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New insights in the modeling and simulation of tree and stand level variables in Mediterranean mixed forests in the present context of climate change / Diego Rodríguez de Prado (2022)  

Public Titre : New insights in the modeling and simulation of tree and stand level variables in Mediterranean mixed forests in the present context of climate change Type de document : Thèse/HDR Auteurs : Diego Rodríguez de Prado, Auteur ; Celia Herrero de Aza, Directeur de thèse ; Felipe Bravo Oviedo, Directeur de thèse Editeur : Valladolid [Espagne] : Université de Valladolid Année de publication : 2022 Importance : 168 p. Format : 21 x 30 cm Note générale : bibliographie Doctoral dissertation, Valladolid University Langues : Anglais (eng) Descripteur : [Termes IGN] allométrie [Termes IGN] climat aride [Termes IGN] croissance des arbres [Termes IGN] Espagne [Termes IGN] Fagus sylvatica [Termes IGN] forêt méditerranéenne [Termes IGN] gestion forestière adaptative [Termes IGN] hauteur des arbres [Termes IGN] inventaire forestier étranger (données) [Termes IGN] modélisation de la forêt [Termes IGN] peuplement mélangé [Termes IGN] Pinus nigra [Termes IGN] Pinus pinaster [Termes IGN] Pinus sylvestris [Termes IGN] puits de carbone [Termes IGN] Quercus pyrenaica [Vedettes matières IGN] Végétation et changement climatique Index. décimale : THESE Thèses et HDR Résumé : (auteur) An increase of droughts intensity and frequency episodes combined with new extreme climate events are predicted to appear in the Mediterranean Basin due to global warming. In this context, mixed forests have become a sustainable opportunity to mitigate the effects of climate change. Species mixing may lead to the provision of a greater variety of ecosystem services and products while increasing temporal stability compared to pure forests. The development of new models that explain different tree and stand level variables may be vital to better understand the structure, composition and dynamics of this type of forests. In addition, it is essential to analyze how climate may influence these variables in order to design adaptive and sustainable management guidelines for mixed forests under future climate change scenarios. In this study, we sought to advance in the modelization and simulation of different tree and stand level variables along a range of different forest and aridity conditions in Spain. To achieve that, climate-dependent models were fitted using data from the Spanish National Forest Inventory and the WorldClim databases. We focused our study on fifteen Mediterranean tree species from the Pinus, Quercus, and Fagus genus. In our first study, we analyzed how climate may potentially influence the maximum stand carrying capacity, by terms of the maximum stand carrying capacity (SDImax), for the species under study in pure stands. This variable was chosen because its importance in (1) managing density and (2) defining species mixing proportions in mixed forest stands. To do that, climate-dependent MSDR models were fitted for each species under study. 35 different climatic annual and seasonal variables (temperature, precipitation, evapotranspiration, aridity indexes) were simultaneously included into the models. In this study, climate was found to have significant influence on MSDR, and therefore on the maximum stand carrying capacity (SDImax). The best climate-dependent MSDR models indicated that climatic variables related to temperature better explained the influence of climate on MSDR. Specifically, seasonal (MXTi) and annual (MXT) maximum temperatures were the most representative climatic variables explaining changes in MSDR. Based on the selected seasonal variables, spring and summer were consistently appeared as key periods. A common trend in SDImax variation for coniferous and broadleaf species was found, with higher SDImax values negatively linked to temperature and positively linked to precipitation. This trend suggested that aridity may play a key role reducing the maximum stand 12 carrying capacity of the main Mediterranean tree species. In addition, the impact of climate on maximum stand carrying capacity was evaluated by the creation of the Q index. In general, broadleaved species presented higher values of Q indexes than coniferous species, suggesting that the maximum stand carrying capacity of the first ones would suffer more the influence of potential climate changes. Our findings highlight the importance of using specific climatic variables to better characterize how they affect MSDR. Since we saw that aridity could play a key role influencing stand level variables such as SDImax, we aimed to analyze how it may influence tree growth and tree allometry. Moreover, we aimed to analyze how species mixing effects may influence these variables on mixed forests. Thus, two more studies focused on 29 two-species Mediterranean mixtures were developed. To study the influence of aridity and species mixing on tree growth, the basal area increment within a span of five years (BAI5), was modelled based on individual tree size, stand development and other variables of site and competition. Two distance independent competition indexes were considered: total stand basal area (BA) representing size-symmetric competition, and the basal area of trees larger than the subject tree (BAL) representing size-asymmetric competition. To uncover the complex mixing effects on basal area increment at tree level, competition indexes were splitting into intraspecific and interspecific components. All possible combinations of competition structures were included and tested in the BAI models. Positive, negative or neutral mixing effects were determined by comparing the intraspecific and interspecific component of the selected models. Then, the biological interactions taking place between species were determined based on size-symmetric and sizeasymmetric competition. Finally, the influence of aridity on basal area increment was studied including the De Martonne Index into the BAI models. A common trend among mixtures was found with higher productivity in mixed than pure stands, suggesting that BAI values may increase with the increment of species diversity. Based on model parameters, a novel approach to determine potential biological interactions between species in mixed forests was also presented in this study. Competition seemed to be the most representative biological interaction in coniferconifer mixtures, since neutralism and facilitation may occur more frequently in conifer-broadleaved and broadleaved-broadleaved mixtures. Our findings also suggested that tree productivity may be significantly limited by arid conditions, excepting for Pinus halepensis and Pinus pinea [...] Note de contenu : 1- Introduction 2- Objectives 3- Data 4- Methods 5- Results 6- Discussion Conclusion Numéro de notice : 24064 Affiliation des auteurs : non IGN Thématique : FORET Nature : Thèse étrangère Note de thèse : Thèse de Doctorat : Systemes Forestiers Durables : Valladolid : 2022 Organisme de stage : Sustainable Forest Management Research Institute (Université de Valladolid) DOI : sans En ligne : https://uvadoc.uva.es/handle/10324/55195 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102046