Page:White - The natural history of Selborne, and the naturalist's calendar, 1879.djvu/449

427 The circumference of trees planted by myself at one foot from the ground (1790).

The great oak in the Holt, which is deemed by Mr. Marsham to be the biggest in this island, at seven feet from the ground, measures in circumference thirty-four feet. It has in old times lost several of its boughs, and is tending to decay. Mr. Marsham computes, that at fourteen feet length this oak contains 1000 feet of timber.

It has been the received opinion that trees grow in height only by their annual upper shoot. But my neighbour over the way, whose occupation confines him to one spot, assures me, that trees are expanded and raised in the lower parts also. The reason that he gives is this: the point of one of my firs began for the first time to peep over an opposite roof at the beginning of summer; but before the growing season was over, the whole shoot of the year, and three or four joints of the body beside, became visible to him as he sits on his form in his shop. According to this supposition, a tree may advance in height considerably, though the summer shoot should be destroyed every year.—

If the bough of a vine is cut late in the spring, just before the shoots push out, it will bleed considerably; but after the leaf is cut, any part may be taken off without the least inconvenience. So oaks may be barked while the leaf is budding: but as soon as they are expanded, the bark will no longer part from the wood, because the sap that lubricates the bark and makes it part, is evaporated off through the leaves.—