While you are right that conduction is not really a problem, and right that embers are really important, it's worth mentioning that radiation from a fire can al

While you are right that conduction is not really a problem, and right that embers are really important, it's worth mentioning that radiation from a fire can also be a significant source of ignition. And a large "flame front" can ignite structures from surprisingly large distances! I haven't read whole article yet, but here's an abstract: Residential losses associated with wildland fires have become a serious international fire protection problem. The radiant heat flux from burning vegetation adjacent to a structure is a principal ignition factor. A thermal radiation and ignition model estimated structure ignition potential using designated flame characteristics (inferred from various types and densities of vegetation) and flame- to-structure distances. Model results indicate that ignitions from flame radiation are unlikely to occur from burning vegetation beyond 40 meters of a structure. Thinning vegetation within 40 meters has a significant ignition mitigation effect. https://www.fs.fed.us/rm/pubs_other/rmrs_1998_cohen_j001.pdf https://www.fs.fed.us/rm/pubs_other/rmrs_1998_cohen_j001.pdf