Parks staff has been fielding a lot of questions these past few weeks about what managers are planning to do to “re-seed” the parks after the October fires.
It’s a lovely thought, but it’s one that should be strongly advised against. Sonoma County’s forests, woodlands, shrub lands and stream sides already have a plan for recovery. In fact, they’ve planned for this wildfire disaster for a long time. And they have practice: they’ve bounced back from many fires over thousands of years.
Nearly every tree species affected by the Tubbs and Nuns fires has a strategy for returning. Some, such as coast live oak, have thick bark and may still be standing with green canopies hanging over blackened understory in places such as Sonoma Valley Regional Park. Trees in this condition will be helped in the years to come because the competition around their bases is gone. If burned, coast live oak have an amazing ability to sprout from the trunk. This can happen as quickly as two months after a fire or sometimes as long as two to three years. It all depends on how much energy is stored in their roots and how the weather plays out.
In fact, most oak species, along with many other native plants, have this ability to resprout, even when the above-ground portions of the trees are completely charred.
Black oak is a species that isn’t quite as hardy in the face of fire as coast live oak, but it still has a plan for regeneration. Because it is deciduous, fall fires have plenty of dry leaves to catch, spread and hold the fire. That said, black oaks have large reserves of nutrients and water that support prolific sprouting. Chances are you’ve seen mature black oaks that grow from many trunks, an indication they survived fires from years before.
Black oaks, like most other oaks, also reseed from acorns that fall on freshly burned soil or are brought in by squirrels and scrub jays who actually prefer burned sites to cache their food for winter. The Creekside Trail in Shiloh Ranch Regional Park will be a place to observe black oaks rebounding.
For plants that didn’t survive the fires or can’t regrow, many have put down abundant seed into the soil. This “natural seed bank” is critical for recovery. In sites where the burn severity is low to moderate, the seed bank will readily respond in the months to come. Plants like the manzanita on Hood Mountain’s ridges largely depend on this strategy. Their seeds can persist for more than 40 years under the shade of their parent plants and only germinate after fire.
Many wildflower species are also represented in the natural seed bed and will respond next spring as rains subside and temperatures warm. We saw that kind of response in Lake County, and we will see it in our burned parks.
Cal Fire experts may recall the time 50 years ago when their post-fire approach was to spread rye grass seed from helicopters to prevent erosion. What they found was it actually made the situation worse because the grass seed out-competed the native vegetation and didn’t hold the soil together as well as the natural plants would have.