Assessing the utility of airborne laser scanning derived indicators for tropical forest management

The objective of this study was to evaluate four airborne laser scanning derived indicators for monitoring tropical forest stands at different stages of sustainable management practices. The traditional monitoring routines are inefficient and time consuming due to the limitation of optical sensors in detecting features below the canopy and to the large areas involved in forest management. Nine production units at different logging cycle stage were surveyed using airborne laser scanning. Non-logged sites were also included in the analysis. For each production unit we computed the above-ground biomass, the proportion of road and trails, the number of emergent trees, proportion of clearings and the time after logging. We analysed the effects of time after logging on each indicator using the generalised linear model. The number of emergent trees was not influenced by the time after logging. However, the above-ground biomass, number of canopy gaps and low-density of returns area responded to the time after logging and showed sensibility to monitoring sustainable forest management (SFM) sites.