[1] The Top Hat Transform function is a grey-level image analysis tool that allows extracting peaks and valleys in a nonuniform background. This function can be applied onto a greylevel Digital Elevation Model (DEM). It is herein applied to quantify the volume of recent incised material in a mountainous Pyrenean watershed. Grey-level Closing operation applied to the Present-Day DEM gives a new image called ''paleo'' DEM. The Black Top Hat function consists in the subtraction of the ''paleo'' DEM with the Present-Day DEM. It gives a new DEM representing all valleys whose sizes range between the size of the structuring element and the null value as no threshold is used. The calculation of the incised volume is directly derived from the subtraction between the two DEM's. The geological significance of the quantitative results is discussed.

Agroforestry systems are fundamental features of the rural landscape of the Indian state of Kerala. Yet these mixed species systems are increasingly being replaced by monocultures. This paper explores how public policies on land tenure, agriculture, forestry and tree growing on private lands have interacted with farmer preferences in shaping land use dynamics and agroforestry practices. It argues that not only is there no specific policy for agroforestry in Kerala, but also that the existing sectoral policies of land tenure, agriculture, and forestry contributed to promoting plantation crops, even among marginal farmers. Forest policies, which impose restrictions on timber extraction from farmers' fields under the garb of protecting natural forests, have often acted as a disincentive to maintaining tree-based mixed production systems on farmlands. The paper argues that public policies interact with farmers' preferences in determining land use practices.