types of jungle

[The Colonel]

I know the canopy type makes a massive difference - old growth, high canopy stuff can be pretty open at ground level because there's not much light makes it that far down. The stuff without the high canopy - including regrown, cleared land can be almost impenetrable due to how thick the brush is.
Rhododendron forest and mangrove swamp are both particularly evil terrain types to try and move in, and the mangroves also tend to have a serious wildlife problem. Most of the things that live in regular jungle will get out of your way as you make an immense amount of noise crashing through the foliage towards them ... in the mangroves, not so much. The crocodiles/gators and carnivorous fish tend to be the big ticket items, closely supported by snakes, biting insects and leeches. Plus an almost infinite range of bacteria to infest the wounds of any survivors.