This study assessed the distribution and growth of two tree species in a seasonal mixed-water inundation
forest near the city of Manaus, and determined the annual growth rates and ages of trees. The aboveground
wood biomass was estimated for each population. Eight plots of 25 x 25 m were established, where all
individuals of the species
Garcinia brasiliensis
and
Hevea spruceana
with heights ≥ 1.0 m were inventoried
and mapped. The levels of inundation were measured on all individuals, while the relative photosynthetically
active radiation (rPAR) was measured in individuals ≤ 10 cm diameter at breast height (dbh). For each
individual, the basal area was determined, and the tree volume estimated. Tree ages and the radial increment rate were determined by using dendrochronological methods. In total, 105 individuals were recorded. In
both populations, most individuals presented dbh smaller than 10 cm.
Hevea spruceana presented more
individuals (n = 80), and higher rates of radial increment, while
Garcinia brasiliensis (n = 25) presented
higher mean age. The duration and height of inundation and the levels of rPAR were different for each
population. It was detected significant correlations between dbh and tree heights, and between dbh and
tree age. The micro-topographical variations appear to exert effects on the structure population and on the
distribution of the studied species. Despite the low rPAR values and variations recorded within the study
site, the different light requirements in each species suggest different ecological niches.
