They note that the effects of logging
can last centuries in the forests
Madrid, Feb 13 (EFE) .- A team of
researchers, with Spanish participation, has consisted forest ecosystems suffer
from disturbances such as logging, for decades, even centuries, and that the
current effects of the Climate change is superimposed on the last consequences.
These are some of the main findings of
a study published in the journal PNAS, in which besides the difficulty in
discerning confirmed, on systems that have been subjected to disturbances for a
long time, between the effects of current climate change and those of past
human actions.
Susana Bernal, one of the authors of
this paper, detailed Efe that the interesting thing about this study is that
itself is a "clear purpose" of climate change on forest ecosystems,
but "not enough" to explain the changes observed.
To reach these conclusions,
researchers analyzed data for two years for the past 50 years -Weather,
atmospheric deposition and export of nutrients and forest inventories of the
Hubbard Brook Experimental Watershed in northeastern US.
One of the variables analyzed was the
change in efficiency in the retention of inorganic nitrogen, in particular
nitrate.
As pointed out by Bernal, nitrogen is
essential for all living beings of a nutrient system.
Besides the growth of forests,
nitrogen influences the carbon absorption capacity of ecosystems.
"The ability of forest ecosystems
to sequester carbon over there in the atmosphere is limited by the availability
of other essential elements, such as nitrogen or phosphorus," he stated
the researcher, who did this work when he was on a scholarship at the
University of Princeton.
The aforementioned American basins,
"perhaps the most studied in the world and more information is
available," have experienced a dramatic decline in the export of nitrogen
in recent decades (about 90 percent), according to Bernal.
Scientists have estimated that as much
climate change could account for 40 percent of that observed in the export of
nitrogen reduction, which usually occurs through the river water, and instead
at least 60 percent could be result of the long-term effects of logging.
Understand the complex interactions
between present and past disturbances is today one of the most difficult
scientific challenges, according to Bernal, today at the Center for Advanced
Studies of Blanes (Superior Council for Scientific Research).
Other work in this direction but few,
stressed, who studied the effect of long-term perturbations with a "data
base so powerful."
This study also involved the Cary
Institute of Ecosystem Studies (USA).