Increasingly, the UK market is demanding evidence to support legality and sustainability claims. For example, the UK public-sector bodies such as housing, schools, hospitals and construction account for around 20 to 40 per cent of timber consumption. Environmental requirements are increasingly demanding that materials come from a sustainable and legal source. Chain of custody serves as proof of the material's environmental soundness. Forest certification is the process of auditing forests to ascertain whether they are managed according to an agreed set of principles and criteria. The paper trail known as the chain of custody tracks the certified raw material or product through every stage of the process, so that manufacturers and specifiers are guaranteed peace of mind. The two main certification schemes available in the UK are the Forest Stewardship Council (FSC) and Programme for the Endorsement of Forest Certification Schemes (PEFC). Forests that are certified for their management standards are able to display that the frequency of planting exceeds that of harvest, and that wildlife as well as indigenous people are protected through careful management of their natural environment. Ensuring that the materials specified are environmentally sourced is an important criterion for public-sector schemes, and increasingly so for private schemes too. The scope of applications for wood products means that there is no need for the specifier to look any further than a reliable timber supplier.