CHAP. CV.

CORYLA'CE^E. QUE'RCUS.

1811

sap is worked with the heart of oak (as it sometimes is), it will ultimatelytend to weaken and injure the building wherein it is used ; for, however fairand weil it may appear at first, it will most assuredly decay in a short time.”(p. 75.) “ For want of examining the original thickness of the sap [wood] of

oak trees, and the progress of its decay, and from finding so much of young treeswasted by the decaying of their sappy coats (which generally occupy a consi-derable space, particularly if the trees were very vigorous at the time of theirbeing felled), sbme have been led to imagine that, by trees lying for anylength of time, the sap [wood] increases in its thickness, or that part of theheart is transformed into sap again, which is by no means the fact; and, if anypart of the heart were subject to such change by so lying, there can be noreason assigned why, in the process of time, the whole should not undergothe like change : but this is absurd, and contradicted by experience; for, afterthe sappy parts are once formed into perfect wood, it ever remains in thatstate until it naturally decays.” (p. 76.)

In felling oak trees the heads of which contain crooked pieces fit for par-ticular purposes in ship-building, care should be taken either to cause the treeto fall on a side that will not injure the crooks, or to separate the branchescontaining these before cutting down the trunk. South mentions the Langley()ak, which was felled in 1758, in the New Forest, and which had a large head,full of knees and crooks. He thus describes the mode in which these werepreserved: —“ The knees and crooks were cut off, one by one, whilst the treewas standing, and lowered by tackles, to prevent their breaking. The twolargest arms were sawed off at such distances from the bole as to make first-rate knees; scaffolds were then erected, and two pit-saws being braced toge-ther, the body was first cut across, half through, at the bottom, and thensawed down the middle, perpendicularly, between the two stumps of arms thathad been left, at the end of one of which stood a perpendicular bough, biggerthan most timber trees. To prevent this being injured, a bed was made ofsome hundreds of faggots, to catch it when it fell.” ( Bath Society's Papers,vol. vi. p. 8.)

Oak Copse is cut down at various periods between 15 and 30 years; the rulebeing, that the principal stems of the plants, at 1 ft. from the ground, shouldnot be less than 6 in. in diameter. In favourable soils in the south and westof England, this size will be obtained in from 12 to 15 years; as, for example, atMoccas Court; but in the colder climate, and in the inferior soil, of the High-lands of Scotland, from 25 to .30 years are required. The cutting over ofcopse is performed at the same season as that in which full-grown trees arefelled, when in both cases the bark is an object as well as the timber; but, inthe cutting over of coppice trees, it is necessary to bear in mind, that the stoolsare intended to shoot up again, so as to produce another crop. To facilitatethis, they require to be cut over smoothly, so as not to lodge water ; and closeto the ground, in order that the shoots for future branches may proceed atonce from the roots, and not at some distance over them; in which case theywould be liable to be blown off. (See the chapter on coppice wood, inthe Encyclopcedia of Arboriculture.)

Disbarking the Oak. The season for disbarking the oak for the tanner is laterthan that for disbarking the birch, the larch, the willow, or any other treethe bark of which is sufficiently valuable to be taken off. In most of the treesmentioned, the sap will be found sufficiently in motion towards the end ofApril: but the oak, relatively to these trees, will always be found a monthlater. As the mode of performing the operation, and managing the barkafterwards, till it is sold to the tanner, is the same in all trees, we shall defergiving it till we treat on the subject of arboriculture generally.

Accidents, Diseases, Insects, Epiphytes, §c. The British oak is not subjecteither to many accidents, or to many diseases; but, like every other plant,it has its parasitical and epiphytical vegetation ; and it is infested by numerousinsects.

Accidents. Oaks are said to be more frequently struck by lightning than

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