Sustainable forest management in poplar plantationsforest health and biodiversity criteria

Resumo

Sustainable Forest Management (SFM) emerged as a response to an increase in awareness of the deterioration of the environment and, in particular, an alarming loss of forest resources. The implementation of SFM is generally achieved through criteria and indicators (C&I), and although different sets of C&I have been implemented according to country, all of them agree that forest health and biodiversity criteria must be keystones in SFM. The objective of this thesis was to test the current indicators and search for new indicators of forest health and biodiversity criteria in poplar plantations, which may be able to assess the sustainability of changing ecosystems. Towards this purpose, a wide variety of both poplar plantations and the remnant patches of natural riparian forests were surveyed. The results suggest that both abiotic and biotic stresses are associated with forest health in monoclonal poplar plantations and may therefore be used as indicators. Although no dramatic phytosanitary problems have been displayed in these poplar plantations so far, the outcomes seem to suggest that soil properties, and mainly coarse fragments, determine tree vitality. Hence, the use of classification functions developed from soil properties would be desirable to ensure that new plantations will be established on suitable lands. In addition, an assessment of 1) digital crown transparency by CROCO software, 2) Sesia apiformis population by a pheromone trapping system or 3) endophytes fungi may be used to evaluate the sustainability in poplar plantations. On the other hand, the studies carried out through three different taxonomic groups, including bird, vascular plant and fungi, showed marked differences on species, structural and functional diversity between poplar plantations and native riparian forests. Nevertheless, a suitable management at local level (minimising the use of harrowing) and at landscape scale (increasing the percentage of poplar plantations in relation to other crops) may favour vascular plant and bird diversity in poplar plantations. The results indicate that these taxonomic groups may be used as indicators of biodiversity for SFM in poplar plantations