Illegal logging has fallen by 22 percent worldwide in the past decade but remains a huge problem from Brazil to Indonesia, a study showed on Thursday. It also said that China was the main importer and processor of illegal timber, often sold to companies in countries including the United States, Japan and Britain as plywood or furniture worth billions of dollars a year. “Total global production of illegal timber has fallen by 22 percent since 2002,” according to the report by the British Chatham House think tank focused on Brazil, Indonesia, Cameroon, Ghana and Malaysia. It said that 17 million hectares (42 million acres) of forests - the size of Uruguay or Florida - had been preserved by the slowdown. Trees also help to slow climate change by storing carbon dioxide, the main greenhouse gas. “Illegal logging remains a major problem,” Sam Lawson , a co-author of the report, told Reuters. “The report shows that stopping illegal logging ... is reasonably cost efficient in terms of the climate and development.” Better enforcement of logging permits helps to raise tax receipts as well as protect forests. The report said that illegal logging had “dropped by 50 per cent in Cameroon, by between 50 and 75 per cent in the Brazilian Amazon, and by 75 per cent in Indonesia in the last decade.” Trends in Ghana and Malaysia were unclear. Together the five account for 40 percent of world illegal production in 2002 - the study assumed that illegal felling rates were unchanged in other nations from Russia to Papua New Guinea. But the 154-page report estimated that more than 100 million cubic meters of illegal timber were still chopped down annually worldwide. “If laid end to end the illegal logs would encircle the globe more than 10 times over,” it said. Illegal timber still accounted for between 35 and 72 percent of logging in the Brazilian Amazon, 22-35 percent in Cameroon, 59-65 percent in Ghana, 40-61 percent in Indonesia and 14-25 percent in Malaysia. In 2008, five importers studied - the United States, Japan, Britain, France and the Netherlands - bought 17 million cubic meters of illegal timber and wood products worth around $8.4 billion, much of it from China. “China is the world's top importer and exporter of illegal wood,” it said, estimating annual Chinese imports of 20 million cubic meters.