V. Trichon et al., IDENTIFYING SPATIAL PATTERNS IN THE TROPICAL RAIN-FOREST STRUCTURE USING HEMISPHERICAL PHOTOGRAPHS, Plant ecology, 137(2), 1998, pp. 227-244
This work emphasises the usefulness of hemispherical photography for i
dentifying spatial patterns in the tropical rain forest structure. Str
uctural variability was investigated at a local (intra-site) scale, in
relation to the forest mosaic, and at a regional (inter-sites) scale,
for its implication in forest typology. Four primary forest sites, fr
om 0.6 to 1 ha, were investigated in Central Sumatra, Indonesia. In a
first instance, a qualitative analysis of the forest 3-D structure was
found to be very helpful in the interpretation of quantitative result
s related to forest dynamics. The quantitative analysis was undertaken
through the assessment of three structural characteristics: (1) the c
anopy openness (CO), or visible sky as seen from all directions of the
hemisphere, (2) the spherical variance (SV), which quantifies the spa
tial dispersion of gaps and, (3) the plant area index (L-p), defined a
s half the surface area of canopy elements per unit ground area. At th
e local scale, maps of the CO values gave an indication about disturba
nce location and extent, providing an interesting document for studies
on forest dynamics. At the regional scale, between-sites comparisons
of CO, SV and L-p values added new information on forest structural di
fferences when compared to dendrometric measurements. These results em
phasised the fact that rain forest may exhibit high structural variabi
lity, even within a same bioclimatic region and a narrow altitude rang
e. Hemispherical photographs could be a quick means of further investi
gating this spatial variability and it's relation to physical environm
ent, thus providing information that is crucial for the refining of fo
rest typology in the area.