timberline

noun

1. the altitude above sea level at which timber ceases to grow.
2. the arctic or antarctic limit of tree growth.

noun

1. the altitudinal or latitudinal limit of normal tree growthSee also tree line

n.1867, from timber + line (n.).

1. A geographic boundary beyond which trees cannot grow. On the Earth as a whole, the timberline is the northernmost or southernmost latitude at which trees can survive; in a mountainous region, it is the highest elevation at which trees can survive. Also called tree line