ESTUDO E MODELAGEM DO CRESCIMENTO EM DIÂMETRO DE POVOAMENTOS DE <i>Pinus taeda</i> L. SUBMETIDOS A PODAS E DESBASTES NA ARGENTINA

Abstract

RESUMOA presente pesquisa foi realizada com o objetivo de estudar e modelar o efeito dos desbastes pré-comerciais e das podas no crescimento diamétrico, em um povoamento de Pinus taeda L. de 15 anos de idade, no Nordeste da Argentina. O estudo localizou-se em solo vermelho argiloso profundo com um delineamento sistemático de faixas para intensidades de desbastes e subfaixas para intensidades de podas. Os tratamentos de desbaste, realizados aos 3 anos de idade, foram: 1666 (sem desbaste); 833; 416 e 208 árvores ha -1 . As podas foram realizadas a partir dos 3 anos e com frequência anual por 2, 3 ou 4 anos consecutivos, com remoção de 30, 50 e 70% da copa viva, respectivamente. O modelo geral obtido por regressão linear permitiu estimar o diâmetro da árvore de área basal média (dg) em função da idade com boa precisão (desvio médio absoluto em percentagem igual a 5.71), sendo as variáveis: árvores remanescentes, copa remanescente e número de podas consideradas nos modelos estimadores dos coeficientes da função geral. Aos 15 anos de idade, os diâmetros variaram entre 25.6 e 41.5 cm, para as densidades de 1666 e 208 árvores ha -1 , respectivamente, sem poda. O crescimento do dg foi afetado negativamente pelas podas e positivamente pelos desbastes. Palavras-chave: regimes de manejo; desrama; tratamentos silviculturais. ABSTRACTThe aim of this research was to study and to model the effect of pre-commercial thinning and pruning on diameter growth, on a 15 th year old stand of Pinus taeda L. in northeastern Argentina. The study was established in a deep red clay soil, with a systematic design of blocks for thinning intensity and sub-blocks for pruning intensity. The thinning treatments, performed at 3 year old were: 1666 (without thinning); 833; 416 and 208 trees ha -1 . The pruning were done annually, starting at 3 year old, and applied by 2, 3 or 4 consecutive years removing 30, 50 and 70 % of the living crown, respectively. The general model obtained by linear regression allowed to estimate, with good precision (mean absolute deviation as a percentage equal to 5.71), the quadratic mean diameter (QMD) in function of age. The variable remnant trees, remnant crown, and number of prunings were considered to estimate the general function coefficients. At 15 year old, the QMD varied from 25.6 to 41.5 cm to 1666 and 208 trees ha -,1 respectively, without pruning. The

Damage by Acromyrmex spp. to an Initial Pinus taeda L. Planting

“…The area planted with species of the Pinus genus in the province of Corrientes, Argentina, reached 312,369.05 hectares in 2015 (Elizondo, 2015) and the most used species in forest plantations in the region is Pinus taeda L. (Pezzutti et al, 2016). Among the silvicultural problems of the forests planted with Pinus, leaf-cutting ants of the Atta and Acromyrmex genus stand out, reaching the level of pest due to the magnitude of the damage they cause to forest plantations (Nickele et al, 2009).…”

Describing the Structure and Relationship of Height and Diameter in an Old Unmanaged Eucalyptus spp. Plantation

“…Regarding the distribution of DBH and H, the DBH showed a positive skew distribution, i.e., higher frequency of trees in the lower classes, while H presented an approximately normal distribution, with a greater number of trees close to the average (30.55 m). This demonstrates that the lack of proper management negatively affects DBH growth, since it is known that the diameter has a higher growth rate in systems managed with thinning, as this procedure provides an increase in spacing between individuals (Assmann, 1970;Schneider et al, 2015;Pezzutti et al, 2016).…”