Anelagem de árvores como tratamento silvicultural em florestas naturais da Amazônia brasileira.

Abstract

The efficacy of two types of tree-girdling as silvicultural treatments in natural forests and the resistance of eight tree species to the girdling treatment were evaluated in a 5 ha arca in the Tapajós National Forest at the margin of BR 163, km 69, in the municipality of Belterra, Pará. The eight species studied were: Garapa guianensis (andiroba, Meliaceae); Pouteria heterosepala (abiu, Sapotaceae); Hevea guianensis (seringueira, Euphorbiaceae); Helicostylis pedunculata (muiratinga-folha-peluda, Moraceae); Couratari oblongifolia (tauari, Lecythidaceae); Sclerolobium crysophyllum (taxi-vermelho, Leguminosae); Virola melinonii (ucuuba-da-terra-firme, Myristicaceae); Bixa arborea (urucu-da-mata, Bixaceae). The two types of girdling (complete girdling; girdling with notching) were analysed within three diameter classes, totalling six treatments. Two trees were selected for each species, totalling sixteen trees for each treatment. Both the complete girdling and girdling with notching can be considered efficient thinning treatments, considering that after five years they already showed high mortality rates. Complete girdling was preferred because it gave the highest mortality in all treatments and permits little healing of the girdled arca. The species Pouteria heterosepala, Helicostylis pedunculata, Hevea g uianensis and Couratari oblongifolia were more resistant to both types of girdling. Girdling can be successfully applied to Sclerolobium crysophyllum, Virola melinonii, Bixa arborea and Carapa guianensis because it gave high average mortality (more than 60%) without utilisation of arboricides.