`A lollipop forest is better than none'

I love the way a young tree sketches out its final form. Even a seedling can tell you what shape it hopes to draw on the sky, 100 feet higher and a century on. Gazing out at our front-of-house trio of oaks, launched from acorns a mere 14 years ago, a half-closed eye expands them easily from leafy, 10-foot saplings into fully-fledged giants of the forest.

It depends, of course, which kind of forest we're talking about: a forester's forest or a birdwatcher's. A forester's oak tree doesn't have all those low, spreading branches for thrushes to perch on: the trunk goes straight up, uninterrupted, for 8 or 10 metres. The wayward forking at the top leader-shoots of our trees should have been singled by pruning years ago. As for the trio's companions on the seaward side of the house - lop-sided, wind-shorn oak survivors, hunched in odd corners of the acre - they're "wolves", in silvicultural terms, and the first to be thinned from any serious forest.

Now that Ireland is launched into the business of broad-leafed forestry, 20-year grants and all, we might as well prepare ourselves for what it's going to look like in the countryside. We're not talking of natural woodland here, but of commercial plantations in blocks quite as dense and disciplined as those of conifer forestry. Indeed, the long commitments of broadleaf growing - 60 to 80 years for ash and sycamore, 100 to 120 years for beech, 120 to 160 years or more for oak - leave even less room for haphazard management.

This comes across forcefully in a glossy paperback from COFORD, the National Council for Forest Research and Development. Growing Broadleaves (£15) is the first up-to-date guide to hardwood silviculture, in Irish conditions, on Irish soils. This book will fix the planning and appearance of many thousands of hectares of deciduous trees, planted on farmland in place of grass or cereals.

Ash, sycamore, wild cherry, beech and oak are the species on offer, a choice decided largely by Irish experience of growth and yield in forests around the country. Ash is most sought-after (think of half a million hurleys used each year) and even fussier about its site than beech or oak - almost none of the land originally bought for State forestry was fit to grow it. All the broadleaf species are planted at what seems an extraordinary density - 6,600 oaks to the hectare, for example, which leaves the young trees 75 cm apart in rows at every two metres. Given their natural space, they would grow big, heavy branches and make forks - which is not what the trade wants at all. Crowded together, the only way is up, and any branches stay small and die and drop off, leaving no big knots in the trunks: this is called "natural pruning".

If the trees were left like this, however, and not allowed to make a decent crown, the crucial 8-10 metres of bare, straight, sawmill-worthy trunk would not put on its proper diameter. Thus, at about 35 years for oak and beech, earlier for ash and sycamore, the plantation is given its first thinning towards the final, carefully selected, crop. Sometimes there will be underplanting, to protect the stems from light, or plantations will be mixed from the start (oak with larch, ash with beech), all of it finely timed to serve the same strategy.

In its early life, crowded and rustling, the plantation should be a happy hunting-ground for insects and birds. It changes colour and mood with the season, which is a lot more than rye-grass does. And if, in its final decades, it looks a bit like a child's drawing of a wood - ranks of lollipop trees with nothing underneath them - a lollipop broadleaf forest is enormously better than none.

I am pleased to see sycamore getting some respect at last, after all the scorn of it as "a weed". It has served the west particularly well, crouched around farmhouses at the very brink of the Atlantic. But sycamore can be noble, too, topping 30 metres in 80 years, and its longevity compares with oaks: there are sycamores 500 years old in central Europe.

The big, old sycamores sometimes have a wavy, decorative grain, making a beautiful veneer for high-class violins: timber of this sort is fetching £1,700 a cubic metre. Even the ordinary tree has a splendidly white wood for furniture - as if to atone for the darkness of its shade.

The big surprise in the list is the wild cherry. It was the tree that puzzled me on a recent visit to Ballycumber, the officially-backed demonstration farm woodland near Clara, in Co Offaly.* But cherry is actually one of the most valuable timber species in Europe, taking a fine, dark polish, like mahogany.

Wild cherry in a hedge, while spectacular in flower and a rapid grower, rarely reaches the potential 25 metres of its 80-year life: a grove of small, suckered trees is its more usual fate in Ireland. It insists on growing branches and hanging on to them, even planted at 4,000 to the hectare. But it is recommended here as an ideal tree for mixtures in small woodlands, or a potentially valuable grove, carefully pruned as it grows, in a corner of the farm.

Broadleaf forestry raises interesting issues of "provenance". The seed for our ash forests can safely come from hedgerow trees. Most of the best mature beeches have already been harvested, but their genes live on in the young trees of naturally regenerated stands. Until recently, most of our oaks plantations were planted from homesaved acorns, but now demand for plants is outstripping supply.

The main author of Growing Broadleaves, Prof Padraic Joyce of UCD, points out that when the big estates sold their prize oaks, "little by way of reconstitution took place and the unwanted culls have matured to form gnarled old trees with heavy branches and poor stem quality. Although such trees are of little commercial value, they are often highly regarded from an aesthetic viewpoint by recreationists and by conservationists."

And in his piece on the wild cherry, he notes: "Its characteristic early and spectacular flowering is highly valued by the public, who regard its blossom as `a thing of beauty' in the landscape, especially along woodland margins. It is also considered to be a source of sustenance for many birds and insects."

Not actually all that much of a recreationist himself, one might imagine. * For details of regular, and free, guided tours of Ballycumber, ring John Brosnan at 01-276 0026 or 087-2320321.