Estimativa do volume de madeira a partir do diâmetro da cepa em uma área explorada de floresta amazônica de terra firme

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

This research was carried within an area of tropical forest of terra-firme, in Breu Branco, Pará, in order to estimate the volume of trees, considering only the diameter of the trunks leftovers, which is necessary for the overseers to precisely estimate the volume of trees that were either illegally took away or were inappropriately cut off, even if respected the forest management plan. The area belongs to the company IBL (Izabel Madeiras do Brasil Ltda), which forest management plan was inspected and authorized by IBAMA. A total of 113 trees with DBH 51 cm, of different species and diameter classes were selected to determine the real cubic volume of commercial trunk. The selection of the species and trees was done according to the companys forest management plan set. The trees were cubed by the method of Hohenadl considering the division of the commercial trunk in ten sections of equals lengths and the volume of each section of the trunk was determined by the Smalian formula. Equations were adjusted to estimate the commercial volume of the trees in function of trunks ). Equations of commercial volume in function of DBH and DBH and height were leftovers (d 0 adjusted too, to comparisons. Due to the presence of trees with irregular shape and non- cylindrical trunks leftovers by the buttresses, different methodologies were tested to estimate the trunks leftovers diameter (d ), which is often measured 30 cm above the meeting with the 0 buttresses. The results showed that d has a high correlation with the commercial volume of 0 trees within an area of forest of terra firme and it can be used in the adjustment of mathematical models in order to estimate the commercial volume of trees. No significant difference between the real and the estimated volume of trees generated through an adjusted linear equation in function of d was found. Therefore it is possible to precisely obtain the 0 volume of trees from their d . The precision of volume equations generated from the d 0 0 compares to those generated from the DBH, within a significance level of 5% by the t test. The results also showed that it is possible to estimate d ofnon-cylindrical trunks by measuring 0 the diameter either on the soil level ( D ) or on the cut level (D ). Factors of estimation of d 0 cs cc obtained by the ratio between either d and D or by the ratio between d and D , can be 0 0 cs cc used to estimate d . The estimations of d were precise (5%) when obtained either from an 0 0 average estimation factor, generated from D , for the sampled population or from cs mathematical equations that estimates the estimation factor as a function of D and D . cs cc Therefore, whenever one uses a volume equation as a function of an unknown d to estimate 0 the volume of a tree with a non-cylindrical trunk and an irregular shape, it is possible to obtain either by the estimation factor of the tree (equation) or the average estimation factor of the d 0 area of the study, obtained from D . Hence, the results leads to conclude that it is possible to cs estimate the volume of trees within an illegally deforested area of land, where there is no data about the harvested volume of wood, by measuring the diameter of the trunk leftovers remained after the exploitation.

ASSUNTO(S)

equação de volume fiscalização de desmatamento volume de madeira manejo florestal diâmetro da cepa exploração florestal floresta amazônica engenharias

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