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Individual-based approach as a useful tool to disentangle the relative importance of tree age, size and inter-tree competition in dendroclimatic studies / Vicente Rozas in iForest, biogeosciences and forestry, vol 8 n° 2 (April 2015)
[article]
Titre : Individual-based approach as a useful tool to disentangle the relative importance of tree age, size and inter-tree competition in dendroclimatic studies Type de document : Article/Communication Auteurs : Vicente Rozas, Auteur Année de publication : 2015 Article en page(s) : pp 187 - 194 Langues : Anglais (eng) Descripteur : [Termes IGN] changement climatique
[Termes IGN] dendrochronologie
[Termes IGN] feuillu
[Termes IGN] hauteur des arbres
[Termes IGN] Quercus pedunculata
[Termes IGN] stress hydrique
[Vedettes matières IGN] Végétation et changement climatiqueRésumé : (auteur) In this work, an individual-based approach was used to assess the relative importance of tree age, size, and competition in modulating the individual dendroclimatic response of Quercus robur L. This was performed in a multi-aged forest in northwestern Spain under a wet Atlantic climate. All trees in five replicated forest stands with homogeneous soil conditions were mapped and inter-tree competition was quantified with a distance-dependent competition index. Tree rings of cored trees were crossdated and total age was estimated on individuals where the pith was missed. The climatic response was evaluated by bootstrapped correlations of individual tree-ring chronologies with climatic records. Inter-annual growth variation, i.e., mean sensitivity, was independent of tree age and bole diameter, but modulated by competition. Water excess in previous summer-autumn and spring negatively affected growth, while warmer September conditions favored growth. Individual response to climate was independent of tree age, but related to the joint effect of tree bole diameter and competition. Larger oaks in less competitive environments responded more plastically to climatic stress, while smaller trees under high competition levels were less responsive to climate. Strong inter-tree competition reduced growth plasticity but amplified the vulnerability of smaller oaks to the particularly rainy conditions of the study area. These findings suggest that inter-tree competition is a relevant size-mediated extrinsic factor that can potentially modulate individual radial growth variation and its response to limiting climatic conditions in temperate deciduous forests. This study highlights the value of individual-based approach as a useful tool that informs about the relative contribution of factors modulating the climatic response of tree-ring growth. Numéro de notice : A2015-120 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.3832/ifor1249-007 Date de publication en ligne : 21/08/2014 En ligne : https://doi.org/10.3832/ifor1249-007 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=75670
in iForest, biogeosciences and forestry > vol 8 n° 2 (April 2015) . - pp 187 - 194[article]Les forêts tempérées face aux conséquences du changement climatique : est-il primordial de favoriser une plus forte diversité d’arbres dans les peuplements forestiers ? / Charlotte Grossiord in Revue forestière française, Vol 67 n° 2 (mars 2015)
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Titre : Les forêts tempérées face aux conséquences du changement climatique : est-il primordial de favoriser une plus forte diversité d’arbres dans les peuplements forestiers ? Type de document : Article/Communication Auteurs : Charlotte Grossiord, Auteur ; Arthur Gessler, Auteur ; André Granier, Auteur ; Damien Bonal, Auteur Année de publication : 2015 Article en page(s) : pp 99 - 110 Note générale : Bibliographie Langues : Français (fre) Descripteur : [Termes IGN] biodiversité
[Termes IGN] changement climatique
[Termes IGN] forêt tempérée
[Termes IGN] peuplement forestier
[Termes IGN] sécheresse
[Vedettes matières IGN] Végétation et changement climatiqueRésumé : (Auteur) Une plus forte biodiversité dans les peuplements forestiers est suggérée comme étant un mode de gestion permettant d’adapter les forêts à l’accentuation des sécheresses dans le futur. Nous présentons ici une synthèse sur la relation entre diversité en essences d’arbre et résistance à la sécheresse des peuplements forestiers tempérés. Des tendances contrastées pour cette relation ont été observées en fonction des types forestiers étudiés, des essences présentes dans le peuplement, ou du contexte pédoclimatique local. La généralisation de modes de gestion forestière intégrant des mélanges de plusieurs essences ne semble donc pas nécessairement assurer une meilleure résistance à la sécheresse des peuplements forestiers tempérés. Numéro de notice : A2015-736 Affiliation des auteurs : non IGN Thématique : BIODIVERSITE/FORET Nature : Article DOI : 10.4267/2042/57901 En ligne : https://doi.org/10.4267/2042/57901 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=78437
in Revue forestière française > Vol 67 n° 2 (mars 2015) . - pp 99 - 110[article]Comparison of methods toward multi-scale forest carbon mapping and spatial uncertainty analysis: combining national forest inventory plot data and landsat TM images / Andrew L. Fleming in European Journal of Forest Research, vol 134 n° 1 (January 2015)
[article]
Titre : Comparison of methods toward multi-scale forest carbon mapping and spatial uncertainty analysis: combining national forest inventory plot data and landsat TM images Type de document : Article/Communication Auteurs : Andrew L. Fleming, Auteur ; Guangxing Wang, Auteur ; Ronald E. McRoberts, Auteur Année de publication : 2015 Article en page(s) : pp 125 - 137 Langues : Anglais (eng) Descripteur : [Termes IGN] carte thématique
[Termes IGN] Etats-Unis
[Termes IGN] Illinois (Etats-Unis)
[Termes IGN] image Landsat-TM
[Termes IGN] inventaire forestier étranger (données)
[Termes IGN] prédiction
[Termes IGN] puits de carbone
[Termes IGN] régression linéaire
[Vedettes matières IGN] Végétation et changement climatiqueRésumé : (auteur) Accurate spatial estimation of forest carbon stocks and their spatial uncertainties at local, regional, national, and global scales is a critical step in global carbon cycle modeling and management. This study aimed at enhancing the methods that are currently used in this area by combining plot data from the forest inventory and analysis program of the U.S. Forest Service and free landsat thematic mapper image data. Three mapping methods including linear regression, sequential Gaussian co-simulation, and block co-simulation algorithm were compared with respect to the accuracy of forest carbon stock estimates obtained for a study area in Southern Illinois, USA. The results indicated that although the linear regression resulted in smaller prediction errors than the sequential Gaussian co-simulation and the block co-simulation approaches, it also produced both negative and unreasonably large estimates, which is a serious drawback. Moreover, the sequential Gaussian co-simulation and the block co-simulation produced not only accurate carbon predictions, but also uncertainties for the local estimates. In addition, the block co-simulation approach scaled up both forest carbon stocks and the input uncertainties from finer to coarser spatial resolutions as is required for mapping forest carbon at national and global scales. Thus, the co-simulation and block co-simulation algorithms resolved an important current methodological challenge. Numéro de notice : A2015-190 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1007/s10342-014-0838-y Date de publication en ligne : 05/08/2014 En ligne : https://doi.org/10.1007/s10342-014-0838-y Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=75966
in European Journal of Forest Research > vol 134 n° 1 (January 2015) . - pp 125 - 137[article]The land use and cover change in Miombo woodlands under community based forest management and its implication to climate change mitigation: A case of Southern Highlands of Tanzania / J.Z. Lupala in International journal of forestry research, vol 2015 ([01/01/2015])
[article]
Titre : The land use and cover change in Miombo woodlands under community based forest management and its implication to climate change mitigation: A case of Southern Highlands of Tanzania Type de document : Article/Communication Auteurs : J.Z. Lupala, Auteur ; L.P. Lusambo, Auteur ; Y.M. Ngaga, Auteur ; Angelingis A. Makatta, Auteur Année de publication : 2015 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] biomasse
[Termes IGN] changement climatique
[Termes IGN] foresterie
[Termes IGN] occupation du sol
[Termes IGN] Tanzanie
[Termes IGN] utilisation du sol
[Vedettes matières IGN] Végétation et changement climatiqueRésumé : (auteur) In Tanzania, miombo woodland is the most significant forest vegetation with both ecological and socioeconomic importance. The vegetation has been threatened from land use and cover change due to unsustainable utilization. Over the past two decades, community based forest management (CBFM) has been practiced to address the problem. Given the current need to mitigate global climate change, little is known on the influence of CBFM to the land use and cover change in miombo woodlands and therefore compromising climate change mitigation strategies. This study explored the dynamic of land use and covers change and biomass due to CBFM and established the implication to climate change mitigation. The study revealed increasing miombo woodland cover density with decreasing unsustainable utilization. The observed improvement in cover density and biomass provides potential for climate change mitigation strategies. CBFM also developed solidarity, cohesion, and social control of miombo woodlands illegal extraction. This further enhances permanence, reduces leakage, and increases accountability requirement for carbon credits. Collectively with these promising results, good land use plan at village level and introduction of alternative income generating activities can be among the best options to further reduce land use change and biomass loss in miombo woodlands. Numéro de notice : A2015-412 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1155/2015/459102 En ligne : http://dx.doi.org/10.1155/2015/459102 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76901
in International journal of forestry research > vol 2015 [01/01/2015][article]
Titre : To die or not to die: Forest dynamics in Switzerland under climate change Type de document : Thèse/HDR Auteurs : Nicolas Bircher, Auteur Editeur : Zurich : Eidgenossische Technische Hochschule ETH - Ecole Polytechnique Fédérale de Zurich EPFZ Année de publication : 2015 Collection : Dissertationen ETH num. 22775 Importance : 188 p. Format : 21 x 30 cm Note générale : bibliographie
A thesis submitted to attain the degree of doctor of sciences of ETH ZurichLangues : Anglais (eng) Descripteur : [Termes IGN] composition floristique
[Termes IGN] dynamique de la végétation
[Termes IGN] forêt alpestre
[Termes IGN] inventaire forestier étranger (données)
[Termes IGN] modèle dynamique
[Termes IGN] Picea abies
[Termes IGN] série temporelle
[Termes IGN] structure d'un peuplement forestier
[Termes IGN] Suisse
[Vedettes matières IGN] Végétation et changement climatiqueRésumé : (auteur) A high diversity of forest ecosystems is found around the globe providing various ecosystem services to humans. Responses of forests to recent increases of drought events have given rise to serious concerns about future forest development. Since anthropogenic climate change is proceeding at an unprecedented rate, the forestry sector is challenged to swiftly develop and plan adaptive management measures that guarantee the sustainable provision of forest ecosystem services in the future. The planning of management strategies is strongly dependent on reliable knowledge on future forest dynamics. To this end, the Swiss government has launched an extensive research program to examine the impact of climate change on Swiss forests. One aim among others is to assess the sensitivity of common forest types of Switzerland to climate change.
Dynamic vegetation models (DVMs) are suitable to provide quantitative assessments of forest sensitivity to climate change, as their flexibility allows considering dynamic vegetation transitions under conditions that do not represent a steady state. Among DVMs, forest gap models portray long-term forest dynamics at the stand scale taking biotic interactions such as competition into account. Recent integration of sophisticated management techniques has substantially extended their range of application from unmanaged to complex mixed-species forests under management, thus making them interesting tools for the assessment of climate change impacts on forest ecosystems. However, forest gap models integrate a large number of ecological processes that still lack an empirical base. This is particularly true for tree mortality – a key demographic process in forest dynamics – where increasing empirical research has been followed by little action in DVMs. Thus, although it is widely acknowledged that empirical functions should be integrated into DVMs to enhance ecological realism, little is known about whet her this approach leads to an increased robustness of model projections.
Given this background, my thesis includes two major objectives: 1) to examine the potential of empirical mortality functions in dynamic vegetation models and 2) to assess the sensitivity of common Swiss forests to climate change.
In Chapter 1 of this thesis, I implemented an inventory- and a tree-ring based mortality function in the forest gap model ForClim and combined them with a stochastic and a deterministic approach for the determination of tree status (alive vs. dead). These four new model versions were tested for two Norway spruces stands, one of which was managed (inventory time series of 72 years) and the other was unmanaged (41 years). Furthermore, I ran long-term simulations (~400 years) into the future to test model behavior under three climate scenarios. I showed that three out of the four mode l versions showed good agreement for stand basal area and stem numbers when compared against inventory data of both forest sites. Due to very similar model behavior, an unambiguous choice of a “best” model version was, however, not possible. In contrast, long -term simulations revealed very different behavior of the mortality models, indicating that the choice of the mortality function is crucial for simulated forest dynamics. Based on these results, I concluded that 1) empirical mortality functions are valuable replacements for current theoretical mortality algorithms in dynamic vegetation models 2) but further tests would be needed to rigorously assess their potential and to better understand interactions of the mortality function with other model processes.
Enhanced use of empirical data in dynamic vegetation models is widely advocated. However, it is largely unknown whether empirically derive d functions are compatible with the wide range of processes and interactions that are usually found in DVMs and thus, whether they lead to an better model performance. In Chapter 2 , I addressed this question with the focus on the inventory-based mortality function that has already been used in Chapter 1 . I used Bayesian methods to recalibrate its mortality parameters within ForClim. I compared its performance with the ForClim version containing the original, empirically fitted mortality parameters and with the current ForClim v3.3 that included a theoretical mortality function. Calibration and subsequent validation was based on inventory data of 30 Swiss natural forest reserves. Similarities between the calibrated and the empirically fitted mortality parameters suggest that the general structure of ForClim is appropriate to integrate empirical mortality functions. However, I found some discrepancies that indicate necessary improvements regarding the role of species’ shade tolerance in growth-mortality relationships and an optimal balance between growth and mortality. Bayesian calibration led to best performance both at calibration and validation sites. Furthermore, it revealed that the sensitivity of ForClim to parametric uncertainty is particularly high for trees in low dbh classes but surprisingly small for standard model outputs such as basal area.
Assessing the sensitivity of common forest stands in Switzerland with a forest gap model makes it necessary 1) to know which forest stands are common and 2) to have suitable data for model initialization. In Chapter 3 , I developed a stratification of the Swiss forest area to identify those forest types of Switzerland that , in terms of their stand structure and tree species composition, are most common in different eco-regions and elevation zones. I used plot data form the third Swiss National Forest Inventory (NFI3) that contained both stand attributes and single-tree data. NFI plots were grouped into eco -regions and elevation zones according to the “Guide for sustainability in protection forests” (NaiS). I further segregated NFI plots into more groups based on two forest stand attributes: vertical stand structure and developmental stage. In a last step, I relied on recommendations of sylvicultural experts for dividing some groups into more strata to strengthen a realistic tree species composition. The stratification resulted in 71 strata that contained 25% of all NFI forest plots. Single-tree data of all NFI plots associated to one stratum were aggregate d. Although the final result is a somewhat “artificial” forest stand, it has the tremendous advantage that NFI plot data can be used directly for stand initialization in the forest gap model ForClim.
In Switzerland, studies on forest sensitivity to climate change often focus on extreme sites where shifts in tree species composition are already visible while less attention is paid to the fate of common forest stands that are most important for Swiss forestry. In Chapter 4, I ran simulations for 71 strata that had been identified in the previous chapter using two model versions to examine their development until the end of the 21 st century (year 2100). Simulations were run with common Swiss forest management strategies and without management. I considered forest development under current climate (1980-2009) and under 11 different climate change scenarios assuming an A2 greenhouse gas emission scenario. According to these simulation results, shifts in structure and composition of Swiss forests have to be expected for the second half of this century. However, high variability among the strata was found due to drivers of small-scaled forest dynamics such as regional climate, elevation gradients and current species composition. I showed that current management regimes can alleviate the negative impacts of climate change but adaptive measures are necessary to be applied at a site-specific and objective-oriented base. In conclusion, model- based assessments on forest sensitivity can only provide reliable decision-making support for forest managers if small-scaled drivers of forest stand dynamics are take n into consideration.
In the Synthesis, I reflect the findings of the previous chapters by discussing the potential of empirical mortality functions in DVMs and the use of forest gap models – as one type of DVM – as tools for decision-support regarding forest management under climate change. I come to the conclusion that empirical mortality functions are capable to further improve the performance of DVMs and to increase our confidence in their projections. However, empirical functions come with limitations, which might constrain avalid applicability. For this reason, I advocate not to focus on one individual function but to aggregate knowledge on mortality mechanism and data from various sources to enhance the validity of the tree mortality mechanism in DVMs beyond individual empirical data sets. Climate change is expected to have strong effects on future development of current Swiss forests at various sites. High variability in forest response to a changing environment underlines the need to plan future forest strategies at the local scale. Forest gap models have limitations that need to be discussed and tackled. Still, I am convinced that they have the potential to play a key role in decision-making processes as they can provide what decision makers need: a comprehensive reflection of essential processes and an adequate spatial resolution.Numéro de notice : 17200 Affiliation des auteurs : non IGN Thématique : FORET Nature : Thèse étrangère Note de thèse : doctoral thesis : Sciences : ETH Zurich : 2015 En ligne : http://dx.doi.org/10.3929/ethz-a-010596194 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81176 Forêt et transition énergétique : la forêt, un sentier pour la transition énergétique et écologique / Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (2011 - 2019; France) (19/09/2014)Permalinkn° 33 - Juin 2014 - Forêt et changements climatiques : apports des données d'inventaire IGN (Bulletin de L'if) / Stéphanie WurpillotPermalinkCarbon stock changes of forest land in Finland under different levels of wood use and climate change / Risto Sievänen in Annals of Forest Science, vol 71 n° 2 (March 2014)PermalinkSpatial patterns of historical growth changes in Norway spruce across western European mountains and the key effect of climate warming / Marie Charru in Trees, vol 28 n° 1 (February 2014)PermalinkForest cutting and impacts on carbon in the eastern United States / Decheng Zhou in Scientific reports, vol 3 (2013)PermalinkThe biometrical influences of stump stocking on sycomore (Acer pseudoplatanus L.) coppice trees: a case study / Valeriu-Norocel Nicolescu in Revista Padurilor, vol 128 n° 3 (3/2013)PermalinkLe statut social d’un arbre influence-t-il sa réponse au climat ? Étude dendroécologique sur le Sapin, l’Epicéa, le Pin sylvestre, le Hêtre et le Chêne sessile / Pierre Mérian in Revue forestière française, vol 65 n°1 (janvier - février 2013)PermalinkL'autécologie des essences forestières et son intégration dans les outils d'aide à la décision : synthèse et évaluation / Alice Michelot (2013)PermalinkShifts in the height-related competitiveness of tree species following recent climate warming and implications for tree community composition: the case of common beech and sessile oak as predominant broadleaved species in Europe / Jean-Daniel Bontemps in Oikos, vol 121 n° 8 (August 2012)PermalinkTracking human impact on current tree species distribution using plant communities / Daniel E. Silva in Journal of vegetation science, vol 23 n° 2 (April 2012)Permalink