European Journal of Scientific Research - EuroJournals

453 Md. Shahadat Hossain and Gouri Rani Banik
Eucalyptus camaldulensis
The regression equation for total was found organic carbon content (kg/tree) was found Y= -6.113 +
3.363X1 + 2.142X2. Here Y represents the total organic carbon content (kg) of tree, X1 represents the
height (m) and X2 represents the diameter at breast height (cm). From the equation it implies that the
total organic carbon content is increased by 3.363 kg for per unit increase in height and 2.142 kg for
per unit increase of DBH. The coefficient of determination (r 2 ) is 0.980 and the relationship was
significant at P>0.01. The result showed a strong positive correlation between height along with DBH
and total organic carbon content of the species.
In the present study it was found that both DBH (cm) and height (m) relating to total organic
carbon was produced higher coefficient of determination (r 2 ) for Dipterocarpus turbinatus (0.973)
Acacia auriculiformis (0.974) and Eucalyptus camaldulensis (0.980) than equations considering
individual parameter viz height or DBH. So the result revealed that both DBH and height is the best
predictor of total organic carbon measurement. This trend was found similar with the result of the
study by Chowdhury, 2005 for Acacia auriduliformis, (0.932) Acacia mangium (0.966), Artocarpus
heterophyllus, (0.968) Gmelina arborea (0.956) and Lagerstroemia speciosa (0.996).
Total organic carbon sequestration (tonne/ha/year) of the studied species
Among the studied species it was found that annual organic carbon sequestration (tonne/ha/year) rate
was maximum in case of Eucalyptus camaldulensis (9.50 tonne/ha/year) and minimum in case of
Dipterocarpus turbinatus (3.04 tonne/ha/year). The rate of organic carbon sequestration of Acacia
auriculiformis was found 8.91 tonne/ha/year. From the figure it is found that although D. turbinatus
has a significant difference between organic carbon accumulation rate with that of A. auriculiformis
and E. camaldulensis but there is no significant difference between organic carbon accumulation rate
of A. auriculiformis and that of E. camaldulensis.
As E. camaldulensis and A. auriculiformis are fast growing species, their annual biomass
production rate is higher than that of D. turbinatus which ultimately results the higher amount of
organic carbon per year in the former two species than that of latter one.
Total number of individuals per hectares was found higher in E. camaldulensis than that of D.
turbinatus and A. auriculiformis. As amount of biomass from which we calculate organic carbon is
directly related to the growing stock, for E. camaldulensis organic carbon accumulation rate per
hectare was found higher. For the same reason higher rate of organic carbon accumulation was found
in A. auriculiformis than D. turbinatus . Another reason for higher rate of organic carbon accumulation
rate for A, auriculiformis and E. camaldulensis studied plantation sites of these two species were
comparatively lower aged. At the early stage of plantations biomass accumulation rate is higher (Pant,
1990). As Organic carbon accumulation is related to biomass accumulation therefore higher the
biomass accumulation rate, higher the carbon accumulation rate. Some results of previous study could
be mentioned here to compare the present findings with previous outcomes.
D. turbinatus plantation accumulated less amount of organic carbon (including biomass and
soil carbon) annually compared to that of A. auriculiformis. The biomass carbon content was also
found highest in A. auriculiformis (Karmakar 2002).
Another similar result was found in the study conducted by Osman et al., 1992 considering
above ground biomass of 4, 5 and 8 years old A. auriculiformis & Pinus caribaea, A. auriculiformis
and D. turbinatus, respectively in the Chittagong University.
A study was conducted to assess the carbon stock in the 11-years old Aphanamixis polystachya
(1991) in Chittagong University campus and it was reported that on an average 239 tonne (i.e 139 /11
= 21.73 tonne/ha/year) carbon was stored in the biomass of the trees per hectare (Miah et al., 2001).
The total dry biomass produced in 38 years old Tectona grandis in Uttar Pradesh was 130 tonne/ha
(Kaul et al., 1979). If the biomass is converted to biomass carbon content, it will be 65 tonne/ha i.e. is
slightly less than the biomass carbon content in studied D. turbinatus plantation of 27 years old