TY - JOUR
T1 - Testing a general approach to assess the degree of disturbance in tropical forests
AU - Sellan, Giacomo
AU - Simini, Filippo
AU - Maritan, Amos
AU - Banavar, Jayanth R.
AU - de Haulleville, Thalès
AU - Bauters, Marijn
AU - Doucet, Jean Louis
AU - Beeckman, Hans
AU - Anfodillo, Tommaso
PY - 2017/5
Y1 - 2017/5
N2 - Questions: Is there any theoretical model enabling predictions of the optimal tree size distribution in tropical communities? Can we use such a theoretical framework for quantifying the degree of disturbance?. Location: Reserve of Yangambi, northeast region of the Democratic Republic of Congo. Methods: We applied an allometric model based on the assumption that a virtually undisturbed forest uses all available resources. In this condition, the forest structure (e.g. the tree size distribution) is theoretically predictable from the scaling of the tree crown with tree height at an individual level. The degree of disturbance can be assessed through comparing the slopes of the tree size distribution curves in the observed and predicted conditions. We tested this tool in forest stands subjected to different degrees of disturbance. We inventoried trees >1.3 m in height by measuring the DBH in three plots of 1 ha each, and measured tree height, crown radius and crown length in a sub-sample of trees. Results: All tree species, independently of the site, shared the same exponents of allometric relationships: tree height vs tree diameter, crown radius vs tree height, crown length vs tree height and consequently crown volume vs tree height, suggesting that similar trajectories of biomass allocation have evolved irrespective of species. The observed tree size distributions appeared to be power laws (excluding the finite size effect) and, as predicted, the slope was steeper in the less disturbed forest (−2.34) compared to the most disturbed (−1.99). The difference in the slope compared to the theoretical fully functional forest (−2.65) represents the metric for assessing the degree of disturbance. Conclusions: We developed a simple tool for operationalizing the concept of ‘disturbance’ in tropical forests. This approach is species-independent, needs minimal theoretical assumptions, the measurement of only a few structural traits and requires a low investment in equipment, time and computer skills. Its simple implementation opens new perspectives for effectively addressing initiatives of forest protection and/or restoration.
AB - Questions: Is there any theoretical model enabling predictions of the optimal tree size distribution in tropical communities? Can we use such a theoretical framework for quantifying the degree of disturbance?. Location: Reserve of Yangambi, northeast region of the Democratic Republic of Congo. Methods: We applied an allometric model based on the assumption that a virtually undisturbed forest uses all available resources. In this condition, the forest structure (e.g. the tree size distribution) is theoretically predictable from the scaling of the tree crown with tree height at an individual level. The degree of disturbance can be assessed through comparing the slopes of the tree size distribution curves in the observed and predicted conditions. We tested this tool in forest stands subjected to different degrees of disturbance. We inventoried trees >1.3 m in height by measuring the DBH in three plots of 1 ha each, and measured tree height, crown radius and crown length in a sub-sample of trees. Results: All tree species, independently of the site, shared the same exponents of allometric relationships: tree height vs tree diameter, crown radius vs tree height, crown length vs tree height and consequently crown volume vs tree height, suggesting that similar trajectories of biomass allocation have evolved irrespective of species. The observed tree size distributions appeared to be power laws (excluding the finite size effect) and, as predicted, the slope was steeper in the less disturbed forest (−2.34) compared to the most disturbed (−1.99). The difference in the slope compared to the theoretical fully functional forest (−2.65) represents the metric for assessing the degree of disturbance. Conclusions: We developed a simple tool for operationalizing the concept of ‘disturbance’ in tropical forests. This approach is species-independent, needs minimal theoretical assumptions, the measurement of only a few structural traits and requires a low investment in equipment, time and computer skills. Its simple implementation opens new perspectives for effectively addressing initiatives of forest protection and/or restoration.
KW - Allometric relationships
KW - Crown volume
KW - Finite size scaling
KW - Operationalization
KW - Restoration strategies
KW - Tree size distribution
KW - Tropical ecology
UR - http://www.scopus.com/inward/record.url?scp=85013436971&partnerID=8YFLogxK
U2 - 10.1111/jvs.12512
DO - 10.1111/jvs.12512
M3 - Article (Academic Journal)
AN - SCOPUS:85013436971
VL - 28
SP - 659
EP - 668
JO - Journal of Vegetation Science
JF - Journal of Vegetation Science
SN - 1100-9233
IS - 3
ER -