Fires, felling and agriculture are whittling Europe's forests down into isolated patches, threatening to speed up desertification and deplete wildlife, a UN report warned Tuesday.
Isolated forest patches, caused through what is called fragmentation, are more vulnerable to climate change and threaten biodiversity, the United Nations Environment Programme report said.
They are also less able "to stabilise soils and supply sufficient water to the cities, companies and communities that rely on such ecosystems," it said.
Although forests in Europe are expanding around 800,000 hectares (1.9 billion acres) a year, fragmentation is threatening the region's potential to combat climate change, it said.
In the Carpathian Mountains across central and eastern Europe, for example, privately owned forests have been felled to make way for hotels and mass tourism, endangering fauna such as bears and lynxes.
Fragmentation, coupled with climate change, is meanwhile increasing the risk of forest fires, burning 500,000 hectares each year in the Mediterranean region, according to the report.
The United Nations "estimates that without better forest management necessary for combating desertification, 80 million people living in the Mediterranean region may have access to less than 500 cubic metres of water each year by 2025."
The UN Environment Programme is working with scientists to draw up maps of areas that need to be replanted to help reconnect fragmented forests. The maps will submitted at a June 14-16 ministerial meeting in Oslo.
Explore further: Land-restoration expert cautions: 'Nature never forgets nor forgives'