'Which should have priority: deer or trees?'

Once again that great Highland estate Glenfeshie is attracting public interest, for the splendid 45,000-acre sweep of the Cairngorm mountains epitomises the key question facing landowners all over Scotland: which should have priority - deer or trees?

Glenfeshie was recently bought by Will Woodlands, a subsidiary of the trust set up by Angela Hobbins, an outstanding philanthropist. When her husband died, she put aside pounds 20m to form the Will Charity which has two main interests - medicine and forestry.

Alas, Mrs Hobbins died in July, but her passion for trees will be immortalised by Will Woodlands' purchase of Glenfeshie. When she spent a week there in June, she was entranced by the beauty and grandeur of the long glen which strikes north and south through the upland wilderness. Yet she was realistic enough to see that most of the higher ground is sadly impoverished and that, if the old Caledonian forest is ever to be restored, drastic measures will be needed.

The disappearance of the ancient forest remains mysterious. If you walk the bare moorland today, you will find abundant relics of the trees which once grew there. Pine roots protrude from the peat-hags, white and withered with age, but proof that the forest once clothed the hills to a height of 2,000 feet.

The main constituent of this great wood was the Scots or Caledonian pine, a beautiful tree with a pinkish glow to its bark, whose branches form lovely shapes when given space to develop. Then, over the millennia, adverse factors whittled the forest away: clearing to make room for agriculture, felling for ship-building or smelting, burning to flush out wolves or human enemies, a general deterioration of the climate and, last but not least, overgrazing by deer and sheep. Today only a few pockets of Caledonian pine remain.

It was Mrs Hobbins's wish that some of the ancient forest should be restored - but how best to do it? For the past 150 years Glenfeshie has been a sporting estate, renowned for its red deer, and today deer dominate the scene, the primary source of income and employment. Yet they are also destructive, and their ceaseless grazing prevents any natural regeneration.

Some conservationists claim all deer numbers should be drastically reduced all over the Highlands, and then the forest would start to re-establish itself. Others claim deer are far too mobile to make such a policy effective: they move from one estate to another and settle in any place that takes their fancy. A more realistic alternative is to bring deer numbers down, but also to fence the survivors out of certain blocks of land.

At the most recent count there were more than 1,200 deer on Glenfeshie, but already the estate stalkers have culled 100 stags, and the total stag cull will be nearly double that of previous years. Yet experience has shown Glenfeshie is particularly attractive to deer and, if any vacuum is created, more animals will come in from neighbouring estates. Will Woodlands therefore hopes it will be allowed to experiment with fencing, so that pine seedlings may have a chance to grow.

The new owners know they are setting out on a long-term journey. Already 28,000 acres of their ground are a national nature reserve, and they are about to meet representatives of Scottish Natural Heritage to renegotiate the agreements made between Lord Dulverton, a previous owner of Glenfeshie, and SNH's predecessor, the Nature Conservancy. They are anxious that members of the public should have maximum access compatible with conservation.

As James Garson, the estate manager, points out, when Will Woodlands decided to buy Glenfeshie it constituted it a charity and this gives it a substantial advantage. Whereas other properties change hands when the owners die, Glenfeshie is assured of consistent management. I hope my spirit will be able to look down and see the place 100 years from now - and I suspect it will smile.