Environmental degradation is causing serious detrimental health impacts for humans, but protecting natural habitats can reverse this and supply positive health benefits, according to a new WWF report. "Our research confirms what we know instinctively: human health is inextricably linked to the health of the planet," says Chris Elliot, WWF's Executive Director of Conservation. 'Vital Sites: The Contribution of Protected Areas to Human Health' notes that the World Health Organization (WHO) estimates between 23 and 25% of the global disease burden could be avoided by improved management of environmental conditions. The report singles out deforestation for its key impacts on human health. "Deforestation is a double blow to human health," says Elliot. "It increases the spread of certain diseases while destroying plants and animals that may hold the key to treating illnesses that plague millions of people." Protecting natural landscapes can contribute positively to human health through protecting future medicinal resources, reducing the impacts of pollution, toxins and weather extremes and providing recreational places that support physical and mental well-being. In the forests of Borneo alone in the past decade WWF reports discoveries of trees and shrubs that may be used to treat cancer, HIV and malaria. In all, 422 new plant species have been discovered in Borneo in the last 25 years, but deforestation puts them and others waiting to be discovered at risk. "When WWF stresses the importance of biodiversity, it's not just because we enjoy a variety of trees or frogs in a forest. It's because the science tells us that those trees and frogs are vital to the forest's health, and the forest's health is vital to our health," says Elliot. The report stresses that while people are good at cultivating plants whose value is known, we have a poor track record at conserving those seen as having little use for humans. The problem is, habitat destruction is eliminating potentially valuable species before they can even be discovered, let alone tested.