Daniel Ruddell of Redstart Forestry writes:
“Fine roots hairs die very quickly when exposed to air, and are the primary means for a tree to take up water and nutrients; they can’t be grafted back on. Your best bet may be to plant more trees further back from the stream, a gift to those who will come after you as well as yourself.
“Please pay close attention if you are trying to berm or cover such roots. These efforts will not restore the roots that have been damaged, but bank armoring (particularly smooth, hard surfaces) will likely accelerate and amplify the force of water on a downstream target.
“Trees are remarkably resilient and will often hold on a lot longer than you might think. Your damaged trees will help stabilize the soils for some time while your new trees get established. Restoration efforts will often place root “wattles”, or even bury trees upside down into stream banks or beds, to create roughened surfaces for these reasons as well as to diffuse stream power in future high water events. Undercut banks with overhanging roots provide excellent habitat for fish and other aquatic organisms.
“Do be aware that trees with damaged root systems can go quickly in a wind storm or other event, so be cognizant of whether your trees pose a hazard in such an event.
“Some estimates suggest undisturbed headwaters streams might have as much as 200 pieces of large woody debris per stream mile, which plays a huge role in diffusing stream power in floods as well as retaining fine sediments that might other clog downstream waterways; there are not many places along our streams today that have wooded buffers that can contribute that. So maybe think about planting more? Just my two cents…”