crown density is the driving variable in a wind-driven crown fire. in much of the area that is being burned presently, white fir has filled in the previously open stands, and thus are ripe for a stand-replacing fire. but where the giant sequoias hang, the stands are open, such that crown-to-crown transfer of fire is not a likely scenario.
but shit happens, so i would not say that a few of the legacy trees are not at some level of risk. However, i know a lot of guys that would go to extreme measures to save them, with aircraft, hotshots, and engine crews. the fire was overdue... so not a big shocker.