INFLUÊNCIA DA EXPLORAÇÃO FLORESTAL DE IMPACTO REDUZIDO SOBRE AS FASES DE DESENVOLVIMENTO DE UMA FLORESTA DE TERRA FIRME, PARÁ, BRASIL EFFECTS OF THE REDUCED IMPACT LOGGING ON THE GROWTH PHASES OF A TERRA FIRME FOREST IN THE STATE OF PARÁ, BRAZIL Luciana Maria de Barros Francez 1 João Olegário Pereira de Carvalho 2 Fábio de Jesus Batista 3

ABSTRACT The influence of reduced impact logging were evaluated on the growth phases of a terra firme forest in the Paragominas region, state of Para, that was logged considering two intensities of timber harvesting. Data were collected in 36 permanent sample plots (0.25ha) randomly distributed among treatments (T 1 – Logged forest, harvesting the stem of commercial trees; T 2 – Logged forest, harvesting the stem and coarse woody debris) and control (T 0 unlogged forest). Three growth phases of the forest were considered: mature (DBH > 40cm); building forest (10cm 10cm). The homogeneity of variances of sub-plots between treatments, growth phases and years was tested by the Bonferroni test, according to the statistics of Bartlett and Levene. An analysis of variance was applied on the number of sub-plots by phases, years and treatments at a 0.005 significance level. The Tukey test was applied for analyzing the interaction between the phases and years. Before logging the percentage of growth phases were: 57.0% building forest, 38.9% mature forest and 4.1% canopy gaps. Logging reduced the areas of mature forest and building forest, increasing the number of canopy gaps, but this increase had no statistical difference. One year after logging the area of mature forest (38.4%) and building forest (53.1%) increased while the areas of gaps (8.4%) decreased. Three years after logging the percentage of mature forest (37.1%), building forest (57.9%) and gaps (5.0%) were similar to those found before logging. The forest growth phases were not influenced by logging, over the study period. The study forest showed that it is able to grow, closing the canopy gaps, even in a short period of time.