Site influence on 22-years-old Pinus taeda L. growth: plant nutritional status.

Abstract

Soil analyses, frequently used on agriculture, has been proved to be useless on predicting forest species growth, considering the problem on sampling the exact soil depth from where the nutrients are obtained. In order to evaluate the influence of site quality on pine trees growth, eight different sites were selected in a commercial Pinus taeda plantation belonging to Klabin, in Telêmaco Borba region, Parana State. Trees were 22 years old and sites were selected by soil type (Latosol and Cambisol), by soil texture (clayey and sandy) and by original vegetation (forest and grass). To characterize the sites, measurements of total height and DBH were taken from at least 50 trees at each site. Three average trees were selected from each site and DBH and total, sawing and cellulose heights were measured. Disks from six different tree positions and needles were collected for nutritional status analysis. K concentration was higher in needles, bark and sapwood in trees from the most productive sites. The most productive sites presented less Ca content on needles from trees that showed strong positive linear correlation (r=0,80) with total soil porosity, pointing that soil aeration porosity is very important on Ca absorption. Trees from these sites presented higher concentration of Zn in the needles and showed the best negative linear correlation coefficients with the growth variables