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Forest attributes such as volume or basal area are concentrated at tree locations and are absent elsewhere. It is, therefore, more meaningful to consider the amount of forest attributes at a prefixed spatial grain, within regular plots of prefixed size centered at the points of the study area. In this way, the diversity of attributes within plots also can be considered and quantified by suitable indexes, giving rise to a diversity surface defined on the continuum of points constituting the area. We analyze the estimation of diversity surfaces when a sample of plots is selected by a probabilistic sampling scheme and diversity within nonsampled plots is estimated using an inverse distance weighting interpolator. We discuss the design-based asymptotic properties of the resulting maps when the survey area remains fixed and the number of sampled points increases. Because diversity surfaces share suitable mathematical properties, if the schemes adopted to select sample points ensure an even coverage of the study areas avoiding large portions of non-sampled zones, it can be proven that the estimated maps approach the true maps. Key words: diversity maps, inverse distance weighting interpolator, design-based consistency, spatial simulation, case study. Les attributs de la foret comme le volume ou la surface terriere sont concentres a l'emplacement des arbres et sont absents ailleurs. Par consequent, il est plus significatif de considerer la quantite des attributs de la foret a une resolution spatiale predeterminee, dans des parcelles regulieres de taille predeterminee, centrees sur les points de la zone d'etude. De cette maniere, la diversite des attributs au sein des parcelles peut egalement etre prise en compte et quantifiee a l'aide d'indices appropries, donnant lieu a une surface de diversite definie sur le continuum de points constituant la superficie a l'etude. Nous analysons l'estimation des surfaces de diversite lorsqu'un echantillon de parcelles est selectionne au moyen d'un plan d'echantillonnage probabiliste et que la diversite au sein de parcelles non echantillonnees est estimee a l'aide d'un interpolateur pondere par l'inverse de la distance. Nous discutons des proprietes asymptotiques des cartes obtenues, qui resultent du plan d'experience, lorsque la zone d'inventaire demeure fixe et que le nombre de points echantillonnes augmente. Puisque les surfaces de diversite partagent des proprietes mathematiques appropriees, si les plans d'echantillonnage adoptes pour selectionner les points d'echantillonnage assurent une couverture uniforme des zones d'etude, en evitant de laisser de larges portions non echantillonnees, on peut demontrer que les cartes estimees se rapprochent des vraies cartes. [Traduit par la Redaction] Mots-cles : cartes de diversite, interpolateur pondere par l'inverse de la distance, coherence basee sur la conception du plan d'experience, simulation spatiale, etude de cas., Introduction Spatially explicit estimates are needed in many environmental and ecological applications for making maps: the increasing practical demand is for information on the spatial distribution of environmental and ecological [...]

Estimation and mapping of forest attributes are a fundamental support for forest management planning. This study describes a practical experimentation concerning the use of design-based k-Nearest Neighbors (k-NN) approach to estimate and map selected attributes in the framework of inventories at forest management level. The study area was the Chiarino forest within the Gran Sasso and Monti della Laga National Park (central Italy). Aboveground biomass and current annual increment of tree volume were selected as the attributes of interest for the test. Field data were acquired within 28 sample plots selected by stratified random sampling. Satellite data were acquired by a Landsat 5 TM multispectral image. Attributes from field surveys and Landsat image processing were coupled by k-NN to predict the attributes of interest for each pixel of the Landsat image. Achieved results demonstrate the effectiveness of the k-NN approach for statistical estimation, that is compatible with the produced forest attribute raster maps and also proves to be characterized, in the considered study case, by a precision double than that obtained by conventional inventory based on field sample plots only.

This work aims to assess the potential of segmentation and object oriented classification techniques of satellite images with medium spatial resolution, for land use/cover (Corine Land Cover, CLC) mapping. The tested procedures are assessed both in term of thematic accuracy and working time, with reference to a study area of about 4000 km2 in central Italy. The automatic procedure is carried out by segmentation of the pan-sharpened image and by subsequent classification using membership and standard nearest neighbour functions. Results are evaluated by sample circular photoplots taken from digital IT2000 orthophotos coverage. In terms of overall accuracy, object oriented classification achieves better results than conventional on screen interpretation. The classification shows difficulties for the identification of the "mixed" classes of CLC nomenclature system; however, even in these cases the object oriented techniques provide higher producer and user accuracy than on screen interpretation. On the whole, since they are able to produce more objective and more accurate cartographic products at similar costs, the application of the tested automatic techniques seems to be preferred to the conventional on screen interpretation for satellite images with medium spatial resolution.

The aim of this work is to test the potential of SPOT5 satellite images for monitoring coppice clearcuts. The clearcuts, delineated by on screen interpretation of the satellite images, are compared with the administrative statistics reported for a sample of 230 administrative units. Administrative statistics result significantly lower than those by satellite images, with an average ratio between clearcut area observed by SPOT5 images within each sample unit and the corresponding administrative statistics equal to 1.45. The underestimation by the administrative data is likely due to the simplified process of authorization of coppice clearcuts as well as the eventual lack of timeliness and/or loss of data that sometimes hinder the information flow from administrative bodies to National Forest Service, that is in charge of feeding the official forest statistics. In the light of the experimentation carried out, an operational procedure by SPOT5 images is proposed for the statistical calibration of administrative data about coppice clearcuts.

Converting beech coppices into high forest stands has been promoted in the last decades as a management goal to attenuate the negative effects that frequent clearcutting may have on soil, landscape, and biodiversity conservation. The silvicultural tool usually adopted is the gradual thinning of shoots during the long span of time required to complete the conversion, that also allows the owner to keep harvesting some wood. This research reports and discusses, in the light of the ecological intensification approach, the results achieved from an experimental test started more than 25 years ago in a 42-year-old beech (Fagus sylvatica L.) coppice with standards in central Italy. The effects of various thinning intensities (three treatments plus a control) on the stand growth and structure are assessed by successive forest inventories. Analyses are integrated by spatial indices to assess stem density and canopy cover. Converting beech coppices into high forest through gradual thinning of shoots proves to be an effective step down the road to silvicultural systems characterized by continuous forest cover, as a tool of ecological intensification suitable to guarantee both public and private interests. Thinning has led to stands with fewer but larger stems, thus accelerating the long conversion process while maintaining both wood harvesting capability and environmental services.