The National Trust has surveyed 50 of its sites and found tree losses have been the greatest in more than two decades and in some cases the Great Storm of October 1987.
High winds and wet weather throughout the winter have seen some places lose hundreds of trees, including many ancient trees.
The National Trust cares for 25,000 hectares of woodland across England, Wales and Northern Ireland.
National Trust nature and wildlife specialist Matthew Oates said: "People love and need trees, and the loss of specimen trees in gardens and parks, and of ancient beeches and oaks in the woods and wider countryside hurts us all, and damages much wildlife. We value and venerate these old sentinels and need to become increasingly aware of the power of the weather.
"Increased storminess, and increased extreme weather events generally, are likely to stress trees further, especially veteran trees. We will have to think carefully about where we establish trees and what species we plant."
The Killerton Estate in Devon has suffered some of the biggest losses, with more than 500 trees blown over by the storms, including 20 significant trees within the design landscape.
South West England and Wales were worst hit. Tatton Park, Attingham Park, Nymans and Scotney Castle also suffered.
A few historically or regionally important trees have been lost, such as a rare black walnut at Hatfield Forest, which was the largest in Essex.
Stourhead head gardener Alan Power said: "Over the past three or four weeks we’ve lost 20 trees in the garden, with up to 400 across the wider estate.
"We've lost one spectacular oak tree, which could well be between 200-250 years old and planted by the man who created the landscape garden at Stourhead.
"Storms like we’ve seen this winter are all part of the estate's history. If people can come along and they do see the trees on the ground they'll realise it's not just a one off, it happens throughout the history of the estate and it is part of working so closely with nature."
Examples of tree losses across National Trust places:
Trengwainton Garden in Cornwall – Around 30 trees have been lost, mainly from the shelterbelt that surrounds the garden. To date, more than 1,000 hours have been spent clearing up the storm damage, with more work still required.
Trelissick in Cornwall –Lost three old lime trees, several mature oak and two very large scots pine in the park
Stourhead in Wiltshire - Up to 400 trees lost across the wider estate, including a 200-year-old oak.
Mottisfont and New Forest in Hampshire – There has been a loss of up to 300 trees across three main areas of wind-blown woodland. In addition to this there have been a number of scattered trees across roads and rivers.
Selborne and Ludshott Commons in Hampshire – Lost around 300 trees, which will require three months clean-up work.
Ashridge in Hertfordshire – Full details not yet known, but a number of ancient and veteran trees have been lost, including a large ash and five pollards in Frisden beeches and in excess of 100 birch trees.
Croft Castle and Parkland in Herefordshire – Lost around 40 trees including a chestnut from the chestnut avenue.
Osterley Park in Middlesex – Lost three 250-300 year old English oaks, two 150 year old cedar of Lebanon and a 100 year old sycamore
Hatfield Forest in Essex – Lost 18th century black walnut and 250 year old oak along with a lot of superficial damage to trees and some structural damage to pollards
Penbryn in Ceredigion - Lost a 5.2m girth ash, which is an exceptionally old ash tree
Castle Ward in County Down – Up to 70 trees have come down over the last few months as a result of the strong winds, including 8 significant trees.