Camping and woodcraft - Scoutmastercg.com

•SouthwestNATURE'S GUIDE-POSTS 57trees," wrote Leonardo, ''show how many years theyhave lived, and their greater or smaller size showswhether the years were damper or drier. They alsoshow the direction in which they were turned, becausethey are larger on the north side than on thesouth, and for this reason the center of the tree isnearer the bark on the south than on the north side."In 1893 this matter was put to a definite test by theNew York State Forest Commission, which directedIts foresters to examine the regularity of the northwardthickening of annual rings in the black spruceof the Adirondacks. The foresters examined 700trees, of varying exposure, noting in each case thecompass-point toward which the longest radius ofwood growth pointed. The result was:North 471 South 1Northeast 81 SoutheastEast 106 West 276Total north and east. 658 Northwest 894%Total south and west. 426%These figures deserve more than a passing glance.Compass-Plants.—Some plants show a decidedpolarity in their habit of growth. The compassplantor rosin-weed {Silphium laciniatiun) that onceabounded on the prairies of the Mississippi valley,from Minnesota to Texas, is a conspicuous example.It is a tall plant with long, stiff leaves, that do notgrow horizontally but with their edges perpendicular.Its natural habitat is the open, shadelessprairie. If plants are examined that grow thus inthe open, especially those in the little swales wherethey are not fully exposed to fierce winds, it will befound that the great majority of them present theirradical leaves north and south. The large flowerheads on short, thick stems point, like the hemlock's"finger," to the eastward, and show no such ten-