Beobachtungen und Untersuchungen über den Ausaperungsverlauf und einige Folgewirkungen in "ribbon-forests" an der oberen Waldgrenze in der Front Range, Colorado
In some ranges of the Rocky Mountains, forest strips (ribbons) running perpendicular to the prevailing wind-direction and alternating with almost treeless meadows (snow glades) can be observed at the upper timberline. This distribution pattern has been called "ribbon-forest". The absence of trees in the glades is attributed to snow masses accumulating on the leeside of the ribbons. These ribbons act like natural snow fences. The author's studies in the Colorado Front Range gives some evidence that the decisive factors keeping the snow glades free from forest are short growing season, creeping snow, brown snow felt fungus (Herpotrichia juniperi), pocket gophers (Thomomys talpoides) and probably muledeer (Odocoileus bemonius) and elk (Cervus canadensis). This paper argues that the influence of Herpotrichia juniperi has been underestimated. However, the above factors would not be so effective if the glades had been provided with more viable coniferous seeds. The ribbons survived by layering for hundreds and even thousands of years. Their position does not seem to have essentially changed during this time.