timber line

1 6.3

A high place on a mountain above which trees cannot grow because it is too cold

noun
/ˈtɪmbər laɪn/

Specialized

: línea de árboles

The hikers stopped to rest near the timber line, where the last stunted trees grew.

Examples

Above the timber line, only grasses and low shrubs can survive the harsh conditions.
As they climbed higher, the landscape changed dramatically at the timber line.
The timber line on Mount Everest is quite high.
As we climbed higher, we reached the timber line at 3,000 meters.
The hikers enjoyed the stunning views above the timber line, where no trees could survive due to the harsh conditions.
As we reached the timber line, I noticed the landscape change dramatically, with only small shrubs dotting the rocky terrain.
Above the timber line, the air was crisp and clear, marking the boundary where tall trees could no longer grow.

Synonyms

tree line

vstimber line

22 5.1

The highest level on a mountain or near the poles where trees stop growing

refers to the same boundary but stresses cold and short growing seasons

treeline

vstimber line

Specialized

3 4.0

The highest or most northern place where trees grow

uses a different main noun but shares identical meaning

timberline

vstimber line

1 7.2

A line on a mountain or in cold regions that marks the highest place trees can grow

is the same meaning but written as one word rather than two

Surface Forms

timber line singular

timber lines plural

Morphology

timber + line

The meaning 'the altitude beyond which trees cannot grow' is directly derivable from combining 'timber' (trees/wooded area) with 'line' (a boundary or limit); together they denote the boundary of tree growth. This compositional, cross-linguistically common pattern (cf. 'tree line') makes the expression predictable for a B1 learner who knows both constituents.

Etymology

Timber line names the clear line on a mountain where timber, an old word for 'trees', stops growing. So it means the height above which you will not find trees.