Loading...
3 results
Search Results
Now showing 1 - 3 of 3
- Assessing forestry biomass by means of field work a geostatistics process : a case in Northern PortugalPublication . Aranha, José; Viana, H.F.; Pedro, Nuno; Rodrigues, RosaliaTo assess Forest Biomass availability requires a hard field work survey and elaborate calculation techniques for vegetation classification and quantification. In March, April and May 2006, 900 sampling plots were surveyed with a help of a portable GIS (Geographical Information System) with GPS (Global Positioning System) capabilities. Within each sampling plot, an extensive field work was made in order to completely classify and quantify available forestry biomass. Data collection was regarding total number of trees within sampling plot, individual trees diameter at breast height, mean tree’s height, mean tree’s volume, mean tree’s canopy height and mean tree’s age. The results showed a range of values from 6.00 up to 21.00 dry ton./ha for adult Pinus pinaster (maritime pine) stands and from 1.00 up to 6.00 dry ton./ha for adult Eucalyptus globulus (eucalyptus) stands, both for thinning stands or for clear cut stands. In a second stage, they were applied geostatistic techniques (e.g. Weighted Inverse Distance, Kriging) in order to extend sampling plot results to fully study area and to create continuous biomass maps.
- GIS-based suitability model for assessment of forest biomass energy potential in a region of PortugalPublication . Quinta-Nova, L. C.; Fernandez, Paulo; Pedro, NunoThis work focuses on developed a decision support system based on multicriteria spatial analysis to assess the potential for generation of biomass residues from forestry sources in a region of Portugal (Beira Baixa). A set of environmental, economic and social criteria was defined, evaluated and weighted in the context of Saaty's analytic hierarchies. The best alternatives were obtained after applying Analytic Hierarchy Process (AHP). The model was applied to the central region of Portugal where forest and agriculture are the most representative land uses. Finally, sensitivity analysis of the set of factors and their associated weights was performed to test the robustness of the model. The proposed evaluation model provides a valuable reference for decision makers in establishing a standardized means of selecting the optimal location for new biomass plants.
- Ecological envelope maps and stand production of eucalyptus plantations and naturally regenerated maritime pine stands in the central inland of Portugal.Publication . Alegria, C.M.M.; Pedro, Nuno; Monteiro, M.C.H.; Roque, Natália; Fernandez, PauloEucalyptus and maritime pine forests provide most of the wood harvested in Portugal. Due mainly to forest fires maritime pine forest has been converted to eucalyptus plantations. In the central inland of Portugal these species are well represented, and their productivities are quite the same. The objectives of the study were: (1) to assess average wood volume, biomass production and carbon content of eucalyptus plantations and naturally regenerated maritime pine stands; (2) to evaluate biomass nutrients concentration of eucalyptus sprouts selection and maritime pine non-commercial thinning; (3) to analyse these forests cover change in relation to the annual burnt areas; and (4) to produce the species ecological envelope maps to foresee future environmental impacts of these forests current distribution. Simulation models were used to assess wood volume, biomass production and carbon content. Field data was collected to evaluate biomass nutrients concentration and to validated simulated data. Forest inventory data and forest cover maps were used to analyse forest cover change. Biogeographical variables were used to produce species ecological envelope maps. It was found that eucalyptus plantations provide higher mean annual wood volume, biomass production and carbon content. Biomass nutrients concentration in eucalyptus sprouts selection were higher than in maritime pine non-commercial thinning, particularly in calcium and potassium. Overall eucalyptus forests area did not increase substantially but the fires in maritime pine forests gave the opportunity for eucalyptus afforestation. That has precluded the opportunity for introducing native broadleaves to respond to climate changes, improve landscape biodiversity and mitigate fire hazard. Implementing good management practices to prevent losses of soil fertility by nutrients exhaustion, organic matter depletion or erosion were found more relevant in eucalyptus plantations than in naturally maritime pine forest. Species ecological envelope maps and production simulation models are key tools for supporting decision in afforestation planning.