Definitions for "Tree line"
(also called timber line) the point on mountain or high elevations beyond which no trees grow. The line varies depending on latitude, climate and soil conditions. Also northern boundary of boreal forest.
Upper limit of normal tree growth. This varies across Scotland depending on the climate and soil type, and ranges from about 150m on the extreme north west coast to above 700m in the north east.
Either the latitudinal or elevational limit of normal tree growth. Beyond this limit, closer to the poles or at higher or lower elevations, climatic conditions are too severe for such growth.