And when they stop clearing the jungle, it will overgrow the cleared land in about one or two generations, Look at the temporary bases built in the South Pacific during WWII.
I think they are deforesting to bring in cattle. These will probably keep regrowth at bay a bit.
Check out Henderson field on Guadalcanal on Google Earth.
I studied the Solomons campaign and visited all those bases on Google Earth..... they are pretty much all there but changed.