TIMBER IN BOGS.
It is stated in the second report of the commissioners on the bogs of Ireland, that three distinct growths of timber, covered by three distinct masses of bog, are discovered on examination. But whether these morasses were at first formed by the destruction of whole forests, or merely by the stagnation of water in places where its current was choked by the fall of a few trees, and by accumulations of branches and leaves, carried down from the surrounding hills, is a question.
Professor Davy is of opinion, that in many places where forests had grown undisturbed, the trees on the outside of the woods grew stronger than the rest, from their exposure to the air and sun; and that, when mankind attempted to establish themselves near these forests, they cut down the large trees on their borders, which opened the internal part, where the trees were weak and slender, to the influence of the wind, which, as is commonly to be seen in such circumstances, had immediate power to sweep down the whole of the internal parts of the forest. The large timber obstructed the passage of vegetable recrement, and of earth falling towards the rivers; the weak timber, in the internal part of the forest after it had fallen, soon decayed, and became the food of future vegetation.
Mr. Kirwan observes, that whatever trees are found in bogs, though the wood may be perfectly sound, the bark of the timber has uniformly disappeared, and the decomposition of this bark forms a considerable part of the nutritive substance of morasses. Notwithstanding this circumstance, tanning is not to be obtained in analysing bogs; their antiseptic quality is however indisputable, for animal and vegetable substances are frequently found at a great depth in bogs, without their seeming to have suffered any decay; these substances cannot have been deposited in them at a very remote period, because their form and texture is such as were common a few centuries ago. In 1786 there were found, seventeen feet below the surface of a bog in Mr. Kirwan’s district, a woollen coat of coarse, but even, network, exactly in the form of what is now called a spencer; a razor, with a wooden handle, some iron heads of arrows, and large wooden bowls, some only half made, were also found, with the remains of turning tools: these were obviously the wreck of a workshop, which was probably situated on the borders of a forest. The coat was presented by him to the Antiquarian Society. These circumstances countenance the supposition, that the encroachments of men upon forests destroyed the first barriers against the force of the wind, and that afterwards, according to sir H. Davy’s suggestion, the trees of weaker growth, which had not room to expand, or air and sunshine to promote their increase, soon gave way to the elements.