In the Mediterranean evergreen oak woodlands of southern Portugal, the main tree species are Quercus ilex ssp. rotundifolia Lam. (holm oak) and Quercus suber L. (cork oak). We studied a savannah-type woodland where these species coexist, with the aim of better understanding the mechanisms of tree adaptation to seasonal drought. In both species, seasonal variations in transpiration and predawn l...

Insect herbivores frequently move about on their host plants to obtain food, avoid enemies and competitors, and cope with changing environmental conditions. Although numerous plant traits influence the movement of specialist herbivores, few studies have examined movement responses of generalist herbivores to the variable ecological conditions associated with feeding and living on an array of ho...

The taxonomy of oaks (Quercus) is always a challenge because many species exhibit variable phenotypes that overlap with other species. The scrub White Oaks of California are no exception. In California, Quercus section Quercus (i.e., White Oaks) includes six species of scrub oaks plus four tree oak species. Field identification utilizes leaf traits and acorns, when available, as well as geograp...

We used logistic regression to identify environmental and management history factors associated with blue oak (Quercus douglasii) sapling recruitment. Recent canopy gaps caused by natural mortality or clearing were positively associated with sapling recruitment. Plots with very high or low levels of tree canopy cover were less likely to have saplings than those with intermediate canopy cover le...

A full automated classification of tree species was tested on single tree level. This approach intends to classify without any parameter input or predefined knowledge. In the forerun it was therefore necessary to build algorithms which combine the LiDAR data based 2D single tree delineation with the spectral information from colour infrared (CIR) images. During the tree species classification t...

BACKGROUND Agrilus bigutattus (Fabricius) is a forest pest of increasing importance in the United Kingdom. The larvae damage weakened native oaks and are thought to contribute to premature tree death. Suspected links with acute oak decline (AOD) are not yet confirmed, but AOD-predisposed trees appear to become more susceptible to A. biguttatus attack. Thus, management may be necessary for contr...

three k-tree distance and fixed-sized plot designs were used for estimating tree density in sparse oak forests. these forests cover the main part of the zagros mountain area in western iran. they are non-timber-oriented forest but important for protection purposes. the main objective was to investigate the statistical performance of k-tree distance and fixed-sized plot designs in the estimation...

Temperate and dry deciduous forest covers major portion of terrestrial ecosystem in India. The two forest types with different dominant tree species differ in litter quality and root exudates, thereby exerting species-specific impact on soil properties and microbial activity. This study aims to examine the influence of forest type or dominant tree species on soil physico-chemical properties and...

Clear-cutting of forests affects the nitrogen cycle and the nitrogen isotopic composition of bioavailable ammonium and nitrate in the soil. Here, we have used nitrogen isotopic variations of tree-rings in red oak (Quercus rubra) and white oak (Quercus alba) as indicators of changes in the nitrogen cycle on a local scale. The delta15N values of late-wood from trees at two remnant forest stands i...

Northern red oak (Quercus rubra) and white oak (Quercus alba) are important components of high-quality mes1c s1tes and are essential as lumber species and hard mast producers. Regeneration of these species has been difficult, and their absence in newly regenerated stands is a major concern of foresters and wildlife biologists Several 1mportant biolog1cal tra1ts of oak species may contribute to ...