Alain Cabanettes

Beneficial Effects of Intercropping on the Growth and Nitrogen Status of Young Wild Cherry and Hybrid Walnut Trees

Growing concern for economic and environmental issues emphasizes the potential value of intercropping systems in temperate regions. However, the selection of relevant tree species to be associated with crops has been little documented. The growth and the nitrogen nutrition of two economically valuable species, wild cherry (Prunus avium L.) and hybrid walnut (Juglans nigra L.×Juglans regia L.), were compared over six years after plantation. These two species were associated with non-irrigated cereal crops in the agroforestry treatment or grown separately (weeded control and fallow). Intercropping increased diameter growth as soon as year 2 in the two species. Leaf biomass assessment using allometric models showed an earlier and greater leaf biomass increase in hybrid walnut than in wild cherry tree. After six years, the relative growth increase of the agroforestry trees with respect to the control trees varied with the parameter considered (diameter at breast height from +26 to +65%, leaf biomass from +54 to +142%) and with the tree species (higher relative growth for hybrid walnut trees). The beneficial effect on tree growth can be accounted for in terms of enhanced nitrogen nutrition. The tree–crop association in intercropping systems, which improves tree growth, might thus allow the planting of more demanding trees on soils of lower fertility.

How to maintain domesticity of usages in small rural forests? Lessons from forest management continuity through a french case study

The management of small private forests in the Western World has been under threat owing to rural and agricultural transformations since the Second World War. The actions put in place to preserve those forests are hard to implement because the forests are managed essentially in an unofficial way that is not clearly understood. Through multidisciplinary approaches, our aims were to understand local forest management processes, to assess the continuities and discontinuities of usages and practices in the Coteaux de Gascogne area of France, and to propose guidelines for future forest management. Forest management is shaped by a traditional but unrecognized social system called the house-centered system, which has contributed to a high degree of domesticity and diversity in forestry practices in this area. If forest management guidelines are to be effective, any guidelines put in place should take into account the roots of the traditional management system and attempt to comply with local social organizations. This is a major challenge regarding the long-term preservation of small private forests.

How to Set Up a Research Framework to Analyze Social-Ecological Interactive Processes in a Rural Landscape

Interdisciplinary research frameworks can be useful in providing answers to the environmental challenges facing rural environments, but concrete implementation of them remains empirical and requires better control. We present our practical experience of an interdisciplinary research project dealing with non-industrial private forestry in rural landscapes. The theoretical background, management, and methodological aspects, as well as results of the project, are presented in order to identify practical key factors that may influence its outcomes. Landscape ecology plays a central role in organizing the project. The efforts allocated for communication between scientists from different disciplines must be clearly stated in order to earn reciprocal trust. Sharing the same nested sampling areas, common approaches, and analytical tools (GIS) is important, but has to be balanced by autonomy for actual implementation of field work and data analysis in a modular and evolving framework. Data sets are at the heart of the collaboration and GIS is necessary to ensure their long-term management and sharing. The experience acquired from practical development of such projects should be shared more often in networks of teams to compare their behavior and identify common rules of functioning.

Modelling the probability of microhabitat formation on trees using cross‐sectional data

The rate of TreM formation per unit diameter growth was modelled as a function of tree diameter at breast height (DBH), and the model was calibrated considering cross-sectional observations TreMs on trees of different sizes. The model predicted realistic TreM formation rates at the tree and stand levels in forests dominated by Abies alba and Fagus sylvatica. This approach opens new perspectives to the analysis of forest biodiversity conservation strategies.

Diversity of woody plant seedling banks under closed canopy in fragmented coppice forests

Abstract• Seedling banks of woody species established under closed canopy have received little consideration in coppice forests despite their potential importance for natural regeneration.• This study aimed to evaluate the influences of canopy composition and of distance from the nearest forest edge on the abundance and species richness of the seedling bank, for different ecological groups of seedlings (age, successional status and dispersal vector) in 68 fragmented coppice stands.• Seedlings were found in 67 stands, with 19 species identified. Eight species present as older seedlings were lacking as first-year old seedlings, suggesting temporal variability of species recruitment. Seedling abundances of species with low-dispersal ability were positively correlated with the abundances of their conspecific adults. Seedling abundance of mid-successional species was negatively correlated with the distance from the nearest forest edge, while mid-to-late successional species seedling abundance presented the opposite pattern.• Our results showed that woody species were able to establish frequently under closed canopy in these fragmented coppices and form a seedling bank which may be used for natural regeneration.Résumé• Peu d’études ont porté sur les banques de semis de ligneux installés sous canopée fermée dans des taillis, malgré leur importance potentielle pour la régénération naturelle.• Nous avons exploré le lien entre l’abondance et la richesse des semis de ligneux, et la composition de la canopée et la distance à la lisière la plus proche, dans 68 peuplements gérés en taillis. Les semis ont été regroupés en fonction de leur âge, et les espèces en fonction de leur mode de dispersion et de leur place a priori dans la succession forestière.• Nous avons trouvé des semis dans 67 peuplements, appartenant à 19 espèces distinctes. Huit espèces présentes sous forme de semis plus âgés, manquent sous forme de semis de l’année, suggérant une variabilité temporelle du recrutement des espèces. L’abondance des semis des espèces à dispersion limitée est corrélée à celle des adultes. L’abondance des semis des espèces post-pionnières nomades, capable de s’installer en pleine lumière, est négativement corrélée à la distance à la lisière, tandis que celle des semis des espèces post-pionnières, plus sciaphiles présente le patron opposé.• Nos résultats indiquent que plusieurs espèces de plantes ligneuses sont capables de s’établir fréquemment sous canopée fermée dans ces taillis fragmentés, formant ainsi une banque de semis potentiellement utilisable pour la régénération naturelle de ces forêts.

Quelle diversité des moyens de gestion des forêts privées familiales de France

Ce travail s’interesse aux proprietes forestieres privees familiales de France metropolitaine dans lesquelles le proprietaire, personne physique individu ou couple autoconsommateur de bois de feu, s’investit sans que cela soit son activite principale. Nous etudions les parametres d’acces aux divers moyens de gestion forestiere a la disposition des proprietaires forestiers prives familiaux. La structure des donnees est pour cela precisee a partir des proximites statistiques entre caracteristiques de la propriete forestiere, caracteristiques socioeconomiques des proprietaires, gestion de la foret, vente des bois et choix gestionnaires etudies. Deux groupes principaux de proprietaires sont soulignes selon leurs moyens de gestion. La distribution de ces deux groupes dans les regions de la metropole est egalement explicitee. Ces elements permettent de preciser des pistes regionalisees pour perenniser et developper la gestion des proprietes forestieres privees familiales, accroitre la recolte de bois et plus globalement une offre de services ecosystemiques de facon ciblee.

Liens entre nature juridique et moyens de gestion des propriétaires forestiers privés français

La forêt privée et ses propriétaires d’Europe ou du continent américain ont été l’objet de plusieurs recherches : Kuuluvainen et al. (1996), Slee et Wiermsum (2001), Hugesson et Ingemarson (2004), Butler et Leatherberry (2004), Rauch (2006), Urquhart et Courtney (2011), Ficko et Boncina (2013), Garcia et al. (2013), Pöllumäe et al. (2014), Petucco et al. (2015), European Forest Institute (2015), Deuffic et al. (2015), Le Jeannic et al. (2015) notamment.

Faut-il s’intéresser à la petite et moyenne forêt privée française ?

Given the extent of French forests and of the wood-processing industries in France, management of the interfaces between society, forest and industry is all-important. The management of these interfaces and the difficulties involved are first described. A new management plan for these interfaces devised by the French government is then presented. The draft for regulating the forest-based economy looks at the economic relationships between forestry, industry and government players. This plan would imply vigorous state intervention at the primary wood processing stage aimed at modernisation, sustainability through diversification, integration with secondary manufacturing as well as broadening sources of timber supply. It would strive to diversify and intensify the channels for selling wood to the wood products industry. This aggressive economic interventionism might however be carried out without previously or concomitantly setting up the specific conditions that enable small and medium-sized forested properties of less than 25 ha to develop, unless a separate scheme for regulating the development of private forests is also established.