Jean-Christophe Hervé

Jean-Christophe Hervé
Institut national de l’information géographique et forestière | IGN · laboratoire inventaire forestier

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80
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Publications

Publications (80)
Data
This data set provides the basic wood density values for 156 tree species obtained from 110605 increment cores (one core per tree) sampled during four consecutive years (2016-2019) by the French NFI within the XyloDensMap project (Leban et al., 2016, 2020). Two different types of increment cores were sampled. • The AGE cores (from the bark to the p...
Article
Wood resources have been essential for human welfare throughout history. Also nowadays, the volume of growing stock (GS) is considered one of the most important forest attributes monitored by National Forest Inventories (NFIs) to inform policy decisions and forest management planning. The origins of forest inventories closely relate to times of ear...
Preprint
Full-text available
(soumis à Forêt Méditerranéenne) Moving from a forest standing tree volume assessment to a biomass assessment requires knowledge of the basic density of wood which, beyond average values by species or group of species, varies greatly within and between species, environmental conditions, and the structural and management properties of the stands. Ba...
Data
The dataset should be cited as follow Leban, J.M., Kerfriden, B., Jacquin, P., Lacarin, M., Taupin, A., Mola, C., Duprez, C., Chabot S., Dauffy, V., Morneau F., Wurpillot, S., Hervé, J. C., 2020. “Wood basic density for 125 tree forest species from the French forests”, https://doi.org/10.15454/XFOPL1. --------------- --------------- ---------------...
Article
Le passage d’une évaluation en volume à une évaluation en biomasse nécessite la connaissance de la masse volumique du bois qui, au-delà de valeurs moyennes par essence ou groupe d’essences, varie beaucoup selon les espèces, les conditions de milieu, et les propriétés de structure et de gestion des peuplements. Se basant sur une innovation de ruptur...
Preprint
The forest transition – or forest-area transition – has been put forward as a land-use concept by A.S. Mather in 1992 (The forest transition. Area 24, 367-379), to describe the historical trend generally observed in the forest area of developed countries, embodied in a V-shaped curve of the forest area over time, and that may serve as a paradigm to...
Article
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Key message French forests exhibit the fastest relative changes across Europe. Growing stock increases faster than area, and is greatest in low-stocked private broadleaved forests. Past areal increases and current GS levels show positive effects on GS expansion, with GS increases hence expected to persist. ContextStrong increases in growing stocks...
Article
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Tree growing conditions are changing rapidly in the face of climate change. Capturing tree-growth response to such changes across environmental contexts and tree species calls for a continuous forest monitoring over space. Based on >10,000 tree-ring measurements sampled across the systematic grid of the continuous French national forest inventory (...
Presentation
Full-text available
Recent growth anomalies patterns across coniferous forests of France and their relationships to climate.
Article
Forest tree species strongly influence forest dynamics and management. French forests have the greatest compositional diversity in Europe, which constrains the quantitative analysis of associated wood resources. A partition of French forests according to dominant tree species composition and stratified by biogeographical regions (GRECO) was develop...
Article
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Key message Volume predictions of sample trees are basic inputs for essential National Forest Inventory (NFI) estimates. The predicted volumes are rarely comparable among European NFIs because of country-specific dbh-thresholds and differences regarding the inclusion of the tree parts stump, stem top, and branches. Twenty-one European NFIs implemen...
Presentation
Context. National forest inventories (NFI) have been little used to explore forest growth changes due to their limited temporal cover. Strong recent climatic warming renews their interest. The systematic and repeated cover of forest areas further enables explorations across a broad range of tree species and climatic gradients, and across spatial sc...
Presentation
Full-text available
In France the new National Forest Plan was established by the law in order to increase the Forest-Wood chain value. It appears possible to increase the annual volume of harvest. These potential increases were evaluated by running the National forest resource model. Based on these results, the stakeholders of the regional forestry wood chains must n...
Article
Full-text available
Key messageRecent growth changes (1980–2007) in Western European forests strongly vary across tree species, and range from +42% in mountain contexts to −17% in Mediterranean contexts. These changes reveal recent climate warming footprint and are structured by species' temperature (−) and precipitation (+) growing conditions. ContextUnprecedented cl...
Presentation
Full-text available
Les forêts, regardées ici comme des ressources, vont se transformer au cours des prochaines décennies, à la fois passivement et de manière programmée, sous l’effet conjugué du changement climatique et de l’évolution des pratiques de gestion. L’objectif de cette communication, réalisée à la demande de l’IGN, est de situer le rôle que doit et va joue...
Presentation
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Résumé Une bioéconomie fondée sur la forêt et le bois implique de concevoir de nouvelles stratégies de gestion pour simultanément adapter la forêt au changement climatique et lui permettre de répondre aux demandes accrues en visant l’optimisation d’un bilan carbone forêt-bois intégré. Par rapport aux inventaires forestiers tels qu’ils existent aujo...
Article
Soil moisture and nutritional characteristics are frequently assessed using plant species and community bioindication, e.g., the Ellenberg system of species indicator values. This method, based on complete inventories of plant species present in plots, is time-consuming, which could prevent its general use for forest or other natural land managemen...
Chapter
The decision to launch a permanent programme of forest inventory in France dates back to 1958, when it was put into law.
Conference Paper
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In the context of climatic change an increasing attention is paid to the ability of forests to store more carbon as increasing carbon sequestration by forests is equivalent to reducing emissions the release of carbon to the atmosphere. Estimating the quantity of carbon sequestered in the forests is usually based upon the National Forest Inventory...
Technical Report
Full-text available
We are a multidisciplinary group of scientists who devoted their research efforts to the forest for many years. We are very concerned by the international debate on the contribution of sustainable forest management to climate change mitigation. Here we wish to inform the larger research community about our deep and converging criticism of the messa...
Presentation
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Illustrations des nombreux travaux déjà disponibles sur la caractérisation des propriétés du bois des plantations de Douglas
Article
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Pourquoi aborder les volumes en commençant par le volume total de l'arbre, peu familier et difficile à appréhender ? Parce qu'il est total, justement : indispensable pour assurer la cohérence des estimations par compartiment (tige, branches, à telle ou telle découpe). Et parce qu'on en a besoin pour les nouveaux enjeux, ceux du carbone par exemple....
Article
Full-text available
• Context While historical increases in forest growth have been largely documented, investigations on historical wood density changes remain anecdotic. They suggest possible density decreases in softwoods and ring-porous hardwoods, but are lacking for diffuse-porous hardwoods. • Aims To evaluate the historical change in mean ring density of common...
Article
Key message Productivity changes in Norway spruce show important regional and local spatial variations, highlighting their context dependence at different spatial scales. These variations suggest the enhancing role of climate warming, and interplay with local water and nutrient limitations. Abstract While forest growth changes have been observed...
Article
Context . Forest resource projections are required as part of an appropriate framework for sustainable forest management. Suitable large-scale projection models are usually based on national forest inventory (NFI) data. However, sound projections are difficult to make for heterogeneous resources as they vary greatly with respect to the factors that...
Article
Full-text available
• Introduction Branch size and branch status (dead or alive) are important characteristics closely related to tree growth and wood quality. The aim of this study was to design models for the diameter and status of branches in Atlas cedar (Cedrus atlantica Manetti). • Material and methods The models were developed from data collected on a set of 32...
Article
Full-text available
Height growth is a trait that contributes to tree species fitness. How height growth responds to environmental changes may therefore provide indications on species ability to compete and maintain, and on changes in tree community composition. Common beech Fagus sylvatica and sessile oak Quercus petraea are the predominant late-successional broadlea...
Article
Studies on wood density variations are necessary for estimating the forest carbon pool. Further, they can help predict the technological properties of wooden end-products. While there have been frequent reports on the relationships between wood density, cambial age, and ring width, there is little information about the historical trend in wood dens...
Article
While forest productivity is usually inferred from height growth indices, retrospective analyses of tree rings have been intensively used to assess long-term trends in forest productivity. However, radial growth is sensitive to the degree of competition between trees and influenced by management practices or local disturbances. Whether radial growt...
Article
Environmental drivers of forest productivity increases have been much debated. Evidence for the suggested role of increasing nitrogen supply is lacking over long-term time scales. Tracking the footprint of environmental factors by using long-term growth records may thus prove decisive. We analysed growth chronologies of common beech in two areas o...
Article
Full-text available
The objective of the study was to provide a stand-scale assessment of long-term productivity changes in even-aged stands and to depict their chronology over the 20th century. We focused on dominant height growth as a proxy for productivity, reconstructed from stem analyses in temporary plots. Height increments from two generations of stands were co...
Article
A large number of plots (306) were sampled for floristic data and variables of soil nutrient availability in a wide range of forest conditions in the Vosges mountains (NE France). Half of the data were used to model species presence/absence as a function of nutritional variables using two numerical methods: parametric logistic regression and non-pa...
Article
Aim To improve our understanding of species range limits by studying how height growth, a trait related to plant survival, varies throughout the geographic range of Fagus sylvatica L. in France.Location The geographic range of beech in France, representing the western area of its European distribution, within which this species exhibits range distr...
Article
Full-text available
In mixed stands, abiotic effects and interspecific interactions on tree height growth remain largely unknown. We investigated the effects of climate, nutrition and stand composition on silver fir (Abies alba Mill.) height growth in the Vosges Mountains (northeastern France). Data were collected from 143 plots established on seven stand types of sil...
Article
Full-text available
IFN field teams describe forest stand composition by evaluating the cover rates (sunlit and total) for each species found on a surface area of 0.20 hectare around the inventory point. As a result of the recent change in the inventory method, the information for 6,000 to 7,000 points, distributed in forests all over metropolitan France is now record...
Article
Full-text available
Aim To analyse the radial growth of silver fir (Abies alba Mill.) in north-eastern France in relation to soil, climate and interspecific competition factors and to check the temporal stability of their effects during the 20th century. Location The Vosges Mountains, located in north-eastern France. Methods Data were collected from 143 plots regularl...
Article
Full-text available
Relationships between site index, environmental variables, and understorey vegetation were examined for Norway spruce (Picea abies (L.) Karst.) in the eastern part of France. The study area concerns all the native range of Norway spruce in France and the northeastern plains. The analysis is based on 2087 plots from the French National Forest Invent...
Article
Full-text available
The French National Forest Inventory was created in 1958 to assess metropolitan forest resources. To stick to new national and international requirements as well as to enhance reactivity, a new inventory method was implemented in 2004. This new method is based on a systematic sampling grid covering the whole territory every year. The size of the me...
Article
The article describes a study on changes in productivity in even-aged beech groves located in North Eastern France between 1900 and 2000. The study is based on a retrospective comparison of growth of two generations, structured as 14 pairs of stands that combine a young and an old, 75 years apart on average and located close to one another in the s...
Article
Full-text available
Statistical relationships between branch basal diameter of living whorls, stem size (height and diameter at breast height) and stand parameters (stand age, site class) were analysed in Norway spruce. The first experimental sample used to calibrate a model consisted of 98 trees from young to old stands growing in Lorraine (Eastern part of France). E...
Article
Three linear mixed-effect models for wood density were constructed with average ring density data measured by X-ray microdensitometry on 10427 heartwood rings collected from 82 sessile oaks sampled in five French regions (Alsace, Lorraine, Orne et Sarthe, Allier, Loir-et-Cher). Two types of forest management (coppice-with-standards and high forest)...
Article
Full-text available
To capture the common feature of various individual growth models for trees in pure and even-aged stands, a generic model with a form parameter according to each species is proposed. With a final objective of implementing this model into simulation software of silvicultural treatments, particular care was taken to structure the model for consistent...
Article
Norway spruce growth was investigated on the scale of eastern France to examine the feasibility of using the National Forest Inventory (NFI) data for establishing fertility indices as a function of various environmental parameters. The methodology used calls on a combination of several different data sources: the NFI dendrometric and ecological dat...
Conference Paper
The objective of this work is to demonstrate that it is possible to establish a linkage between these Growth and Wood Quality models and the available forest geographic information. We intend to present a method which enables to produce for the French Vosges mountain area (i) a map of forest ecological conditions (which combine climatic, trophic an...
Article
The logistic model proposed by Courtillot and Gaudemer to describe the growth of biodiversity during geological ages is more explored here and further developed. A new parameterisation is first proposed. Another expression of this model is obtained by introducing a new variable representing the number of ecological niches. It appears that the rates...
Article
Full-text available
Le thème des changements de productivité à long terme est étudié grâce à des données au niveau du peuplement acquises dans un réseau de placettes mesurées depuis 60 ans dans 4 forêts de chênes du nord de la France. Ces 4 forêts sont réparties selon un gradient climatique, allant des sites océaniques (Normandie) aux sites plus continentaux (Lorraine...
Article
We addressed the topic of long-term growth trends by using stand-level data gained in a network of permanent plots measured since 1930 in 4 Oak forests of northern France. These forests spread along a climatic gradient, from the atlantic sites (Normandie) to the more continental sites (Lorraine). In each forest, 10 plots have been observed, in stan...
Article
Modelling the number of rings in indi6idual logs of Norway spruce. In timber production, there is a need to select the right log for a given end-product. To achieve this objective, individual tree characteristics (total height, diameter at breast height and age) and external measurements made on the log shape were combined. In this study, three po...
Article
Full-text available
Ring average density, earlywood and latewood widths and densities were measured through microdensitometry on radial strips. The strips were sawn in two radii sampled at various heights from 82 oaks (Quercus petraea Liebl.) split into stands and regions (24 200 available rings). Mixed models were constructed with age from the pith and ring width as...
Technical Report
Full-text available
The aim of the project is to compare different methods to evaluate the quality of a the timber forest resource for Norway spruce. One of these methods consists to predict the internal structure of tree stems, for which usual tree measurements are known (DBH, age and total height) but past silviculture is unknown. A modelling approach was developed...
Article
Full-text available
In order to predict the influence of silvicultural practices on knottiness and canopy structure, models were constructed to predict branch characteristics of Corsican Pine (Pinus nigra Arnold ssp. laricio (Poiret) Maire var. corsicana) from usual tree measurements. Thirty-six trees were sampled from a broad range of age, stand density and site inde...
Article
The estimation of herbaceous primary productivity is usually derived from successive independent surveys. In order to avoid negative estimates, ecologists often use positively-censored estimators, i.e. they keep positive values but replace negative values by zero. The statistical properties of these positively-censored estimators are analysed in th...