I had another letter from a frequent correspondent recently, Dr Seaghan Ua Conchubhair of Oranmore in Co Galway. Dr Ua Con chubhair often writes to provide welcome encouragement and add a little extra information when the facts in "Weather Eye" are right, and to chide me gently if, as happens now and then, I get them wrong. His contribution on this occasion was prompted by a recent quote on this page from John le Carre's novel, A Small Town in Germany, which went in part: ". . . the trees were curved from childhood, bent by the blustering wind". Dr Ua Conchubhair remarked that trees like that are common in parts of Co Galway, and he was reminded of the time many, many years ago, when his father, a botanist, told him why this should be so.
A little wind is good for trees. It ensures an adequate supply of carbon dioxide for photosynthesis, and it facilitates the dissemination of pollen and seeds. But too much of it is harmful. In parts of the country regularly exposed to very strong winds, individual trees can be seen to have an asymmetrical appearance, with the branches appearing to be swept away to leeward - trailing like a wind-vane away from the deforming gales.
The condition arises because buds which would have produced branches on the windward face are swept away in infancy, and growth is restricted to the sheltered side. In Ireland, not surprisingly, the axis of deformation tends to be aligned from a south-westerly or westerly direction, although local anomalies to this general rule can be found in places where the topography is complex and obtrusive.
At first glance, trees like this give the appearance of "leaning away from the wind". But in most cases the trunks are vertical; the leaning illusion is produced by the asymmetry of the foliage. It may sometimes happen, however, that young trees are blown over or loosened in the soil after taking root; if normal vertical growth is then subsequently resumed, a permanent curvature of the trunk is apparent near the ground.
When trees regularly exposed to very strong winds grow within 10 miles or so of the sea, another factor contributes to their deformation. "Salt-burn", which occurs when the air is laden with sea salt, accentuates tree damage by attacking the foliage on the windward side.
In general, trees and bushes growing outside their optimum environment - both as regards their preferred climate and the general soil conditions - are more susceptible to malformation by wind and salt than those comfortably ensconced in their ancestral habitat.