TREE HEIGHTS

Dominion, Volume 31, Issue 142, 12 March 1938, Page 10 (Supplement)

TREE HEIGHTS

Walking-Stick Measure It is not an easy thing to estir ?T :e by the eye the height of any tree. The position in which it stands, the width and shape of the crown, and whether pointed or rounded, the amount or stem showing, all affect the apparent height of a, tree, with the result that really tall trees may look small ana comparatively small trees look tall. Hence the amount of controversy that rages about the heights of our trees. But it is actually very simple to find approximately the height of any t ree < provided a point can be selected from which both the top and base of the tree can be seen. There are many kinds ot tree-height-measuring instruments to be got. called hypsometers or dendrometers, but a walking-stick can be made to suffice. Measure the length .of the stick or a fixed length of stick, marking it with notches. Another notch is marked at, say, one-tenth of this length. The stick is suspended in front of the eyes, so that one line of sight to the top of the tree passes through the top notch and that to the base through the bottom notch. Another line of sight passes through the notch at the one-tenth point to a point on the tree, whose height should then be measured. This height, multiplied by ten, will give the total height of the tr in Britain no tree exceeds 160 feet in height. One of the tallest is a silver fir at Inveraray. This is barely half the height of some of the Western American giants, but these are, of course, much older. Yet it is doubtful whether even with age British trees will ever exceed the 200-foot mark. There are, for instance, many Douglas firs which have not taken much more than 60 years to reach 120 feet, but they are making little progress beyond that, as their tops are repeatedly broken or damaged by gales. The Scots pine is never a tall tree. Its usual best is about SO feet, although occasionally it reaches 100-120 feet. The larch and the spruce are, on the whole, age for age, taller trees than the pine. The best pine average one foot per year up to the age of 80 years, whereas the annual growth of the larch and spruce may be one and a ha-f feet, .and the Douglas fir, the Sitha spruce, and some silver firs, two feet.