The use of forests of Eucalyptus has become each time more expressive in Brazil, over all on
account of the excellent production in volumetric terms for them reached and the good
characteristics of the gotten wood. Some companies of the forest sector are in search of the
increase of the wooden production for unit of area, trying to identify, in regimes of handling,
the technique that strong adds more quality to the end item for them generated. In this context,
the present work was developed to search the bests plantations spacing for clonal forests of a
interspecific hybrid of Eucalyptus grandis and Eucalyptus urophylla, to maximize the
production of the stem biomass per hectare, and as a complementary objective to analyze the
influence of the plantation spacing in the annual increment in diameter, height, stem volume
and volume per hectare, basal area throughout the age, beyond the percentage of bark of the
trees and basic density of the wood in the last year. The data came from the Duraflora
Company and are proceeding from a clonal test exploration that aims at the increase of the
productivity and improvement of the quality of the substance cousin through the study of
plantations spacing. The used statistical delineation was the systematic with continuous
quantitative factor, 16 treatments and 40 repetitions, considering that the variation between the
treatments was only the spacing between the trees and the space between lines was a constant
of 3 meters. With this arrangement, the vital area for tree was about 1,50m2 (6,667 trees per
hectare) until 15,75m2 (635 trees per hectare). The trees height and the diameter breast height
- DBH had been measured to the age of 36, 48, 60 and 72 months, and only in the last year
three trees of each treatment had been sampled to determinate the individual tree volume and
the wood basic density, so the stem biomass was estimated per hectare. The analyzed data of
growth of the plantation in diameter, basal area and height of the 36 to the 72 months allowed
to conclude that the increase of the plantation spacing, increase too the diameter and height of
the trees, presenting the same trend in the two variables, however, the height less intensely.
The evolution of the basal area - BA of the forest along the years portraits that the
accumulated plantation spacing had presented the greater results in BA, due to the biggest
frequency of individuals per hectare. The density and stem volume was analyzed on the 72
months, and it was evidenced that in the ample plantations spacing it had greater volumetric
production per tree in function of the biggest available vital area for its development; It was
also evidenced that trees with the greater diameters had less bark that the accumulated
plantations spacing, where exists a bigger frequency of lesser trees, as much in diameter how
much in height. From these results, the choice of the best plantations spacing was established
of form that the stem biomass production per hectare was maximized in an interval where the
vital area for plant favored the growth in diameter and the wooden formation of the bigger
basic density, thus varying of 3,30m 2 4,95m 2 per tree, that corresponds to the 3x1,10m,
3x1,35m and 3x1,65m plantations spacing.
