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Sick trees

Sick trees

作者:花虔樘  时间:2019-03-02 01:09:10  人气:

The health of British trees, already among the worst in Europe, continued to decline last year, according to the Forestry Authority, part of the Forestry Commission. ‘The decline,’ say its researchers, ‘was particularly marked for Scots pine and oak.’ Derek Redfern, the authority’s chief pathologist, identified insects and wind damage as likely causes. The survey revealed that more than 80 per cent of oaks had lost a quarter or more of their crown density – a normal measure of tree sickness – compared with 54 per cent in 1990. Attack from winter moths is identified as the main problem. For Scots pine, where ‘wind throw’ is a major problem, especially for trees planted in exposed areas on thin soil, the proportion of sick trees rose from 41 per cent to 64 per cent. Other countries have blamed the thinning of tree crowns on air pollution, mainly acid rain. But, says Redfern,