Family Fagaceae
Quercus Robur

The Oak is the largest and longest-lived of our native trees and a very familiar object in the landscape in most parts of the British Isles. The sturdy, massive trunk, the broad, rounded outline of its head, its wide-spreading lower limbs, the wavy form of its leaves, and the egg-and-cup-shaped fruit, are characters that cannot be confused with any other tree.
The human centenarian is regarded with reverence, although he may have nothing beyond his great age to commend him; but we think of the long period of history of which he has been a spectator, possible an active maker of history. The huge Oak has probably lived through several such periods. Compared with the Oak, man is but of mushroom growth. It does not produce an acorn until sixty or seventy years old, and even then it is not mature. Not till a century and a half have passed over its head is its timber fit for use, and as a rule it is not felled under the age of two hundred years. Many oaks are left to a much greater age, or we should not have still with us so many venerable specimens, and where they have not been left until partially decayed, the timber is found to be still very valuable when finally cut down.
One of these patriarchs of the forest, known as the Gelenos Oak, and stood about four miles from Newport, Monmouthshire, cut down in 1810, yielded 2,426 cubic feet of sound timber and six tons of bark. The timber and bark from this one tree were about equal to the average produce of three acres of oak coppice after fifteen years’ growth.
The Oak is most abundant on clay soils, but is at its best when growing in deep sandy loam, where there is also plenty of humus. Its roots, in such soil, strike down to a depth of about five feet.
Full-grown, it varies in height from sixty to one hundred and thirty feet, and difference depending upon situation; the tallest being those that have been drawn up in forests, at the expense of their branches. Trees growing freely in the open are of less height, and are made to appear comparative dwarfs by the huge proportions of the bole. In the forest this may be up to ten feet in girth, but in isolated specimens, may be as much as thirty-six feet.
The thick, rough bark is deeply furrowed in a large network pattern, which affords temporary hiding-places for many kinds of insects. The Oak is more persistently attacked by insects than any other tree, and one authority has tabulated about five hundred that get their living, mainly or entirely, from their attacks on the foliage, bark, or timber. With some species this warfare is waged so extensively that in some years, by early summer, the trees are almost divested of their foliage, and a new crop of leaves becomes a necessity. But the reserve forces of the Oak are quite equal to this drain, and the tree does not appear to suffer.
The Oak flowers in April or May and the blossoms are of two distinct forms – male and female. The males are borne at intervals along a hanging stalk, two or three inches in length. They are green and inconspicuous. The female flowers are fewer, and will be found on short erect stalks above the male catkins. Each female flower consists of a calyx, invested by a number of overlapping scales, and enclosing an ovary with three styles. The ovary is divided into three cells, each containing two seed-eggs. An acorn should therefore contain six kernels, but, as a rule, only one of the seed-eggs develops. The overlapping scales at the base of the female flower become the rough cup that holds the acorn.
Under the name “Common Oak” two distinct species, Quercus Robur and Q. petraea are included. The former is most abundant in the south of England occurring as a native tree in the deeper, heavier soils. Q. petraea is common in the west and north on shallower and sandier soils. Q. Robur may easily be distinguished by the presence of two lobes at the base of each leaf and by the absence of the minute star-shaped hairs which characterise the under surface of the leaves of Q. petraea. The stalks of the leaves and acorns vary considerably in length in both species. Also, the fact that hybrids between the two are of widespread occurrence has led to considerable confusion in identification and to the view that there is only one variable species of Oak in Britain.
Several Oaks of foreign origin are also grown in our parks and open spaces; among then the Holm Oak (Quercus Ilex) whose evergreen leaves have toothed or plain edges, and occasionally the lower ones developed holly-like marginal spines. It has a much thinner, more even bark than out native Oak, and of a black colour.
The Turkey Oak (Quercus Cerris) is a much larger tree, attaining similar heights to our British species, but more pyramidal in form and with thick, greyish bark. The stalk less acorn-cups are covered with mossy scales, and the whole tree is of straighter growth, and the branches are not so gnarled and twisted as Quercus Robur.