Dudukuhan Tree Farming Systems in West Java: How to Mobilize Self-Strengthening of Community-Based Forest Management? - Smallholder Tree Growing for Rural Development and Environmental Services - page 95

of 400-1,800 m a.s.l. The study was conducted in three sample villages that were
purposively selected according to their watershed location (upstream, mid-stream,
and downstream). The villages selected are Cisarua, Curug Bitung, and Parakan
Muncang.

4.2.2 Tree Diversity and Dudukuhan Profiles

The tree diversity and profiles of dudukuhans were assessed through an inventory
of 36 dudukuhans. Three dudukuhans of each type were inventoried in each of three
villages. The Dynamic Sample Unit method (Sheil et al. 2002) was used to conduct
the inventories. The method uses 40-m long transect lines to measure species rich-
ness, tree density, and tree basal area. The transect line is divided into eight tree
sampling units as depicted in Fig. 4.1. Within each unit a maximum of five trees are
measured. Trees must have a diameter at breast height (dbh 1 ) greater than 10 cm.
For each sampling unit, the following data were recorded: the number of trees, the
species of trees, the dbh of each tree, and distance of the fifth tree from the transect
line (d1, d2, d3 … as depicted in Fig. 4.1). The maximum distance a tree can be
from the transect line is 20 m (d7). The maximum distance for searching in each
cell before deciding it is 'empty', is 15 m (d6). Tree diversity in dudukuhan systems
was determined using the Shannon-Weiner (H') Index (Smith 1990).
Multiple Regression analysis was used to describe the relationship between
number of species, number of trees and dudukuhan profiles, to understand farmers'
perceptions of the dynamic composition of tree species and number of trees in
dudukuhan systems based on dudukuhan size, tree density and tree basal area, ele-
vation of plot, and the number of trees and tree species in dudukuhan systems.
Significance level of each regression coefficient is indicated at 1%, 5% and 10%
levels. The number of species and the number of trees served as the dependent vari-
ables. Dudukuhan size, tree density, basal area, elevation, the number of tree

d1

d8

d4

d5

d2

d3

d6

15 m

10 m

d7

20 m

Fig. 4.1 Tree sample units along 40 m of transect line