Estimation of growth, volume accumulation and carbon sequestration of Eucalyptus grandis plantations in up country region of Sri Lanka
2003
Nissanka, S.P. | Ariyaratna, C.H.K.
The study was initiated to estimate the growth and wood volume accumulation and carbon sequestration potential of Eucalyptus grandis plantations in the up country region of Sri Lanka and to determine the change of soil properties under E. grandis plantation with maturity. In this study, five different age classes of E. grandis plantations were selected from different divisions of Annfield estate at Hatton in Nuwara Eliya district. Sampling units were chosen randomly and the size of a sampling unit was 20x20 (400 sq m) with minimum of four replicates. The tree height and diameter at breast height (dbh) were measured in each tree in the sampling plot. Soil samples were taken to analyze soil chemical and physical properties. A relationship between height and diameter was developed to estimate the height by measuring dbh. Parabolic was found to be the best model with high R square value of 0.91. A linear relationship between volume and basal area was also developed to predict the tree volume by measuring the dbh, and it showed a very high R square value of 0.99. The 19-year-old E. grandis stand showed an average volume of 3.02 cu m/plant (125 plants/ha), and this is 46% below than that of standard stocking rate recommended by the Forest Department. On the other hand, 19-year-old well-managed stands will sequester approximately 234.51 Mt of carbon per hectare. With the age, nutrient content in the soil reduces and the organic carbon increases. Under stocked, application of improper silvicultural applications, use of poor quality seed materials and encroachments are the main reasons for the low volume production in the Annfield Estate. Therefore, applying proper silvicultural techniques, such as use of good planting materials, fertilization, plant density and management, and other management practice, will enhance the productivity as well as the carbon sequestration in the E. grandis in the up country region of Sri Lanka
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