Caracterização do potencial madeireiro de uma floresta intensamente explorada no sudeste paraense.

Abstract

The Amazon is the largest remnant of humid tropical forest on earth, representing about 40% of the world's tropical forests, and therefore plays a strategic role in the preservation, maintenance, and conservation of biodiversity. Logging causes disturbances to its horizontal structure and floristic composition. The exploitation of natural forests anthropized causes a reduction in the usable stock of commercial species for future harvests. The denomination used here, anthropized forest, is equivalent to the literature term degraded forest. The degraded forests suffered a reduction of the canopy, with no change in land use and in the remaining forest cover, providing the growth of forest species. The main source of degradation is from overexploitation of timber forest resources. The objective of this work is to characterize the wood potential through dendrometric parameters of a degraded forest in southeastern Pará. The study area is in the municipality of Dom Eliseu, Southeast Paraense. Fifty permanent plots were inventoried. Phytosociological parameters, diversity and similarity indices, forest dynamics, classification of species by ecological groups, and basic density of the wood were obtained. A total of 15,959 individuals with DBH ≥ 5 cm were inventoried and 382 species were identified. 57.33% of the species belong to the shade tolerant and 39.01% to the shade intolerant ecological group, and 3.66% could not be classified. The study area showed high diversity (H' = 4.62) and equability of 0.78 for individuals with DBH ≥ 5 cm. The diametric distribution showed a concentration of 54.28% of the individuals in the diametric class 5 to 10 cm, 44.59% in the classes 10 to 50 cm, and only 1.13% in the classes above 50 cm DBH. The IVI is fundamental for the quantitative study of floristic composition, structure, function, dynamics, distribution, and environmental relationships of the plant community. The species that presented the highest IVI were Cecropia distachya, Schizolobium parahyba var. amazonicum, Sagotia racemosa, Inga alba and Protium altsonii. During the monitoring period an ingress rate of 3.8% was recorded, where the species Inga ssp and Sagotia racemosa showed the highest rate and ingress. The mortality rate observed was 5.5%, where the species Cecropia distachya and Inga ssp showed the highest mortality. The higher mortality rate than the ingress rate indicates a negative balance in the forest dynamics. The IPA in basal area was 0.85 m².ha-1.year-1 and in volume was 2.60 m³.ha-1.year-1, which shows that tropical forests can grow above the value indicated by the legislation. The average value of basic density found for the species inventoried was 0.648 g.cm-3, being the wood density an important parameter in the technological definition and commercial use and an excellent indicator to determine the quality of the wood. The analysis of IPA's showed that degraded forests have timber potential, with many species with medium and heavy basic density wood.