Permanent sample plots
Monitoring forest ecosystem methodologies
Forest dynamics can be defined as change in forest structure and floristic composition of tree communities (Brassard & Chen 2010). It is described by three ecological processes (Lewis et al. 2004) : mortality and recruitment which correspond to the number of individuals which disappear and appear in each tree population (Delcamp 2007), and various types of growth: stem growth (radial and apical) and crown extension (vertical and lateral) (Madelaine-Antin 2009). The study of the temporal dynamics of a forest requires the establishment of a research-based PSP (Permanent Sample Plot) (Alder & Synnot 1992).
In Reunion, few permanent plots exist to monitor long-term dynamics in ecosystems and distinguish the effects of anthropogenic activities from natural processes varying spatially over time. The first one-hectare permanent plot with landmarks and marked trees was established in 1990 in the Mare Longue Nature Reserve. Inventories were then extended to 2 other hectares in 2000 and 2003. Mare Longue Forest its clearly marked as a reference site with its feature low altitude forest—the only remaining one in the Mascarene Islands—, part of the National Park (nature reserve) and now a UNESCO World Heritage Property, its existing research history, and time coverage of data.