How past natural disturbances and human land use dynamics shape the current structure and composition of moist Afromontane forests

Historical knowledge of the landscape is essential to understand the current ecosystem. We studied how common natural disturbances and land use changes are, and how these histories affect current forest structure and tree species composition. We used data from 44 key informant interviews and inventories from 125 forest sites. Regarding natural disturbances, we found that they are rather infrequent, even if there are reports from many places of occasional wildfires, storms causing windfalls, landslides and various dieback of trees. Shade coffee management at various intensities is common throughout the forests at elevations where coffee can be grown. Part of the area has been subjected to logging. There is evidence of rather widespread abandonment in the late 19th century, but also more recent abandonments. Hence, some areas that now are forested have previously been settlements and open farmland areas. These natural disturbances and land uses histories are highly diverse, resulting in heterogeneous influence on the current forest structure and tree species composition. For example sites, with current coffee management have less lianas and somewhat different trees than sites regenerated after large scale disturbances. We conclude that current structure and composition of forests are the outcomes of diverse current and historical human land use management practices. Given that large scale natural disturbances are rather infrequent, the base-line landscape was likely dominated by undisturbed forests. Thus, conservation strategies should explicitly target undisturbed stands alongside the sustainable utilization of resources.