It’s tempting, after a disaster of any proportion, to do something immediately to try to fix the situation. In the case of wildfire, revegetating the burned area quickly is often seen as an essential step, especially if the fire occurs just before the rainy season, to prevent erosion, flooding, and—in the worst cases—mudslides like those that recently occurred in Montecito, CA, just after the Thomas Fire.
An article from the Ventura County Star offers some advice for those who are planning to take action: Don’t. Ventura County is one of the two California counties affected by the Thomas Fire. “You may be tempted to help nature’s process by spreading seeds on hillsides stripped bare of vegetation, but erosion, flooding, fire danger, and weed removal are the possible consequences,” the article warns. It goes on to explain that fast-growing groundcover like ryegrass helps in the short term but then dries out quickly, potentially providing fuel for future fires. A better course, it advises, is to let the native plants come back naturally. It also recommends measures such as wattles and erosion control blankets. The recommendations come from the California Native Plant Society and Channel Islands Restoration.
One factor in the decision, of course, is how hot the fire burned and whether the remaining seeds are viable. This article published a few years ago in Erosion Control reports on studies conducted for the Bureau of Land Management and Santa Barbara County—the other county in which the Thomas Fire occurred. (Scroll down to the sidebar at the end of the article.) The studies compare revegetation on post-fire soil treated with hydromulch and untreated soil. They concluded that the hydromulch greatly reduced erosion without interfering with the regrowth of native vegetation.