Cheatgrass is the curse of our western rangelands. It's an annual that grows fast with lots of dense folliage, then dries off in late July. When it burns, the seeds survive. The dry grass burns extra hot which kills native grasses and sagebrush. Then the next spring, the surviving cheat seeds grow fast and they're the only thing left to grow.
It was accidentally introduced from Russia in the late 1800's and has spread all over the west.
Its the shorter than natural interval between fires that kills out the native species not the temperature of the actual fire. Shorter intervals favor annuals much more than long lived perennials.
