Let's take a closer look now at the different types of terrain we encounter while hiking in the Himalayas. At lower altitudes (below 2500m) in the valleys we are likely to encounter forest or trees. The tree-line indicates the upper altitude at which the forests ends and meadows, scrubs or barren landscape starts. Above this altitude there is usually insufficient water, air, heat or soil for larger trees to grow. Similar to the snow-line, the tree-line is different on East-South facing slopes (more solar exposure, more evaporation, less water in soil, likely to find dry grass sooner) vs North-West facing slopes (shady, more water in soil, more forest).

On Open Street Maps forest is marked by green colored regions. On Survey of India maps additional detail is given on the type of trees in and the density (open, fairly dense, sense) of the forest (see below).