Fires in Southern California

I heard in passing this morning that the FBI is looking into arson as a possible cause for some of the fires in southern California. Part of the news story mentioned that someone they were looking at appeared "well organized". I'm not sure where back in the archives, but I think I wrote long ago that things like wildfires could be a successful terrorist tool, one to which we are much more vulnerable than plane hijackings and similar threats. I hope that this does not turn out to have been the case, but where else is it possible to inflict millions of dollars of damage to property and possibly the economy with such a low threshold for causing the damage? Our natural landscape is vulnerable-