Forest
1 :a dense growth of trees and underbrush covering a large tract
Jungle
1 a :an impenetrable thicket or tangled mass of tropical vegetation b :a tract overgrown with thickets or masses of vegetation
forest强调覆盖面积大(covering a large tract),jungle强调热带植被（tropical vegetation）及植被的繁茂杂乱.jungle通常是指热带雨林(tropical jungle),而forest则可泛指森林