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In French mountain areas, the heterogeneity of forests, the fragmentation of ownership and accessibility constraints hamper inventory and management actions. To ensure the sustainability of ecosystem services provided by forests, it is necessary to evaluate them while taking into account the local and global socio-economic context. The PROTEST project aims to build a methodology for territorial analysis of forest resources, based on advances in remote sensing, GIS, forest dynamics modelling and territorial foresight. The study area of the project is the Geopark Massif des Bauges (France) that contains 50000 ha of forests. The first task is to produce a map of forest resources, based on airborne lidar remote sensing, and of its accessibility, based on the Sylvaccess model. The second task is to implement a territorial foresight work and define forest management scenarios that combine environmental and societal determinants. Societal factors and their possible evolutions will be defined on the basis of field surveys and expert opinions. Depending on these factors and on a typology of parcels, scenarios of forest management will be proposed to simulate the behavior of owners. In the third task, these scenarios will be integrated into a spatialized model of forest dynamics, in order to simulate the evolution of the forest mosaic at the parcel level. Linker functions will be integrated to evaluate ecosystem services (wood production, biodiversity, carbon stock...) from simulated forest characteristics. The results will be used to support participatory workshops that will aim to define a forest management strategy supporting the territorial development.

A survey of cable logging contracts was conducted in 5 of the 8 Alpine countries, namely: France, Germany, Italy, Slovenia and Switzerland. The goals of the survey were to set a general reference for cable logging rates, to identify eventual differences between countries and to determine the effect of technical work parameters (i.e. piece size, removal per hectare, line length) on actual contract rates. With a total sample size of 566 units, the mean removal and rate were 165 m3 ha-1 and 42.9 EUR m-3, respectively. Both removal per hectare and contract logging rates varied considerably and the study found significant differences between countries. Switzerland stood out from the group with the highest removal (345 m3 ha-1), but also the highest contract rate (79.5 EUR m-3). Removal per hectare was lowest in Italy with just 58.3 m3 ha-1, and logging rate lowest in Slovenia at 29.3 EUR m-3. Logging rates were highly correlated with the average labour rate of each country. Technical factors such as tree size, line length and tract size explained about 40% of the variability in logging rates. Therefore, 60% of the variability is explained by other technical factors not included in our data and by non-technical factors, such as local market dynamics.

National audience; Sustainable forest management requires a precise knowledge of the forest resource and existing infrastructure, to consider harvesting scenarios. LIDAR, a remote sensing technology, is used by many countries to model and map the forest resource . In France, forests are more heterogeneous (in species and structures). An area-based method has been adapted to calibrate empirical models relating dendrometric parameters measured in the field with metrics derived from LIDAR (thanks to a research program ANR-Foresee). The results show that it is possible to characterize forest resources in different forests: from plain with beech or pine regular forest to mountain covered by heterogeneous fir-spruce forests. The accuracy of LIDAR inventories is equivalent to that of traditional field methods. Moreover, LIDAR allows to achieve a continuous mapping of modeled variables, and calculations at different scales (plots, forest). If thousands of square kilometers have been mapped using LIDAR data, demonstrators are underway at ONF to evaluate the operational use of these innovative methods, before a possible implementation to large scales.

National audience; Le projet dynamique des grandes trouées en forêt de montagne (Alpes du Nord) a rétrospectivement reconstitué la cicatrisation d’ouvertures anciennes, d’origine naturelle ou sylvicole, pour les principaux types de peuplement des Alpes du Nord. Aux étages montagnard et haut montagnard, dans des contextes stationnels non contraignants, il faut 20 à 25 ans pour refermer une trouée sans régénération pré-existante. Le peuplement est alors dominé par les bas perchis (entre 5 et 10 cm de diamètre) qui atteignent une densité de l’ordre de 1000 à 1500 tiges.ha-1. A 30 ans, le peuplement est dominé par les haut perchis (entre 10 et 15 cm de diamètre) qui atteignent une densité de l’ordre de 600 à 800 tiges.ha-1. Au cours de ces 30 premières années, dans le secteur externe, les stades de développement les plus avancés (perchis) sont cependant essentiellement constitués d’essences pionnières (bouleau, saule,…) et de sorbier. Le remplacement par les essences résineuses (épicéa, sapin) se dessine dans les stades de développement moins avancés (régénération) et, vers 30 ans, la hauteur des essences résineuses rejoint voire dépasse celle des essences pionnières et du sorbier. La fermeture du couvert est beaucoup plus lente : •à l’étage subalpin. Si elle ne s’appuie pas sur une tâche de régénération pré-existante, il faut plus de 50 ans pour qu’une trouée se referme. La concurrence des essences pionnières est aussi très importante dans le secteur externe, •dans les contextes stationnels contraignants, en particulier sur sols secs superficiels où le GSM préconise de ne pas ouvrir de trouées (hêtraies-sapinières sèches, 5.3, sapinières-pessières peu humides, 6.4). Des observations similaires ont été faites dans des contextes très humides (mégaphorbiaies), en dehors de l’étude. •dans les trouées les plus grandes (de l’ordre d’une dizaine d’hectares), probablement en raison de l’éloignement des semenciers. Par contre, dans une gamme de taille de trouées s’étalant de 0,2 ha à 2 voire 3 ha, on ne note pas d’effet notable de la taille de la trouée sur la vitesse de fermeture du couvert. Les travaux du sol (crochetage en plein ou localisé) accélèrent considérablement la fermeture du couvert.