Archives par mot-clé : Forests

Soil carbon debt of 12,000 years of human land use

by J. Sanderman et al., July 2017 in PNAS


Human appropriation of land for agriculture has greatly altered the terrestrial carbon balance, creating a large but uncertain car- bon debt in soils. Estimating the size and spatial distribution of soil organic carbon (SOC) loss due to land use and land cover change has been difficult but is a critical step in understand- ing whether SOC sequestration can be an effective climate mitigation strategy.

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Why there are so many species of tropical trees and other organisms

by Washington University in St-Louis, June 29, 2017 in ScienceDaily


If aliens sent an exploratory mission to Earth, one of the first things they’d notice — after the fluffy white clouds and blue oceans of our water world — would be the way vegetation grades from exuberance at the equator through moderation at mid-latitudes toward monotony at higher ones. We all learn about this biodiversity gradient in school, but why does it exist?

La crédibilité climat de l’UE menacée par les règles concernant la forêt

by  Dr. Joanna House, 16 juin 2017, in Euractiv


L’atténuation du changement climatique grâce au secteur forestier doit être mesurée par une approche scientifique objective. Elle ne doit pas permettre aux États de masquer les impacts des politiques responsables de l’augmentation nette de leurs émissions.

Dr Joanna House est maitre de conférence en sciences et politique environnementales à l’Institut Cabot, à l’Université de Bristol. Elle co-signe cette tribune avec d’autres spécialistes de l’environnement. 

Earth’s forests just grew 9% in a new satellite survey

by J.F. Bastin et al., May 11, 2017 in ScienceDaily

in Science May 11, 2017

The Age of Exploration may be long past, but even in the 21st century, our maps can still get a major update. Using satellite imagery, a new study has found hidden forests all over the world—almost enough for a second Amazon—in areas with little moisture known as drylands.

 


A new estimate of dryland forests suggests that the global forest cover is at least 9 percent higher than previously thought. The finding will help reduce uncertainties surrounding terrestrial carbon sink estimates.

See also L‘équipe d’un chercheur belge découvre 467 millions d’hectares de forêt passés sous les radars

Methane emissions from trees

Tree trunks act as methane source in upland forests

by University of Delaware, March 30, 2017


Methane is about 25 times stronger than carbon dioxide, with some estimates as high as 33 times stronger due to its effects when it is in the atmosphere.

Because of methane’s global warming potential, identifying the sources and « sinks » or storehouses of this greenhouse gas is critical for measuring and understanding its implications across ecosystems.

Daniel L. Warner, Samuel Villarreal, Kelsey McWilliams, Shreeram Inamdar, Rodrigo Vargas. Carbon Dioxide and Methane Fluxes From Tree Stems, Coarse Woody Debris, and Soils in an Upland Temperate ForestEcosystems, 2017; DOI: 10.1007/s10021-016-0106-8