분비나무는 산성암(70%, acidic rock), 변성암(20%) 지역에 집중적으로 분포하였고 두 종의 공통적인 모암은 변성암 지역으로 분석되었다.
The birch tree was abundant in acidic rock (70%) and metamorphic rock (20%), and the common parent rock of both species was identified as metamorphic rock.