Victor IFEANYI

Diversified tree-based system are practices that intentionally include functional biodiversity at multiple spatial and/or temporal scales in order to maintain ecosystem services that provide critical inputs to agriculture, such as soil fertility, pest and disease control and pollination. This system is a component of social-ecological systems that depend on certain combinations of traditional and contemporary knowledge, cultures and practices. As ecosystem services are generated and regenerated within a tree-based system, it was imperative to estimate carbon stock in a diversified tree-based system in an arboretum in Forest Resources and Wildlife Management Department, University of Benin. This study determined the tree biomass and predicted the carbon pool in the study area. The biomass carbon accumulation was evaluated using non-destructive method in a completely randomized design. A total of 87 trees were sampled from 8 sample plots measuring 15 x 15 m with an area of 0.22 ha in the study using two input variables (diameter and height). Mean tree height and diameter were pooled together and the best fit allometric regression model was used to estimate Aboveground biomass (AGB) in this study. The result showed that the largest DBH was 64.9 cm while the tallest tree was 26.79 m. In estimating the AGB in the diversified tree-based system, Ketterings et al., 2001 model (AGB=aDb (0.066D2.59) indicated the highest modelling efficiency (R2=1.000, AIC=-40.25, Std. error 1.34). Regression analysis also revealed that most of the carbon was stored in the aboveground biomass with an estimation of 137,216.81 kg ha-1 in the study area. Furthermore, the total carbon stock (AGB + BGB) and carbon sequestered were 77,390.28 and 284,022.3 Mg C ha-1 respectively. Furthermore, to predict the monetary values to be derived from Kyoto carbon credit scheme, the tons of CO2 sequestered in the tree based diversified system amounted to $8,520,669. This study concluded that for the Department to benefit from the carbon credits scheme (Kyoto protocol), it is recommended that an ecosystem services payment policy should be in
place in order to sustain the environmental benefits derivable from the tree-based systems.

Diversified tree-based system are practices that intentionally include functional
biodiversity at multiple spatial and/or temporal scales in order to maintain ecosystemservices that provide critical inputs to agriculture, such as soil fertility, pest and diseasecontrol and pollination. This system is a component of social-ecological systems that
depend on certain combinations of traditional and contemporary knowledge, cultures andpractices. As ecosystem services are generated and regenerated within a tree-basedsystem, it was imperative to estimate carbon stock in a diversified tree-based systeminanarboretum in Forest Resources and Wildlife Management Department, Universityof
Benin. This study determined the tree biomass and predicted the carbon pool in the studyarea. The biomass carbon accumulation was evaluated using non-destructive methodinacompletely randomized design. A total of 87 trees were sampled from8 sample plots
measuring 15 x 15 m with an area of 0.22 ha in the study using two input variables
(diameter and height). Mean tree height and diameter were pooled together and the best
fit allometric regression model was used to estimate Aboveground biomass (AGB) inthis
study. The result showed that the largest DBH was 64.9 cm while the tallest tree was
26.79 m. In estimating the AGB in the diversified tree-based system, Ketterings et al., 2001 model (AGB=aDb (0.066D2.59) indicated the highest modelling efficiency(R
2=1.000, AIC=-40.25, Std. error 1.34). Regression analysis also revealed that most of
the carbon was stored in the aboveground biomass with an estimation of 137,216.81kgha
-1
in the study area. Furthermore, the total carbon stock (AGB + BGB) and carbonsequestered were 77,390.28 and 284,022.3 Mg C ha
-1 respectively. Furthermore, topredict the monetary values to be derived from Kyoto carbon credit scheme, the tons of
CO2 sequestered in the tree based diversified system amounted to $8,520,669. This studyconcluded that for the Department to benefit from the carbon credits scheme (Kyotoprotocol), it is recommended that an ecosystem services payment policy should be inplace in order to sustain the environmental benefits derivable fromthe tree-based system.