This forms a persistent and striking border around individual crowns that are visible from the ground.
Trees with slender trunks have relatively small crowns because of their lesser ability to resist deflection in wind.
They therefore sway widely in wind and are more likely to collide with neighbors.
He suggested that the growing tips were sensitive to light levels and stopped growing when nearing the adjacent foliage.
Some suggest that trees exhibit this phenomenon to prevent leaf-eating insect larvae from spreading.
All the pictures accompanying this article were taken there.
Photo credit
Sources:Mechanical Abrasion and Intercrown Spacing/Crown shyness in maturing boreal forest stands/WikipediaviaTYWKIWDBI
