Quantificação do rendimento em volume para laminação do paricá (Schizolobium parahyba var. amazonicum) em sistema de integração pecuária e floresta no município de Abel Figueiredo, Pa.

Abstract

Paricá (Schizolobium parahyba var. amazonicum) is a promising species for use in reforestation because of its rapid growth in height and diameter. The characteristics of its wood allow it to be used for various purposes, with emphasis on the panel industry. As a way of maximizing and diversifying production, the wood from the same trunk can be used for more than one segment. The aim was therefore to adjust and compare different thinning equations to determine the volume and variety of products, as well as the estimated yield in lamination in a paricá plantation inserted into a livestock and forest integration system. The study was carried out on a farm located in the municipality of Abel Figueiredo, in the south-east of Pará. The paricá plantation was planted on 50ha, in a Cattle-Forest Integration cropping system. Part of the forest was planted in January 2019, with a spacing of 3.5x3.5m, while the other was planted in February 2020, with a spacing of 4x 2m between trees. The forest inventory was carried out on 53 500m² circular plots, where the DBH of 2,461 trees was measured with a tapping machine, after which two trees from each plot were cubed non-destructively using the Criterion RD 1000 optical dendrometer. Of the 106 trees cubed, 50% of the data collected was used for adjustment and 50% for validation. Three equations were tested to estimate each of the following dendrometric variables: total height, individual volume and taper. The adjusted coefficient of determination, standard error of the estimate in percentage, Akaike information criterion, Bayesian information criterion and the graphical distribution of the residuals were used as criteria for selecting the best adjusted model. The forest’s diametric distribution was modeled using the Weibull probability function. The Stoffels and von Soest, Spurr and Schöepfer models were selected to adjust the hypsometric, volumetric and tapering relationships, respectively. The estimated average volume of the plantation was 121.2374 m³ ha-1, for an inventory error of 10.64%. A rolling volume of 49.9784 m³ ha-1 was estimated for the first stratum for assortment category 2, while the second stratum showed 0.3918 m³ ha-1 and 54.9313 m³ ha-1 for assortment categories 1 and 2, respectively. The third stratum had 8.1358 m³ ha-1 and 156.5605 m³ ha-1 of rollable volume for assortment categories 1 and 2. The estimated average rolling yield for sorting 1 logs was 90.23% and 91.19% for the second and third strata. For assortment 2 logs it was 83.82%, 83.91% and 85.99% for the first, second and third strata, respectively. The thinning functions proved to be an alternative for estimating the volume of trees, multiproducts and rolling yield of paricá, demonstrating the viability of implementing the species in an iPF system for commercial purposes in the laminate industry.