Agroforestation of Grasslands in Southeast Asia: WaNuLCAS Model Scenarios for Shade-Based Imperata Control During Tree Establishment - Smallholder Tree Growing for Rural Development and Environmental Services - page 144

Fig. 6.7 The age of the tree when the simulations predict that Imperata dies due to shade of four
tree species under different weeding regime (partial and no weeding) and different tree spacing (as
defined in Fig. 6.4)

Table 6.4 provides information on the length of the initial cropping period (stage
A) and this ' Imperata regrowth window' for the different tree species and tree spac-
ings shown in Fig. 6.6. The shortest duration of the Imperata regrowth window (1.9
year) was obtained for Acacia mangium at narrow spacing, with initial strip weed-
ing. The longest period (>10 years) was obtained for S. macrophylla at wide spacing
and partial weeding. Overall, the trees systems that rapidly close canopy to end
phase A also have a short period B (Fig. 6.8); the predicted length of phase B is 1.85
year + 0.5 * length of phase A. However, there is some variation around this relation-
ship. The three points above the trend line refer to: P. falctaria and H. brasiliensis at
wide spacing and partial weeding, and to S. macrophylla at narrow spacing.

6.3.2 Results for the Philippine Site

6.3.2.1 Effect of Hedgerow Spacing on Tree Growth

Tree growth performance was lower under closer hedgerow spacing (1 × 3 for tim-
ber tree species and 5 × 5 for fruit tree spacing) than when grown under wider