§ Mr. Redmond
asked the Secretary of State for the Environment whether he is aware of the growing anxiety that microscopic bacteria which feed on methane gas are killing off trees and plants in England and Wales; whether this is due to defective pipes which distribute the gas; and whether he will have detailed and extensive investigations made into this matter.
§ Mr. Peter Walker
Owing to the characteristics of natural gas and its method of distribution, there is a greater risk of leakage which might affect trees when old street mains carry natural gas than when they are carrying town gas. For this reason both before and after conversion special leakage tests are made by gas boards and there is a systematic programme of repairs to mains. When natural gas leaks, bacterial action on the methane in the gas can reduce the oxygen content in the soil. A detailed study is being carried out in three sample areas in order to keep a check on the possible effects of natural gas on trees. In addition a number of local authorities have been asked to report details of tree deaths.192W
Relatively few cases of tree deaths due to natural gas have so far been reported. My Department, in conjunction with the Department of Trade and Industry and the Gas Council, will continue to keep a close watch on the position.