While fire is a natural part of the lifecycle of these forests, it’s important to note that the specific forest management practices that have been implemented over the last century have drastically changed the character of the fire regime in western forests.
Most of our pine species have evolved to burn every few decades. During these burns, a fire sweeps through the forest floor, killing most of the trees which have cropped up since the previous fire but haven’t had time to mature. The older, taller trees survive because their characteristic thick, flaky bark protects their trunks from the heat of the burn (interestingly, the smoke from the burn causes the cones in the taller trees to open up and fall into the freshly carbonized soil, creating the next batch of seedlings). The younger trees don’t have this yet, and anyway they usually aren’t tall enough to keep their branches out of the fire, which leads to the major issue here.
Fire prevention over the last hundred years has resulted in forests with a wide mix of trees at various canopy heights, which fire ecologists have taken to calling ladder fuels, because the trees are taller than the saplings which would usually be cleared out and shorter than old growth trees, providing a “ladder” for fire to jump into the canopies of older forests. These forests are not in any way whatsoever equipped to deal with canopy burns. All of their fire defenses are near the ground, in the bark, and there’s a high likelihood that once the fire reaches the canopy it will at least kill the tree, if not spread through the canopy and destroy the forest.
It goes without saying that the physics involved here, when the fire is burning from the ground up to hundreds of feet in the air and consuming all of the available fuel, are magnitudes different than a typical brush fire on the forest floor. While these fires weren’t impossible in prior to the emergence of forest management practices, those practices have unambiguously resulted in more and more severe fires by increasing the volume and density of fuels in these forests.
To that end, I wouldn’t be all that surprised if the fire really has consumed all of Big Basin.