantation (Rs. 2,347,740.37).
These estimates shall be presented to assess the carbon dynamics in E. grandis plantations in
upcountry Sri Lanka.
Keywords: Eucalyptus grandis, Carbon sequestration, Climate change, Carbon stock