07 Dec 2012:
Populations of Large, Old Trees
Are Dying Off Worldwide, Report Says
Populations of large, old trees, which provide critical ecosystem services, are declining across the planet
and could eventually disappear altogether in some regions, according to a report by three leading ecologists. Writing in the journal Science
, the scientists say the loss of large trees is occurring in all kinds of forests and at all altitudes, from Yosemite National Park in the U.S., to African savannahs, to Amazon rainforests and northern boreal forests. In California, Costa Rica, and Spain, for instance, such trees could disappear within a century, the authors wrote. The losses are being driven by numerous factors, including land clearing, agricultural expansion, human-designed fire regimes, logging, invasive species, and climate change. “We are talking about the loss of the biggest living organisms on the planet, of the largest flowering plants on the planet, of organisms that play a key role in regulating and enriching our world,” said Bill Laurance
, a scientist at James Cook University in Australia, who authored the report along with David Lindenmayer of the ARC Centre of Excellence for Environmental Decisions (CEED) and Jerry Franklin of Washington University. In addition to providing critical food and shelter for numerous species and playing critical roles in hydrological systems, large trees also store significant amounts of carbon.