Search results for "Oaks"
showing 6 items of 6 documents
Considerazioni tassonomiche sulle querce caducifoglie della Sicilia
1998
On the basis of literature, herbarium and field investigations, a survey on the species of deciduous oaks occurring in Sicily is presented. A morphological description fitted with photos and drawings and completed by some chorological and ecological observations is reported for each species. Finally it is emphasized that the phenotypical variability observed in Sicily among the Q. pubescens group, even if let to consider the S.Thyrrhenian area as a probable speciation center of the group, on the other hand should also be related to the deforestation, which favoured the genetic mixing among populations.
Carbon stock increases up to old growth forest along a secondary succession in Mediterranean island ecosystems.
2019
The occurrence of old-growth forests is quite limited in Mediterranean islands, which have been subject to particularly pronounced human impacts. Little is known about the carbon stocks of such peculiar ecosystems compared with different stages of secondary succession. We investigated the carbon variation in aboveground woody biomass, in litter and soil, and the nitrogen variation in litter and soil, in a 100 years long secondary succession in Mediterranean ecosystems. A vineyard, three stages of plant succession (high maquis, maquis-forest, and forest-maquis), and an old growth forest were compared. Soil samples at two soil depths (0-15 and 15-30 cm), and two litter types, relatively undec…
Saproxylic beetle assemblages in the Mediterranean region:Impact of forest management on richness and structure
2010
Forests cover almost 30% of the Mediterranean region today, yet forest management activities have influenced structure and composition of both natural and planted forests. To date no study has been conducted to evaluate the impact of forest management on saproxylic beetle assemblages, although it is known that the Mediterranean is a biodiversity hotspot with a long-lasting human pressure on natural habitats. We provide an overview of saproxylic beetle assemblages of three forest types (mature Pinus halepensis forests, mature Pinus brutia forests, young Quercus calliprinos forests) in the East Mediterranean region using a one-year sample from 12 forest plots located in the north of Israel. T…
Three-dimensional axisymmetric cloak based on the cancellation of acoustic scattering from a sphere.
2013
This Letter presents the design, fabrication, and experimental characterization of a directional threedimensional acoustic cloak for airborne sound. The cloak consists of 60 concentric acoustically rigid tori surrounding the cloaked object, a sphere of radius 4 cm. The major radii and positions of the tori along the symmetry axis are determined using the condition of complete cancellation of the acoustic field scattered from the sphere. They are obtained through an optimization technique that combines genetic algorithm and simulated annealing. The scattering cross section of the sphere with the cloak, which is the magnitude that is minimized, is calculated using the method of fundamental so…
Revisione tassonomica delle querce caducifoglie della Sicilia
1999
Taxonomical revision about the deciduous oaks of Sicily.— On the basis of literature, herbarium and field investigations, a survey on the species of deciduous oaks occurring in Sicily is presented. A morphological description fitted with drawings and completed by some chorological and ecological observations is reported for each species. Finally it is emphasized that the phenotypical variability observed in Sicily within the Q. humilis group, even if let to consider the S.Thyrrhenian area as a probable speciation center of the group, on the other hand should also be related to the deforestation, which favoured the genetic mixing among the populations. The present study brought to the recogn…
Does the genetic diversity among pubescent white oaks in southern Italy, Sicily and Sardinia islands support the current taxonomic classification?
2020
AbstractMolecular diversity analysis of deciduous pubescent oaks was conducted for populations from Calabria, Sicily and Sardinia. The aims of this study were twofold. First, to provide data on the genetic diversity of pubescent oaks from an understudied area which currently exhibits one of the highest concentrations of pubescent oak species in Europe. Second, to verify if these groups of oaks are genetically distinct and if their identification is in accordance with the current taxonomic classification. Molecular analyses of leaf material of 480 trees from seventeen populations belonging to putatively different pubescent oak species (Quercus amplifolia,Q. congesta,Q. dalechampii,Q. ichnusa…