This winter's extreme winds caused the biggest loss of trees in more than 20 years, according to the National Trust.
Some of their sites have seen the greatest number of trees knocked down since the Great Storm of 1987.
A number of rare and historic specimens have been lost, including the largest tree in Essex.
Researchers from the Trust are worried that the winds will have severely weakened many older trees.
The National Trust is one of Britain's biggest landowners and look after 25,000 hectares of trees across England, Wales and Northern Ireland.
After the extreme weather of the past few months they've now carried out a survey at more than 50 of their sites.
While they don't know the full number of trees that have gone, they say it is the greatest loss of trees in two decades.
In some cases, greater damage has been done than during the Great Storm of 1987.
The saturated state of the earth following the prolonged downpours had greatly weakened the soil. As a result of the 10-15 storms over the winter, many trees gave way.
'It is definitely the greatest period of loss since January 1990,' said Matthew Oates from the Trust.
'In 1987 and 1990 it was really the volume that was lost that was worrying, this time it is the quality of the trees. We've lost a lot of significant, old sentinel trees, ancient beech, oak and ash trees.'
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