The paper presents a wheelslip measurement method for small farm tractors (AGT835 T) adapted for skidding, with mechanical and hydrostatic mechanical transmissions. The research focused on uphill skidding, as slip values measured in uphill skidding are higher than in downhill skidding. A comparisonwas made of the performance of tractors carrying equal load but equipped with mechanical and hydrostatic transmission systems. The hydrostaticdrive causes higher negative load values in downhill skidding, and slightly higher slippage.

In this paper we investigate the potential production and implications of a global biofuels industry. We develop alternative approaches to consistently introduce land as an economic factor input and in physical terms into a computable general equilibrium framework. The approach allows us to parameterize biomass production consistent with agro-engineering information on yields and a "second generation" cellulosic biomass conversion technology.

An accurate estimate of carbon fluxes associated with tropical deforestation from the last two decades is needed to balance the global carbon budget. Several studies have already estimated carbon emissions from tropical deforestation, but the estimates vary greatly and are difficult to compare due to differences in data sources, assumptions, and methodologies. In this paper, we review the different estimates and datasets, and the various challenges associated with comparing them and with accurately estimating carbon emissions from deforestation.

As data sets of multiple types and scales proliferate, it will be increasingly important to be able to flexibly combine them in ways that retain relevant information. A case in point is Amazonia, a large, data-poor region where most whole-basin data sets are limited to understanding land cover interpreted through a variety of remote sensing techniques and sensors. A growing body of work, however, indicates that the future state of much of Amazonia depends on the land use to which converted areas are put, but land use in the tropics is difficult to assess from remotely sensed data alone.

China has long been experiencing intense land use/cover changes (LUCC). Undesirable land use/cover changes have resulted in widespread land degradation. This study examines the temporal and spatial dynamics of land use change and land degradation as evident from land use survey datasets (1991-2001). Six prominent land degradation processes were identified, namely: desertification, secondary salinisation, loss of agricultural use, deforestation, grassland degradation and loss of wetland. Rates of conversion were calculated and distribution patterns were mapped with the aid of GIS.