Willows are pioneers of raw, moist habitats (“Have returning wolves really saved Yellowstone?” HCN, 12/8/14). Except for the few, but often common, species capable of vegetative reproduction, dense grasses are anathema to willow spread, and young plants grow fastest.
The story of moisture-loving riparian species, such as willows and sedges, catching sediments is writ large in the soils. At the same time, creek down-cutting is normal. As the site dries, willow roots follow the receding water table, while short-rooted sedges are replaced with drier-site grasses. Eventually, the hydrologic regime becomes tenuous for established willows and completely lacking for seedlings that are not attached to a parent.
The recovery process, as far as willows goes, can be initiated on the exposed sediments of abandoned beaver dams but equally on fresh flood-deposited sediments. I doubt any ecologist would ever say “might never be repaired.” That’s just the human time perspective. Renewal can play out on a timescale inconvenient to researchers.
In my own field of re-vegetation, the role of the natural recovery of riparian strips is often blocked by establishing herbaceous plants — often with good reason, weeds being the alternative. Woody plants then are transplanted at enormous cost. The best re-vegetation programs assist the natural recovery process rather than assuming nature can do nothing.
Richard Prodgers
Dillon, Montana
This article appeared in the print edition of the magazine with the headline Of time and wounds.
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