Changes in the spatial distribution of tree species in a terra firme rain forest in Brazilian Amazonia after logging.

Abstract

The objective of this paper was to determine changes in the spatial distribution of tree species in a logged compared to an unlogged forest of the Tapajós National Forest in the municipality of Belterra, State of Pará, Brazil, over an eight-year period. The distribution pattern was determined for trees > 5 cm dbh and, also, for trees > 30 em dbh. The relationship (a quadrate method) discussed by McGinnis was selected to be used in this study. Forty-seven percent of species with trees > 5 cm dbh showed clumped distribution in the studied forests. Geissospermum sericeum Benth & Hook., Minquartia guianensis Aubl., Pouteria bilocularis (H. Winkler) Bachni, Protium guacayanum Cuatrec, Sclerolobium chrysophyllum Poepp. et Endl. and the Sapotaceae family (9 species) occurred in clumps of small trees (S em < dbh < 30 cm) and big trees (dbh > 30 cm) in both the logged and undisturbed forest. Trees in all sizes of these species certainly have aggregation characteristics in different light conditions during the whole growth-cyele. Only Scelerolobium chrysoplwllum out of fourteen species that occurred aggregated in all forest conditions was light demanding. The shade tolerant Lecythis lurida (Miers) Mori and Manilkara huberi (Ducke) Standl. showed also aggregated distribution for small and big trees in the unlogged forest. An aggregated distribution is not always directly correlated to abundance, considering that most of the clumped species had less than seven trees per hectare.