What can be done? Here, nothing other than replanting. There will always be a few teenage boys who do things like this. I think the Forest Service can be faulted for not closing the area but this would have been hugely controversial. It's hindsight. Many of the other fires were caused by lightning strikes.
There is a bigger and more fundamental issue and the solution is beyond dispute. Forest fire is a healthy and natural part of forest life here. Experts study old growth forests and they see that there were several natural, low intensity forest fires every decade. It can literally be seen in the trees and we can see the positive impact thereafter. These fires remove brush and the "ladder fuels" that allow the fire to climb to the tops of the biggest trees and they thin the forest. A century of putting out forest fires and not removing the overstocked trees and brush mechanically has created a situation in which the fires are so hot and intense that everything is destroyed. You go to ponderosa pine forests in eastern Oregon where the brush has been removed and then "controlled burns" have been conducted at optimum times in late spring and just marvel at the health of the forest. Contrary to what many environmentalists believe, this is what a natural forest looks like, not the overgrown tangle you see in many pictures. I have seen old pictures of untouched forests in Oregon and they don't look anything like the ones we admire today.
I owned 40 acres of second-growth douglas-fir in southern Oregon that was tangled and choked. The trees were way overstocked so they couldn't grow well and were susceptible to disease. A forest fire would have moved through at unbelievable speed. I did a lot myself and hired fire crews on standby to do the rest. You just wouldn't believe what happened. The remaining trees were "released" and they starting growing vigorously. Forest health improved dramatically.
The people at the Forest Service understand this and they do as much of it as their budget allows, but it is a pittance compared to what is necessary. We are willing to pay thousands of workers to fight forest fires but not to clear brush and remove ladder fuels in our national forests so fires can be beneficial. This is what our Congress has done. Tragic. I so wish we would take care of our national forests.
Update: Read this to be utterly disgusted. Two fires have merged and the total is now 31,000 acres.