Fire plays a regenerative role in your watershed. It is a specific and unique role, shaped by the winds and rains, the shape of the hills, the adaptations of the plants and animals. In most US watersheds, fire has been suppressed or applied in the wrong season or with the wrong intensity and frequency. Loving open fire means overcoming what we have been taught is a "natural" fear of flames, and learning what the watershed "desires," to be productive and diverse.
In the 1980s, Rob Hansen worked at The Nature Conservancy's 3,300-acre Creighton Ranch Reserve in the Tule River watershed, which feeds into the San Joaquin Valley (300 to 400 feet above sea level) in California. Creighton Ranch is the remnant of a valley?once filled with lakes, wetlands, and savanna? that has been 96-percent destroyed. Rob also worked at a smaller, drier site on the San Joaquin Valley's desert/grassland edge, called the Pixley Rural Pools Reserve.
While we could have consulted dozens of fire managers, Rob arrived with great bioregional credentials as teacher, consultant, and steward. He speaks with the new intimacy demanded by local fire work. He is modest. He cannot "restore" in the sense of bringing back every animal and plant. He can "rehabilitate," encouraging native wildflowers and pollinators and complex-ity by burning back the Euro-Mediterranean exotics that invaded with sheep and cattle. The modesty of the new restorers is both painful (Creighton Ranch is too small for pronghorn to return) and honorable (the fire-based restoration requires eternal stewardship). Rob's realism and joy point to a future local love for fire at home. ?PW
In this part of the Valley, in this bioregion, fires burn in the fall after good years of rain have watered lots of grass and the grass has dried out. When a fire's underway and the smoke plumes ascend, certain birds key in. Swallows from far and wide converge and catch insects?grasshoppers primarily?as they flee the flame front. The swallows have a heyday.
During the fire and immediately afterwards, Swainson's hawks search where the ground is black. A squirrel that blends into the dry gold grasses stands out pretty well against burned and blackened earth. The hawks also scavenge the big insects, grasshoppers and crickets, that may have had their wings singed.
Later in the fall and in winter, mountain plovers arrive and forage where fires have occur-red. They like to either see the ground or forage on the ground in very short grass. (They avoid fields where European?invasive?annuals have flourished for a year or two and are covered with dried-up brome and Hordeum, or barley.) Mountain plovers can be difficult to find in the Valley; a good place to go looking is a burned grassland.
We occasionally see burned side-blotch lizards, the commonest lizard here. If they are not able to get down into a ground-squirrel burrow, they can certainly perish. But most survive, and afterwards, when the ground is black, you can see them too, like the hawks, foraging for insects.
When fire is frequent enough?every two or three years in our grasslands?the fuel load never gets so large that the heat gets down into the burrows. The flame front passes any point in a field so quickly that it's probably not cooking anything down in a squirrel burrow. I suspect squirrels, toads, darkling beetles, garter snakes, whatever else is down in there, are doing pretty well.
Life goes on immediately after a fire. Within just minutes or hours, lots of animals are out
foraging and carrying out their regular activities. Harvester ants, for instance, are back again, just pulling out seeds and gathering and packing them around their little ant colony entrance.
In the 1800s, there were certainly both natural wildfires and human-set burns; both probably took place in fall. At the time Western settlers got here, the Yokuts were doing most of the burning or had a hand in it. So when we set fires now, we're not looking at fire as a means to restore the natural fire regime to some pre-human period. We're bringing back fire primarily to encourage native species, to give them some edge against the European exotics that arrived with cattle and sheep, and that otherwise leave the natives so little space.
If you read Holland's plant community descriptions, it has accounts of vast wildflower fields. There are just so few places today where you can see vast wildflower fields on the floor of the San Joaquin Valley. The one time when we can see something that looks a bit like these early descriptions is in the spring following a fall burn. It's pretty impressive.
So we work with fire, our past history, and the landscape as it exists, trying to give native species, especially forbs and wildflowers, a better chance to flourish.
When the "thatch" of one to three years of annual grasses builds up, it creates a dry mass or mat of dead grass on the ground. The thatch does two things: it intercepts sunlight, and it catches a lot of the early-morning moisture that might otherwise fall on these grassland soils. The moisture's an important water source; we only get six to ten inches of rain a year. Burning the thatch bares the soil surface and exposes seeds to a lot more sun, a lot more of the first rains.
The native annual wildflowers appear to be adapted to periodic fire; they respond positively to fire-burned openings. If there's a huge biomass of non-native grasses lying on top of their seeds, they don't compete very well. Fire gives the natives a competitive edge.
Fire is almost an analog of grazing, because grazing opens the thatch layer and makes it possible for annual forbs to compete against exotic grasses. If you look at a little game trail where squirrels or jackrabbits have run across the fields, they trample the thatch down and have, in a way, the same sort of impact as grazing or fire. They create an area where there's not much grass left. Sun and water get to that spot real quickly. So the following spring, those little squirrel trails often blossom with the best native flowers, which are not found in the neighboring thatch layer.
Because grasses are all wind-pollinated, there are no animal pollinators associated with Creighton's grasslands. But once we have fire, we have more Goldfields ( Lasthenia), Gilias ( Gilia), Pink Owl's Clover ( Orthocarpus), and Larkspur ( Delphinium), and we see a broader array of pollinating wasps and flies. A lot of the solitary bees?the native species, not the European honeybees?return to the fields.
Alkali sacaton ( Sporobolus sp. ) is the most important native perennial bunchgrass, especially at Pixley. Sporobolus needs to be carefully thought about, because after a long stretch of time with no burning, the thatch layer is dense and there's a lot of fuel to carry the fire. And the bunchgrass itself usually has a lot of old, dead leaves lodged in it. During the first burn, the whole plant can be completely consumed. But once an area burns, and if burning returns in intervals of two to three years, fire appears to do to the bunchgrass what periodic grazing does?it stimulates it. The sacaton puts on a lot of new growth the year after a burn.
Although both cows and fires reduce fuel loads, open up thatch, and convert grass back to nutrients, cow pies in this part of the Valley do not decompose very rapidly. A lot of nutrients get tied up in the manure and remain trapped for a long time. We see dried cow pies that literally sit there for ten years after the cattle have been taken off. A burn pretty quickly reconverts a lot of nitrogen and phosphates, including the nutrients in cow patties.
So fires bring about fairly dramatic and rapid change. Grazing may have less of an immediate impact and more of a maintenance effect. Grazing can be used once we get a grassland the way we would like it to be, through burning.
In the interface zone, the I-zone, the inherent people-danger of a grassland fire is pretty small. I'm sure there's some chance that a risk-reduction insurance company guy would probably tell me to shut up, but if the burns are done well, you can just step over a flame front. The fuels here are not like in a forest.
In our part of the Valley the population density is low. When we do the burns there are literally no neighbors. The Valley?still largely agricultural, with neighbors involved in agriculture?knows about doing burns to get rid of stubble, and so on.
At other sites, with either dairies or residences within a quarter mile, we contact those folks ahead of time and do our best to keep them informed so that they're not having to react to the fire. We want them to know there will be a short smoky incident and that we'll do our best to minimize the smoke time, and certainly look after things like safety when the fire is anywhere near a well-traveled road.
We also check with the authorities. Ag-zone burns are done under agricultural burning permits, handled by either a county or air pollution control district. At times, we'll have our crews and equipment ready, but either the humidity is too low and the fires would be too flashy, or the wind is too strong and we'd be dealing with a dicey situation to meet permit requirements. So we have to wait.
The county has the right to limit the number of burns or a certain acreage of burns anytime; so even for such innocuous fires as prescribed burns, on a "non-burn day" we're the ones who sort of pull that short straw.
On private wildlife preserves, like Creighton, we can use more than our professional Nature Conservancy staff. We make an announcement to our membership in our newsletter and to folks on our mailing list. They can come out and volunteer to help, either preparing black lines or handling suppression or follow-up. If the interested public (especially urbanites) has a chance to actually be part of these grassland fires and see the beneficial results, to understand that fire has been?and probably still can and should be?a natural part of grasslands, that it keeps the grasslands in grasses and wildflowers, that it keeps perennial woody vegetation from encroaching, I hope they'd come to understand fire as good news.