Forest In France Research Articles

The effect of oak wood source, location of seasoning and coopering on the composition of volatile compounds in oak-matured wines

The effect of geographical origin and place of seasoning and coopering of oakwood on the concentration of 20 compounds extracted into, or formed in, Chardonnay, Cabernet Sauvignon and model wines during barrel maturation is described. The oak from which the barrels were fabricated was sourced from the Vosges and Limousin regions and the Troncais forest in France, and from Ohio in the USA, and was seasoned in either Australia, France or the USA. Wines matured in Vosges oak barrels contained the highest concentrations of cis and trans-oak lactone and eugenol. The Limousin oak barrels imparted lower levels of cis-oak lactone and eugenol to the wines than did the other French oaks. However, the Limousin-oaked wines were richer in these compounds than the American-oaked wines. These results reflected the previously reported composition profiles of the oak-wood from which the barrels were fabricated. Oak seasoned and coopered in Australia generally imparted more cis-oak lactone, eugenol and the coopering products vanillin and furfural into the wines than did the oak seasoned in France or the USA. Although medium toast had been specified for all barrels, there was considerable variability in the concentration of compounds formed by coopering in the wines. Apparent random microbiological activity in the wines also contributed substantially to variation in wine composition. As a likely result of coopering and microbiological variability, few consistent origin or seasoning effects on the compounds resulting from coopering or microbiological action during oak maturation were observed.

Multi-year model analysis of GPP in a temperate beech forest in France

In this paper gross primary production (GPP) predicted by FORUG is compared with GPP calculated from eddy covariance measurements for a beech forest in France (Hesse). Two photosynthesis formulations at leaf level are compared: the biochemically supported approach described by Farquhar et al. [Farquhar, G.D., Von Caemmerer, S., Berry, J.A., 1980. A biochemical model of photosynthetic CO 2 assimilation in leaves of C3 species. Planta 12B, 549–587] (BCF) and an empirical light response curve (LRC). Five consecutive years (1996–2000) of measured GPP are compared with FORUG model predictions. Results did not discriminate between both model formulations, but good agreement between modelled and measured GPP support the reliability of FORUG for both photosynthesis approaches. Although some discrepancies appeared, the parameterization combining literature and fitted parameters can be considered as a useful strategy. Residuals were analysed to find explanations for discrepancies between model predictions and data. The increase in residuals over the years, indicate that interannual variability of GPP is not only determined by direct climatic effects. Due to interfering long-term effects, a combination of several climatic factors (drought, temperature), acclimation, environmental and management impacts account for the interannual variation in GPP. However, the long-term effect of drought appeared to be the most important driver of the interannual variability in GPP. Taking into account these long-term climate effects will be an essential step in development of better performing ecosystem models.

Gestion et gouvernance forestières : l’évolution de l’action publique

La progression des préoccupations sur les changements globaux et les questions nées des aléas climatiques des dernières décennies, la préservation de la biodiversité et les politiques européennes correspondantes, la décentralisation : autant d’éléments de changements forts dans le contexte de l’action forestière publique en France. Des réponses novatrices ont été apportées à ces évolutions par les professionnels, avec l’appui des pouvoirs publics : l’écocertification et la création de l’interprofession, notamment. L’action publique s’est recentrée sur des biens publics tels que le climat, la biodiversité, ou l’énergie. Elle a développé des approches territoriales à côté ou à la place des approches thématiques. L’État conserve en France un rôle régulateur important, à côté de l’Europe et des collectivités qui sont maintenant très présentes dans le paysage institutionnel forestier.

Les aspects sociaux d'une invasion biologique en forêt domaniale de Compiègne : la construction sociale dePrunus serotina

Prunus serotina invasionin the national forest of Compiegne: a social construction. American black cherry (Prunus serotina Ehrh.) is an invasive tree species which is spreading throughout European temperate forests. The most heavily invaded forest in France is Compiegne forest whose landscaping for forestry and entertainment purposes dates from the mid-XIXth century. Prunus serotina alters forest stand and landscape patterns, and impedes forest management so that the forest escapes from the managers' and owners' control. The authors, an ethnologist, a sociologist and an ecologist, aim to capture and understand the identification processes of both the species itself and its effects on the ecosystem by different social and occupational groups of forest users. Beside the theoretical goals of this case study, several critical points are derived in a decision-making perspective to make forest users, as well as the general public, better aware of the rather unrecognized biological invasion phenomenon.

Rodent paleofaunas as indicators of climatic change in Europe during the last 125,000 years

This paper presents a quantitative reconstruction of the European late Pleistocene paleoclimate based on 72 rodent assemblages of five sequences from France, Germany and Bulgaria, covering the last interglacial–glacial cycle. They show a pattern of severe changes in temperature, with reduced precipitation during the coldest periods. A tentative correlation between the isotopic and palynological records and the paleotemperature changes is shown. These changes are consistent with variations in atmospheric circulation patterns in response to an expanding–retracting Fennoscandian ice-sheet. They can be attributed to the enhancement–weakening of the Scandinavian-Polar anticyclone and its associated dry winds, the south–north shifting of the North Atlantic Polar Front, and the varying supply of moist air from the Atlantic. Qualitative paleoenvironmental analysis shows broadleaved-deciduous forests in France and Bulgaria during most of the studied period. Taiga and tundra appeared in eastern France during the lower Würm. The German sequence indicates the presence of coniferous forests. These results are broadly consistent with other paleobiological records (mammalian, avian and insect faunas, isotopic record in dental tissue, palynology). The main discrepancies with the paleoclimate inferred from the palynological record are found during the coldest periods and are probably due to the interaction between vegetation, climate, and atmospheric CO 2 levels.

The Influence of Landscape Structure on Female Roe Deer Home-range Size

Animal distribution and abundance are greatly affected by the availability of their food resources, which also depends on landscape structure. Lothar hurricane in 1999 had profoundly modified the structure of the forests in France, affecting the habitat quality of ungulates. We tested whether the variations in home-range size of 23 female roe deer were influenced by the fragmentation of the landscape caused by Lothar in the Chize forest, namely by the increase in heterogeneity associated with the localized massive tree felling. Home-range size was studied in the summers of 2001 and 2002 and we found that variation in home-range size was mainly explained by only one landscape variable: edge density. Home-range size decreased as edge density increased, which is consistent with the fact that edges are good browsing habitats for roe deer. The result of this study suggests that, after 2 years, the hurricane had improved the quality of the home ranges by creating more forest heterogeneity and increasing the contacts between the different vegetation patches within the home range. These results highlight the fact that spatial heterogeneity is likely to be a key factor influencing the distribution and local population density.

Short-term effect of windstorm disturbance on saproxylic beetles in broadleaved temperate forests: Part II. Effects of gap size and gap isolation

The short-term effect of windthrow gap size and isolation for saproxylic beetle abundance, species richness and assemblage composition was studied in managed oak-hornbeam forest in France. The main gap effects did not increase with gap area. Non-metric multi-dimensional scaling (NMDS) and ANOSIM tests showed that all gaps, even small, differed from closed-canopy controls in terms of saproxylic species composition. However, only mid-size gaps were distinct from large and especially small gaps. The highest Bray–Curtis dissimilarity occurred between mid-size gaps and closed-canopy controls, and not between large gaps and controls. Partly in agreement with the resource concentration hypothesis, floricolous beetles were more abundant in mid-size and large gaps than in small ones. However, pioneer xylophagous species did not increase and late-successional xylophagous species did not decrease in abundance with increasing gap area. A peak in cumulative and mean local species richness was measured in mid-size gaps, but assemblage composition in mid-size gaps was not intermediate between small and large gaps, which does not fully comply with the intermediate disturbance hypothesis. From IndVal results, no strictly characteristic species were detected in small gaps, but several ones in mid-sized and large gaps. On the whole, scolytids and pioneer xylophagous beetles were favoured in gaps by an increase in felling density in the 78 and 314 ha surrounding landscapes, respectively. Individual species responses in occurrence or abundance were varied. As the faunistic peculiarity in the gaps was mainly confined to mid- and large-sized gaps, retaining uncleared gaps above 0.5 ha in size is recommended to improve saproxylic gamma diversity in forests.

Short-term effect of windstorm disturbance on saproxylic beetles in broadleaved temperate forests: Part I: Do environmental changes induce a gap effect?

Windstorm created small gaps with large amounts of sun-exposed dead wood in managed oak–hornbeam forest in France in 1999. The short-term effect of these gaps for saproxylic beetle abundance, species richness and assemblage composition were compared with closed-forest stands and seedling–sapling stands. We observed a strong differentiation of saproxylic assemblage in gaps compared with undisturbed stands but richness was only slightly higher in gaps. Contrary to expectations, the abundance of primary wood consumers on the whole, highly dominated by bark beetles, was as high in undisturbed plots as in gaps. However, longhorn and buprestid beetles responded positively in gaps. The later-successional xylophagous beetles on the whole were not significantly less abundant in gaps, in spite of the lower abundance of some shade-preferring species (Anobiidae, Eucnemidae, Melandryidae). Gap changes had a positive impact on the floricolous and xylomycetophagous insects, even if the species response was contrasted. Saproxylic communities were also distinct in gaps and in seedling–sapling stands. Both species richness and number of characteristic species were higher in gaps than in seedling–sapling stands. The abundance of later-successional xylophagous and xylomycetophagous insects was equal in gaps and in seedling–sapling stands. The abundance of saproxylic predators seemed to follow the population levels of all xylophagous insects. Because of their richness and faunistic dissimilarity with other open stands and closed-canopy controls, uncleared gaps may enhance the gamma diversity at the forest scale. In response to management issues underlying this research project, saproxylic diversity would benefit from the maintenance of some uncleared gaps. Moreover, in managed temperate, deciduous forests, my results suggest to retain more sun-exposed harvesting residue in fellings in order to enhance biodiversity.

Conséquences de la forêt méditerranéenne sur les écoulements de crue Synthèse des recherches menées en France

Click to increase image sizeClick to decrease image sizeThree experimental watersheds allow studying hydrological consequences of Mediterranean forest in France. Results are very different from one to other, in relation with complexity of rain-runoff relationship. Forest cut does not systematically increase floods. Considerations about hydrological processes allow understanding apparent contradiction between different results.

Volatile organic compounds (VOCs) emitted from 40 Mediterranean plant species:: VOC speciation and extrapolation to habitat scale

Forty native Mediterranean plant species were screened for emissions of the C5 and C10 hydrocarbons, isoprene and monoterpenes, in five different habitats. A total of 32 compounds were observed in the emissions from these plants. The number of compounds emitted by different plant species varied from 19 ( Quercus ilex) to a single compound emission, usually of isoprene. Emission rates were normalised to generate emission factors for each plant species for each sampling event at standard conditions of temperature and light intensity. Plant species were categorised according to their main emitted compound, the major groups being isoprene, α-pinene, linalool, and limonene emitters. Estimates of habitat fluxes for each emitted compound were derived from the contributing plant species’ emission factors, biomass and ground cover. Emissions of individual compounds ranged from 0.002 to 505 g ha −1 h −1 (camphene from garrigue in Spain in autumn and isoprene from riverside habitats in Spain in late spring; respectively). Emissions of isoprene ranged from 0.3 to 505 g ha −1 h −1 (macchia in Italy in late spring and autumn; and riverside in Spain in late spring; respectively) and α-pinene emissions ranged from 0.51 to 52.92 g ha −1 h −1 (garrigue in Spain in late spring; and forest in France in autumn; respectively). Habitat fluxes of most compounds in autumn were greater than in late spring, dominated by emissions from Quercus ilex, Genista scorpius and Quercus pubescens. This study contributes to regional emission inventories and will be of use to tropospheric chemical modellers.

δ15N of forest soil and understorey vegetation reflect the former agricultural land use.

Since the middle of the 19th century, the area covered by forests in France has doubled. These new forests grow on previous agricultural lands. We have studied the influence of this agricultural history on the 15N abundance of present-day forests planted on farmlands in the Vosges mountains (north-eastern France) between 1898 and 1930. Different types of land use were identified from old cadastres (1814-1836) of 16 farms. Ancient forests adjacent to farmlands were used as controls. Former pastures, meadows, croplands, gardens and ancient forests were compared for soil δ15N (fraction <50 µm and total soil), C/N, P and N content and fern (Dryopteris carthusiana) δ15N. The mean δ15N of soil increased in the order ancient forests (+0.0‰)<pastures (+1.4‰)<croplands (+1.6‰)<meadows (+2.5‰)<gardens (+3.8‰). This increase in soil δ15N with the intensity of former land use was related to the former input of 15N-enriched manure, and to an activation of soil nitrification leading to 15N-depleted nitrate export on previously manured parcels. Fern δ15N increased in the same order as soil δ15N in relation to past land use. The mean δ15N of fern in ancient forests (-4.4‰) and former pastures (-3.4‰) was 5‰ lower than soil δ15N and the two variables were strongly correlated. The δ15N of fern in formerly manured parcels varied little (cropland: -2.7‰, meadows: -2.6‰ and gardens: -2.2‰) and independently of soil δ15N, suggesting that the soil sources of fern N differed between unmanured and manured parcels. Understorey plant δ15N and soil δ15N appear to be excellent tracers of previous land use in forests, and could be used in historical studies. The persistence of high isotopic ratios in previously manured parcels, almost a century after afforestation, suggests a long-term influence of former land use on the N cycle in forest soils.

Taste Thresholds of Phenolic Extracts of French and American Oakwood: The Influence of Oak Phenols on Wine Flavor

The concentration of the total phenol fraction in extracts of both green and seasoned oakwood from Ohio in the USA and from the Limousin and Vosges regions and the Tronçais forest in France was measured by both UV absorbance at 280 nm and by the Folin-Ciocalteu reagent. The concentration of phenols in both white wine and model wines stored in barrels made from the same wood samples was also measured. Taste thresholds of the aroma-stripped extracts in a white wine and in a model wine were determined by duo-trio difference testing. The concentration of the phenolic fraction in the extracts varied with oak source, but not with seasoning (<i>i.e.</i>, wood drying). Taste thresholds varied with both of these parameters. The concentration of phenols in the barrel-aged wines was near to or below their sensory thresholds, indicating that the contribution of oak polyphenols to the taste of a wine is likely to be no more than a subtle one and to depend on the training and sensory acuity of an individual observer. The sensory thresholds of extracts containing aroma volatiles were much lower than those of the aroma-stripped extracts, suggesting that it is the oak-derived volatiles that provide the primary sensory cue that a wine has received oak-treatment.

A comparison of models simulating rainfall interception of forests

Rainfall interception models have been validated using observations from a coniferous forest in France and a deciduous forest in the Netherlands. The models differ in level of complexity. This complexity, however, appears to have only a secondary effect on the results. The most sensitive factor in the models is shown to be the evaporation rate of the intercepted water. The evaporation rate is determined from the atmospheric vapour pressure deficit and the aerodynamic resistance using the Penman equation. In the models, the aerodynamic resistance is approximated from momentum transport. This approximation leads to an overestimation of interception. The models can be improved by using a simple and well-known correction for the aerodynamic resistance.

Protection Forest in France

Protection Forest in France

Diurnal variation in the concentration of α- and β-pinene in the landes forest (France)

The study deals with the identification and the determination of the main monoterpenes (α- and β-pinene) released by the pines in the Landes Forest in France. The measurements were taken after preconcentration using TENAX-GC and thermal desorption. The diurnal variation of atmospheric concentration of α- and β-pinene is established; it is less than 0.5 ppbV in the daytime and varies from 2 to 4 ppbV in the night-time. These variations are explained by the fact that the photochemical reactions and the turbulence phenomena to which the terpenes are exposed change quite radically from day to night. The terpene concentration, higher at 5 m than at 25 m, would seem to confirm the existence of a terpene source at ground level.

By L. BOURGENOT “The History of the Broad Leaved Forest in France”

By L. BOURGENOT “The History of the Broad Leaved Forest in France”

Forests of France.

Forests of France.

Forests of France

Forests of France

The Forests of France

The Forests of France

The Forests of England and the Management of them in Bygone Times French Forest Ordinance of 1669, with Historical Sketch of Previous Treatment of Forests in France

The Forests of England and the Management of them in Bygone Times French Forest Ordinance of 1669, with Historical Sketch of Previous Treatment of Forests in France