No Convincing Evidence For Decline In Tropical Forests, Says University Of Leeds Geographer - AFP

[hatrack]

Claims that tropical forests are declining cannot be backed up by hard evidence, according to new research from the University of Leeds. This major challenge to conventional thinking is the surprising finding of a study published 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 deforestation. "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 problems. "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."

EDIT

http://www.terradaily.com/reports/No_Convincing_Evidence_For_Decline_In_Tropical_Forests_999.html

[proud2BlibKansan]

1. Which part of the trees are being chopped down

does this guy not undertstand??

[OKIsItJustMe]

4. Like he said, it's complicated

In California, between logging and fires, I assume that the forests are diminishing, but what about the country as a whole? In New York, the trend is just the opposite:
http://www.fs.fed.us/ne/newtown_square/publications/brochures/pdfs/state_forests/ny_forest.pdf

Forest cover is the predominant type of natural vegetation in New York. The original forests in New York covered nearly the entire land area. By 1880, most of the forest land was cleared for agriculture, leaving only about 25 percent of the land in forest. The 1993 inventory shows 62 percent of the land in forest. In view of the population growth and development that has taken place since colonial settlement began around 1625, the present level of forest cover is remarkable. Reasons for this are threefold. First, growth has been concentrated in areas adjacent to New York City and several other large cities. Second, there has been a sizable decrease in the amount of land used for farming. The land used for cropland and pasture covers 18 percent of the State today, a substantial decline from the 28 percent farmed in 1968. Although some of the lost farmland has been developed, most of it was left abandoned and has reverted to forest land through natural regeneration. This process has helped offset the loss of other forest land for development. Third, forest land conserved as part of stateowned parks, state forests, and recreation areas has increased.

...

The author is no cook. You might want to read the entire article before jumping to conclusions.

[RaleighNCDUer]

6. There is a huge difference between temperate forests and

tropical forests.

A temperate forest may have 40 species per acre, while a tropical forest may have 400. Tropical forests are incredibly more diverse, and their loss is equivalently more profound. Preservation and re-forestation is almost entirely a temperate forest phenomenon. The forest losses in Brazil, Central America, Indonesia, and central Africa are NOT being replaced at anything near the rate they are being destroyed. Maybe it is not happening quite as quickly as was thought, but that just makes it a slower moving train wreck.

[OKIsItJustMe]

7. I'm sorry if I was unclear

I didn't mean to say that temperate forests and tropical forests were equivalent, only that our perceptions may be misleading (using an illustrative example which might be a bit more familiar to residents of the US.)

(Read the article.)

[RaleighNCDUer]

9. OK, I see what you're saying, but I disagree with the premise.

A premise which, actually, is not in agreement with the text of the article, which is that the data is unclear, contradictory and incomplete.

With the certain knowledge of 10,000 acres of old growth tropical forests being cleared daily, I think that the differences in the numbers is more easily attributable to inaccurate older data, when the satellite and computer systems were less comprehensive than we have today. If there is reforestation in previously cut areas, there still remains the fact that a reforested 30 year old forest cannot be compared to a primal, uncut forest with 500 year old growth, either in biologic density or as a carbon sink.

[OKIsItJustMe]

10. Actually, I don't think we disagree at all

My only point was that things are complicated; that knowledge is incomplete; that there may be things going on that are not quantified.

I agree with all of your other points.

[XemaSab]

8. Don't assume that our forests are diminishing

Most forests in California are on public land. I think it's probably staying pretty steady over the long term here. :shrug:

[OKIsItJustMe]

11. Thank you for reinforcing my point

Without precise measurements, who can say?

[papau]

2. No Convincing Evidence" is not what Dr Grainger said-the extent isn't known-but decline is fact

[phantom power]

3. You know, this is the kind of topic where I don't see the need for "debate."

It's hard for me to believe that this can't be resolved one way or another with satellite imagery.

[OKIsItJustMe]

5. It would seem like it, but...

...

He is cautious about the apparent slight rise. "We would expect to see some increase in estimates as we use more accurate satellite sensors. This is even apparent in FAO"s data. It is sad that only in the last 10 years have we begun to make full use of the satellite technology at our disposal."

...

To give us more reliable data Dr Grainger says we need a World Forest Observatory to monitor changes in forests in the tropics and elsewhere. "What is happening to the tropical forests is so important, both to the peoples of tropical countries and to future trends in biodiversity and global climate, that we can no longer put off investing in an independent scientific monitoring programme that can combine satellite and ground data to give a reliable picture," he said.

...

[losthills]

12. Numbers of trees don't tell the story.

Once ecosystems have been destroyed, you can't get them back by planting the same number of trees.

There is much wrong with this picture, and one of the things wrong is that the author is starting with United Nations data. Another is that he is not an ecologist....