Seed production of Araucaria angustifolia in plantation and in natural forest at Central-South of the Parana State

Abstract

Seed production was evaluated and compared between a plantation of Araucaria angustifolia with 60 years old and trees of natural occurrence in a Mixed Ombrophyllous Forest fragment in an advanced stage of succession, located at Irati National Forest, Parana State. Females strobilus were collected from 27 trees in natural forest and 24 trees of the Araucaria plantation, distributed in diameter classes, even the whole number of strobilus were counted in each tree. For each strobilus was collected data of weight, diameter, number and weight of the seeds. Student’s t test was used to compare both typologies mentioned analyzing the following variables: number of strobilus per tree, number and weight of seeds per strobilus, number of strobilus in each dbh class and production of seeds per hectare. The production per tree was higher in natural forest and seed production per hectare was higher in Araucaria plantation. The production of strobilus per dbh class showed similar values between the two forest typologies and in each class, the variability found was high. Morphological characteristics of the strobilus and seeds such as: diameter, weight, number of seeds per strobilus and unit weight of the seed had higher mean values in the natural forest.