The term krummholtz refers to trees showing deformity in some way. Often, they have branches that curve usually in a specific wind direction. The dwarf forest of the treeline is not necessarily one made of trees unless the trees also show deformity, not all do. These types of tree live in a very harsh climate with extreme cold in winter and extreme heat in summer. High winds make root stabilization difficult especially if soil is loose.
Both types of trees occur worldwide. Scientists study them in the Rocky Mountains, in Puerto Rico and the word itself comes from Germany. Common trees that tend toward deformity or krummholtz are balsam fir, red spruce, black spruce, subalpine fir and larch, Englemann spruce, and limber and lodgepole pine. The Canadian boreal forest and New Hampshire’s White Mountain offer striking examples of the krummholtz form.
Trees need the proper amount of sun, water, food, and sunlight for proper growth and development. Unfortunately, in high altitudes, such as where krummholtz and dwarf forests grow, one or more of these requirements is lacking. Often, soil temperature makes it difficult for the nutrients to get into the soil and into the tree. The leaves retain the carbon but the normal growth does not happen.
The dwarf forest has shorter trees and has not gotten the needed nutrients that the type of forest in another altitude would have. Climate and changes in climate result in the movement of these two forests. Treeline refers to the place in the mountains where the trees grow. At some point, near the top, trees no longer grow.
Major differences occur in the two types of forest: index is one difference; light is another. The leaf area index tells how much carbon the leaf has. In dwarf trees the carbon balances are more than those in the krummholtz trees. Dwarf trees appear more productive and grow in more fertile soil. Krummholtz mats grow in different directions including outwardly with branches reaching like fingers or with their branches growing into the soil and coming out again. Dwarf trees usually grow under another tree or canopy.
Scientists believe that krummholtz trees help in the natural process of hydrology. For the snow that accumulates from the mats burying them and protecting them from the severe winter and wind. After the snow melts, birds or the wind carry them to other parts of the tundra to start developing a new forest.