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 
great accuracy.

???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