2015/03/11 by Andrew T. Tredennick, Niall P. Hanan · 25 citations
Agricultural and Biological Sciences · Environmental Science · Mathematics · #Agroforestry #Alternative stable state #Biology #Ecology #Ecology and Vegetation Dynamics Studies #Ecosystem #Ecosystem dynamics and resilience #Geography #Mathematics #Plant and animal studies #Tree (set theory)
paper · doi:10.1086/680475
published in The American Naturalist 185(5), E153-E165 (University of Chicago Press)
openalex publication_date 2015/03/11 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/30
Contemporary theory on the maintenance and stability of the savanna biome has focused extensively on how climate and disturbances interact to affect tree growth and demography. In particular, the role of fire in reducing tree cover from climatic maxima is now well appreciated, and in certain cases, herbivory also strongly affects tree cover. However, in African savannas and forests, harvest of trees by humans for cooking and heating is an oft overlooked disturbance. Thus, we incorporate tree harvest into a population dynamic model of grasses, savanna saplings, savanna trees, and forest trees. We use assumptions about the differential demographic responses of savanna trees and forest trees to harvest to show how tree harvest influences tree cover, demography, and community composition. Tree harvest can erode the intrinsic basin of attraction for forest and make a state transition via fire to savanna more likely. The savanna state is generally resilient to all but high levels of tree harvest because of the resprouting abilities of savanna trees. In the absence of active fire suppression, our analysis suggests that we can expect to see large and potentially irreversible shifts from forest to savanna as demand increases for charcoal in sub-Saharan Africa. On the other hand, savanna tree species' traits promote savanna stability in the face of low to moderate harvest pressure.