Patrício, Maria do Sameiro; Monteiro, Maria do Loreto; Tomé, Margarida
There is considerable interest today in estimating the biomass of trees and
forests for practical forestry issues, sustainable management, carbon and nutrient flux
and other scientific purposes. For these reasons, aboveground biomass was studied in
Castanea sativa high forest stands located in the Northwest of Portugal. The most
widely used procedure for stand biomass evaluation is the regression estimation
method, in which the stand biomass is predicted through the sum of the predicted biomass
of individual trees. In this study, thirty-four old sweet chestnut trees, located in
three stands, were felled, measured and weighted to evaluate the aboveground biomass
by components. Several linear and nonlinear equations were fitted...
Patrício, Maria do Sameiro; Monteiro, Maria do Loreto; Nunes, Luís; Mesquita, Susana; Beito, Sónia; Casado, José; Guerra, Hélia
In a chestnut high forest converted into coppice, 4 permanent plots were established
in 1994. These plots are being managed according to the silvicultural models
proposed by Bourgeois (1992) and adapted to our conditions. The treatments are: T1
= Model 1: small dimensions; T2 = Model 2: medium dimensions; T3 = Model 3:
Large dimensions; Control = coppice without intervention. In 2003, a 2nd thinning was
applied in order to select the more straight and cylindrical shoots without defects. The
principal dendrometrical parameters (such as: number of stumps per hectare;
number of shoots per hectare; mean total height of the shoots; dominant height of the
shoots; mean DBH...
Nunes, Luís; Monteiro, Maria do Loreto; Patrício, Maria do Sameiro; Alpuim, Teresa; Martins, Lucílio
Growing sweet chestnut (Castanea sativa) in high forest stands is a lucrative
investment. Wood with medium and large dimensions can attain interesting
profitability levels. Furthermore, forest producers are interested of new on this
species and decision criteria for the best management are needed for landowners.
So, accuracy is very important when evaluating volume in standing trees. Based on
regression theory, it is developed predicting equations of wood volume as a function
of tree variables easily measured (fast and cheap), such as diameter at breast height
(DBH) and tree total height (h). Variable selection in volume equations was based on
a stepwise modified procedure (linear models) and using generalized-F...
Castro, João Paulo; Azevedo, João; Martins, Luís
The rising demand for sweet chestnut (Castanea sativa) in Portugal and elsewhere in Europe has led to more intensive management practices to increase nut production. This intensification has potentially increased the widespread of ink and chestnut blight diseases, causing decline in sweet chestnut orchards health and production and limiting the establishment of new planted areas. In this study we estimated chestnut decline along the last twenty years (1986 to 2006) in the northern part of Portugal using 1986, 1995 and 2006 aerial photography to quantify the damage at the tree level within fixed sample plots according to a categorical scale....
Moreira, César; Castro, João Paulo; Azevedo, João
In this paper we analyzed changes in landscape composition and structure over the 1958-2005 period in the França parish (Bragança, northeastern Portugal). Agriculture decreased from 22% to 5% of the area of study. Forests and shrublands became the dominant land uses occupying together 73% of the area of study in 2005. Structurally the landscape became more homogeneous. We speculate that the types of change observed
and the tendency for their magnification in the near future will have functional effects on this landscape, namely
the creation of condition for the occurrence of catastrophic disturbance events such as wildfires.