Search results for "Forestal"

Institutions et mécanismes de gouvernance des transactions :

2013

Institutions and governance mechanisms for transactions : the case of logging in Cameroon Following Masahiko Aoki (2010), we postulate that transactions between actors integrate not only an economic dimension but also a social dimension. This means that transactions’ equilibrium cannot be analyzed only in economic terms. They also include relational aspects that we define as social aspects. Through the study of a local forestry exploitation in Cameroon compared with a communal forestry exploitation in France, we highlight two crucial factors : the dissociation of the functions of mayor and chief of village and the coexistence of payments in cash and payments in nature. The first factor unde…

Advanced earth observation approach for multiscale forest ecosystem services modeling and mapping (MIMOSE)

2014

In the last decade ecosystem services (ES) have been proposed as a method for quantifying the multifunctional role of forest ecosystems. Their spatial distribution on large areas is frequently limited by the lack of information, because field data collection with traditional methods requires much effort in terms of time and cost. In this contribution we propose a methodology (namely, MultIscale Mapping Of ecoSystem servicEs - MIMOSE) based on the integration of remotely sensed images and field observation to produce a wall-to-wall geodatabase of forest parcels accompanied with several information useful as a basis for future trade-off analysis of different ES. Here, we present the applicat…

ESPERIMENTO DI SIMULAZIONE DELLA FORMAZIONE DEI RILL A SCALA DI PARCELLA

2016

Nella memoria sono riportati i risultati di un esperimento di simulazione della formazione del canale di un rill condotto in una parcella avente una dimensione 2x7 m2 ed una pendenza del 14% realizzata dal Dipartimento di Scienze Agrarie e Forestali dell’Università di Palermo. Una rete di solchi, costituita da due canali principali, è stata, dapprima incisa sul suolo manualmente e successivamente modellata utilizzando una corrente idrica limpida. Sui solchi modellati è stato effettuato, in corrispondenza di 11 sezioni trasversali della parcella, il rilievo delle caratteristiche geometriche e idrauliche utilizzando un profilometro. L’indagine ha inoltre previsto la realizzazione sia di un mo…

VERIFICA DI UNA TECNICA FOTOGRAFICA PER IL RILIEVO DELLA GEOMETRIA DI UN CANALE IN TERRA

2016

Nella memoria sono riportati i risultati delle verifiche di applicabilità di una tecnica image-based per il monitoraggio dei processi di erosione canalizzata. L’indagine, in particolare, ha avuto lo scopo di testare l’uso di modelli tridimensionali del terreno (DTM) ottenuti con l’impiego di un numero elevato di fotografie della stessa scena acquisite da differenti punti di vista (Tecnica “Structure-From Motion” SFM e “Multi-View-Stereo MVS). Il DTM tridimensionale (3D) è stato generato utilizzando il software open source Autodesk 123D Catch mentre per la creazione del Digital Elevation Model DEM (2.5D) è stato impiegato il software CloudCompare. Dei due canali in terra utilizzati nella spe…

Primo contributo all'estensione di alcune serie climatiche siciliane mediante analisi di serie dendrocronologiche

2008

The effects of post-pasture woody plant colonization on soil and aboveground litter carbon and nitrogen along a bioclimatic transect.

2013

Abstract: We investigated the effects of woody plant colonization of abandoned pastures on soil and litter organic carbon (C) stocks and nitrogen (N) content along a bioclimatic transect in a semi-arid environment (Sicily, Italy). Soil samples were taken in three successional stages (grazed pasture, shrubland, forest) within each of three bioclimates (supramediterranean - “supra”, mesomediterranean - “meso”, thermomediterranean - “thermo”). Organic C and N in litter and soil (0-10 cm and 10-30 cm depth) were determined, as well as soil bulk density. Especially at 0-10 cm depth, changes in C and N contents along successional stages differed among bioclimates. Soil organic carbon (SOC) stock …

Assessing dye-tracer technique for rill flow velocity measurements

2018

Abstract Rill erosion is considered one of the most important processes affecting soil because of the large amount of soil loss. The rill network acts as sediment source and is able to transport both rill flow-detached particles and those delivered from the interrill areas. Small flow depth in a rill and steep slope values of its bed affect significantly flow hydraulics. When rill flow velocity is measured using a dye-tracing method, the mean velocity is calculated by multiplying the measured surface velocity of the leading edge of the tracer plume by a correction factor. The main uncertainty of the dye-tracing technique stands in the relationship between mean and surface flow velocity. In …

Comment on “Effects of different tillage practices on the hydraulic resistance of concentrated flow on the loess plateau in China” by J. Sun et al

2020

Abstract For concentrated flows, which are characterized by small water depth and steep sloping beds, hydraulic conditions different from those typical of streams and rivers occur. In this study a new theoretically deduced flow resistance equation was tested using the experimental data by Sun et al. for three different tilled surfaces (Manual Dibbling, MD, Manual Hoeing, MH, and Contour Drilling, CD). At first, the profile parameter-relationship, which is the relationship between the velocity profile parameter Γ, the channel slope and the flow Froude number, was calibrated using rill flow data by Di Stefano et al. Then, the applicability of this relationship was tested by the measurements o…

Impact of climate, soil properties and grassland cover on soil water repellency

2021

Abstract Numerous soil water repellency (SWR) studies have investigated the possible causes of this temporal phenomenon, yet there remains a lack of knowledge on the order of importance of the main driving forces of SWR in the context of changing environmental conditions under grassland ecosystems. To study the separate and combined effects of soil texture, climate, and grassland cover type on inducing or altering SWR, four sites from different climatic and soil regions were selected: Ciavolo (CI, IT), Csolyospalos (CSP, HU), Pwllpeiran (PW, UK), Sekule (SE, SK). The investigated parameters were the extent (determined by repellency indices RI, RIc and RIm) and persistence (determined by wat…

Discussion on 'Estimating depth-averaged velocities in rough channels'

2002

In this short communication the four estimate criteria of the depth-averaged local velocity proposed by Byrd et al. (Earth Surface Processes and Landforms, 2000, Vol. 25, pp. 167-173) are compared both with the three-point method of Bathurst and with the average velocity obtained by integrating the velocity profile (FPa2) suggested by Ferro and Pecoraro (Water Resources Research, 2000, vol. 36, pp. 2761-2770). The comparison was carried out using 84 velocity profiles measured by an acoustic Doppler velocimeter in a rectangular flume with a gravel bed. Copyright © 2002 John Wiley and Sons, Ltd.