The objective of the present work connected the forest structure with the characteristics abiotics present in the Biological Reserve of the Brazilian timber trees (Rebio of the Brazilian timber trees), located in the local authorities of Tuneiras do Oeste and Cianorte – PR for analysis of the existence of effect of edge. The study was that I carry out in a transect opened edge / interior of the forest, East divided in 10 pieces of 20m x 10m with 20m of spacing between them, given abiotic (light, moisture and temperature) they were sampled randomly in 5 collections in each one of the pieces. For analysis of the vegetable structure they were sampled in the total 361 individuals, there was measured CAP (circumference height of the chest) of same and his heights were appreciated. The data abiotics of temperature lessened when edge / interior was felt, the relative moisture increased as the forest was entered, the light varied due to clearings presence in the transect, mainly in the piece 2, this one with great lianes presence. The statistical tests presented correlation between the factors light and moisture, with the parameters of middle volume and middle height, demonstrating a change in the forest structure, it is tied to the edge effect, it was not possible to stipulate precisely a distance, to put from 200 meters edge inside is obvious the change in the structure. The correct handling to minimize the effect of edge is of extreme importance in unities of conservation that present wombs impactantes to his outline.