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Large trees dominate carbon storage in forests east of the cascade crest in the united states pacific northwest / David J. Mildrexler in Frontiers in forests and global change, 3 (11/2020) 

Public Citation [article]  inFrontiers in forests and global change > 3 (11/2020) . - 1-15 Titre : Large trees dominate carbon storage in forests east of the cascade crest in the united states pacific northwest Type de document : Électronique Auteurs : David J. Mildrexler ; Logan T. Berner ; Beverly E. Law ; Richard A. Birdsey ; William R. Moomaw Année de publication : 2020 Article en page(s) : 1-15 Langues : Anglais (eng) Catégories : [CBNPMP-Géographique] Etats-Unis [CBNPMP-Thématique] Gestion forestière (conservation de la biodiversité, réserves biologiques) [CBNPMP-Thématique] Relations climat-végétation Résumé : Large-diameter trees store disproportionally massive amounts of carbon and are a major driver of carbon cycle dynamics in forests worldwide. In the temperate forests of the western United States, proposed changes to Forest Plans would significantly weaken protections for a large portion of trees greater than 53 cm (21 inches) in diameter (herein referred to as “large-diameter trees”) across 11.5 million acres (∼4.7 million ha) of National Forest lands. This study is among the first to report how carbon storage in large trees and forest ecosystems would be affected by a proposed policy. We examined the proportion of large-diameter trees on National Forest lands east of the Cascade Mountains crest in Oregon and Washington, their contribution to overall aboveground carbon (AGC) storage, and the potential reduction in carbon stocks resulting from widespread harvest. We analyzed forest inventory data collected on 3,335 plots and found that large trees play a major role in the accumulated carbon stock of these forests. Tree AGC (kg) increases sharply with tree diameter at breast height (DBH; cm) among five dominant tree species. Large trees accounted for 2.0 to 3.7% of all stems (DBH ≥ 1” or 2.54 cm) among five tree species; but held 33 to 46% of the total AGC stored by each species. Pooled across the five dominant species, large trees accounted for 3% of the 636,520 trees occurring on the inventory plots but stored 42% of the total AGC. A recently proposed large-scale vegetation management project that involved widespread harvest of large trees, mostly grand fir, would have removed ∼44% of the AGC stored in these large-diameter trees, and released a large amount of carbon dioxide to the atmosphere. Given the urgency of keeping additional carbon out of the atmosphere and continuing carbon accumulation from the atmosphere to protect the climate system, it would be prudent to continue protecting ecosystems with large trees for their carbon stores, and also for their co-benefits of habitat for biodiversity, resilience to drought and fire, and microclimate buffering under future climate extremes. Lien pérenne : DOI : 10.3389/ffgc.2020.594274 Permalink : https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=143452 Mildrexler, David J., Berner, Logan T., Law, Beverly E., Birdsey, Richard A., Moomaw, William R. 2020 Large trees dominate carbon storage in forests east of the cascade crest in the united states pacific northwest. Frontiers in forests and global change, 3: 1-15.

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Consultable Article (2020) URL

À propos des variantes émergentes du canyoning dans le sud de l’Europe et en Amérique du Nord / André Suchet (2010)

Public Citation est un tiré à part de 75 - 2010 (Géographie et cultures) Titre : À propos des variantes émergentes du canyoning dans le sud de l’Europe et en Amérique du Nord Type de document : Tiré à part de revue Auteurs : André Suchet, Auteur Année de publication : 2010 Importance : 229-246 Langues : Français (fre) Catégories : [CBNPMP-Géographique] Canada [CBNPMP-Géographique] Etats-Unis [CBNPMP-Géographique] Europe [CBNPMP-Thématique] Relations et interactions individus-milieux Résumé : Après avoir construit le concept d’éthique de pratique, cette recherche expose les cas du wild-boaring et du clean canyoneering qui constituent des variantes émergentes du canyoning. L’éthique du clean canyoneering, c’est-à-dire progresser techniquement sans poser de points fixes en canyon, s’inscrit dans une expérience précise du wilderness états-unien. À l’inverse, l’éthique du wild-boaring se compose d’un esprit de conquête, héritier de la spéléologie exploratoire et de l’alpinisme européen du XIXe siècle. Il s’agit de traverser de nouveaux sites, même s’ils se trouvent encombrés, buissonnants et peu accessibles. L’article traite des relations à l’environnement. Lien pérenne : DOI : 10.4000/gc.1677 Permalink : https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=144696 Suchet, André 2010 À propos des variantes émergentes du canyoning dans le sud de l’Europe et en Amérique du Nord. Géographie et cultures, 75 : 229-246.

Exemplaires (1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
28213	Suchet	Tiré à part	Bureaux	Espaces naturels sensibles	Consultable

Scale dependence of native and alien species richness in North American floras / Michael W Palmer in Preslia, 78 (2006) 

Public Citation [article]  inPreslia > 78 (2006) . - 427-436 Titre : Scale dependence of native and alien species richness in North American floras Type de document : Électronique Auteurs : Michael W Palmer Année de publication : 2006 Article en page(s) : 427-436 Langues : Anglais (eng) Catégories : [CBNPMP-Géographique] Etats-Unis [CBNPMP-Thématique] Plantes subspontanées, naturalisées, envahissantes Résumé : I analyzed data from 1870 vascular floras from regions within North America to assess whether the determinants of native and alien diversity vary as a function of spatial grain. Moving window multiple regression revealed that richness of both native and alien species exhibit the expected species-area relationship, latitudinal gradient, elevation gradient, and year of publication effect. However, the strength of these factors varied between native and alien species, and as a function of scale. Alien diversity was more predictable than native diversity, and is more strongly related to elevation and latitude. For both groups, the latitudinal gradient is most pronounced at broad grains, and the elevational gradient is most pronounced at fine grains. Permalink : https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=142470 Palmer, Michael W 2006 Scale dependence of native and alien species richness in North American floras. Preslia, 78: 427-436.

Documents numériques

Consultable Article (2006) Adobe Acrobat PDF