By Mark Kinver
Science and environment reporter, BBC News
About one third of the world's forests are harvested for wood products
World forests face the dual challenge of climate change and the global economic crisis, a key UN report says.
It suggested that although the economic slowdown might reduce deforestation rates in the short term, it was also likely to lead to other problems.
One concern, would be a lack of investment in the sector and in forestry management.
The study by the UN Food and Agriculture Organization (FAO) was published on Monday.
It is timed to coincide with the start of UN World Forest Week.
CTS Nair, one of the report's lead authors and the FAO Forestry Department's chief economist, said the economic crisis was having "tremendous impacts - both positive and negative".
Forests cover 30% of total land area
Six million hectares of primary forests are lost each year
Annual net loss of forest cover is about 7.3m hectares
Native trees: ranges from seven species in Iceland to
more than 7,780 in Brazil
(Source: FAO Forest Resources Assessment 2005)
"You will find the forestry industries in a number of countries almost on the verge of collapse," he told BBC News.
For example, he said the construction of starter homes in the US and Canada had fallen from about two million units at the end of 2005 to less than 500,000 now.
This had led to a dramatic fall in the demand for wood products, which was affecting forest-based industries and export markets in developing nations.
However, Mr Nair added, the downturn was having some beneficial effects.
"We are seeing a decline in the prices of soya beans, palm oil and rubber etc," he explained.
"The prices have fallen drastically, so this means that the incentives for cultivating these crops have also gone down.
"As a result, the pressure to clear primary forest stands is also declining."
The report, State of the World's Forests 2009, also showed that the health of forests varied from region to region of the world.
"We see advances being made in places like Europe, but losses being made in places like Africa and especially developing countries," Mr Nair observed.
"For example, what we see in the case of Africa is that there is a growing population yet the productivity within agriculture has remained extremely low.
"There is very little diversification in terms of sources of income so there is a very high dependency level on land use and natural resources, such as timber."
"On the other hand, in places such as Asia where there has been rapid economic growth, people have moved out of agriculture to some extent and the pressure on the land has declined."
In recent years, the importance of the world's forests as carbon sinks has featured prominently in global climate policy discussions.
An initiative called Reducing Emissions from Deforestation and Degradation (Redd), which is likely to involve developed nations paying tropical forest-rich nations not to cut down trees, appears to be gaining support.
Mr Nair gave the scheme a cautious welcome: "In theory, it is an excellent idea but its implementation is going to be extremely tricky.
"If you look at the people involved in forest clearing, it is different people in different regions.
"For example, in Latin America, it is largely cattle rangers and soya bean planters. In South-East Asia, it is palm oil and rubber plantations.
"What we find is that it is not the smallholders, it is the big players who are working within a global market.
"So far, only the issue of what it is trying to achieve has been examined, the issue of how we are going to implement it has not really been discussed or examined."