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Artigues-près-Bordeaux, France

Rasheed F.,French National Institute for Agricultural Research | Rasheed F.,University of Lorraine | Rasheed F.,CNRS Laboratory of Woody Plants and Crops Biology | Richard B.,French National Institute for Agricultural Research | And 10 more authors.
Tree Physiology | Year: 2011

Genetic differences in 13C (isotopic composition of dry matter carbon) have been evidenced among poplar genotypes at juvenile stages. To check whether such differences were maintained with age in trees growing in plantations, we investigated the time course of 13C as recorded in annual tree rings from different genotypes growing at three sites in southwestern France and felled at ∼15-17 years. Wood cores were cut from tree discs to record the time course of annual basal area increment (BAI). The isotopic ratio 13C was recorded in bulk wood and in extracted cellulose from the annual rings corresponding to the period 1996-2005. Discrimination against 13C between atmosphere and tissues (Δ 13C) was computed by taking into account the inter-annual time course of 13C in the atmosphere. Annual BAI increased steadily and stabilized at about 8 years. An offset in 13C of ∼1‰ was recorded between extracted cellulose and bulk wood. It was relatively stable among genotypes within sites but varied among sites and increased slightly with age. Site effects as well as genotype differences were detected in Δ 13C recorded from the cellulose fraction. Absolute values as well as the genotype ranking of Δ 13C remained stable with age in the three sites. Genotype means of Δ 13C were not correlated to annual BAI. We conclude that genotypic differences of Δ 13C occur in older poplar trees in plantations, and that the differences as well as the genotype ranking remain stable while trees age until harvest. © The Author 2011. Source


Eglin T.,French Environment and Energy Management Agency | Martin M.,French National Institute for Agricultural Research | Maurice D.,University of Lorraine | Nicolas M.,Office National des Forets | And 3 more authors.
Revue Forestiere Francaise | Year: 2014

Forest managers and decision-makers require more knowledge of forest soils and better references for understanding soil functioning. At REGEFOR 2013, the “Collecting and using data on forest soils” workshop identified a large under-exploited source of data in development organizations and research laboratories. Software was available for making these resources easier to discover and accessible via Internet. As the data is scattered and the data sets are not harmonized, much remains to be done to enable this data to be used (eg: incorporation into databases, production of metadata and common semantic standards, clarification of ownership rights, data transfer protocols between applications). The workshop also discussed ways of improving coordination between the production and management of data, in particular considering the advantages and limitations of centralization within a single information system. © AgroParisTech, 2014. Source


Fiquepron J.,Institute Pour le Developpement Forestier
Revue Forestiere Francaise | Year: 2012

Faced with water quality issues in some agricultural areas, forests are considered valuable for the production of drinking water. Furthermore, foresters can enhance the protection of water resources - an excellent example of environmental service. Can the protection of drinking water be considered a full-fledged forestry activity? The purpose of this article is to review the development potential for foresters arising from this service, based on work conducted in private forests. Examining different aspects of services provided by forests, the article describes several methods for economic evaluation depending on whether the focus is simply on the role played by the existence of forests, forestry activities in favour of water or the naturalness of forest-sourced water. To develop water protection services by forests, the CNPF-IDF [National Forestry Centre/Forestry Development Institute] leads a working group on legal issues, whose goal is to devise and test a standard contract between foresters and freshwater utilities. Source


Lebourgeois F.,Agro ParisTech | Drenou C.,Institute pour le developpement forestier Toulouse | Bouvier M.,Center Regional Of La Propriete Forestiere Of Bretagne | Lemaire J.,Institute Pour le Developpement Forestier
Revue Forestiere Francaise | Year: 2015

The relations between crown architecture (healthy, resilient, dying trees; the ARCHI [architectural tree analysis method] Protocol), radial growth and climate (1950-2009) were investigated on 94 pedunculate (Quercus robur L.) oaks sampled in Western France, living in comparable site conditions (acidic soil with a 120 mm water reserves in the subsoil)) and similarly managed (H0 = 24 m; G = 25 m2/ha; no thinning since 2003). While the differences in growth levels according to crown architecture as observed in 2010 appear to go back a long time, the growth curves have consistently diverged more and more over time, in particular following the droughts of 1976 and 1989-1990. An analysis of the growth ring/climate relationship shows that abundant rainfall in December and April contributes to the formation of wider rings whereas water shortages in the summer have a strong opposite effect and one that is intensified in the case of degraded crowns. A comparison of the responses for the 1950-1980 and 1981-2009 periods shows that dying trees were always very susceptible to summer and spring water shortages (from May to July), whereas for the healthy and resilient trees, susceptibility to summer drought has increased very strongly in the recent period. This suggests that the response of all oak stands to the intensification of environmental stresses (increasingly frequent drought) is becoming more homogeneous. Over the 2003-2009 period, all three morphotypes exhibited the same resistance (i.e., the ability to maintain a growth level while subject to a stress). Concerning resilience, the trees characterised as resilient from an architectural standpoint also appeared resilient in terms of growth, showing an ability to return to the pre-crisis level of growth, or even a higher level. © AgroParisTech, 2015. Source


Lambert J.,National Polytechnic Institute of Toulouse | Drenou C.,Institute Pour le Developpement Forestier | Denux J.-P.,National Polytechnic Institute of Toulouse | Balent G.,French National Institute for Agricultural Research | Cheret V.,National Polytechnic Institute of Toulouse
GIScience and Remote Sensing | Year: 2013

In Europe, the 2003 summer heat wave damaged forested areas. This study aims to compare two approaches of NDVI time series analysis to monitor forest decline. Both methods analyze the trend of vegetation activity from 2000 to 2011. The first method is based on a phenometric related to spring vegetation activity, calculated for each year during the 2000-2011 period. In the second method (BFAST), the trend comes from the decomposition of the NDVI time series into three additive components: trend, seasonal and remainder. The two approaches gave similar results for estimated trends. The main advantage of BFAST is its ability to detect breakpoints in the linear trend. It allowed to highlight here the impact of exceptional events, like 2003 summer drought, on the development of forest stands. In the last part of our study, we implemented a validation based on in situ observations. Health status of silver fir stands was estimated analyzing the trees architecture. Significant relationships were highlighted between the indicator of spring vitality derived from remote sensing images and the observed status of forest stands. © 2013 Copyright Taylor and Francis Group, LLC. Source

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