Below are some recent photographs of sycamore trees (Platanus occidentalis) in limestone bedrock at Herrington Lake, Kentucky (about37.78^o N, 84.71^o W). As you can see, the tree roots and trunks exploit joints in the rock, and accelerate weathering both by physically displacing limestone slabs and widening joints by root growth, and by facilitating biochemical weathering along both live and dead roots.

These are some nice examples of root/bedrock interaction, and the general phenomena are not uncommon, though usually much more difficult to see. The Herrington Lake shores also appear to illustrate a process by which the sycamores accelerate weathering and mass movements (other trees are also involved, but Platanus occidentalis seems to be the most common and effective):

1. Plants colonize the exposed bedrock, with roots exploiting bedrock joints.

2. Tree roots accelerate weathering and loosen joint blocks.

3. While the tree is still alive, root growth envelopes rock fragments and the trees provide a physical barrier to downslope transport.

4. When the tree dies, the rock fragments are released downslope.

Science fiction and popular science writer Arthur C. Clarke once wrote that "any sufficiently advanced technology is indistinguishable from magic." Riffing on that theme, I once gave a talk in which I proclaimed that "any sufficiently improbable event is distinguishable from the miraculous." Some definitions of "miracle" invoke the divine or supernatural, but I have in mind the definition (in this case from the Merriam-Webster dictionary) as: "an extremely outstanding or unusual event, thing, or accomplishment." The point of the argument is that, due to the inescapable, irreducible role of geographical and historical contingency in Earth surface systems, all such systems (landscapes, ecosystems, soils, etc.) are unique in some respects (a formal argument along these lines is presented in this article: Phillips, J.D.  2007.  The perfect landscape.  Geomorphology 84: 159-169.). Thus the probability of existence of any given state of any given system at a given point in time is infinitesimally low. This exceedingly low probability makes nearly any environment in some senses extremely outstanding and unusual, and thus a miracle.