COMPETITION VERSUS GROWTH OF TREES IN A RAINFOREST AT AMAPÁ STATE - BRAZIL

Vatraz, Silvane; Silva, José Natalino Macedo; Alder, Denis

doi:10.5902/1980509833358

Acessibilidade / Reportar erro

Brasil

Español English

sumário « anterior atual seguinte »

Sumário

Artigos • Ciênc. Florest. 28 (03) • Jul-Sep 2018 • https://doi.org/10.5902/1980509833358 copy

COMPETITION VERSUS GROWTH OF TREES IN A RAINFOREST AT AMAPÁ STATE - BRAZIL

Authorship SCIMAGO INSTITUTIONS RANKINGS

ABSTRACT

The objective of this study is to make, comparatively, of different distance independent competition indices (IID) in three dimensions of plots, and to identify those that more correlate with diametric increment (IPA DAP), in order to determine which best explains inter-tree competition in the arboreal stratum in a dense ombrophylous forest. This study was conducted with the Project Good Management data (Embrapa / CIFOR / ITTO) - Sustainable management of production forests on a commercial scale in the Brazilian Amazon, developed by Embrapa Amazônia Oriental in the area of Jari Florestal SA, in the municipality of Vitória do Jari, State of Amapá. Three permanent plots were used of one hectare each (100 x 100 m), on which were measured all trees with DBH ≥ 20 cm. The following IIDs were compared: G (basal area / ha), BAL (Basal Area of Larger Trees), Glover and Hool and Stage. The competition indices were evaluated by analysis of linear correlation coefficients between each index and the PAI DBH (cm-¹) variable. The significance of the correlation coefficients was evaluated by p value (α = 0.05). All variations of indexes tested resulted in correlations of up to 20%, considered to be very weak. This indicates that IIDs can represent only partially the competition in tropical natural forests. However, among the indexes, the BAL index is the IID that presented the highest correlation with the PAI DBH (r = -0.212 and p = 0.000) in plots of 50 mx 50 m and, therefore, even if it has a low correlation, it is the indicated for competition studies on diametric growth in natural tropical forests. A spatial relationship of the IIDs was detected, where the correlation decreases with the increase of the plot size. Additional research is recommended to evaluate the effects of competition on tree growth, as well to increase understanding of intraspecific and interspecific competition in order to improve knowledge of the competition dynamics in tropical forests.

Keywords:
competition indexes; natural forest; diameter growth; Amazônia

Tabela 1 Índices de competição independentes da distância avaliados neste trabalho

Índice	Fórmula	Autores/Fonte
Área basal	$G = \sum_{i = 1}^{n i} g_{i}$	Martin; Ek (1984MARTIN, G. L.; EK, A. R. A comparison of competition measures and growth models for predicting plantation red pine diameter and height growth. Forest Science , Bethesda, v. 30, p. 731-743, 1984.)
BAL (Basal Area of Larger Trees)	$B A L = \sum_{i = 1}^{n} g m$	Wykoff (1990WYKOFF, W. R. A basal area increment model for individual Conifers in the Northern Rocky Mountains. Forest Science , Bethesda, v. 36, p. 1077-1104, 1990.)
Glover e Hool	$I_{G H} = \frac{d_{i}^{2}}{{\bar{d}}^{2}}$	Glover; Hool (1979GLOVER G. R.; HOOL, J. N. A basal area ratio predictor of loblolly pine plantation mortality. Forest Science, Bethesda, v. 25, p. 275-282, 1979.)
Stage	${I C}_{S T A G E} = \frac{g_{i}}{g_{q}}$	Stage (1973STAGE, A. R. Prognosis model for stand development. Washington: [s. n.], 1973. 32 p.)

Tabela 2 Correlações lineares entre os índices independentes (IID) e a variável IPA DAP (cm ano-1) em árvores individuais do estrato arbóreo em Floresta Ombrófila Densa, localizada em Vitória do Jari-AP

Índice	Área de competição	IPA DAP (cm ano^-1)
Índice	Área de competição	r	p-valor
G	Parcelas de 20 m x 20 m	-0,074	0,145
BAL		-0,090	0,075
Glover e Hool		0,178	0,000
Stage		0,184	0,000
G	Parcelas de 50 m x 50 m	-0,104	0,039
BAL		-0,212	0,000
Stage		0,151	0,003
G	Parcelas de 100 m x 100 m	-0,090	0,074
BAL		-0,160	0,001
Glover e Hool		0,101	0,044
Stage		0,102	0,044

Universidade Federal de Santa Maria Av. Roraima, 1.000, 97105-900 Santa Maria RS Brasil, Tel. : (55 55)3220-8444 r.37, Fax: (55 55)3220-8444 r.22 - Santa Maria - RS - Brazil
E-mail: cienciaflorestal@ufsm.br

Acompanhe os números deste periódico no seu leitor de RSS

[TFN1] Em que: n = número de árvores com DAP maior que a árvore-objetivo; gm = área transversal (m²) das árvores com DAP maiores que a árvore-objetivo; n i = número de árvores da parcela; g = área transversal (m²); _i² = diâmetro da árvore-objetivo (cm) elevado ao quadrado; = diâmetro médio do povoamento (cm) elevado ao quadrado; gi = área transversal da árvore-objetivo (m²) e gq = área transversal da árvore média (m²) (definida pelo diâmetro quadrático).