Gauthier Ligot

Gauthier Ligot
University of Liège | ulg · Gembloux Agro-Bio Tech

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About

49
Publications
13,580
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Introduction
My research focuses on monitoring and modelling the dynamics of mixed and irregular forest stands in both temperate and tropical forests. I also teach courses in Forest Biometrics and Forest Economics.
Additional affiliations
October 2014 - present
University of Liège
Position
  • Research Assistant

Publications

Publications (49)
Article
Full-text available
Initiated by the World Wildlife Fund (WWF) more than a decade ago in North Kivu, single-species plantations of Eucalyptus saligna and Grevillea robusta constitute, with other village plantations, the current legal source of wood-energy for the communities bordering the Virunga National Park (PNVi). This study assesses the growth and productivity of...
Article
Full-text available
La surface de la pessière wallonne a diminué de 30 % entre 1980 et 2010. L’exploitation d’un grand nombre de peuplements arrivés à maturité ces deux dernières décennies et un faible taux de replantation expliquent cette tendance. La crise des scolytes que nous avons connue ces dernières années, si elle a accentué la pression sur la ressource en épi...
Article
Tree growth and mortality are two central processes in mixed and structurally complex moist tropical forests, yet accurate estimates of the variables needed to model them remain sparse and scattered. It is thus still difficult to predict forest evolution at a local scale and build reliable management plans. To help fill this gap, for 1–7 years we a...
Article
• Key message The best options to parametrize a radiative transfer model change according to the response variable used for fitting. To predict transmitted radiation, the turbid medium approach performs much better than the porous envelop, especially when accounting for the intra-specific variations in leaf area density but crown shape has limited...
Article
Common allometric patterns have been reported across the tropics and good performance on independent data was retrieved for the most recent pantropical model predicting tree aboveground biomass (AGB) from stem diameter, wood density and total height. General models are undoubtedly useful for the estimation and monitoring of biomass and carbon stock...
Article
Full-text available
Forest health problems arising from climate change, pests and pathogens are a threat to the main timber tree species. As a result, silver birch (Betula pendula Roth) has become a precious asset for meeting oncoming forestry challenges in western Europe. However, silviculture guidelines to produce high-value birch logs in this region are lacking. Pr...
Article
Full-text available
Description of the subject. Pericopsis elata (Fabaceae) is a long-lived light-demanding tree from African rain forests that produces timber of high economic value. Natural populations suffer from overexploitation and a deficit of natural regeneration. Plantations could increase its production and limit the pressure on natural forests. However, we l...
Article
SIMREG is a non-deterministic tree-level distance independent forest model that can simulate forest growth, yield and management on a regional scale while representing the wide diversity of composition, structure and management found in forest stands. It is composed of several sub-models to represent the main forest dynamics (growth, recruitment, r...
Article
Full-text available
The recent identification of Douglas fir needle midge (Contarinia pseudotsugae Condrashoff) (Diptera: Cecidomyiidae; Genus Contarinia) in Western Europe represents a new and previously unrecognised threat to the Douglas fir resource in the United Kingdom and Ireland. This article provides an overview of Douglas fir needle midge, its morphology, eco...
Book
Full-text available
La durabilité de l’aménagement des forêts naturelles d’Afrique centrale est tributaire d’une connaissance approfondie de la dynamique démographique des populations d’arbres commerciaux. Cette dynamique est étudiée dans des dispositifs destinés à être suivis sur le long terme, dénommés parcelles et sentiers. Si la démarche méthodologique d’installat...
Article
Full-text available
Given the multiple abiotic and biotic stressors resulting from global changes, management systems and practices must be adapted in order to maintain and reinforce the resilience of forests. Among others, the transformation of monocultures into uneven-aged and mixed stands is an avenue to improve forest resilience. To explore the forest response to...
Article
Alors que les peuplements résineux wallons ont traditionnellement été gérés par coupe à blanc et plantations, de plus en plus de propriétaires forestiers se tournent aujourd’hui vers une gestion qui favorise le renouvellement naturel des peuplements tout en maintenant un couvert permanent. Une des clefs de voûte de cette gestion est la maîtrise du...
Article
Transforming even-aged coniferous stands into multi-aged ones is attracting growing interest in Europe. However, applying this silvicultural treatment, maintaining a continuous cover and relying on natural regeneration require a deep understanding of the factors driving interspecific competition in the understorey. In particular, knowledge of speci...
Article
Full-text available
Caractériser la dynamique d’une forêt est essentiel pour la gestion forestière. Les houppiers des arbres forment un élément clé de cette dynamique ; mais, en forêt tropicale, les mesurer n’est pas simple. Cette étude teste l’utilisation d’images aériennes à haute résolution pour estimer la croissance diamétrique des arbres, en intégrant des mesures...
Article
Tropical forests in Central Africa host unique biodiversity threatened by human degradation of habitats and defaunation. Forests allocated to conservation, production and community management are expected to have different conservation values. Here, we aimed to identify the determinants of the conservation value of tropical forests in southeastern...
Article
Full-text available
We present a recruitment model for pure and mixed beech and oak stands in Belgium, the first empirical model for this forest type in this geographical area. Data from the Wallonia National Forest Inventory were used to fit the model. We adopted a zero-inflated formulation where model parameters governing species’ behaviour were simultaneously fitte...
Article
Full-text available
Given the multiple abiotic and biotic stressors resulting from global changes, management systems and practices must be adapted in order to maintain and reinforce the resilience of forests. Among others, the transformation of monocultures into uneven-aged and mixed stands is an avenue to improve forest resilience. To explore the forest response to...
Article
Full-text available
In tropical Africa, evidence of widely distributed genera transcending biomes or habitat boundaries has been reported. The evolutionary processes that allowed these lineages to disperse and adapt into new environments are far from being resolved. To better understand these processes, we propose an integrated approach, based on the eco-physio-morpho...
Article
Full-text available
La connaissance du volume exploitable est une information essentielle tant pour la gestion que pour le contrôle de l’exploitation forestière. En Afrique centrale, l’estimation des volumes repose essentiellement sur l’utilisation de tarifs de cubage à une entrée, spécifique à chaque essence, et prédisant le volume exploitable à partir du diamètre de...
Article
Full-text available
Edited journal version available on request. The sustainability of the polycyclic logging system in tropical forests has been increasingly questioned for a variety of reasons, and particularly in central Africa as commercial species, mostly light-demanding long-lived pioneer species, usually fail to recover a stable number of large trees after exp...
Article
Full-text available
Aim Large tropical trees form the interface between ground and airborne observations, offering a unique opportunity to capture forest properties remotely and to investigate their variations on broad scales. However, despite rapid development of metrics to characterize the forest canopy from remotely sensed data, a gap remains between aerial and fie...
Article
Full-text available
Aim: Large tropical trees form the interface between ground and airborne observations, offering a unique opportunity to capture forest properties remotely and to investigate their variations on broad scales. However, despite rapid development of metrics to characterize the forest canopy from remotely sensed data, a gap remains between aerial and fi...
Article
Tropical forests play a key role in regulating the terrestrial carbon cycle and climate change by storing a large amount of carbon. Yet, there is considerable uncertainty about the amount and spatial variation of aboveground biomass (AGB), especially in the relatively less studied African tropical forests. In this study, we explore the local-scale...
Article
Full-text available
1.Architectural traits that determine the light captured in a given environment are an important aspect of the life‐history strategies of tropical tree species. In this study, we examined how interspecific variation in architectural traits is related to the functional traits of 45 coexisting tree species in central Africa. 2.At the tree level, we m...
Article
Full-text available
Aim: Large tropical trees form the interface between ground and airborne observations, offering a unique opportunity to capture forest properties remotely and to investigate their variations on broad scales. However, despite rapid development of metrics to characterize the forest canopy from remotely sensed data, a gap remains between aerial and fi...
Article
Full-text available
Although the importance of large trees regarding biodiversity and carbon stock in old‐growth forests is undeniable, their annual contribution to biomass production and carbon uptake remains poorly studied at the stand level. To clarify the role of large trees in biomass production, we used data of tree growth, mortality and recruitment monitored du...
Article
Full-text available
Mixed and multi-layered forest ecosystems are sometimes more productive than monospecific and single-layered ones. It has been suggested that trees of different species and sizes occupy complementary positions in space, which would act as a mechanism to increase canopy light interception and wood production. However, greater canopy light intercepti...
Article
Full-text available
In natural forests of Central Africa, several studies indicate a dramatic decrease in commercial trees, including species of concern for conservation. Enrichment planting with these species will favor both the long-term recovery of their populations and biodiversity conservation in logged forests. In this study, we analyzed the survival and growth...
Article
Full-text available
To develop silvicultural guidelines for high-value timber species of Central African moist forests, we assessed the performance of the pioneer Milicia excelsa (iroko, Moraceae), and of the non-pioneer light demander Pericopsis elata (assamela, Fabaceae) in logging gaps and in plantations in highly degraded areas in south-eastern Cameroon. The survi...
Article
Le traitement en futaie irrégulière et mélangée utilisant la régénération naturelle est de plus en plus encouragé. Pourtant, son application reste délicate notamment lorsqu’il est question de la gestion de l’éclairement pour contrôler la composition de la régénération. Afin d’apporter de nouveaux points de repères aux gestionnaires forestiers, nous...
Article
Establishing mixed species, uneven-aged forests by relying on natural regeneration is increasingly encouraged. Nonethless, it is difficult to achieve in practice particularly when it comes to controlling the composition of regeneration by managing exposure to light. With a view to providing forest managers with guidance, we tracked the growth of 27...
Thesis
Full-text available
Continuous-cover forestry has the goal of relying on natural regeneration, and maintaining irregular stand structure and tree species mixture. However, maintaining mixture of species with different shade tolerances appears arduous with such a silvicultural system. Successfully managing irregular and mixed forests, relying on natural processes, requ...
Article
Radiation is fundamental in forest ecosystem ecology as it drives plant photosynthesis, morphogenesis, and fluxes of carbon, water, and energy between soil, vegetation, and the atmosphere. Though all approaches of forest radiative transfer models (FRTM) share general properties, they differ greatly in terms of calibration parameters, required assum...
Article
Full-text available
Régénérer naturellement le chêne apparaît très délicat en Ardenne et cela se traduit déjà par un déficit marqué de jeunes chênes au niveau régional. Afin de rechercher des solutions sylvicoles à ce problème, vingt-sept régénérations naturelles de hêtre et de chêne ont été suivies entre 2007 et 2011. L’analyse montre clairement les besoins en lumièr...
Article
Full-text available
Les dégâts d'écorcement inquiètent de très nombreux gestionnaires forestiers. Depuis plus de 10 ans, des inventaires sont réalisés annuellement et des outils de diagnostic ont été développés afin d'en quantifier l'ampleur en Région wallonne. L'examen de ces données met en évidence le rôle prépondérant des densités de cerfs ainsi que de la structure...
Article
Full-text available
The mid-successional sessile oak (Quercus petraea (Matt.) Liebl.) and the late-successional European beech (Fagus sylvatica L.) are two major species of temperate forests. According to the literature, in mixed stands, large canopy openings should promote the growth of the light-demanding oak over the shade tolerant beech. Nevertheless, foresters wh...
Conference Paper
Full-text available
During recent decades, populations of large herbivores have increased. Consequently, their pressure on forest vegetation has been exacerbated and, in some forests, has reached levels that have reduced the diversity of forest ecosystem services. Assessing the balance between timber production and hunting remains a crucial question for forest users (...
Conference Paper
Full-text available
Canopy gaps are areas of high regeneration potential and, in uneven-aged forest, gaps are therefore places of particular care for the forest manager. Nevertheless the cartography and characterization of canopy gaps are complex issues. This paper addresses the fundamental question of the canopy gap definition: what is the minimal area, the maximal h...
Article
Full-text available
Using lying deadwood or coarse woody debris (CWD) as an indicator of biodiversity and of sustainable forest management is on the rise among national and local forest inventories. Nevertheless choosing the most suitable sampling method is difficult as it depends mostly on CWD abundance and dimensions. In addition the CWD volume estimates of differen...
Article
Full-text available
• Context Over the past few decades, the impact of large herbivorous ungulates on forest vegetation has been clearly highlighted. Among those impacts, bark stripping of coniferous trees is one of the most damaging. Bark stripping leads to rot development, inducing serious loss of timber value. • Aims The present study aimed firstly at evidencing th...
Article
Full-text available
During the last decade, management of woodlands in the Sudanian region of Benin has been based on enrichment with valuable tree-species. Yet, no previous research has been undertaken to support enrichment design with respect to plant eye view, tree growth magnitude or survival capacity under local forest environments. To fill in this gap, Ripley’s...
Data
Full-text available
Using lying deadwood or coarse woody debris (CWD) as an indicator of biodiversity and of sustainable forest management is on the rise among national and local forest inventories. Nevertheless choosing the most suitable sampling method is difficult as it depends mostly on CWD abundance and dimensions. In addition the CWD volume estimates of differen...
Article
Full-text available
Bark peeling by red deer (Cervus elaphus L.) has become a serious issue for productive forests in western Europe. The damage is particularly severe on species such as spruce, as these become vulnerable to fungus attacks that result in considerably depreciated timber. This article presents a monitoring setup for recent bark peeling damage in spruce...
Article
Full-text available
Au moment où nous prenons clairement conscience de leur importance au sein de la forêt ardennaise, les populations de chênes sont en diminution, concurrencées par le hêtre qui se régénère plus efficacement et qui est moins abrouti par les abondantes populations de cervidés. Pourtant, la valeur ajoutée des chênes en hêtraie ardennaise est évidente,...

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Projects

Projects (3)
Project
The CARE Forest is life aims to study forest ecosystems and, more generally, landscape structures with a low degree of anthropisation, whether in temperate or tropical regions.
Archived project
Project
Due to major human pressures, the Earth ecosystems have now entered into the Anthropocene era and the sixth mass extinction period. In this context, the concepts of biodiversity and ecosystem services (ES) have raised to objectify and measure the impacts of humans on ecosystems and their relationships. Among global terrestrial ecosystems, tropical forests are particularly important hosts of biodiversity and providers of ES. Many human pressures, such as agricultural conversion, logging, hunting, commercial poaching and over-harvesting lead to deforestation, forest degradation and defaunation. The consequences on tropical forests are highly variable, depending on many local contextual factors. In Central Africa in particular, biodiversity and ES have been far less studied than in other tropical regions, despite the vital roles of these tropical forests in the livelihoods of tens of millions of people. Despite high tree cover in forests across the region, management differs in such a way that conservation value and ES might also differ among forest allocations. Therefore, the objective of this thesis is to assess the conservation value of tropical forests in southeastern Cameroon, as well as the supply of ES and use by local populations, in three contrasted forest allocations: a protected area, a Forest Stewardship Council-certified logging concession, and three community forests. First, we assess the conservation value of the three forest allocations, examining species richness and composition of two taxonomic groups: mammals inventoried with 44 camera traps, and dung beetles inventoried with 72 pitfall traps (Chapter 2). We also aim to identify the determinants of forest conservation value, disentangling the effects of forest allocations, proximity to human settlements (villages and roads), and local forest habitat. Mammal and dung beetle species show lower species richness in the community forests than in the protected area, and intermediate values in the logging concession. Proximity to human settlements and disturbance is negatively correlated to species richness of both groups, negatively correlated with species body mass, and associated to the loss of the most threatened mammal species. A high replacement of species among forest allocations (i.e., spatial turnover) shows that conservation initiatives should integrate many sites, and not only large isolated areas. The high conservation value of the protected area is confirmed, and the logging concession can play a complementary role in conservation strategies through landscape connectivity. In contrast, community forests are particularly defaunated due to their proximity to roads and villages, but they still provide wild proteins to local populations. Second, we assess the perceptions of the supply of ES by tropical forests to local populations, and the determinants of these perceptions (Chapter 3). We have evaluated the significance and abundance of ES by conducting a questionnaire survey with 225 forest stakeholders. The most significant ES perceptions are provisioning services (93% of respondents) and cultural services (68%), while regulating services are much less reported (16%). The perceptions of ES abundance are relatively homogeneous among forest allocations and respondents. Bushmeat provision is identified as the only significant ES for local populations that is not supplied in sufficient abundance. Third, we depict the use of ES by local populations in three villages, as well as evaluating its determinants and sustainability (Chapter 4). We have used diverse interviews and field surveys to assess three provisioning services (bushmeat, firewood, and timber) and five cultural services (cultural heritage, inspiration, spiritual experience, recreation, and education). On average, local populations consume 56 kg of bushmeat person-1 year-1 (hunting zones covering between 40 and 307 km² per village), 1.17 m³ of firewood person-1 year-1 (collection zones between 3 to 6 km² per village), and 0.03 m³ of timber person-1 year-1. A proportion of 25% to 86% of respondents recognize the importance of cultural services. The main determinants of ES use are spatial variables (forest allocations, population size, and deforestation rate) and we also show slight differences between Baka and Bantu people in the use of cultural services. Firewood and timber are used sustainably in this area, whereas bushmeat hunting and consumption has exceeded sustainability thresholds. The conclusions of the thesis (Chapter 5) summarize the major findings, and give practical implications for tropical forest management and future research.