TITLE:
Mixed-Species Allometric Equations to Quantify Stem Volume and Tree Biomass in Dry Afromontane Forest of Ethiopia
AUTHORS:
Mindaye Teshome, Carlos Moreira Miquelino Eleto Torres, Gudeta Weldesemayat Sileshi, Patricia Povoa de Mattos, Evaldo Muñoz Braz, Hailemariam Temesgen, Samuel José Silva Soares da Rocha, Mehari Alebachew
KEYWORDS:
Carbon Stock, Site-Specific Model, Robust Regression, Natural Forest
JOURNAL NAME:
Open Journal of Forestry,
Vol.12 No.3,
May
9,
2022
ABSTRACT: Volume and biomass equations are essential tools to determine forest
productivity and enable forest managers to make informed decisions. However,
volume and biomass estimation equations are scarce for Afromontane forests in
Africa in general and Ethiopia in particular. This limits our knowledge of the
standing volume of wood, biomass, and carbon stock of the forests therein. In this study, we developed a new mixed-species
volume and biomass equations for Afromontane forests and compared them
with generic pantropical and local models. A total of 193 sampled trees from
seven dominant tree species were used to develop the equations. Various volume
and biomass equations were fitted using robust linear and nonlinear regression.
Model comparison indicated that the best model to estimate stem volume was ln(v)=-9.909+ 0.954*ln(d2h), whereas the best model to estimate biomass was ln(b)=-2.983+ 0.949*ln(ρd2h) . These equations explained over 85% of the variations in the
stem volume and biomass measurements. The mean density and basal area of trees
in the forest with d ≥ 2 cm was 631.5 stems·ha-1 and 24.4 m2·ha-1.
Based on the newly developed equations, the forest has on average 303.0 m3·ha-1 standing volume of wood and 283.8 Mg·ha-1 biomass stock. The newly developed allometric equations
derived from this study can be used
to accurately determine the stem volume, biomass, and carbon storage in the Afromontane forests in Ethiopia and
elsewhere with similar stand characteristics and ecological conditions. By
contrast, the generic pan-tropical and
other local models appear to provide biased estimates and are not
suitable for dry Afromontane forests in Ethiopia. The estimated stem biomass
and carbon stock in the Chilimo forest are comparable with the estimates from
various tropical forests and woodlands elsewhere in Africa, indicating the
importance of dry Afromontane forest for climate change mitigation.