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Rosewood ( Aniba rosaeodora) essential oil is a valuable ingredient that has long been used in the perfume and cosmetic industries. The main rosewood timber quality parameters are its essential oil yield and quality. A hydrodistillation method has been developed for yield determination, but it is time consuming. Here we tested the applicability of near infrared (NIR) spectroscopy for determining essential oil yield directly from wood powder. Essential oil from 139 wood powders was extracted via hydrodistillation. The measurements were based on the ratio between the extracted essential oil mass and the oven-dried wood mass and were correlated with the wood powder NIR spectra. The calibration model statistical findings demonstrated that NIR could be a fast and feasible alternative method for selecting trees with a high essential oil yield potential. NIR-based predictions obtained in an independent validation set indicated a high correlation ( r2 = 0.92) with laboratory essential oil yield measurements. This NIR model could help wood managers in selecting trees with a high essential oil yield potential and in developing sustainable rosewood management strategies.

Land reform settlements (LRS) in the Brazilian Amazon have been suggested to hold promise for the successful implementation of incipient efforts to reducing emissions from deforestation and degradation (REDD). However, differences in forest cover, deforestation behaviour and settler welfare plus the inevitable overlap of upcoming REDD efforts with existing conservation policies, mean that scope and impact of REDD in LRS will not be uniform across settlements. Based on evidence from a case study of four LRS and a Brazilian Amazon regional analysis of opportunity costs, this paper explores the actual scope for targeting initial Brazilian REDD efforts to LRS and discusses potential welfare and equity implications based on scenario analysis. While our findings confirm considerable economic scope for compensation-based schemes for avoided degradation and deforestation, the pre-existence of legal use right limitations in combination with the distribution of forest cover among LRS means that less than half of settlements - poorer - will be able to derive economic gains. Exploring a mix between incentives and disincentives seems to offer the most promising future regarding efficiency and equity successful results. The paper concludes with the implications of the results in the international debate on the constraints ahead to implement the REDD principles.

Forest management policies in tropical countries have undergone a paradigm shift in the 1980s. International environmental policies have recommended redirecting natural resource management from state control to approaches giving responsibilities to local people. In Niger, forest cooperatives and firewood rural markets characterized the transition in forest policies toward the integration of rural people in forest management. Forest management principles have been progressively adapted to the social and ecological context, since the establishment of the first cooperatives in 1986. Changes in forest policies concerned two fronts: forest management governance and forest management technical instruments. In this paper, the impact of governance and technical instruments on forest management is studied in two types of firewood rural markets found in Niger. Both rural markets have been designed to bring about a governance shift in favour of rural people. In one type of rural market, rigorous technical instruments were added, consisting in a rotational system among several plots to be harvested in the forest. This paper shows that in the implementation of rural markets, the shift is mainly on governance of forest management, and not so much on technical instruments. The general management principles remain based on scientific knowledge and are not enforced by rural people. These principles have been shown to be inappropriate with regard to Sahelian people’s representation of space, but because they are scientific, they cannot be questioned. The study suggests that sustainable forest management will be better served by interesting rural people in the rural markets, and thereby promoting their appropriation of forest resources, than by defining rigorous technical rules.

Présentation de l'éditeur : The multiple-value nature of forests has long been appreciated and used by forest-dependent people in the tropics. Explicitly managing for some or all of these values, multiple-use forest management, is stipulated in the laws of many countries, but its formal implementation in the tropics is thought to be rare. This paper reports on three regional assessments carried out to identify and draw lessons from on-the-ground initiatives in multiple-use forest management in the Amazon Basin, the Congo Basin and Southeast Asia. In all three regions, information was collected through interviews with country-based forestry experts, forest managers and technicians. A complementary, Web-based questionnaire further examined the reasons for the successes and failures of multiple-use forest management initiatives. The paper concludes that forest managers need more support if they are to realize the potential of multiple-use forest management. Greater effort is needed to eliminate unfair competition from operators whose sole objective is to extract timber, with little or no concern for multiple uses. In most countries, the demarcation of a permanent forest estate and the development of national land-use plans would increase investment in multiple-use forest management. Improving the value of logged-over forest through silviculture would also increase the uptake of multiple-use approaches

The often-claimed environmental and social benefits of forest certification remain to be empirically evaluated. Despite numerous publications on the impacts of tropical forest certification, virtually all are based on secondary sources of information and not on field-based measurements. This paper proposes an empirical research framework for a carefully designed field-based evaluation of the ecological, social, economic, and political impacts of tropical forest management certification taking into account location-specific contextual factors which shape certification outcomes. The paper also suggests that solid methodological quantitative and qualitative approaches be used to build proper counterfactuals on which to base the comparisons for inferring impacts, all informed by a thorough theory-of-change and through processes that bring stakeholders together. The proposed research framework represents a first step towards the design and future implementation of evaluation research in the context of tropical forest certification on a global basis. It is hoped the research framework proposed contributes to learning from past mistakes, building on lessons learned and enhancing decision-making towards the maintenance of forest values over the long term, and for the benefit of society as a whole. (Resume d'auteur)

The mechanistic model GO+ describes the functioning and growth of managed forests based upon biophysical and biogeochemical processes. The biophysical and biogeochemical processes included are modelled using standard formulations of radiative transfer, convective heat exchange, evapotranspiration, photosynthesis, respiration, plant phenology, growth and mortality, biomass nutrient content, and soil carbon dynamics. The forest ecosystem is modelled as three layers, namely the tree overstorey, understorey and soil. The vegetation layers include stems, branches and foliage and are partitioned dynamically between sunlit and shaded fractions. The soil carbon submodel is an adaption of the Roth-C model to simulate the impact of forest operations. The model runs at an hourly time step. It represents a forest stand covering typically 1 ha and can be straightforwardly upscaled across gridded data at regional, country or continental levels. GO+ accounts for both the immediate and long-term impacts of forest operations on energy, water and carbon exchanges within the soil–vegetation–atmosphere continuum. It includes exhaustive and versatile descriptions of management operations (soil preparation, regeneration, vegetation control, selective thinning, clear-cutting, coppicing, etc.), thus permitting the effects of a wide variety of forest management strategies to be estimated: from close to nature to intensive. This paper examines the sensitivity of the model to its main parameters and estimates how errors in parameter values are propagated into the predicted values of its main output variables.The sensitivity analysis demonstrates an interaction between the sensitivity of variables, with the climate and soil hydraulic properties being dominant under dry conditions but the leaf biochemical properties being most influential with wet soil. The sensitivity profile of the model changes from short to long timescales due to the cumulative effects of the fluxes of carbon, energy and water on the stand growth and canopy structure. Apart from a few specific cases, the model simulations are close to the values of the observations of atmospheric exchanges, tree growth, and soil carbon and water stock changes monitored over Douglas fir, European beech and pine forests of different ages. We also illustrate the capacity of the GO+ model to simulate the provision of key ecosystem services, such as the long-term storage of carbon in biomass and soil under various management and climate scenarios.

International audience; To allow for the production of timber while preserving conservation values, forestry regulations in the Congo Basin have made Forest Management Plans (FMP) mandatory in logging concessions. This paper uses original high-resolution maps of forest-cover changes and official records on the activities of logging concessions to analyze the impact of FMP on deforestation in this region. We apply quasi-experimental and difference-indifference approaches to evaluate the change in deforestation in concessions managed under an approved FMP. We find that between 2000 and 2010, deforestation was 74% lower in concessions with an FMP compared to others. Building on a theory of change, further analyses revealed that this decrease in deforestation takes time to occur and is highest around communities located in and nearby logging concessions, and in areas close to previous deforestation. These findings suggest that FMP help avoid deforestation by allowing logging companies to rotate cycles of timber extraction, thereby avoiding the overexploitation of areas that were previously logged, and by the better regulation of access to concessions by closing former logging roads to limit illegal activities such as shifting agriculture, hunting and the illegal harvest of timber or fuel-wood.

After more than 20 years and substantial investments of time and money, Forest Stewardship Council (FSC) certification of tropical forest management is due for a stringent impact evaluation. For any social, ecological, and economic outcomes to be attributed to FSC certification, rival explanations need to be ruled out. We recognize that different types of knowledge about FSC impacts derived from information gathered through a range of methods can satisfy the evidence-needs of different stakeholders. But this paper describes a roadmap based on rigorous methods to assess whether FSC certification delivers on its expected outcomes and the underlying mechanisms through which changes can be attributable to FSC. To this end, background studies that provide contextual knowledge related to implementation of FSC certification are proposed to account for any positive self-selection biases and to capture the temporal dynamics of certification including changes in the sociopolitical and economic contexts that influence certification decisions. (Resume d'auteur)

In 2014 Decree 14/018 laying down the rules for granting forest concessions to local communities, followed by Ministerial Order 0/25 on the same issue was published in the DRC. This paper aims to analyse the abovementioned legislation with respect to participatory ma nagement of forests. The explicit recognition of the duality of a customary de facto local community forest and a modern legal entity (concession) is an innovation. However, viewed from the perspective of the long-established habits within the country, the question remains whethe r these legal measures can be sufficient for ensuring the sustainable development of these community-held forested areas. Allowing community concessions up to 50,000 ha demonstrated a shift in the government policy away from the industrial timber cultivation model. However, an ar ea this size is much larger than the communities can monitor, particularly in the case of artisanal charcoal or wood exploitation. (Resume d'auteur)

Malaysia has been endowed with a beautiful tropical forest which provides various ecosystem services such as carbon dioxide absorption, water supply and soil stabilization to the community. It is also a timber source for wood-based industries generating RM22 billion in 2016. However, there are illegal encroachment activities in the forests causing the forests to be degraded as well as conversion of land use to agriculture. The enforcement activities carried out by the authorities have resulted in the degraded areas being reclaimed and the forest areas are being restored with planting of local species with commercial value. To date many degraded forest areas have been restored using different approaches. This paper aims at presenting Malaysia's experiences and initiatives in forest restoration and rehabilitation of degraded forests. These activities have created opportunities to improve the forest ecosystem. There are also many challenges need to be addressed in order the forest restoration and rehabilitation to be successful. These challenges will also be discussed.

While attention to logging in the tropics has been increasing, studies on the long-term effects of silviculture on forest dynamics and ecology remain scare and spatially limited. Indeed, most of our knowledge on tropical forests arise from studies carried out in undisturbed tropical forests. This bias is problematic given that logged and disturbed tropical forests are covering now a larger area than the so-called primary forests. The Tropical managed Forests Observatory (TmFO), a new network of permanent sample plots in logged forests, aims to fill this gap by providing unprecedented opportunities to examine long-term data on the resilience of logged tropical forests at regional and global scales TmFO currently includes 24 experimental sites distributed across three tropical regions, with a total of 536 pem1anent plots and about 1200 ha of forest inventories. In this paper we will present the main results generated by the network on the impact of logging on Carbon and timber recovery, as well as biodiversity changes in the Amazon basin and South East Asia.

Community forest management (CFM) is considered an alternative way to protect forests while providing income for smallholders. Since the mid-1990s, the number of CFM projects has rapidly increased in the Brazilian Amazon, although most of them still face several difficulties. In this paper, we discuss the obstacles to the financial viability of CFM in this region and propose some ways to overcome them. Based on evidence from five case studies, we assess the extent to which sustainable forest management for commercial timber production contributes to smallholder income. We show that harvesting timber only provides a limited cash income to smallholders, even though forest covers 80% of their landholding. Market access to timber is very uncertain and smallholder communities often fail to make a profit from their timber. Minimum remunerative public prices and support for timber marketing are thus needed. Simpler and more flexible procedures are required to reduce the high transaction costs of obtaining a permit and increase smallholder involvement in legal forest management for commercial purposes. Finally, a better assessment of timber potential in smallholder forest reserves through systematic inventories would be useful to avoid arousing false expectations.

The Forest Stewardship Council (FSCJ label is one of t he most robust and widely accepted standards aimed at assessing long-term sustainable forest management worldwide. Through audits, accredited certification bodies assess the level or conformity of a company's performance against the standard to grant or not the certificate on behalf of the FSC. In this paper, we assess the scope auditors have to shape the implementation of the FSC standard in Brazil. Our work is based on the analysis of certification bodies· rules and of 250 full assessment and annual audit reports covering the period 2005-2017. including native and plantations reports. All reports were publicly available on FSC database. The analysis was completed with interviews with key informants. We show that most indicators of the Brazilian FSC standard leave no scope for interpretation. However, companies are certified and re-certified with a significant number of minor non-conformance with social, legal and environmental indicators. We conclude that some indicators are too broad and need to be clarified. Also, conformity with some indicators depends on actions from governments. The development of new national standards is an opportunity to limit the risks of interpretation of indicators. The updating of standards is also an opportunity to clarify the role of public policies in respect of specific indicators. States wishing to promote FSC certification could seize this opportunity to identify what improvements are needed in the functioning of their institutions and public policies.

Industrial forest concessions cover about 45 million hectares in Central Africa. This paper discusses the weaknesses of the current concession model and initiatives for helping it evolve; it then proposes a new type of concession, entitled 'Concessions 2.0', adapted to the future challenges presented by the overlapping among the rights and modes of the harvesting of multiple resources. This proposed model is based on four features: (i) mapping and recognition of the customary territories within and around the industrial concession, (ii) timber revenue sharing indexed on the extension of the customary territories and contractual management agreements within the communities, (iii) allowance of commercial exploitation of non-timber resources by entitled claimers under the supervision and/or in association with the concessionaire, and (iv) inclusive governance for the management of overlapping rights over the concession area. (Resume d'auteur)

Harvesting from common resources has been studied through experimental work in the laboratory and in the field. In this paper we report on a dynamic commons experiment, representing a forest, performed with different types of communities of resource users in Thailand and Colombia, as well as student participants. We find that all groups overharvest the resource in the first part of the experiment and that there is no statistical difference between the various types of groups. In the second part of the experiment, participants appropriate the common resource after one of three possible regulations is elected and implemented. There is less overharvesting after the rules are implemented, but there is a significant amount of rule breaking. The surprising finding is that Colombian villagers break the rules of the games more often than other groups, and even more so when they have more trust in members of the community. This observation can be explained by the distrust in externally proposed regulations due to the institutional and cultural context.

International audience; Government based Payments for Ecosystem Services (PES) have been criticized for not maximizing environmental effectiveness through appropriate targeting, while instead prioritizing social side-objectives. In Mexico, existing literature on how the Payments for Ecosystem Services-Hydrological program (PSA-H) has targeted deforestation and forest degradation shows that both the process of identifying the eligible areas and the choice of the selection criteria for enrolling forest parcels have been under the influence of competing agendas. In the present paper we study the influence of the PSA-H multi-level governance on the environmental effectiveness of the program-the degree to which forest at high risk of deforestation is enrolled-building from a "policyscape" framework. In particular, we combine governance analysis with two distinct applications of the policyscape framework: First, at national level we assess the functional overlap between the PSA-H and other environmental and rural programs with regard to the risk of deforestation. Second, at regional level in the states of Chiapas and Yucatan, we describe the changing policy agenda and the role of technical intermediaries in defining the temporal spatialization of the PSA-H eligible and enrolled areas with regard to key socioeconomic criteria. We find that, although at national level the PSA-H program has been described as coping with both social and environmental indicators thanks to successful adaptive management, our analysis show that PSA-H is mainly found in communities where deforestation risk is low and in combination with other environmental programs (protected areas and forest management programs). Such inertia is reinforced at regional level as a result of the eligible areas' characteristics and the behaviour of technical intermediaries, which seek to minimise transaction costs and sources of uncertainty. Our project-specific analysis shows the importance of integrating the gover-nance of a program in the policyscape framework as a way to better systematize complex interactions at different spatial and institutional scales between policies and landscape characteristics.

Reconciling conservation and livelihoods is a concern wherever forests are important in local people's lives. We plead for engaging these people in survey activities to clarify what is important to them, as a first step in conservation planning. This will help to address their priorities and gain their guidance and support for interventions. This paper presents the results of such a survey with the community of Kwerba in Mamberamo, a remote and little known part of Indonesian Papua. Views and priorities were explored through interviews, scoring exercises, community mapping and a field survey. Whereas small gardens provided most staple food, culture and livelihoods were linked to the forest. People scored primary forest highest for nearly all use categories. Primary forest was particularly highly valued as a source of construction materials, ornaments and rituals, and as a hunting place. We developed a list of the overall most important plants and animals. Many natural resources were used, but few were commercially exploited. The community had rules to control access to certain areas and resources. Taboos to restrict access to sacred places were also maintained. Our evaluation identified opportunities to achieve conservation outcomes jointly with the Kwerba people. In follow-up activities, the community presented local government with a land-use plan for their territory. The government recognized the value of our approach and requested training to implement it more widely in the region.

Certification schemes have played an increasing role in global environmental governance. The Forest Stewardship Council (FSC) is emblematic of these new forms of private environmental governance based on market values. Although there have been many studies on the impacts of FSC, this remains a controversial issue. Drawing on a critical review of the methodologies used to date to assess the impacts of forest certification schemes, this paper identifies three challenges that evaluation scholars have to address in order to assess the FSC scheme in terms of environmental effectiveness: developing a point of reference to which certification measures must be compared; extending and contextualising the scope of the evaluation; and analyzing all effective management measures that contribute to obtaining the environmental result observed before examining the specific role of certification.

International audience; The success of long-term sustainable management of natural resources depends on local people’s support. Assessing local people’s attitudes, taking into account their needs, and respecting their opinions should become a management priority. In India, in the last 20 years, community needs and aspirations in forest management were handled through Joint Forest Management with varying degrees of success. Recently, the Forest Rights Act (2006) was passed to recognize and vest forest rights in forest dwelling communities. This major policy development is still in implementation, but little is known about how this devolution process will affect people’s attitudes toward forests. In this paper, we analyze associations between attitudes toward state controlled forests (Reserved Forests) and (i) awareness about the Forest Right Act, (ii) attitudes toward the State Forest Department, and (iii) participation in forest management groups of mostly tribal forest dwellers in the district of Kodagu (Karnataka). We collected information with a structured questionnaire among 247 villagers living under three different land tenure and management regimes: (1) private coffee plantations, (2) Reserved Forest, and (3) National Park. The results of the multivariate analyses show that people are more likely to appreciate Reserved Forests if they have more knowledge about the Forest Rights Act and if they have positive attitudes toward the State Forest Department. A sobering result in our sample is that participation in formal forest management groups is negatively associated to attitudes toward Reserved Forests, suggesting the Joint Forest Management model doesn’t necessarily help the transition from coercion to consent. Increasing local people awareness about their rights and improving their relations with the formal forest stewards remain priorities for sustainable forest management to emerge in India.

Le changement climatique est un enjeu croissant pour la société. Pour affronter cet enjeu, des instruments innovants en matière de Politique Publique (PP) sont nécessaires mais émergent difficilement dans les sociétés. Le Programme de Paiement pour Service Environnementaux (PPSE), adopté dès 1996 au Costa Rica, constitue une innovation singulière en termes de d'instrument PP pour lutter contre déforestation. Cette communication analyse les conditions qui ont permises l'adoption rapide et de l'évolution de cette politique. Mobilisant un cadre d'analyse cognitif des PP sur la longue durée, nous montrons que 1) le PPSE constitue un changement cognitif de la vision de la foret, 2) son adoption correspond à un changement des coalitions de cause dominantes dans le système politiques de gestion des espaces ruraux forestiers, 3) que ce changement est induit par une redistribution des ressources résultantes de modifications des variables externes et internes au système. Cette analyse permet de discuter les hypothèses de changement des PP énoncés dans le cadre de l'ACF et de mettre en perspective les évolutions récentes du PPSE à l'aune des processus d'apprentissage et d'évolution des coalitions de cause.

The Brazilian Amazon is one of the world’s largest tropical forests. It supplies more than 80 % of Brazil’s timber production and makes this nation the second largest producer of tropical wood. The forestry sector is of major importance in terms of economic production and employment creation. However, the Brazilian Amazon is also known for its high deforestation rate and for its rather unsustainably managed timber resources, a fact which puts in the balance the long-term future of the forestry sector in the region. Since the mid- 1990s, with strong support from World Wildlife Fund (WWF), the number of tropical forests certified by the Forest Stewardship Council (FSC) has significantly increased. This is especially true for projects sponsored by large scale companies. The number of community- based forest management projects has also increased. Certification of community-based forest enterprises (CFEs) was initially a goal for the sponsors and community members. Certification is viewed as a way to reach alternative timber markets. In Brazil, the state of Acre has the highest concentration of CFEs certified by FSC. Most of them have been implemented with the support of environmental NGOs and public funds. Environmental NGOs strongly defend the advantages of certification for communities; however, in reality, this option is not that advantageous. Despite all the efforts, the number of participants in each project remains low. Why is this occurring? In this paper, we analyze the underlying motives of a few individual’s participation in CFEs certification projects. We aim to present and discuss some factors that shape the success of CFEs and their later certification. The results are based on surveys conducted in two certified CFEs in the state of Acre., L’Amazonie Brésilienne, l’un des plus grands massifs forestiers mondiaux, est à l’origine de 80 % de la production de bois du Brésil. Les taux de déforestation élevés (malgré un certain ralentissement ces dernières années) et le rythme d’exploitation peu durable des ressources remettent en cause la pérennité du secteur forestier dans la région. Depuis le début des années 1990, avec le soutien du WWF, le nombre d’entreprises forestières certifiées par le FSC (Forest Stewardship Council) a considérablement augmenté dans le domaine privé. C’est aussi le cas, mais dans une très moindre mesure, de l’exploitation forestière communautaire, en particulier dans l’Etat de l’Acre. Les ONGs défendent de manière générale les multiples avantages de ce type de certification pour les communautés vivant en Amazonie. Pourtant, en dépit des multiples incitations financées à fonds perdus, le taux d’adhésion des communautés locales reste faible. Cet article analyse les facteurs responsables de la faible participation des populations aux projets de certification de l’exploitation communautaire des forêts. L’analyse est basée sur des enquêtes de terrains menées au sein de deux communautés forestières de l’Etat de l’Acre certifiées par le FSC.

International audience; Rural people in developing countries including India continue to access a number of types of 'forests' to meet specific needs such as fuelwood, fodder, food, non-timber forest produce and timber for both subsistence and income generation. While a plethora of terms exist to describe the types of forests that rural people use—such as farm forests, social forests, community forests and small-scale for-ests—the expression domestic forest has recently been proposed. Domestic forest is a term aimed at capturing the diversity of forests transformed and managed by rural communities and a way to introduce a new scientific domain that recognises that production and conservation can be reconciled and that local communities can be effective managers. This paper argues in the context of the central Western Ghats of south India that while the domestic forest concept is a useful umbrella term to capture the diversity of forests used by rural people, these domestic forests are often not autonomous local forests but sites of contestation between local actors and the state forest bureaucracy. Hence, a paradigm shift within the forest bureaucracy will only occur if the scientific forestry community questions its own normative views on forest management and sees forest policy as a means to recognise local claims and support existing practices of forest dependent communities.

International audience; The relationship between tropical forests and global climate change has so far focused on mitigation, while much less emphasis has been placed on how management activities may help forest ecosystems adapt to this change. This paper discusses how tropical forestry practices can contribute to maintaining or enhancing the adaptive capacity of natural and planted forests to global climate change and considers challenges and opportunities for the integration of tropical forest management in broader climate change adaptation. In addition to the use of reduced impact logging to maintain ecosystem integrity, other approaches may be needed, such as fire prevention and management, as well as specific silvicultural options aimed at facilitating genetic adaptation. In the case of planted forests, the normally higher intensity of management (with respect to natural forest) offers additional opportunities for implementing adaptation measures, at both industrial and smallholder levels. Although the integration in forest management of measures aimed at enhancing adaptation to climate change may not involve substantial additional effort with respect to current practice, little action appears to have been taken to date. Tropical foresters and forest-dependent communities appear not to appreciate the risks posed by climate change and, for those who are aware of them, practical guidance on how to respond is largely non-existent. The extent to which forestry research and national policies will promote and adopt management practices in order to assist production forests adapt to climate change is currently uncertain. Mainstreaming adaptation into national development and planning programs may represent an initial step towards the incorporation of climate change considerations into tropical forestry.

Co-management of forest resources is a process of governance that enables all relevant stakeholders to participate in the decision-making processes. Illegal logging and forest degradation are currently increasing, and logging bans are ineffective in reducing forest degradation. At the same time interest in forest plantations and concern about poverty problems of neighboring people whose livelihoods depend on forest services and products continue to increase rapidly. Governments have identified the development of small forest plantations as an opportunity to provide wood supplies to forest industries and to reduce poverty. However, the development of small plantations is very slow due to an imbalance of power and suspicion between communities and large companies. This paper proposes a framework for linking social, economic and biophysical dynamics to create multi-agent simulations and explore scenarios of collaboration for plantations. Multi-agent simulation is a branch of artificial intelligence that offers a promising approach to dealing with multi-stakeholder management systems, such as common pool resources. It provides a framework which allows analysis of stakeholders' (or agents') interactions and decision making. Each stakeholder has explicit communication capacities, behaviors and rationales from which emerge specific actions. The purpose of this modeling is to create a common dynamic representation to facilitate negotiations for growing trees. A system of governance involving multi-stakeholders, especially local communities and wood based industries appearing to offer the most promising pathway to accelerating plantation development, local community poverty alleviation and forest landscape improvement. © 2005 Elsevier Ltd. All rights reserved.

National audience; In order to predict the evolution of forest stands, and thus to facilitate forest management, researchers have developed different types of models of stand dynamics. In this paper, we illustrate the interest of such models as management tools. We consider three applications : (i) in a pure, even-aged oak stand, the use of a model in order to take into account the effect of productivity changes on growth ; (ii) in mixed, uneven-aged stands of spruce and fir, the comparison through simulation of a classical thinning to a thinning with openings ; (iii) in large-scale areas, the modelling of the dynamics of species composition of mixed stands. We finally discuss the limitations of models and future perspectives for research in this field.; Pour prédire l'évolution des peuplements forestiers, et ainsi faciliter l'aménagement, les chercheurs ont mis au point différents types de modèles de dynamique forestière. Dans cet article, nous illustrons l'intérêt de ces modèles comme outils pour la gestion. Nous présentons 3 applications : (i) dans un peuplement régulier de chênes, l'utilisation d'un modèle pour prendre en compte l'effet d'un changement de productivité sur la croissance ; (ii) dans un peuplement mélangé irrégulier épicéas - sapins, la comparaison par simulation d'un scénario sylvicole classique et d'un scénario d'éclaircies par trouées ; (iii) à l'échelle d'un massif forestier, la modélisation de l'évolution de la composition de peuplements mélangés. Nous discutons ensuite des limites des modèles ainsi que des perspectives de recherche.

The recent development of individual based and spatially explicit models raises the question of how to simulate relevant initial states for these models, and more particularly how to simulate realistic spatial structures. This is especially true for forest stand modelling.In this paper, we first review briefly the main simple steps in the simulation of forest stands with realistic spatial structure : (i) spatial structure analysis and ecological interpretation, (ii) expert simulation through classical point processes and ad hoc values of the parameters, and (iii) precise fitting of a spatial structure model using L(r) and L12(r) functions as criterion. We illustrate the advantages and limits of these steps on a real forest stand in mixed Oak - Scots pine forest near Orléans (France).We then propose a specific method - a mimetic point process - in order to simulate spatial structures similar to real patterns. This point process is based on a generalised Gibbs process, whose global cost function directly depends on the difference between the real measured values of L(r) and L12(r) functions, and the corresponding values computed on the simulated pattern at each iteration of the algorithm. We applied this method on a mixed Oak - Scots pine forest stand, and thus obtained an improved simulated pattern, that can be used as initial state for individual based forest growth models.We finally discuss the limits of this method, and its possible, Le développement récent des modèles individus-centrés spatialement explicites pose de nouvelles questions sur les méthodes de simulation des états initiaux de ces modèles, et plus particulièrement : comment simuler des structure spatiales réalistes. C'est tout particulièrement vrai pour les modèles forestiers. Dans cet article, nous proposons tout d'abord une revue bibliographique des principales méthodes de simulation de peuplements forestiers : (i) l'analyse et l'interprétation écologique de la structure spatiale, (ii) la simulation par expertise, et (iii) l'ajustement de modèles de structure spatiale en utilisant les fonctions L(r) et L12(r) comme critère d'ajustement. Nous illustrons les avantages et les limites de ces méthodes sur un dispositif expérimental en forêt mélangée Chêne - Pin sylvestre dans la forêt d'Orléans.Nous proposons ensuite une méthode spécifique - un processus mimétique - pour simuler des structures spatiales similaires à des structures réelles. Ce processus est basé sur un processus de Gibbs généralisé dont la fonction de coût total dépend directement de la distance entre les valeurs réelles des fonctions L(r) et L12(r) et les valeurs simulées à chaque itération de l'algorithme. Nous avons appliqué cette méthode sur un peuplement mélangé Chêne - Pin sylvestre, et avons obtenu un peuplement simulé plus réaliste, qui peut être utilisé comme état initial pour un modèle forestier individus-centré.Nous discutons enfin des limites de cette méthode, et de son intérêt pour faciliter le transfert des modèles vers les gestionnaires forestiers.