The trust said community ownership was right "but don't abandon those communities", following the release of a joint Government and CABE report on asset transfer (HW, 26 November).
The charity, which manages spaces across the UK, said it had just taken on the former Pleasley Colliery near Mansfield and was supporting a friends group to manage the site.
"We provide the framework for them to safeguard the site," said Land Trust chief executive Euan Hall. "Should volunteer numbers dwindle or problems occur, we provide support as a fail-safe.
"The community needs to be supported, not just for few months or years but long term. That way we are not just creating the regeneration areas of the future."
But Hall asked: "Is it right to expect volunteers to do in their precious spare time what full-time, highly trained people get paid for?
"Open a space and suddenly you have to deal with public liability, financial control, land management, fundraising, marketing, biodiversity and planning."
The CABE report Community-Led Spaces did not go far enough in pointing out that most public open space was a liability, not an asset, said Hall. Some of it needed costly refurbishment or maintenance work and would not generate revenue or be subsidised.
"There are complex and onerous tasks in land ownership, not to mention liability. Financial implications could mean volunteers work not only for free but actually pay for the privilege," Hall explained.
"This tends to mean the work is left to a few hardy souls, gradually becoming more disenchanted. There has to be a constant source of support, not just during set up.
"If the trust is provided with an endowment or other income, we can offer the expertise, carry the risks and do the dirty work, allowing the community to manage land in a way that suits its needs."