Managing diameter growth and natural pruning of Parana pine, Araucaria angustifolia (Bert.) O Ktze., to produce high value timber

摘要

The objective of the present work was to analyse diameter growth and the relationship of natural pruning and various morphological characteristics of Parana pine (Araucaria angustifolia (Bert. ) O Ktze.) growing on diffèrent sites in southern Braziland to formulate silvicultural strategies for producing high quality timber for this species. Data on four hundreds trees in both natural and planted forests were collected On temporary sample plots each containing 25 Parana pines. The size of the knottycore within Parana pine stems was modeled with the predictor variables height of the lowest dead branch, height to crown base and maximum radial increment of stem at 1.3 m. The results of our study show that crown width is a good estimator of diameter growth and is closely related to stem diameter at 1,3m above ground. Restricting crown expansion such that average annual radial increment is 4 mm/year at 1.3 m for a stem grown for 6,3 years compared to one grown for ,36 years with less crown restrictionsuch that the average annual radial increment is about 75% greater (7 mm/year) results in a knotty core volume that is about 75% less for the slower growing tree. Managers can use this model to guide silvicultural decisions needed to achieve the production goal of high quality wood of Parana pine.