Table 5. Forest structure at community and household levels, as determined by forest inventory.


Variable Community total
(n = 42 plots, area = 1.05 ha)
Community-level means (SDs) of household plot data† (n = 30)
Community A Community B Community A Community B
Predominant height (m)‡ 30.9 (3.4) 30.6 (3.8)
Tree diameter at breast height (cm) 27.4 (4.9) 26.1 (2.1)
Percent crown cover 41.0 (10.0)* 32.0 (8.0)*
Number of trees with diameter at breast height > 10 cm 564 trees/ha 459 trees/ha 15.6 (1.9)* 13.5 (2.2)*
Estimated number of rubber trail trees per household§ 31,742 23,629
Number of species 169 146 13.1 (2.0)* 11.0 (2.0)*
Total basal area of trees (m²/ha) 54.8 (22.9)* 40.6 (15.6)*

*P < 0.05, two-tailed t-test at mean plot level.
†Sample plots 250 m² in size within household rubber trails.
‡Measured as the mean height of the tallest trees in the stand, based on 100 stems/ha (see West 2004).
§Estimated as trees/ha × mean hectare in rubber trail forests per household.