2.2 Biomass Data collection
The studied forest was stratified into three forest strata based on the
altitudinal variation. Strata one was found at an altitudinal range of
between 1500-1800m while strata two and three were located between the
altitudinal range of 1801-2000m and 2001-2300m respectively. Following
the methodologies recommended in Picard et al ., (2012), area and
species-specific allometric equations were formed involving a
semi-destructive approach. Thirty individuals were systematically
selected and sampled for measuring biomass along the three forest
strata. In order to minimize the error of sampling and to obtain the
representative tree and samples, diameter distributions were taken into
account during tree selection. Accordingly, the trees were classified
into five DBH classes and each class having six individuals per DBH
class ranging from 10-20 cm, 20.1-30 cm, 30.1-40 cm, 40.1-50 cm and
greater than 50 cm.Experienced persons climbing on live trees using
ropes did the measurement of diameter at 2m interval in each section of
a tree. Using data obtained by climbing live trees, aboveground biomass
of trunk, branches and leaves were estimated. Generally, three random
small branches with less than 10cm basal diameter per individual plant
were destructed and trimmed. The measurements of fresh biomass (in kg)
were divided into two parts: measuring trimmed fresh biomass and
measuring untrimmed fresh biomass.