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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 Effect of host tree density and apparency on the probability of attack by the pine processionary moth / Margot Regolini in Forest ecology and management, vol 334 ([15/12/2014])
[article]
Titre : Effect of host tree density and apparency on the probability of attack by the pine processionary moth Type de document : Article/Communication Auteurs : Margot Regolini, Auteur ; Bastien Castagneyrol, Auteur ; Anne-Maïmiti Dulaurent-Mercadal, Auteur ; et al., Auteur Année de publication : 2014 Article en page(s) : pp 185 - 192 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Végétation
[Termes IGN] densité de la végétation
[Termes IGN] hauteur des arbres
[Termes IGN] Insecta
[Termes IGN] insecte nuisible
[Termes IGN] Pinus pinaster
[Termes IGN] xylophageRésumé : (auteur) The pine processionary moth (PPM, Thaumetopoea pityocampa) is the main defoliator of pines in the Mediterranean area, necessitating constant surveillance and regular pest management. A sound understanding of the spatial distribution of infested trees, both within and between stands, is required to increase management efficiency. We hypothesized that both host tree density at stand scale and tree apparency at individual tree scale were responsible for between- and within-stand patterns of PPM infestation. We tested these hypotheses on a sample of 171 maritime pine stands in the Landes de Gascogne, the largest plantation forest in Europe. We showed that PPM infestation (percentage of infested trees) decreased significantly with stand density, and was therefore greater in older than in younger stands. The probability of a pine tree being attacked increased significantly with tree height and proximity to the edge of the stand. Mortality rates of exposed sentinel egg batches did not differ with distance from the stand edge. We discuss three likely explanations for higher infestation of taller trees at stand edges: better survival of larvae on sun-exposed trees, and random interception vs. active host selection by gravid females. Our findings suggest that stand management could be adapted in order to decrease the risk of damage by the pine processionary moth, and that predictive tools for infestation dynamics can be based on forest growth models. Numéro de notice : A2014-745 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1016/j.foreco.2014.08.038 En ligne : https://doi.org/10.1016/j.foreco.2014.08.038 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=75920
in Forest ecology and management > vol 334 [15/12/2014] . - pp 185 - 192[article]European perspective on the development of planted forests, including projections to 2065 / Gert-Jan Nabuurs in New Zealand Journal of Forestry Science, vol 44 (Decembre 2014)
[article]
Titre : European perspective on the development of planted forests, including projections to 2065 Type de document : Article/Communication Auteurs : Gert-Jan Nabuurs, Auteur ; Mart-Jan Schelhaas, Auteur ; et al., Auteur Année de publication : 2014 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] approvisionnement
[Termes IGN] conversion forestière
[Termes IGN] Europe (géographie politique)
[Termes IGN] feuillu
[Termes IGN] Pinophyta
[Vedettes matières IGN] Economie forestièreRésumé : (auteur) Background : The 27 countries in the European Union have a combined total of 177 million ha of forested and other wooded land. These are mainly characterised as semi-natural, multi-functional forests. Only about 13 million ha are characterised as plantationsi, although an additional 47 million ha are regarded as planted forests (Forest Europe 2011). European forests are highly diverse due to centuries of management in countries with different cultural objectives. Often the current management is nature oriented and so forests may not be used primarily for wood production. Wood provides only a small part of the income for many of the 16 million private owners according to the Confédération Européenne des Propriétaires Forestiers (CEPF 2013). These circumstances, plus sluggish demand for wood brought about by the current economic crisis, have generated challenges for the forestry sector. Demand for wood is expected to increase with expansion of the green economy and an increased emphasis on the use of bioenergy.
Methods : Three forest management scenarios (analysed with the EFISCEN model) were used to project supply in response to demand for wood from EU forests over the next 50 years.
Results : Shortening of broadleaved forest rotation length and planting 50% of the felled area with fast-growing coniferous species could increase coniferous wood supply from 473 to 561 million m3 y-1. Demand could reach more than 1200 million m3 y-1 by 2065.
Conclusions : Conversion of 50% of broadleaved forest in EU27 countries to coniferous forest is not likely to satisfy the increased demand for wood expected by 2065.Numéro de notice : A2014-689 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1186/1179-5395-44-S1-S8 Date de publication en ligne : 26/11/2014 En ligne : https://doi.org/10.1186/1179-5395-44-S1-S8 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100675
in New Zealand Journal of Forestry Science > vol 44 (Decembre 2014)[article]A hybrid framework for single tree detection from airborne laser scanning data: A case study in temperate mature coniferous forests in Ontario, Canada / Junjie Zhang in ISPRS Journal of photogrammetry and remote sensing, vol 98 (December 2014)
[article]
Titre : A hybrid framework for single tree detection from airborne laser scanning data: A case study in temperate mature coniferous forests in Ontario, Canada Type de document : Article/Communication Auteurs : Junjie Zhang, Auteur ; Gunho Sohn, Auteur ; Mathieu Brédif , Auteur Année de publication : 2014 Article en page(s) : pp 44 - 57 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] arbre (flore)
[Termes IGN] détection d'objet
[Termes IGN] hauteur des arbres
[Termes IGN] méthode de Monte-Carlo
[Termes IGN] modèle stochastique
[Termes IGN] Pinophyta
[Termes IGN] traitement d'imageRésumé : (Auteur) This study presents a hybrid framework for single tree detection from airborne laser scanning (ALS) data by integrating low-level image processing techniques into a high-level probabilistic framework. The proposed approach modeled tree crowns in a forest plot as a configuration of circular objects. We took advantage of low-level image processing techniques to generate candidate configurations from the canopy height model (CHM): the treetop positions were sampled within the over-extracted local maxima via local maxima filtering, and the crown sizes were derived from marker-controlled watershed segmentation using corresponding treetops as markers. The configuration containing the best possible set of detected tree objects was estimated by a global optimization solver. To achieve this, we introduced a Gibbs energy, which contains a data term that judges the fitness of the objects with respect to the data, and a prior term that prevents severe overlapping between tree crowns on the configuration space. The energy was then embedded into a Markov Chain Monte Carlo (MCMC) dynamics coupled with a simulated annealing to find its global minimum. In this research, we also proposed a Monte Carlo-based sampling method for parameter estimation. We tested the method on a temperate mature coniferous forest in Ontario, Canada and also on simulated coniferous forest plots with different degrees of crown overlap. The experimental results showed the effectiveness of our proposed method, which was capable of reducing the commission errors produced by local maxima filtering, thus increasing the overall detection accuracy by approximately 10% on all of the datasets. Numéro de notice : A2014-631 Affiliation des auteurs : LASTIG MATIS+Ext (2012-2019) Thématique : FORET Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2014.08.007 Date de publication en ligne : 20/10/2014 En ligne : https://doi.org/10.1016/j.isprsjprs.2014.08.007 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=75047
in ISPRS Journal of photogrammetry and remote sensing > vol 98 (December 2014) . - pp 44 - 57[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 081-2014121 RAB Revue Centre de documentation En réserve L003 Disponible Impact of management on nutrients, carbon, and energy in aboveground biomass components of mid-rotation loblolly pine (pinus taeda L.) plantations / Dehai Zhao in Annals of Forest Science, vol 71 n° 8 (December 2014)
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Titre : Impact of management on nutrients, carbon, and energy in aboveground biomass components of mid-rotation loblolly pine (pinus taeda L.) plantations Type de document : Article/Communication Auteurs : Dehai Zhao, Auteur ; Michael Kane, Auteur ; Robert Teskey, Auteur ; et al., Auteur Année de publication : 2014 Article en page(s) : pp 843 - 851 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Végétation
[Termes IGN] nutrition végétale
[Termes IGN] pineraie
[Termes IGN] Pinus taeda
[Termes IGN] puits de carbone
[Termes IGN] récolte de boisRésumé : (Auteur) Context : To sustainably manage loblolly pine plantations for bioenergy and carbon sequestration, accurate information is required on the relationships between management regimes and energy, carbon, and nutrient export.
Aims : The effects of cultural intensity and planting density were investigated with respect to energy, carbon, and essential nutrients in aboveground biomass of mid-rotation loblolly pine plantations, and the effects of harvesting scenarios on export of nutrients were tested.
Methods : Destructive biomass sampling of a 12 years-old loblolly pine culture/density experiment, and analysis of variance were used to assess the effects of cultural intensity (operational vs. intensive) and six planting densities ranging from 741 to 4,448 trees ha−1. Two harvesting scenarios (stem-only vs. whole-tree harvesting) were assessed in terms of energy, carbon, and nutrient export.
Results : The concentrations of energy, carbon, and nutrients varied significantly among stem wood, bark, branch, and foliage components. Cultural intensity and planting density did not significantly affect these concentrations. Differences in energy, carbon and nutrient contents among treatments were mainly mediated by changes in total biomass. Nutrient contents were affected by either cultural intensity or planting density, or both. Stem-only harvesting removed 71–79% of aboveground energy and carbon, 29–45% of N, 28–44% of P, 44–57% of K, 51–65% of Ca, and 50–61% of Mg.
Conclusions : Stem-only harvesting would be preferred to whole-tree harvesting, from a site nutrient conservation perspective.Numéro de notice : A2014-579 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1007/s13595-014-0384-2 Date de publication en ligne : 22/05/2014 En ligne : https://doi.org/10.1007/s13595-014-0384-2 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=74769
in Annals of Forest Science > vol 71 n° 8 (December 2014) . - pp 843 - 851[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 016-2014081 SL Revue Centre de documentation Revues en salle Disponible Economics of harvesting uneven-aged forest stands in Fennoscandia / Janne Rämo in Scandinavian journal of forest research, vol 29 n° 8 (October 2014)PermalinkImpact of local slope and aspect assessed from LiDAR records on tree diameter in radiata pine (Pinus radiata D. Don) plantations / Hanieh Saremi in Annals of Forest Science, vol 71 n° 7 (October 2014)PermalinkIntegration of Lidar and Landsat to estimate forest canopy cover in coastal British Columbia / Oumer S. Ahmed in Photogrammetric Engineering & Remote Sensing, PERS, vol 80 n° 10 (October 2014)PermalinkQuantification et cartographie de la structure forestière à partir de la texture des images Pléiades / Benoit Beguet in Revue Française de Photogrammétrie et de Télédétection, n° 208 (Octobre 2014)PermalinkSocial status-mediated tree-ring responses to climate of Abies alba and Fagus sylvatica shift in importance with increasing stand basal area / François Lebourgeois in Forest ecology and management, Vol 328 (September 2014)PermalinkImpact de l'année 2003 sur la vitalité du douglas vert sur le secteur du Parc naturel régional du Haut-Languedoc / Jean Lemaire in Forêt entreprise, n° 218 (septembre-octobre 2014)PermalinkCross-correlation of diameter measures for the co-registration of forest inventory plots with airborne laser scanning data / Jean-Matthieu Monnet in Forests, vol 5 n° 9 (September 2014)PermalinkDeriving Predictive relationships of carotenoid content at the canopy level in a conifer forest using hyperspectral imagery and model simulation / Rocío Hernández-Clemente in IEEE Transactions on geoscience and remote sensing, vol 52 n° 8 Tome 2 (August 2014)PermalinkEstimation of the timber quality of scots pine with terrestrial laser scanning / Ville Kankare in Forests, vol 5 n° 8 (August 2014)PermalinkImproved capability in stone pine forest mapping and management in Lebanon using hyperspectral CHTIS-Proba data relative to Landsat ETM+ / Mohamad Awad in Photogrammetric Engineering & Remote Sensing, PERS, vol 80 n° 8 (August 2014)Permalink