The wedge-work of roots is a powerful and effective agent of weathering and performs an important part in breaking up solid rock. Since the indurated rocks, as a rule, are covered by mantle rock of considerable thickness the actual penetration of their seams, joints, and crevices by roots is concealed. In some cases, too, the mantle rock is of so great thickness that even the longest roots fail to reach the solid rock below. On bare rocky cliffs where there is sufficient moisture, trees, in some cases of large size, grow from crevices and joints where their seeds have sprouted. As they grow their roots penetrate the openings and wedge their sides apart sometimes prying off unstable rock masses and toppling them over—the final overthrow occurring oftentimes during a windstorm which may blow down the trees.
Proceedings of the Iowa Academy of Science
©1919 Iowa Academy of Science, Inc.
Thomas, A. O.
"An Illustration of the Wedge-Work of Roots,"
Proceedings of the Iowa Academy of Science, 26(1), 477-480.
Available at: https://scholarworks.uni.edu/pias/vol26/iss1/45