Reineke's Density Index Research Articles

DIAGRAMA DE MANEJO DA DENSIDADE PARA Pinus taeda NO ESTADO DO PARANÁ

Este trabalho teve como objetivo desenvolver um Diagrama de Manejo da Densidade (DMD) para definir momentos ótimos para aplicação de desbastes e corte final em povoamentos de Pinus taeda L., no estado do Paraná. A base de dados utilizada no estudo é oriunda de plantios de Pinus taeda estabelecidos no estado do Paraná, nas regiões Centro-Oeste, Sul e Campos Gerais, além de dados coletados na Floresta Nacional de Irati (FLONA de Irati) e em um experimento com diferentes espaçamentos existente no Campus da UNICENTRO (Universidade Estadual do Centro-Oeste), no município de Irati. Foram utilizadas 1.023 parcelas sem desbastes, com idades variando de 7 a 44 anos. Foi ajustado o modelo de densidade de Reineke (1933) para obter o Índice de Densidade de Reineke (IDR), construindo-se então, o DMD similarmente à metodologia proposta por McCarter e Long (1986) e Dean e Baldwin (1993), o qual tem como componentes básicos o IDR e um sistema de equações que relacionam o diâmetro médio quadrático (dg) e o volume do povoamento (V) com a densidade (N), altura dominante (hdom) e o diâmetro médio quadrático. O sistema de equações ajustado para a construção do DMD apresentou estatísticas adequadas de ajuste e precisão, possibilitando a definição das densidades iniciais para atingir um dado diâmetro de tamanho desejado no corte final, bem como conhecer as idades em que devem ser realizadas as intervenções e a prognose da produção de cada colheita.

Estimation of forest stand parameters using airborne LIDAR data

This study was carried out to examine the potential of LIDAR (Light Detection and Ranging) data in estimating some forest stand parameters. The stand parameters including Basal Area (BA), Number of Trees (N), Reineke's Density Index (RDI), and Mean Diameter at Breast Height (MDBH) were determined by field measurement at 30 sampling plots from the stands with different characteristics. The LIDAR metrics including the height percentiles (50th, 90th, 95th, and 99th) and the ratio of non-ground points (NGP) were calculated based on the LIDAR points that correspond to the sampling plots. Correlation analysis was conducted to investigate the relationships between the LIDAR metrics and stand parameters. There were no associations between the LIDAR metrics and the stand parameters, BA and RDI. On the other hand, statistically significant (p<0.01) correlations were determined between the LIDAR metrics and the stand parameters, N and MDBH (highest correlation coefficients (r) are 0.70 and 0.72, respectively). The same analyses were also carried out for the sampling plots (19 plots) taken from the pure conifer or conifer-dominated stands. A clear increase was observed in the correlation coefficients of the relations between the LIDAR metrics and the stand parameters. The highest correlation coefficients calculated for the N and MDBH were 0.82 and 0.84, respectively. In addition, statistically significant but weak relationships were found between the NGP and the stand parameters, BA and RDI when the 19 conifer plots were used (r is 0.46 and 0.58, respectively). Therefore, it may be concluded that if stands parameters are estimated with LIDAR data in complex forest ecosystems, the forest stands should be pre-stratified by definite criteria. The regression models developed by means of stepwise procedure explained 0.82% and 0.70% of the variation in N and MDBH, respectively. As a result, the N and MDBH can be predicted at plot level in conifer-dominated forest stands using airborne laser scanning data. Keywords: Airborne laser scanning, Forest stand parameters, Forest stand structure, Forest inventory

Stand growth scenarios for Tectona grandis plantations in Costa Rica

Management scenarios with rotation lengths of 20 and 30 years were developed for different site qualities (high, medium and low) under two different management options (high individual tree growth versus high stand growth) for teak ( Tectona grandis L.f.) in Costa Rica. The scenarios are based on data collected in different regions in Costa Rica, representing different site conditions, offering a variety of possible management options for high-quality teak yield. Three competition indices were used for modeling the competition and for the definition of intensities and the plantation age at thinning. The maximum site occupation (MSO) and the Reineke density index (RDI) provide conservative stand density management limits, resulting in the need to execute several thinning frequently. The competition factor (CF) matches the field observations and seems to be more appropriate for the growth characteristics of the species. Final stand densities varied between 120 and 447 trees ha −1, with mean diameter at breast height (dbh) of 24.9–47.8 cm, and mean total heights between 23.0 and 32.4 m, depending on rotation length and site quality. The mean annual increment of total volume (MAI Vol) at the end of the rotation varied from 11.3 to 24.9 m 3 ha −1 year −1, accumulating a total volume over rotation of 268–524 m 3 ha −1. The most suitable scenario for teak plantations for high-quality sites is the 30-year-rotation scenario with five thinnings of intensities between 20 and 50% (of the standing trees) at the ages of 4, 8, 12, 18 and 24 years. After the sectioning of the merchantable stem in 4-m length logs, the merchantable volume varied between 145 and 386 m 3 ha −1, with an estimated heartwood volume of 45–195 m 3 ha −1, both depending on rotation length and site quality.