Search results for "Forest"
showing 10 items of 3780 documents
Simple flume with a central baffle
2016
Abstract In this paper the stage-discharge relationship of a flume with a central baffle is theoretically deduced using the Buckingham-Theorem of the dimensional analysis and the self-similarity theory. The new stage-discharge equation is calibrated by the measurements carried out by Peruginelli and Bonacci using a baffle having a given throat length and five different values of the contraction ratio. Finally, for a given throat length, a relationship linking the discharge with the upstream water depth, the contraction ratio and the contracted width is deduced.
Comment on "Measuring the flow resistance of submerged grass"
2004
In this short note, the experimental data of Wilson and Horritt (2002.Hydrological Processes16: 2589–2598), jointlywith the measurements by Kouwenet al. (1969.Journal of Irrigation and Drainage Division, ASCE95: 329–342)and by Raffaelliet al. (2002 InProceedings XXVIII Convegno di Idraulica e Costruzioni Idrauliche, Cosenza, Italy;223–230), arefirstly used to test Kouwen’s approach. All experimental data are then used to calibrate aflow resistanceequation that was theoretically deduced by dimensional analysis and self-similarity theory
SELVICOLTURA ALPINA E SELVICOLTURA APPENNINICA: ELEMENTI DI CONTATTO E DI DIFFERENZIAZIONE
2009
Riassunto Il rapporto tra boschi e popolazioni locali sulle Alpi come sugli Appennini, seppur in momenti storici differenti, è stato caratterizzato dalla distruzione e sfruttamento intensivo, protrattisi fino alla metà del secolo scorso, cui hanno fatto seguito la ricostituzione sia mediante rimboschimenti sia con il miglioramento dei boschi esistenti. Partendo dai presupposti sui quali si è imperniata l’attività forestale che ha caratterizzato, nel corso degli ultimi cinquant’anni, l’approccio selvicolturale nei due contesti e da una puntuale e documentata analisi, nel lavoro vengono evidenziati gli elementi di differenziazione tra la selvicoltura naturalistica applicata in ambiente alpino…
La biodiversità dei boschi siciliani. Parte I: l’avifauna
2014
È stata censita la diversità delle specie ornitiche presente in alcune tipologie forestali della Regione Siciliana e la relazione tra le ornitocenosi, le scelte gestionali ed i diversi fattori abiotici e biotici. L’analisi della species richness (= numero delle specie) dimostra che essa è correlata con il bioclima, il diametro massimo degli individui arborei, il valore trofico di tutti gli strati di vegetazione ed il valore trofico dello strato arboreo. I boschi meso-supramediterranei sono più ricchi di specie rispetto ai boschi termomesomediterranei. L’importanza del diametro massimo degli individui arborei, che esprime indirettamente anche il tipo di gestione di un bosco, viene spiegata d…
Grassland fire effect on soil organic carbon reservoirs in semiarid environment.
2011
The effect of fire on soil organic matter content is highly variable and depends on several factors including fire intensity, soil type and nature of burned material. Grassland in semiarid environment are often managed by shepherds with annual burning in order to enhance pasture recovery. The aim of this work was investigating the effect of fire as grassland management tool on soil organic carbon (SOC) reservoirs and on post-fire plant recovery. The study was conducted on Hyparrenia hirta grassland and Ampelodesma mauritanicus grassland, located in the Province of Palermo, in the north of Sicily. Soil samples were collected at two depth (0-5 and 5-20 cm) before and after experimental fire a…
The effects of grazing history, soil properties and stand structure on the communities of saprotrophic fungi in wood-pastures
2022
Wood-pastures are threatened anthropogenic biotopes that provide habitat for an extensive group of species. Here we studied the effect of management, grazing intensity, time since abandonment, historical land-use intensity, soil properties and stand conditions on communities of saprotrophic fungi in wood-pastures in Central Finland. We found that the proportion of broadleaved trees and soil pH are the major drivers in the communities of saprotrophic fungi in these boreal wood-pastures. In addition, tree species richness, soil moisture, historical land-use intensity and time since abandonment affected the communities of saprotrophic fungi. Current management or grazing intensity did not have…
ESTIMATING SOIL PARTICLE-SIZE DISTRIBUTION FOR SICILIAN SOILS
2009
The soil particle-size distribution (PSD) is commonly used for soil classification and for estimating soil behavior. An accurate mathematical representation of the PSD is required to estimate soil hydraulic properties and to compare texture measurements from different classification systems. The objective of this study was to evaluate the ability of the Haverkamp and Parlange (HP) and Fredlund et al. (F) PSD models to fit 243 measured PSDs from a wide range of 38 005_Bagarello(547)_33 18-11-2009 11:55 Pagina 38 soil textures in Sicily and to test the effect of the number of measured particle diameters on the fitting of the theoretical PSD. For each soil textural class, the best fitting perf…
Dahrsa-Kallenders, ar Peelikkumu no ihsahm derrigahm Mahzibahm, kà Pirschukohkus, Kesberes un Wihnakohkus pareisi buhs apgraisiht un labbi audsinaht;…
1796
Chimpanzees surviving in a fragmented high‐altitude forest landscape of the Congolese Albertine Rift
2021
This paper documents a community of eastern chimpanzees (Pan troglodytes schweinfurthii Giglioli, 1872) inhabiting three relict forest fragments situated on the Lake Albert escarpment, down the Ituri highlands, of eastern Democratic Republic of the Congo (DRC). The area explored had a combined forested surface of ±18.15 km2 in 2017, shrinking by 1.2% per year between 2010 and 2015. Between 2015 and 2017, we found 160 chimpanzee nests along 37.6 km of pilot walks, some up to 2,000 m altitude. Another 123 nests logged along 6.7 km transects led to an estimate of chimpanzee density of 4.62 weaned individuals per square kilometer of forest habitat. Camera‐trap images and direct observations rev…