While talking to Ruth Nussbaum, the co-founder and co-director of ProForest, I was feeling guilty about my notebook. I needed one urgently, so had dashed into the nearest newsagent and bought the first I saw.

But I should have looked for one with a Forestry Stewardship Council (FSC) mark that guaranteed the paper came from forests managed in a sustainable way.

Just as individuals fail to follow through their theoretical commitment to environmental issues in their purchasing choices, so do many businesses, governments, and non-government organisations.

Forestry and its related manufacturing industries are complex businesses, often involving long and convoluted supply chains.

It can be hard for even the most well-meaning UK-based retailer to find out whether the timber product they buy has come from a well-managed forest or not.

And governments which have committed to buying supplies only from sustainable sources need to do a lot of research to trace back everything from schoolbooks and pencils, to loo rolls and disposable hospital operating gowns, to their origin in a tropical or temperate forest.

Dr Nussbaum and her co-director Neil Judd set up ProForest in 2000 after they had spent several years working in forest certification.

They realised many companies and organisations needed practical advice and training from forestry experts, if they were to understand all the issues involved in sustainable forest management, and meet the requirements of certification.

Dr Nussbaum said: "What we try to do is to bridge the gap between policy commitment and practice.

"For example, lots of banks have policies that say they won't invest in companies that are contributing to bad forest management.

"But how does a bank manager in Hull make sure a Bolivian supplier is managing a forest well?"

The company now employs 14 staff, all of whom have higher degrees in natural resource management, or the biological sciences.

They have an extraordinary range of skills and work experience in more than 40 countries, and speak ten languages between them.

Some are ecologists and some have a background in agro-forestry, while others have worked as ethnobotanists, or in community development with forest dwellers and forestry workers. Dr Nussbaum explained: "We have to have staff who are as comfortable in a policy debate in Hong Kong as when they are deep in a forest two days' travel from anywhere."

Sometimes, ProForest actually helps to develop international standards in forestry and the use of other natural resources.

For example, they have advised the Round Table on sustainable palm oil, an initiative which brought together the World Wildlife Fund, Unilever, Swiss supermarkets, and producers in Malaysia and Indonesia.

Palm oil is an ingredient in hundreds of the processed foodstuffs we buy from supermarkets.

Primary rainforest is being felled to make way for oil palm plantations, with great loss of biodiversity, implications for climate change, and a negative impact on local people.

ProForest advisors have helped the Round Table to develop a definition of what sustainable' actually means in palm oil production, and precisely what good technical, social, and environmental management approaches are needed.

Recently, they have been working on ways to identify and map high conservation value forests and how to train company employees so they understand which parts of the forests where they are working are most vulnerable and need greatest protection.

They are the official advisors to the UK government on its sustainable timber purchasing policy, and are also involved in the European Union's major programme trying to combat illegal logging and the resulting destruction of forests - a major problem in countries from Russia to Indonesia.

The Royal Horticultural Society uses the organisation's auditing service to ensure wood products from unsustainable sources are not sold at the Chelsea Flower Show.

ProForest advisor Joyce Lam is helping Marks & Spencer to ensure its range of furniture comes from well-managed sources, by establishing a chain of custody' following back the supply chain through China, where most of it is manufactured, to the other countries which supply the timber.

Advisor Ishmael Jesse-Dodoo is working closely with the five largest timber companies in Ghana to help them meet the standards needed for certification.

It should soon be possible to buy FSC-marked teak garden furniture from one of these companies.

The UK market is currently flooded with non-certified teak - the kind often found at weekend sales in temporary venues - and this comes mainly from Burma, a country with a poor environmental and human rights record.

Looking at satellite pictures of Brazil or Indonesia, the scale and rapidity of old-growth forest destruction is daunting.

But Dr Nussbaum believes that a pragmatic, positive approach will yield real benefits: She added: "You're not going to stop people using natural resources. The best way to save the planet is not to boycott companies, but to work with people to find sustainable ways of doing it."

n Contacts: ProForest: www.proforest.net Forest Stewardship Council: www.fsc-uk.org