Tese
Dinâmica de Carapa guianensis aubl. em Floresta Amazônica submetida a tratamentos silviculturais
Fecha
2019-02-15Autor
Francez, Luciana Maria de Barros
Institución
Resumen
This study aimed to evaluate the effect of silvicultural treatments on the structure, growth, and the
dynamics of the community and population of Carapa guianensis Aubl., after 30 years of harvesting, in
the Tapajós National Forest, Pará, in order to determine the most appropriate silvicultural treatment for
the growth of the species. In 1981 and 1983, 60 plots of 50 x 50 m were randomly established,
subdivided into 25 subplots of 10 x 10 m, where all trees with DBH ≥ 5 cm were measured. In each
plot of 50 x 50 m, five subplots were sorted, and at the center of each one of those five, one plot of 5 x
5 m was allocated to measure the individuals of 2.5 cm ≤ DBH < 5 cm (sapling). Each plot of 5 x 5 m
was divided into four triangles of 6.25 m², which one was sorted for the measurement of the seedlings
(H ≥ 30 cm, DBH < 2.5 cm). Four treatments were established according to the different intensities of
the silvicultural treatments, besides the control area (T0 – unlogged area; T1 – logged area; T2 –
logged area + thinning up to 20%; T3 – logged area + thinning up to 40%; T4 – logged area + thinning
up to 60%). The floristic diversity, phytosociology, diametric distribution, and natural regeneration rate
of the forest and of C. guianensis were investigated. In addition, the probabilistic chain of transition to
C. guianensis was done. The floristic revealed an area rich in terms of family, gender, and species.
The species with the highest value of importance were Rinorea guianensis Aubl., Protium apiculatum
Swart, and Rinorea Riana Kuntze. T1, T2, T3, T4 showed greater oscillation in density and species
when compared with T0. The forest took on average 30 years to restore the initial basal area while C.
guianensis did not resume the basal area before logging. Among the applied treatments, T2 presented
the best increments of basal area, both for the community and for C. guianensis. In all treatments,
mortality was higher than ingrowth, except for T4. Most trees, regardless of treatment, were more
likely to remain in the same diametric class with a higher probability of mortality in small and medium
diameter classes. The models generated through the Markov chain allow estimates with values close
to those observed, although, it does not show efficiency regarding the disposition of the trees in the
different diametric classes. The seedlings were more sensitive to the changes caused by the opening
caused by the logging accompanied by the thinning; however, the sapling revealed a smaller number
of individuals. Therefore, silvicultural interventions are necessary, through the enrichment and/or
transplantation of young individuals as well as the amelioration of those already present in the area to
ensure the resilience of C. guianensis and other species considered as commercial.