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Fertilization modifies forest stand growth but not stand density: consequences for modelling stand dynamics in a changing climate / Hans Pretzsch in Forestry, an international journal of forest research, vol 95 n° 2 (April 2022)  

Public [article]  inForestry, an international journal of forest research > vol 95 n° 2 (April 2022) . - pp 187 - 200 Titre : Fertilization modifies forest stand growth but not stand density: consequences for modelling stand dynamics in a changing climate Type de document : Article/Communication Auteurs : Hans Pretzsch, Auteur ; Peter Biber, Auteur Année de publication : 2022 Article en page(s) : pp 187 - 200 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] Allemagne [Termes IGN] allométrie [Termes IGN] analyse comparative [Termes IGN] azote [Termes IGN] changement climatique [Termes IGN] croissance des arbres [Termes IGN] densité du peuplement [Termes IGN] dynamique de la végétation [Termes IGN] éclaircie (sylviculture) [Termes IGN] gestion forestière [Termes IGN] modèle statistique [Termes IGN] nutriment végétal [Termes IGN] Pinus sylvestris [Termes IGN] puits de carbone [Vedettes matières IGN] Foresterie Résumé : (auteur) Knowledge of the maximum forest stand density and the self-thinning process is important for understanding, modelling and scheduling thinnings in silviculture. The upper trajectories of stem number, N, vs mean diameter, dq or mean tree volume vs stem number are often used for quantifying maximum stand density. The long debate about how site conditions modify these relationships is presently revived due to global change. A crucial question is whether environmental conditions alter the trajectories themselves or just the velocity at which stands move along them. Our contribution is based on fully stocked plots from long-term Scots pine (Pinus sylvestris L.) fertilization experiments along an ecological gradient in South Germany. This allows us to compare the self-thinning trajectories of fertilized and unfertilized plots under different environmental conditions. We can show that repeated fertilization with nitrogen did not change the N ~ dq trajectories. Assuming that fertilization affects forests in a similar way as an ongoing atmospheric N-deposition, this means that presently growth, mortality, and volume accumulation in forest stands proceed faster in time but still follow the same N ~ dq allometric trajectories. Furthermore, we found that the level of the self-thinning line generally increases with the annual precipitation. The allometric self-thinning exponent, however, did not respond to environmental conditions. Finally, we quantitatively demonstrate and discuss the implications and consequences of the results regarding understanding and modelling forest stand dynamics, carbon sequestration and the development and adaptation of silvicultural guidelines in view of climate change. Numéro de notice : A2022-261 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1093/forestry/cpab036 Date de publication en ligne : 30/07/2021 En ligne : https://doi.org/10.1093/forestry/cpab036 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100249 [article]

Wood density reduced while wood volume growth accelerated in Central European forests since 1870 / Hans Pretzsch in Forest ecology and management, vol 429 (1 December 2018)  

Public [article]  inForest ecology and management > vol 429 (1 December 2018) . - pp 589 - 616 Titre : Wood density reduced while wood volume growth accelerated in Central European forests since 1870 Type de document : Article/Communication Auteurs : Hans Pretzsch, Auteur ; Peter Biber, Auteur ; Gerhard Schütze, Auteur ; Julia Kemmerer, Auteur ; Enno Uhl, Auteur Année de publication : 2018 Article en page(s) : pp 589 - 616 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] analyse diachronique [Termes IGN] biomasse [Termes IGN] changement climatique [Termes IGN] densité du bois [Termes IGN] Europe centrale [Termes IGN] forêt tempérée [Termes IGN] puits de carbone [Termes IGN] volume en bois [Vedettes matières IGN] Végétation et changement climatique Résumé : (Auteur) Forest stand growth dynamics in Central Europe have accelerated since 1870 due to a rise in temperature, extended growing seasons, and other components of climate change. Based on wood samples from the oldest existing experimental plots in Central Europe, we show that the dominant tree species Norway spruce (Picea abies (L.) H.Karst.), Scots pine (Pinus sylvestris L.), European beech (Fagus sylvatica L.), and sessile oak (Quercus petraea (Mattuschka) Liebl.) exhibit a significant decrease in wood density since more than 100 years. While stand and trees grow faster with respect to wood volume, we can show that wood density decreased by 8–12% since 1900. These results object a naïve direct transformation of volume growth trends into an accelerated biomass production. Since 1900, stand biomass increment increased 9–24 percentage points less compared to volume increment (29–100% increase reduces to 20–76%). For a given stem diameter and annual ring width, tree stability against windthrow, wood strength, energy content and C sequestration are even reduced under recent conditions. The generally decreased late wood density, partly going along with an increased early wood fraction, suggests the observed extension of the growing season and fertilization effect of dry deposition as the main causes. Our results indicate that current increased wood volume growth rates must not be straightforwardly converted into sequestrated C and biomass harvest potentials assuming historic values for wood density. This should be taken into account in monitoring, modeling, and utilization of carbon and biomass in forests under global change. Numéro de notice : A2018-466 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.foreco.2018.07.045 Date de publication en ligne : 03/08/2018 En ligne : https://doi.org/10.1016/j.foreco.2018.07.045 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91145 [article]