Ana Cristina Gonçalves*, Susana Saraiva Dias** e

Alfredo Gonçalves Ferreira***

*Professor Auxiliar

***Professor Catedrático

ICAM. Universidade de Évora. Departamento de Engenharia Rural, Apartado 94, 7002-554 Évora

**Equiparada Professora Adjunta

ICAM. Instituto Politécnico de Portalegre. Escola Agrária de Elvas, Apartado 254, 7350-903 ELVAS

Sumário. A consciencialização, em muitos países, da crescente importância do papel das florestas, fez com que se olhassem os diferentes tipos de formações, não só na óptica da produção de madeira ou casca, mas também do ponto de vista ambiental, ecológico, estético, de recreio, social e cultural. É neste contexto que foram sendo introduzidas alterações na gestão dos povoamentos de modo a implementar modelos de silvicultura, que promovessem as estruturas irregulares e mistas, que são mais consentâneas com a multiplicidade de produções que se pretendem obter nos povoamentos florestais. Os modelos de silvicultura, inicialmente desenvolvidos para povoamentos puros regulares, podem ser adaptados a esta realidade. Neste trabalho apresentam-se os modelos gerais de silvicultura, à escala do planeamento regional, que promovem a alteração da estrutura e composição dos povoamentos. Há no entanto que considerar, que para determinadas estações e para determinadas produções, os povoamentos puros serão mais indicados.

Changes in Composition and Structure of the Forest Stands

Abstract. The increasing awareness, in many countries, of the importance of the forest brought a renewed interest in forest stands either for timber or bark production or for their environmental, ecological, aesthetic, recreation, social and cultural roles. In this context changes have been introduced in the management of the forest stands in order to implement silvicultural models that promote uneven aged and mixed structures, which are better suited to the multiplicity of productions of these forest stands. The silvicultural models, which were initially developed for pure even aged stands, may have to be adapted to this new reality. This study presents the general silvicultural models at regional forest planning level, which promote the alteration of structure and composition of the stands. However it should be pointed out, that for certain sites and for certain productions pure stands are better suited.

Key words: model of silviculture; conversion; transformation; management; flexibility

Altération de la Composition et Structure des Peuplements Forestiers

Résumé. La prise de conscience, dans beaucoup de pays, de la croissante importance du rôle des forêts, est à l'origine d'un changement d'attitude vers les différents types de formations, non seulement dans l'optique de la production en bois ou écorce, mais aussi du point de vue environnemental, écologique, esthétique, de récréation, social et culturel. C'est dans ce contexte que l'on a introduit des modifications dans la gestion des peuplements afin de mettre en oeuvre des modèles de sylviculture, promouvant les structures irrégulières et mélangées, qui sont plus adaptées à la multiplicité de productions recherchées dans les peuplements forestiers. Les modèles de sylviculture, initialement développés pour des peuplements réguliers, peuvent être adaptés à cette nouvelle réalité. Dans ce travail sont présentés les modèles généraux de sylviculture, à l'échelle de la planification régionale, qui promeuvent la modification de la structure et la composition des peuplements. Il faut néanmoins considérer, que pour certaines stations et pour certaines productions, les peuplements purs seront les plus adaptés.

Mots clés: modèle de sylviculture; conversion; transformation; gestion forestière; flexibilité

Texto completo disponível apenas em PDF.

Full text only available in PDF format.

Bibliografia

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* E-mail: acag@uevora.pt