Land ownership in Scotland has become even more concentrated despite two decades of land reform legislation, with green capital investors becoming increasingly dominant, a study has found.

Andy Wightman, the land reform campaigner who published a groundbreaking look at Scottish land distribution in 2012, has calculated that half of all privately owned rural land in Scotland, or 3.2m hectares (7.9m acres), is held by just 433 people and companies, with only 2.76% of rural Scotland held by community groups.

His analysis shows that hereditary peers own less land than previously, while the number of private investors who specialise in financially lucrative “green capital” schemes to create forestry and peat restoration projects has surged.

Scotland’s third largest landowner is Gresham House, an investment firm taken over recently by the US private equity firm Searchlight Capital; Wightman’s detailed analysis of Land Registry records has established it owns 53,775 hectares across 161 separate holdings.

The Duke of Buccleuch, who was Scotland’s largest private landowner when Wightman did his last survey in 2012, has been voluntarily selling land to local residents, yet is still second, holding 66,345 hectares, 32% less than in 2012.

Buccleuch Estates has been supplanted as Scotland’s largest landowner by Anders Povlsen, the Danish Asos mail order billionaire, who owns 88,296 hectares spread across 12 estates; his Highland empire has grown by 37% since 2012.

Povlsen is one of a number of extremely wealthy Scandinavians buying up Highland estates, including Strathconon Estates Ltd (previously known as Kirkbi Estates Ltd), an arm of the philanthropic investment firm owned by the family of the Lego heir Kirk Kristiansen.

Wightman calculates that the estate at Strathconon near Inverness has grown to 36,933 hectares, making Kirkbi Scotland’s ninth largest private land owner. Kirkbi believes its holdings to be slightly smaller, at approximately 34,500 hectares.

Wightman’s data has come from records held by Registers of Scotland, the official land register, and more accurate land mass data from Ordnance Survey. That has allowed him to recalculate the figures he originally published in 2012 in his book The Poor Had No Lawyers. Modern records show that 440 owners owned half of Scotland’s private land in 2012, not the 432 he originally reported.

Wightman and other land campaigners argue the latest data is evidence that the Scottish parliament’s attempts to empower community buyouts to diversify rural landownership has failed, despite enacting several laws to strengthen right to buy laws and asset transfers.

Despite several significant buyouts, including the sale of 4,000 hectares on Langholm Moor to local residents by Buccleuch Estates and the purchase of the island of Ulva off Mull, part-funded with £4.4m from the government-backed Scottish Land Fund, sales of that scale are very rare.

Scottish government figures show the amount of community-owned land has grown by just 40,048 hectares in the last decade, from 172,294 hectares in 2012 to 212,342 hectares. By comparison, Scotland’s state-owned forestry agency owns 656,000 hectares.

In 2013, Alex Salmond, the then first minister, set a target of 1m hectares in community ownership by 2020, yet under Holyrood’s right to buy laws only 0.24% of rural Scotland had come into community ownership over the Past 20 years, Wightman said.

“Scotland has the most concentrated pattern of land ownership in Europe,” he said. “There’s nothing in the current reforms which will make any substantial change to that. If we’re serious about changing that, we need to embrace reforms which will absolutely deliver.”

Pressed to do more to diversify ownership by the Scottish Land Commission, a quango set up in 2017, the Scottish government is proposing new powers to allow ministers to break up large estates of more than 1,000 hectares that go on sale into smaller parcels, a process known as lotting.

Ministers argue that lotting will allow more communities, farmers, woodland-creators and businesses to own land, at more affordable prices. The dramatic surge in land acquisitions by natural capital investors such as Gresham House has pushed land prices to record levels and substantially increased competition.

Community Land Scotland, which represents community owners and is campaigning for a new target to reach 10% of rural land to be community-owned by 2030, argues lotting will have little impact since only a tiny fraction of rural land is sold each year.

Wightman and CLS argue that more radical action is needed, such as including inherited land and company share transfers in land reform measures, and properly taxing land, alongside much greater financial support and shared ownership options for community buyers.

Wightman has found investment firms such as Gresham House build up significant overall holdings by buying smaller forests, estates or farms that escape the new 1,000-hectare threshold for lotting. He has encountered another investment firm trying to buy 14 properties covering nearly 6,000 hectares, none of which would meet the lotting threshold.

Gresham House, which markets its forestry projects as tax-efficient investments, insists they are ultimately owned by its clients. “Forests managed by Gresham House make a major contribution to Scotland’s rural economy and support hundreds of jobs,” it said.

Mairi Gougeon, the Scottish government’s land reform secretary, said the “targeted and proportionate” powers set out in the land reform bill would apply to more than 50% of Scotland.

“I would like to see us own more of our own land and waters and for that public ownership to be clearly undertaken in the interests of everyone who lives in Scotland. But without the full powers, resources and levers of independence, our ability to do so is limited,” she said.