Nine-tenths of owners were prompted to buy woodlands to get in more in touch with wildlife, said Woodlands.co.uk, which creates and sells small woods.
Owners planted more than 220,000 new trees in recent years, it said. They put up 3,800 nest boxes, dug 350 ponds and installed 350 beehives.
Spokeswoman Hannah Bourne said: "Private individuals preserve our woodlands. This is wildlife gardening on a grand scale with average wood sizes of 9.2 acres."
Colleague Angus Hanton said: "Gardeners often take inspiration from woodlands for wild and natural planting schemes, such as those at this year’s Chelsea Flower Show.
"These owners have gone one step further in safeguarding pieces of woodland across the UK, where they can enjoy an abundance of flora and fauna in its natural habitat."
The survey found 14 per cent of owners had invited local community groups into their woodland, while owners made over 60 visits a year to their land.
Reasons for buying included a desire for relaxation and solitude, fulfilling interests in wildlife or conservation, and sourcing a supply of wood fuel.
97% have been trained for owning a wood
69% know the names of more tree species than before buying their wood
66% obtained tree and wood advice from magazines
60% are self-taught using technical manuals and publications
53% got advice from private foresters and other small wood owners
38% got advice from the Forestry Commission
34% have taken woodland management courses