IMPORTÂNCIA DO MANEJO DE FLORESTAS NATIVAS PARA A RENDA DA PROPRIEDADE E ABASTECIMENTO DO MERCADO MADEIREIRO

The best decision-making is a difficult task in forest management because it involves a large number of market and production variables. We simulated growth and yield of loblolly pine in high-quality sites, aiming to indicate thinning regimes and planting densities that maximize the production of large diameter logs (minor diameter >35 cm), as well as economically evaluating such regimes. We used the software OpTimber-LP for forest optimization problems. Simulations involved four planting densities (1,111; 1,600; 2,000; and 2,500 plants/ha); three thinnings with different weights, frequencies and ages of application; and clear cut at 25 years. Such combinations totalized in 2,916 simulated regimes. We calculated ANPV considering variations in interest rates, besides costs of production and returns resulting from thinnings and from clear cut. The findings indicated great productions of large diameter logs in regimes with low planting densities. Heavy thinnings (60% removal of trees) highlighted by being ideal to almost all thinnings, mainly in regimes with densities of 2,000 and 2,500 plants/ha. This intensity also was ideal to the first thinning, regardless the planting density. The most productive regimes presented large diameter log volumes ranging from 480 to 260 m³/ha, for regimes with 1,111 and 2,500 plants/ha, respectively. ANPV ranged from ~1.300 to ~2.100 R$/ha. As conclusion, less dense regimes provide largest productions in large diameter log, but lowest productions in total volume; as consequence, ANPV was larger in denser regimes, once the revenue obtained from high-value logs did not overcome that one obtained from finer (and consequently cheaper) logs. High-density regimes may produce less timber volume due to only one improper thinning, whereas low-density stands may have production really affected when are subjected to consecutive improper thinnings.A produção brasileira de madeira industrial baseia-se essencialmente nas plantações florestais, porém, somente no setor de serraria existe ainda uma parcela apreciável de toras de origem de florestas nativas, desconsiderando o uso da madeira para fins energéticos. Com a criação de concessões florestais deu-se um passo importante rumo ao manejo das florestas nativas do norte do país. Já no extremo sul existem florestas nativas somente em estágios de recuperação, em propriedades familiares e cujo manejo é muito restrito. No presente artigo argumenta-se sobre a importância de manejar as florestas nativas, mesmo em pequenas propriedades. Para isto, toma-se como exemplo o caso da Áustria, cujo território é dominado por florestas nativas em pequenas propriedades. A tradição deste uso é baseada em uma legislação adequada, no trabalho do serviço de extensão e de pesquisa que geram um ambiente no qual os benefícios materiais e imateriais da floresta se aliam aos interesses da sociedade e aos econômicos dos proprietários. O manejo das pequenas unidades florestais permite alcançar um regime de sustentabilidade periódico, cujas intervenções silviculturais partem das condições locais, sendo o objetivo central a árvore e não o povoamento. Este procedimento de manejo, atualmente recomendado para a produção de madeira de elevado valor econômico, é descrito de maneira resumida

IMPORTÂNCIA DO MANEJO DE FLORESTAS NATIVAS PARA A RENDA DA PROPRIEDADE E ABASTECIMENTO DO MERCADO MADEIREIRO

The Brazilian production of industrial timber depends mainly on forest plantations; only in the sawmill sector, there is still the use of a considerable amount of logs originating from natural forests. Recently forest concessions were created; this was an important step toward the management of native forests in the North. In the very South of Brazil, native forests exist mainly in stages of regeneration, belonging to small-scale farmers with restricted opportunities for management. The present article argues the importance of native forest management even when they belong to small landowners. An example from Austria is given where small ownership is dominating native forests. There is a framework of traditional use, an adequate legislation and the effort of extension service, able to ally immaterial social benefits and economic interest of forest owners. The management of generally small forest units is aiming a so-called periodic sustainability; decisions of silvicultural treatments are based on local conditions, where to an individual tree is given more attention than to the stand; the objective of management is mainly timber of high value; a summarized description of practical procedure is given