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This paper describes the detennination of sheet erosion rates by using dendrogeomorphological methods on exposed tree roots, Two sites on the northern slope of the Guadarrama Mountains, Central Spain, were studied: a popular trail in a Scots pine forest (Senda Schmidt, Valsain) growing on granites and gneisses, and an open holm-oak forest on granitic slopes (Monterrubio), These sites were selected because they showed high denudation morphologies due to accelerated soil-erosion processes caused by human influence (trampling by continuous trekking and overgrazing), resulting in exposed roots, The method applied is based on the morphological pattern of roots, defined by the growth-ring series of the sampled roots, In order to confinn the validity of the criteria used and to make the estimations of erosion more accurate, several anatomical indicators of exposed and non exposed Pin us sylvestris roots were characterized, The study entailed a statistical analysis of exposure time and erosion depth. The influence of environmental factors affecting the variation in velocity of the erosion processes was also examined. With a significance level of 95%, the mean erosion rates were in the range of 1.7 2.6 mm/year (29 44 Mw/year) on Senda Sclnnidt over the last 101 years, and 1.1 1.8 mm/year (19 31 t/halyear) in Monterrubio over the last 42 years. Using a multifactor analysis of variance, we observed a change in the erosion rates as a fimction of position on the path along Senda Schmidt. In Monterrubio, however, we reached no significant conclusions, apart from an inverse relationship between erosion and slope gradient that was difficult to interpret.Climate conditions in Senda Sclnnidt and the accuracy of dating Scots pine indicate that the evaluation on P sylvestris roots is fairly reliable, which is not the case for oak roots. Although this paper is based on the application of an existing method, its novelty lies in being the first attempt in Spain to estimate 'accelerated' sheet erosion rates (due to recreational activities and overgrazing) using dendrogeomorphological techniques, supplemented by anatomical indicators for P sylvestris.

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Landform-based physiographic maps, also called land systems inventories, have been widely and successfully used in undeveloped/rural areas in several locations, such as Australia, the western United States, Canada, and the British ex-colonies. This paper presents a case study of their application in a developed semi-urban/suburban area (Segovia, Spain) for land use planning purposes. The paper focuses in the information transfer process, showing how land use decision-makers, such as governments, planners, town managers, etc., can use the information developed from these maps to assist them. The paper also addresses several issues important to the development and use of this information, such as the goals of modern physiography, the types of landform-based mapping products, the problem of data management in developed areas, and the distinctions among data, interpretations, and decisions.