Ecology and Development Series No. 10, 2003 - ZEF

Description of the study area and sampling designAframomum corrorima and Piper capense, are collected from naturally growing plants onthe forest floors. The main food crops are maize, sorghum and teff. Coffee is the major cashcrop growing in the area, followed by chat (Catha edulis).3.2 Sampling design and location of plotsA systematic sampling design was used in this study to collect data on vegetation andenvironmental variables (Figure 3.3). In the natural high forest, sampling plots were laid ina north-south compass direction, which also coincides with the steepest altitudinal gradientsfrom a higher altitude down to the Geba river valley, on both the northern and southernsides of the rivers. The plots were spaced 300 m along the transect lines. The distancebetween two neighboring transect lines was 500 m. Nested plot design was used to sampleplants of different sizes and different environmental variables (Figure 3.4).Figure 3.3. Partial view of the layout of the study plots within the forest landscape. Dotsrepresent the study plots.32