Some products are not covered by the EU Timber Regulation (EUTR), which requires companies to make sure that the wood their products are made from comes from a legal source.
The WWF study was designed to see if companies that were selling non-EUTR covered products - such as chairs, musical instruments and toys - had done sufficient checks to ensure they were at least made from wood from legal sources. 26 products from 17 different companies were tested.
In nearly a third of the products sent for laboratory analysis, the results found that the wood was different to the one declared by the retailer, and nearly half of the companies were selling products made from timber from areas that experience high levels of illegal logging.
Most of the companies were either unable or not prepared to tell researchers where the wood came from, even when they were told by WWF that they were selling products made of high risk wood. Some, however, have engaged with WWF to work out how best to improve their processes.
In the WWF timber testing work there were seven companies selling timber from regions where there are risks of illegal logging. These companies did not have information on their websites about their policy on ensuring the wood in their products is from a legal or sustainable source.
Julia Young, Manager of WWF's Global Forest and Trade Network programme at WWF-UK said: "We purchased goods from 17 companies, and not one could provide evidence that they had carried out sufficient due diligence. We cannot continue to have a market where customers cannot be sure the product they buy is made from the wood declared. In the absence of better information from companies that their wood has come from a legally or sustainably logged forest, customers are in the dark.
"We're calling for improvements to the EUTR, as currently companies can still legally sell certain products that have been made of illegally logged wood. We also want far more transparency on sourcing practices and performance.
"We are heartened that as a result of this work, new businesses are now engaging with us to find out how to improve their due diligence, and 40 others have already signed up to our campaign. The forest campaign involves a pledge to buy from legal and sustainable sources. This is the right way to go and we want more companies to take this challenge and their responsibility seriously."
Almost 70,000 people have signed the WWF-UK #SaveForests petition.
The European Union Timber Regulation (EUTR) puts obligations on businesses that trade in timber and timber related products. It applies to timber originating in the domestic EU market, as well as from third non-EU countries.
Report - Do Timber Products in the UK Stack UP?
The European Union Timber Regulation (EUTR)
WWF-UK #SaveForests petition
WWF Global Forest and Trade Network UK