Greg Deitrick

Please consider an Internet search for "Jack Cohen wildfire".  He was a wildfire scientist with the Forest Service and is now I think associated with the National Fire  Protection Association (NFPA).  Much of his work focused on the ignition of buildings during wildfire, but his presentations often reference actual data, which provides a more accurate picture of the wildfire processes than you would otherwise have.  

One learning relevant to your situation is that wildfires have the potential of creating ember storms (which, by the way, is one of the primary mechanisms for building ignition) which can be blown something like a half mile from the fire.  So if there are  fuels that can  be ignited by embers, such as your meadow, they may still catch fire even if there are fire breaks that stop the progression of ground fires.  I suggest you consider the strategy of protecting things of value assuming that the meadow burns.  The NFPA explains how to make buildings fire resistant - it really isn't very difficult.  And I think their recommendations might provide good guidance on what to do with other valuables.  Protecting animals and people within a wildfire is relatively difficult because they have a much lower tolerance to heat than plants and dead materials.

FWIW, I recall Jack Cohen saying that deciduous trees are incapable of maintaining a crown fire, but I don't have a reference.

I am new to gardening and fairly new to Missoula.  I think I want to build a hugel.

My rural property extends east-west across a small canyon running north-south(ish).  There is a perennial creek running down the canyon floor surrounded by trees and heavy brush.  The remainder of the canyon floor is meadow with scattered conifers.  Previously the meadow was a used as a pasture but for the past 40 or 50 years it has not been grazed or worked; the grasses grow about 3-4 ft high each year.  This hillsides are wooded with mature conifers.

I think my primary constraint is sun exposure.  No part of my property gets direct sun for the first or last few hours of the day (it's blocked by the hillsides forming the canyon), and most of my property is shaded much of the rest of the day because of the abundance of mature conifers.  I've also noticed that the short Missoula growing season starts several weeks earlier in sunny locations than it does in shadier locations.  I've found that a narrow strip running east-west across the canyon floor along the south edge of my gravel driveway gets the most sun; partly because it is about midway between the hills forming the sides of the canyon, and partly because the driveway cuts a gap through the trees.

My plan is to build a "long & narrow" hugel running east-west and use the south face of the mound as my primary growing area.  The north face of the mound would face the driveway, which is raised 2 or 3 feet above the adjacent meadow, so that face would be significantly shorter than the south face.  The location is close enough to the creek to be irrigated from that with a small solar powered pump, I would think, so that isn't my primary motivation for a hugel.  Rather, I am hoping that by forming a mound the growing area will warm up in the spring earlier than would an on-grade growing area.  And I'm fixated on using only the dirt in place, I guess because that seems to be the most sustainable strategy with the least collateral impact.  Burying logs and branches, which I have on hand, will allow for the formation of a mound without bringing in additional dirt.

Most of the native dirt on the property is rocky clay which is good for building gravel driveways.  In fact I'm pretty sure the material used to build up the driveway was removed from the hillside.  It is also good for growing knapweed.  I suspect that the canyon floor, where the grasses have been growing & decaying in place for 40 years, is probably among the best topsoil on the property.  My plan is to excavate down to at least the bottom of the "good" topsoil, and place that soil on the top of the hugel.  Other excavated dirt will be used to infill around the wood.  I will want a path along the south side of the hugel, so I could excavate topsoil from there to add that also to the top of the hugel.  I imagine the path area will then get backfilled with rocks and stones sifted from the dirt that goes into the hugel; I always end up with extra rocks whenever I dig around here.  If not I have wood chips or pine straw for backfill.  This will probably mean that pretty much all of the dirt will get moved twice.

The only "mulch" generated by the property in any significant quantity are pine needles, which I think I want to not put into a hugel.  I have only a small lawn and I don't usually bag the clippings except when I need them for something such as covering grass seed.  I suppose I could cut some of the meadow grasses to have straw.  I do have large piles of noxious weeds that have been pulled over the past 3 years.  Can I put that in the hugel?  I have 3 neighbors with horses, and 3 neighbors with a few chickens each.  Would they likely have wastes that would benefit the hugel?

Depending on how things go with another project I may start work on the hugel in October or so.  Otherwise it would be next spring.

Any suggestions?

We went to a presentation by Jack Cohen, Fire Science Researcher with the USDA Forest Service (retired I think).  One of his videos on the topic is here: https://www.youtube.com/watch?v=vL_syp1ZScM  I think he is currently working for or with FireWise: https://www.nfpa.org/Public-Education/By-topic/Wildfire/Firewise-USA

His message is that structures survive wildfires provided the owners follow a few simple, inexpensive steps summarized (for example) here: https://www.nfpa.org//-/media/Files/Firewise/Fact-sheets/FirewiseHowToPrepareYourHomeForWildfires.pdf.  The most critical steps are:  1.
don't have a flammable roof (many asphalt shingles are perfectly adequate), 2. don't allow wind-blown embers to enter the structure through vents, pet doors, or other openings (e.g., close your windows before you evacuate), and 3. remove everything that could be ignited by embers that is in contact with your house or within 5 feet of the house.

The big scary flames are rarely the cause of structure fires.  Experiments indicated that very intense crown fires will not char structures 100 ft from the trees, and although structures 30 ft from the trees may get charred if the crown fire is intense, but even these ignitions typically self-extinguish.  Further, almost never do the forest conditions necessary for intense crown fires extend so close to a structure.  Deciduous trees are all good.  He showed footage of a row of eucalyptus trees in a suburban neighborhood that survived a fire even though the surrounding houses burned.

Structures that burn during wildfire events do so because wind-blown embers ignited the house or ignited materials up next to the house.  Don't have a stupid roof, seal your house against embers, and remove all tinder within 5 ft of the house and you've eliminated the vast majority of your risk of fire due to wildfires.