Continental trees coming to a wood near you

Some of our best-loved species are at risk as environmental conditions change more rapidly than at any time since the last ice age

Corsican pine and walnut trees will replace beech and silver birch in the British landscape as global warming accelerates, a conference will be told next week.

Corsican pine and walnut trees will replace beech and silver birch in the British landscape as global warming accelerates, a conference will be told next week.

Spruce and oak will give way to sweet chestnut and Douglas fir, as the face of the countryside changes, while ash will boom for a time before dying back.

And it will all happen so fast that trees planted now will mature in a very different climate, forestry experts will tell the conference, organised by the Royal Horticultural Society (RHS) and the Forestry Commission, among others. It has even scheduled a French speaker to describe conditions around Bordeaux, expected to be replicated in southern England as the climate changes more rapidly than at any time since the last ice age.

Climatologists predict that global warming will bring Britain milder and wetter winters, and hotter and drier summers. Trees will quickly feel the difference.

Elliott Morley, the environment minister, who is to open the conference at Surrey University, says that the situation "may well be more urgent than we thought".

Experts believe that beech, which is particularly vulnerable to drought, will perhaps be the worst affected of all. Dr Chris Prior, head of horticultural sciences for the RHS, says: "It will be stressed under hot and dry conditions, particularly where it's growing on shallow soil. There's a definite feeling that in 50 to 100 years it won't thrive at all in the south-east of England."

Research showed that beech simply stopped growing for several years after the hot, dry summer of 1976, while hundreds of thousands of silver birch trees - another species susceptible to drought - died. Sessile oak is also expected to suffer from lower summer rainfall, while Norway and Sitka spruce are likely to do badly in the south, but better in the north as temperatures rise.

Corsican pine, by contrast, is expected to spread all over the country, and sweet chestnut, another tree with Mediterranean roots, as it were, is also expected to thrive. Walnut, which also likes heat, is predicted to be another winner. But ash and Douglas fir, while prospering initially, are likely to suffer as global warming continues.

The Forestry Commission says that the south will be hardest hit, with young trees and those in streets and hedgerows the first to suffer.

Sir Crispin Tickell, who has been environmental adviser to both John Major and Tony Blair, adds: "The current tree population is the product of a particular climate, and there is a risk that the environment is going to be substantially changed quite quickly.

"We are dealing with the possibility of fairly rapid change. If this is abrupt, say in the next 10 to 15 years, then a lot of trees could be at risk."

Dr Richard Smithers of the Woodland Trust adds: "There will be all sorts of changes in the way trees react and compete with each other. Different species will need to move across our landscape at different rates. This century we will go through a warming that has not been experienced for at least 10,000 years. It will almost certainly lead to a substantial change in our woods."

The great drought of 1976, he adds, was billed as an event that happens only once every 300 years, but now something similar is being forecast every decade. But what if there were two or three drought years in a row?

"That's when the face of the countryside could change big time," he says. "It does not even bear thinking about."

WINNERS

Ash

Sweet Chestnut

Corsican Pine

Douglas Fir

Walnut

LOSERS

Beech

Silver Birch

Norway Spruce

Sessile Oak

Sitka Spruce

HOSEPIPE BAN - AND IT'S ONLY JUNE

Summer is yet to begin in earnest, but householders across southern Britain already face a ban on hosepipes after one of the driest winters on record. Southern Water has ordered restrictions in parts of Sussex and warned that they are likely to spread.

Met Office figures show that rainfall across the country between November and May was the fourth lowest since 1914. A spokewoman for Southern Water said: "The past six months have all been below average. Even though it's rained recently that has only really helped to suppress demand by stopping people going out in the gardens."

Lizzie Thornton