Studio idrogeologico degli acquiferi profondi del Sinis(Sardegna Centro-Occidentale)

Sinis area is located in the north western sector of Campidano plain, to the North of the Gulf of Oristano. In that sector of Sardinia underground waters constitute the most important water resource for agriculture. In Sinis area two deep aquifers have been placed. The first, placed in the western part, is constituted by sands and gravels and it is overhung by a very thick clayey marl’s layer. The water yeld of the confined aquifer has been determined by pumping tests from which it results that the pumping rate varies between 6 and 13.5 l/sec. The average Transmissivity is 1.7 x 10-3 m2/s. The other aquifer system, already known and studied for a long time, belongs to the alluvial multilayered aquifer of Campidano. It is constituted by very permeable layers of sands and gravels alternated to impervious or semi confining silty clay layers. The Transmissivity of this aquifer results superior to 10-3 m2/sec. Pumping rates are at least 6-7 l/sec. Chemical analysis showed that some samples of water taken in the southern part of Sinis present some anomalous values and they show thermal waters typical characters. This fact is confirmed by the average temperatures around 23°C. It could be a ground water recharge by deep thermal waters, with which waters coming from Montiferru would be mixed

Estimation of biomass and carbon stocks: the case of the Atlantic Forest

The main objective of this paper is to present and discuss the best methods to estimate live above ground biomass in the Atlantic Forest. The methods presented and conclusions are the products of a workshop entitled "Estimation of Biomass and Carbon Stocks: the Case of Atlantic Rain Forest". Aboveground biomass (AGB) in tropical forests is mainly contained in trees. Tree biomass is a function of wood volume, obtained from the diameter and height, architecture and wood density (dry weight per unit volume of fresh wood). It can be quantified by the direct (destructive) or indirect method where the biomass quantification is estimated using mathematical models. The allometric model can be site specific when elaborated to a particular ecosystem or general that can be used in different sites. For the Atlantic Forest, despite the importance of it, there are only two direct measurements of tree biomass, resulting in allometric models specific for this ecosystem. To select one or other of the available models in the literature to estimate AGB it is necessary take into account what is the main question to be answered and the ease with which it is possible to measure the independent variables in the model. Models that present more accurate estimates should be preferred. However, more simple models (those with one independent variable, usually DBH) can be used when the focus is monitoring the variation in carbon storage through the time. Our observations in the Atlantic Forest suggest that pan-tropical relations proposed by Chave et al. (2005) can be confidently used to estimated tree biomass across biomes as long as tree diameter (DBH), height, and wood density are accounted for in the model. In Atlantic Forest, we recommend the quantification of biomass of lianas, bamboo, palms, tree ferns and epiphytes, which are an important component in this ecosystem. This paper is an outcome of the workshop entitled "Estimation of Biomass and Carbon Stocks: the Case of Atlantic Rain Forest", that was conducted at Ubatuba, São Paulo, Brazil, between 4 and 8 December 2006 as part of the Brazilian project "Ombrophylus Dense Forest floristic composition, structure and function at the Núcleos Picinguaba and Santa Virginia of the Serra do Mar State Park", BIOTA Gradiente