Another Life/Michael VineyThe yew tree just inside our gate was planted about 15 years ago as a small, prostrate starfish of twigs and leaves, fresh from its garden centre pot. Today it is simply huge - still only a couple of feet high, but stretching its branches in a multi-layered golden star, nearly five metres across.
All the fresh growth is a singing lemon-yellow, a brilliance that will slowly subside through the summer into yew's more usual and sombre green.
The tree is, of course, a clone of a special cultivar, just as the tall, dark towers of fastigiate "Irish" yews are cloned descendants of the original upright sapling brought down from Cuilcagh Mountain. That was in 1740, whereas Summergold, my gloriously recumbent golden cultivar, was bred and multiplied in Holland only in 1968.
Clones have been part of human cultivation since the very first cuttings were pushed into the soil and took root. Most cultivated olive trees, for example, have carried on the same genetic lines for thousands of years.
Clones support much of the massive gardening industry, as new vegetative propagation techniques enable growers to produce, perhaps, 20,000 identical individual seedlings from the tissue of a single plant.
But how much cloning is too much, how many clones too many? We seem to be drawing the line at people, but are getting used to the idea that, once the snags are ironed out, fields of cloned cattle and flocks of cloned sheep are only a matter of time.
How about cloned forests? Whole hillsides of cloned conifers wouldn't, perhaps, seem that odd; one Sitka spruce looks much like the next, to most people. But what about plantations of cloned oaks, ash, sycamore? Will we mind dividing woodland into "wild"and "factory" trees, the latter with near-identical heights, trunk-sizes, number and angle of branches and so on? Research for clonal forestry is actually well on its way in Ireland.
Until the current cutbacks in planting, Irish forest nurseries were producing 80 million plants a year, all but 13 million of them conifers. The best million of them, in forestry terms, are grown from rooted cuttings.
These cuttings are taken from a "hedge" of saplings grown from seeds taken from the best 50 or so Sitka families. By this method, one seed can produce up to 60 cuttings each year.
But there are pressures for even cheaper and more rapid mass production of genetically superior plantlets, both of conifers and broadleaved trees.
COFORD and Coillte are developing a new kind of micropropagation called somatic embryogenesis, in which seed embryo cells are cultured into clones known as "emblings" (a science-fiction sort of word: "The emblings crowded in around him, soft and silent, their blank faces lifted to the moon.").
This can be used to clone oak trees that are old enough to show their superior qualities (superior, that is, for timber production). The trouble is, says one COFORD report, "there are no tested, proven superior families of oak that would warrant the extra cost of vegetative propagation". Oaks are slow to provide the necessary acorns; it can take seven years for a good crop to occur. Once the cell lines are set up, however, they go on producing emblings like tireless machines; one cell line, in culture since 1995, continued to produce good quality embryos every six to eight weeks for the next six years.
There are concerns in Coillte - not very serious ones, I imagine - about the public acceptance of "clonal oak". And while the research for cloned Sitka spruce presses forward, the risks in planting whole forests with repetitions of the same genes are fully recognized. Forestry gurus Padraic Joyce and Niall O'Carroll agreed in their recent book, Sitka Spruce in Ireland (COFORD, €30) that the danger of relying too much on clonal forestry is even greater than planting too many monocultures of exotic species; the best defence against diseases and pests is diversity.
A thrush will still perch on a cloned oak, caterpillars will munch its leaves, lichens adorn its trunks and twigs. Even the wind will conspire to make one cloned tree just a little different from the next. But we shall know how they were made.
A magnificent celebration of difference in trees, whether engineered by nature or by people, makes the new Cassell's Trees of Britain and Northern Europe, (Weidenfeld Nicolson, £50) by David More and John White, the only book of its kind I shall ever need. Its hefty 800 pages (£50 in the UK) cover more than 1,800 species and cultivars, painted on the spot and in every diverse detail of bark, leaf and flower by the remarkable David More.
All the trees he shows are to some extent "imperfect", just as they grew and were damaged here and there by wind and insects, people or just time. There are 44 pages of wonderful oaks - all different, all real.