Archive for Forest dieback
There was a fascinating meeting at the International Institute for Environment and Development last night. Professor Virgílio Viana, visiting fellow and director general of the Amazon Sustainability Foundation talked about the project he oversees in the Amazonas, the largest Brazilian Amazon state. A short summary of what he covered is in this video:
Viana’s presentation outlined the successes of the project, which has seen a switch in governmental policy from handing out free chainsaws towards a cultural value of seeing standing trees as being worth more than felled ones. Read the rest of this entry »
While much of the alarm over global deforestation centres on the Amazon rainforest, which continues at a shocking rate, African rainforests receive relatively little attention. Yet a study published today in Nature demonstrates the increasing size of the carbon sink these forests contain: similar to Amazonian forests in per unit area terms.
A large international team of scientists, headed up by Simon Lewis at the University of Leeds, found that across 79 plots in ten African countries, the above-ground carbon storage increased by 0.63 Mg C per hectare per year, between 1968 and 2007. Scaling up to include unmeasured material — roots, small trees, rotting trees and so on — brings the continental increase in carbon storage to 0.34 Pg C (that’s 340 million tonnes of carbon) per year. Read the rest of this entry »
Old growth forest on the western United States is dying back at an increasing rate, accoring to a study published this week in Science magazine. The study, led by USGS biologist Phil van Mantgem, found that background mortality rates — those not directly attributable to some catastrophic effect, such as fire — have risen rapidly in recent decades.
The study, which used census data from 67 long-term plots located in ancient forests (average age 450 years, some sites in excess of 1000 years), found that mortality rates had increased at the vast majority of sites, whereas recruitment rates — replacement of dead trees with new ones — had neither increased or decreased over the same period.
The dieback couldn’t be pinned down to any local effects, such as pollution, local competition or fire prevention measures. Instead, say the study’s authors, regional warming and the ensuing water problems it brings — faster snowmelt leading to longer summer drought — are putting the strain on the trees. Read the rest of this entry »