Nature Notes

Volume IV No. 1 - July, 1931

Carbonized Wood - An Index From The Past
By D. S. Libbey

Recently there have been found several large logs which are completely buried under an overburden of volcanic tuff and agglomerate. Some of the logs exceeded fifty feet in length and they were found resting in a horizontal position without any evidence of roots or stumps. Also there were no small branches attached to the logs but several small branches found detached indicative that both the logs and the smaller branches had probably floated to the place where they were subsequently covered by the heavy burden of volcanic material. The depth at which these logs were found in the volcanic tuff varied from 22 to approximately 60 feet with the conditions thoroughly indicating that there had been no disturbance since the time of their entombment.

The site of this find is about 23 miles directly west from the Rim of Crater Lake along the banks of the Rogue River where excavation by a steam shovel is being made on the now Diamond Lake Road just above Union Creek. The carbonized wood is unquestionably found in-site and the volcanic material - ash and pumice - apparently at some time in the past had completely dammed the Rogue River and caused a reservoir or a lake to be formed. Subsequently the Rogue has worn its channel through the deposit of fragmental material and is now resting upon a vesicular lava rock.

This material has an exceedingly interesting story to tell. The material was buried under a thick overburden of consolidated volcanic ash and pumice and is completely turned to charcoal. The logs necessarily were entombed under very thick loads of hot ashes and the heat, coupled with the rapidity in which the volcanic ejecta fell, resulted in the oxygen of the air being excluded which is essential to prevent combustion of entombed wood. As a result the wood material was changed to carbonized wood or natural charcoal. Such material is capable of preservation indefinitely and its presence can be discovered even thousands or even millions of years later.

The presence of charcoal buried in the midden heaps where prehistoric man abided is one of the most certain means to prove the existence of early human habitation. This is mentioned in order to illustrate the degree to which charcoal is indestructible under normal conditions and that it is such a splendid time marker by which the record of the past may be read.

The carbonized wood being buried under volcanic ejecta, ashes and pumice necessarily forces the conclusion that a very terrific volcanic explosion occurred to bury and carbonize the logs. The fact that the logs were changed to natural charcoal forces the conclusion that the ash and pumice was still exceedingly hot when it came to rest. The volcanic tuff was found in several places to be interbedded with water laid sand and gravels of a heterogeneous nature, suggesting a lake deposit in which glacial material was deposited and also the very definitely cross-bedded strata suggest off-shore conditions.

A complete assortment of the material is being preserved and a record being made of the essential facts concerning the find, so that we may correlate this find with subsequent discoveries of fossil wood, carbonized vegetation or any other material which may be subsequently found. This will enable the scientific investigators to piece together a coherent story concerning the origin of Crater Lake and possibly lend more data to prove or disprove the several theories which are prevalent concerning the destruction of old Mount Mazama. Did the cone of Mount Mazama collapse and then subsequent eruption build up the three volcanic cones now found within the caldera? Did a terrific explosion blow of the top of Mount Mazama, leaving the gigantic caldera which Crater Lake occupies and subsequent eruption build up the volcanic cone of Wizard Island and the two smaller cones which are of insufficient height to protrude above the water level of the lake?

Did the volcanic ejecta, ash and pumice, which buried the logs and changed these to charcoal, come from the eruption of Mount Mazama prior to its final collapse or explosion? Did the ejecta come forth at the time of Mount Mazama's final destruction? Is the ejecta in question the explosive material of some adnate volcanic cone rather than material erupted from Mount Mazama? All of these questions are easier to ask than to answer. In our small way it is our hope to accumulate the evidences of the past as we are able to discover them and thus be able to piece together the correct story by eliminating the less probable hypothesis.

Beavers In The Park
By D. S. Libbey

This season we are delighted to learn that within the area of Crater Lake National Park we have living colonies of the American Beaver (Castor Canadensis Pacificus), the national emblem of our sister nation to the north. It is the largest rodent on the continent and a member of the squirrel family which as adapted itself to life in the water.

Mr. Fred Patton, one of the oldest employees of Crater Lake National Park, called our attention to numerous beaver dams and fresh beaver cutting along the west margin of the park in the vicinity of Copeland Creek. Mr. Patton discovered the beaver activity while engaged in his work of opening a motor way.

Specimens of the fresh beaver cuttings have been placed on exhibit in the Community House and it is the plan to have guided motor caravans conducted to the scene of the activity by the ranger force. Also very careful efforts will be made to have the area adequately patrolled to preserve the colony of beavers and to prevent their extermination by poachers in the subsequent trapping season.

The pelt of the beaver is connected with the earliest exploration of North America, and fur trading in the days of the Old West was carried on extensively. Vast areas were discovered and developed because of the powerful incentive to seek out the beaver and obtain his pelt.

It is our goal to preserve our beaver friends. Their works have never ceased to be of perennial interest to man. So extensive the dam, so large the trees felled by no other tools than their chisel-like incisors, and so great the tracts of land flooded by the dams that the beavers have become known as the emblem of industry.

A beaver dam is never complete. The busy colony is constantly repairing it, adding fresh cuttings and shifting driftwood, stones and earth so that they are inextricably piled together. The obstructions create the pools of still water so desired by the beaver, and the cuttings from last winter show clearly the snow levels at which the animals were able to work.

The series of dams has materially changed the erosional activity of the creek and has resulted in basins which are splendid reservoirs for catching and preserving vegetable life which slowly decomposes and yields the necessary humus material. This results in offering favorable food supply for a more vigorous growth of flowers and trees which find their ideal habitat in a swamp.

The series of beaver colonies was found about the 5,250 foot elevation in the park.


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