Answer: timberline

AnswerCrossword Clue
TIMBERLINEMOUNTAIN DEMARCATION
TIMBERLINETree-growth limit
TIMBERLINEHigh point of East Germany's trees?
TIMBERLINEMountain demarcation (italicized)
timberlinethe upper limit of timber trees on a mountain
timberlinethe altitude above sea level at which timber ceases to grow