1,721,128 research outputs found
Controllo dell'uso dell'acqua negli ecosistemi forestali
No full textDopo una breve analisi dei fattori ambientali che controllano l’evapotraspirazione dalle coperture vegetali, vengono considerati i probabili effetti sul bilancio idrologico dei diradamenti, dall’invecchiamento dei soprassuoli forestali, dall’espansione della foresta su terreni abbandonati dall’agricoltura e dal pascol
Seed colour and post-fire bird predation in a Mediterranean pine forest
No full textIn a Pinus halepensis Mill. forest, a field experiment was designed to evaluate post-fire seed predation as affected by combinations of seed
colour and soil substrates: light grey and black seeds combined with light grey ash, dark grey ash and pale brown sand. A survey of bird species
inhabiting the area was also carried out and polyphenolic content of seed coat was assessed in seed lots of different colour. Light grey seeds
were observed to be less predated on light grey ash, suggesting eucrypsis as a protective strategy against bird predation. On the contrary, no
clear pattern was observed for the predation of black seeds on different substrates. In the study area both bird species breaking the seed coat and
eating the endosperm and bird species swallowing the whole seed were monitored. We have estimated that more seeds were swallowed than
broken, in all colour categories. Light grey seeds, which were found to have a higher content of polyphenols, were predated more than black
seeds when exposed on the same substrate. Thus, no evidence was produced that the amount of polyphenols in seed coat could protect seeds
from predation
Comportamento ecofisiologico di latifoglie forestali nei processi di rinaturalizzazione di piantagioni di conifere
No full textUso delle abbondanze isotopiche del carbonio (d13C) nello studio dell’ecofisiologia della rinnovazione naturale di latifoglie (Quercus cerris L. e Fraxinus ornus L.) in piantagioni di Pinus radiata D. Don
No full textImpact of climate change on Mediterranean forests: acclimation or vulnerability? Geophysical Research Abstracts 10 07154.
No full textLeakage and spillover effects of forest management on carbon storage: theoretical insights from a simple model
Full text linkLeakage (spillover) refers to the unintended negative (positive) consequences of forest carbon (C) management in
one area on C storage elsewhere. For example, the local C storage benefit of less intensive harvesting in one area
may be offset, partly or completely, by intensified harvesting elsewhere in order to meet global timber demand. We
present the results of a theoretical study aimed at identifying the key factors determining leakage and spillover, as a
prerequisite for more realistic numerical studies.We use a simple model of C storage in managed forest ecosystems and
their wood products to derive approximate analytical expressions for the leakage induced by decreasing the harvesting
frequency of existing forest, and the spillover induced by establishing new plantations, assuming a fixed total wood
production from local and remote (non-local) forests combined.We find that leakage and spillover depend crucially on
the growth rates, wood product lifetimes and woody litter decomposition rates of local and remote forests. In particular,
our results reveal critical thresholds for leakage and spillover, beyond which effects of forest management on remote
C storage exceed local effects. Order of magnitude estimates of leakage indicate its potential importance at global
scales
Printed Strain Gauge on 3D and Low-Melting Point Plastic Surface by Aerosol Jet Printing and Photonic Curing
Full text linkPrinting sensors and electronics directly on the objects is very attractive for producing smart devices, but it is still a challenge. Indeed, in some applications, the substrate that supports the printed electronics could be non-planar or the thermal curing of the functional inks could damage temperature-sensitive substrates such as plastics, fabric or paper. In this paper, we propose a new method for manufacturing silver-based strain sensors with arbitrary and custom geometries directly on plastic objects with curvilinear surfaces: (1) the silver lines are deposited by aerosol jet printing, which can print on non-planar or 3D surfaces; (2) photonic sintering quickly cures the deposited layer, avoiding the overheating of the substrate. To validate the manufacturing process, we printed strain gauges with conventional geometry on polyvinyl chloride (PVC) conduits. The entire manufacturing process, included sensor wiring and optional encapsulation, is performed at room temperature, compatible with the plastic surface. At the end of the process, the measured thickness of the printed sensor was 8.72 μm on average, the volume resistivity was evaluated 40 μΩ∙cm, and the thermal coefficient resistance was measured 0.150 %/°C. The average resistance was (71 ± 7) Ω and the gauge factor was found to be 2.42 on average
Thinning affects water use efficiency of hardwood saplings naturally recruited in a Pinus radiata D. Don plantation.
No full textPlantations for timber production combine the productive to the nursery function for natural regeneration of native species. Thinning plays a crucial role in recruitment and establishment of native species, by modifying the irradiance regime beneath the canopy cover. It also promotes the secondary succession towards a more stable forest, which is a main goal in protected areas. The present study was carried in a timber plantation of Pinus radiata D. Don, located in the National Park of Cilento and Vallo di Diano (Southern Italy). The ecophysiological responses of saplings of two hardwood species, Quercus cerris L. and Fraxinus ornus L., according to two contrasting (low and high) relative irradiance (RI) regimes were analysed. Leaf and tree ring d13C values were employed as indicators of water use efficiency (WUE) to explore plant responses to light regime. A preliminary methodological comparison between bulk wood and extracted holocellulose showed no significant differences in d13C between the two materials. Results indicate lower d13C values, thus suggesting a lower WUE, at higher RI regimes (corresponding to heavy thinning) for both the studied species. Furthermore, Q. cerris d13C values are lower than those of F. ornus. These results suggest that, under the same light conditions, the mesophile Q. cerris exhibits a weaker stomatal control than the xerophile F. ornus, which keeps higher WUE. In the mesic environment studied, Q.cerris may overcome F. ornus in the long run, owing to a heavy thinning
Microclima luminoso, rinnovazione naturale e distribuzione spaziale di Abies alba Mill. nell’Abetina di Laurenzana, Basilicata
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