Ecology and Development Series No. 10, 2003 - ZEF

Impacts of human use on the forest vegetationThe population structure of coffee also varies in the different forest categories(Table 5.8). The SEMIFOR-OLD has the highest abundance of coffee trees. However, theproportion of seedlings is highest in the NATFOR and lowest in the SEMIFOR-PLAN. Thehighest proportion (75%) of the abundance of mature coffee trees was recorded in theSEMIFOR-PLAN and the lowest in the NATFOR (Table 5.8).Table 5.8. Total abundance, proportion of seedlings (< 1.5 m tall) and mature trees (> 1.5 mtall), and basal area of coffee in five forest categories. Note that total abundanceis number of stems per 10 sample plots of 400 m 2 (0.4 ha).SEMIFOR-NATFOR SECFOR SEMIFOR-NEW SEMIFOR-OLD PLANTotal abundance 7448 8021 8417 10221 7861Seedlings (%) 74 69 51 43 25Trees (%) 26 31 49 57 75Basal area (m 2 /ha) 1.4 1.7 3.8 6.3 7.85.3.4 Differences in abundances and vegetation structureThe results of the analysis of the differences in total abundance in different height classes ofthe five forest categories are presented in Tables 5.9 - 5.10. The ANOVA tables of theheight classes can be found in Appendix 5. The five forest categories were highlysignificantly different (P < 0.001; Table 5.9) from each other with respect to totalabundance. The differences in abundance of all height classes were also highly significant(P < 0.001; Table 5.9).Table 5.9. Results of one-way ANOVA for differences in abundance among the forestcategories in different height classesHeight class F 4, 45 P-valueTotal abundance 21.269 < 0.001HC 1 13.963 < 0.001HC 2 28.860 < 0.001HC 3 13.319 < 0.001HC 4 6.853 < 0.00188