No convincing evidence for decline in tropical forests
University of Leeds
8 January 2008
'Claims that tropical forests are declining cannot be backed up by
hard evidence, according to new research from the University of
This major challenge to conventional thinking is the surprising
finding of a study published today in the Proceedings of the US
National Academy of Sciences by Dr Alan Grainger, Senior Lecturer
in Geography and one of the world's leading experts on tropical
"Every few years we get a new estimate of the annual rate of
tropical deforestation,??? said Dr Grainger. ???They always seem
to show that these marvellous forests have only a short time left.
Unfortunately, everybody assumes that deforestation is happening
and fails to look at the bigger picture ??? what is happening to
forest area as a whole.???
In the first attempt for many years to chart the long-term trend
in tropical forest area,
he spent more than three years going through all available United
Nations data with a fine toothcomb ??? and found some serious
???The errors and inconsistencies I have discovered in the area
data raise too many questions to provide convincing support for
the accepted picture of tropical forest decline over the last 40
years,??? he said. ???Scientists all over the world who have used
these data to make predictions of species extinctions and the role
of forests in global climate change will find it helpful to
revisit their findings in the light of my study.???
Dr Grainger does not claim that tropical deforestation is not
occurring, as there is plenty of local evidence for that. But
owing to the lack of frequent scientific monitoring, something for
which he has campaigned for 25 years, we cannot use available data
to track the long-term global trend in tropical forest area with
???The picture is far more complicated than previously thought,???
he said. ???If there is no long-term net decline it suggests that
deforestation is being accompanied by a lot of natural
reforestation that we have not spotted.???'
Gabriel L. Espinosa
> BioEnergy and Sustainable Technology Society