What's going on in the Outwoods

Fly Agaric mushrooms

The Outwoods in Autumn

The drought conditions that we experienced during the spring and summer this year look set to resulted in an early autumn, with many trees preparing to shed their leaves two or three weeks earlier than usual.

All of a tree's life processes are dependant on water; food manufacture, transport, storage and use all require water as do the trees defence mechanisms.

The largest single use of water in a tree is for the transport of dissolved nutrients and chemical messages from the root system to the leave. The movement of these essential materials takes place in columns of cells called xylem vessels, which are just below the bark. In the leaves are small holes called stomata through which carbon dioxide, which is used in photosynthesis, enters the leaves. On reaching the leaves water evaporates through the stomata, pulling up more water behind it. The rate of water movement through the tree can be rapid, in an ash tree for example water can move at a rate of 85 ft per hour, which means that a mature ash tree can get through 50 gallons of water a day!! In drought conditions, when a tree can't get sufficient water, it slows down the rate of water loss through its leaves by closing the stomata. As a result the tree is unable to absorb carbon dioxide, closing down the process of photosynthesis. When photosynthesis slows or stops so does the trees growth processes. As a result of the drought this summer the trees have grown very slowly and their annual growth rings will be much smaller than would be the case in a normal year. Another consequence of the prolonged period of dry weather will be that, because they've not been able to photosynthesise, the trees have used up valuable stored energy making making them more susceptible to attack by pests and disease. The long term effects on trees of this years dry summer is likely to be minimal, however with the climate becoming so unpredictable, trees and wildlife in general have much to contend with.