Abstract:
ABSTRACT: Khaya (Khaya senegalensis) being a new forest plantation species, its growth
performance under Sri Lankan conditions has not been evaluated. Further, carbon
sequestration by forest plantations, which forms an important option in climate change
mitigation, has not gained much attention in Sri Lanka. Hence, the present study aimed at
assessing the growth performance and carbon accumulation of Khaya plantations in Sri
Lanka. The tree height and tree diameter were measured non-destructively in identified age
classes and biomass was estimated with allometric equations. Khaya in Kurunegala division
(Intermediate Zone) has achieved 39.98 cm and 18.31 m of dbh and height, respectively, by
the age of 18-20 years, whereas in Anuradhapura division (Dry Zone) it was 22.21 cm and
12.41 m, respectively. Significantly higher dbh and tree height (p<0.05) indicates the better
site conditions in the Kurunegala division for superior growth of Khaya compared to those
in the Anuradhapura division. The dbh and tree height of Khaya showed a strong correlation
in both divisions. Significantly higher (p<0.05) biomass of Khaya was recorded in
Kurunegala than in Anuradhapura division. The average carbon sequestration of K.
senegalensis was 88.98 and 127.92 t/ha in Anuradhapura and Kurunegala divisions,
respectively. Khaya plantations in Anuradhapura division (741.92 ha) and Kurunegala
division (475.20 ha) have accumulated 21,785 t and 27,969 t of carbon, respectively. Growth
performances evaluated in the present study can guide the future decision making process in
establishment of forest plantations in Sri Lanka. Regional baseline carbon estimates of
Khaya generated by this study could effectively be utilized for carbon budgeting programmes
until validated further by increasing the frequency of measurements of variables and
developing allometric relationships specific for K. senegalensis.
