1. Background
Pouteria adolfi-friederici is a tall tree of high forest, up to50
m tall, with the long, straight, more or less fluted trunk, and with
buttresses at the base. It is an emergent or upper canopy species in
montane moist forest and grows between 1350-2450m altitudinal ranges.
The Phytogeographic distribution of the species includes Ethiopia,
Sudan, Uganda, Kenya, the Democratic Republic of Congo, Zambia, Malawi,
and Zimbabwe (Hedberg et al., 2003). This species is a high-value timber
tree used for all types of woodwork. Although classified as ’not
threatened’ on a global basis, the species and the high forest
associated with it is rapidly being cut down and very little is being
done to either conserve representative forests or replant the species in
Ethiopia (Tesemma, 1993; Hedberg et al., 2003).
Allometric equations relate simply recorded variable (e.g. tree
diameter, height) to other structural and useful features (Niklas,
1994), which is the most common and reliable method for estimating
biomass, net primary production, and biogeochemical budgets in forest
ecosystems (Gower et al., 1999). They have been developed to satisfy
various purposes in forest ecology and management. Diameter at breast
height (DBH) is commonly used as the only independent variable and most
allometry develops an allometric relationship between DBH and component
biomass (Gower et al., 1999). Some investigations proposed to
incorporate tree height (H) as the second predictor and produce the
DBH–H combined equation to increase the accuracy of biomass estimates
(Ketterings et al., 2001). The allometric technique estimates the entire
or partial (by compartments) mass of a tree from measurable tree
dimensions, including trunk diameter and height, using allometric
equations (Kangas and Maltamo, 2006). Thus, dendrometric parameters of
all the trees are measured and using the allometric equation the biomass
of the stand is estimated by summing the biomass of individual trees.
Generalized models have immense potential for large-scale carbon budgets
computed from inventory data, (Pastor et al., 1984). When estimating the
above-ground biomass of a forest, the uses of species-specific equations
are preferred because trees of different species may differ greatly in
tree architecture and wood density. However, due to the great number of
different tree species in humid tropical rainforests and enormous
efforts needed to develop these equations. Species-specific allometric
equations for the humid tropics are almost absent while relatively few
mixed-species equations have been developed (Ketterings, et al., 2001).
This study was aimed to develop a species-specific allometric equation
for Pouteriaadolfi-friederici , which can help the precise
estimation of forest carbon stock in south western Ethiopia.