Crescimento e produção de um plantio de Tectona grandis, submetido a desbaste no município de Iracema (RR)

Abstract

There has been an increase in the plantation of exotic forestall species in Brazil. An example of this can be observed in the eucalyptus plantation of vast diversity in the southern, southeast and central western regions. In Amazonia, the lumber industry is very impressive, especially when it comes to the extraction of timber from native forests, but a wide range of norms and legal impositions have inhibited this activity. A way of decreasing the pressure on native forests, for example, eucalyptus, African mahogany and Teak, in order to maintain the availability of the lumber sector and provide the entrepreneurs of this sector with expectation of growth and greater employment rate. The objective of this assignment was to evaluate the effect of the first thinning over the growth and production of Tectona grandis, (11 years old), with initial spacing of 3.0 x 2.0 meters, in Iracema region in the State of Roraima. The experimental outline used were randomized blocks, with four treatments and three replicates, the sample (without thinning) the removal of 20%, 30 % and 40 % of the basal area related to the experiment. There was significant difference to the level of 5% to the diameter at breast height (DBH), total height, dominant height and an increase in the diameter. The maximum DBH observed was 15.67 cm and the sample with removal of 40% of basal area showed the greatest average per individual total volume with the bark and without bark. The maximum production in volume was obtained with the sample, however in greater individual numbers. The morphometric parameters of this population were influenced by the thinning, while only the dimension of the projection and the formation of the canopy showed no difference in the samples. The degree of slenderness, the diameter and the length of the foliage increased according to the impact of the thinning, whereas with the altitude of the insertion e inverse occurred because the greater densities provided greater averages. In the sample it was observed that the insertion a maximum of 4.25 m of the canopy. The maintenance of 60% of the basal area in relation to the sample provided greater gains in DBH, basal area, total volume with bark and commercial volume without bark, which concludes that this sample was the best indicated until present.