Nature Notes

Volume IV No. 3 - September, 1931

Snow Pressure Bend
By Clyde E. Gilbert, Ranger-Naturalist

The trees inside the rim of Crater Lake and on the steep slopes of the surrounding peaks show a distinct bend near the base. The bend might be accounted for by some as due to soil creep. "Soil creep" is the gradual downward slipping of the soil on the steep hillsides. This is usually caused by alternate freezing and thawing of the soil aided by the water table in the early spring. Since the soil on the slopes is quite shallow and many of the tree roots are anchored in solid rock, it is very improbable that soil creep is responsible for the bend. Also in the case of soil creep the base would have moved down slope and the tops tilted upward. If a resulting bend occurred it would be in the opposite direction to that found in Nature.

It appears more probable that snow pressure on the trees for six months or more of the year forces the trees out of the line of normal growth and causes a distinct crook that is called "snow bend". The tree is most affected while it is very small. Some times it is pressed flat on the ground beneath huge drifts of snow for several months. During the growing season the sun draws the tree back into an upright position but before it can completely straighten the snow falls and again presses the tree out of line. Every year the growing tree, aided by the sun, gains a bit in the battle, but even the larger trees show a distinct "snow bend" that is never outgrown.

Assisting Nature
By E. U. Blanchfield, Ranger Naturalist

Visitors to the park this summer are extremely interested in the planting activity on the Rim from the entrance of the Rim Road to the Lodge. The rim walk winds through this planted area among native shrubs and flowers.

As the soil on the Rim is pumice and not favorable to plants, rich soil has been transplanted from bogs and stream banks and spread over the pumice.

At the head of the Lake Trail is an excellent planting layout of mountain ash, black twinberry, red twinberry, pink spirea, and native grass which forms an intersection of the lake and rim walks.. In the shaded locations under the mountain hemlocks are planted western bleeding hearts, alpine phlox and mountain valerian, The false green hellebore, Coville's aster, fireweed and Crater Lake currant are all prominent at this season on the Rim edge. The Crater Lake currant is being used as a creeping plant to beautify the new Sinnott Memorial Building. In between the rocks of the building are planted a matted beard tongue, the lace fern, seedum, softening the lines of the architecture. These plants have been obtained from the rock crevices on the side of Garfield Peak.

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