Effect of Age on Tapering and Assortment in Araucaria angustifolia Stands

The objective of this research was to evaluate the effect of age on adjust taper functions and evolution of the assortment of male and female trees of Araucaria angustifolia stands. Sixty trees were sampled in a plantation located in the municipality of Laranjeiras do Sul, Paraná state, Brazil. The fifth degree polynomials were adjusted to the whole data set, and they were stratified into age classes. The evolution of the tapering and assortment of trees was analyzed with age. The results showed a slight advantage in the use of equations adjusted for age classes and a significant improvement in the stem form with increasing age. The female trees presented higher growth (0.9975 m3) than the male trees (0.9384 m3) at 30 years of age. Volumes for the noblest assortments are produced only when the stand reaches the age class of 11 to 15 years.

本研究旨在探究树龄对狭叶南洋杉（Araucaria angustifolia）人工林雌雄林木削度函数拟合效果及材种分级演变的影响。研究于巴西巴拉那州南拉日热拉斯市的一处人工林内采集了60株林木样本。对全部数据集进行五次多项式拟合，并按龄级进行分层处理。基于树龄维度分析林木削度与材种分级的演变规律。研究结果表明，采用按龄级拟合的方程具有小幅优势，且随着树龄增长，林木干形会得到显著改善。在30年生林分中，雌树单株材积（0.9975立方米）高于雄树（0.9384立方米）。仅当林分达到11至15年的龄级时，方可产出顶级材种的材积。