Nature Notes

Volume III No. 2 - August, 1930

Bugs -- Part II
By Earl U. Homuth

The first effort in control with funds provided in 1925 was begun in May with the arrival of Mr. J. E. Patterson. A stand against the invasion was made on the southern front. Infested trees were felled and burned upon the snow. Tall stumps now standing give evidence of the difficulties encountered. The great masses of snow will not support a man's weight until, by alternate thawing, freezing, and packing, it becomes sufficiently solid. This is usually about May 15. Caterpillar tractors were used to gain access to infested areas from the roads, and here camps were established. The excessive cost under these conditions was not taken into consideration when appropriations were made; as a result the work was, and still is considerably hampered.

The first season's work seemed a complete failure, and seemed to establish the epidemic as beyond control, and to indicate that the people of Oregon and California must prepare to watch, helplessly, their forests disappear. Three successive years' work were so discouraging that in 1928 no appropriation was made for control work.

Nevertheless, in Crater Lake National Park a great deal of study and thinking and planning was done. Obviously a new method of attack must be developed. A group under the direction of Mr. J. E. Patterson, associate entomologist of the Bureau of Entomology, having suffered reverse, were not yet defeated.

Several results of their tireless efforts developed. It was discovered that a beetle emerging from a certain species of tree, returned to that species to breed. Thus a beetle developing in the lodgepole pine returned to the lodgepole; if in a yellow pine, it returned to the yellow pine. As ninety percent of the trees attacked were lodgepoles, effort could be expended upon areas where lodgepole were exclusive or at least predominant.

Another important discovery was the fact that larvae hatched in a thin-barked tree would die if the felled tree were exposed to a sun temperature of 85 degrees F. for a period of one hour. A longer period of time would be necessary if the temperature was lower, but allowing for this, the result would be the same. The lodgepole is a thin-barked tree.

Based upon these new discoveries a systematic, definite, and strenuous effort was again innaugurated to control and eradicate the infestation. When we consider the great areas of forest to be covered, the character of the terrain and the conditions in early season, the difficulties to be encountered may be appreciated. The results attained, however, have been encouraging. A few figures indicating these results will be added later. The method of operation will be first considered.

A preliminary survey is first made of an infested area. An expert entomologist is generally called upon to assist in this. From his study will be obtained the information regarding the number of men necessary to carry out the program, and the time necessary. Since the beetles begin to fly -- to leave the trees -- about July 1 and nothing can be accomplished for the season, thereafter, time is also of the substance of this project.

The work is divided into four parts: spotting, falling, rolling, and the keeping of records. The spotting crew is usually made up of two spotters and a compassman. The felling gang consists of three men in a crew, two fallers and a limber. The rolling crew calls for four peavy men, one axeman, and a checker. Records are kept by the spotting crew.

With the Spotting crew, the compassman is in charge and should be thoroughly familiar with both compass work and spotting. Also he should have a general knowledge of the area to be covered, so as to take full advantage of the topography of the region. Base lines are established (since in this park no governmental land survey has been made) and these equally divide the area; they are generally run north and south or east and west to facilitate running lines with a compass. Spotters should be capable men, physically, with a thorough knowledge of the work. Previous experience with a falling crew is invaluable, since this gives experience in determining a good "bug" tree.

Strips are systematically run thru the area from the base line. The compassman stays in the middle of the strip, with spotter "A" on his left and "B" on his right. They stay abreast of each other. In an area where trees are scattered, an extra spotter may be assigned to the middle of the strip. Where infested trees are numerous, the extra spotter is not necessary. With two spotters in the crew the strip does not exceed three hundred feet.

When an infected tree or a group of trees is discovered, the spotter finding them calls "Bugs". The group stops. He then blazes on both sides of the tree and puts a number on the blazes. These numbers are in sequence, each spotter having a series, as from 1 to 100 or 1001 to 1100. When the series inn his note book is used he obtains a new series from the compassman. When he has finished marking a group of trees, he calls the inclusive series in the group to the compassman, who then enters the group and the numbers upon his map.

The crew moves on to the outer limit of the area, then turns and runs another strip parallel to the first, and continuing this until the entire area is covered.

The Fallers should be experienced men, both in falling and limbing. Each crew is furnished with a map entering the location and the numbers of the trees. They pass thru the strips, cutting as they go. They fall the tree in as nearly a north-south line as possible, which allows the maximum effect of the suns' rays, this being the entire object of the treatment. Shade from other trees is, of course, considered. The tree is limbed as far as necessary to prevent shading. The stump is peeled. In case of the White Pine, the bark is too thick to permit the heat of the sun to penetrate; therefore the bark is peeled from these trees.

As each tree is felled, the number of the tree is written on the stump, and also on a pad which is turned in to the "spotters" in the evening.

The Rolling crew, of peavey men and axemen are taken from the falling crews, and the checker should be a spotter, or someone familiar with the region. The checker carries a map and leads the crew to the trees, each of which is rolled half over, thus exposing the remaining surface to the sun. This rolling is of course done after sufficient time has elapsed to allow for the destruction of beetle larvae on the surface originally exposed. The rolling must be done accurately to allow all surfaces to be finally exposed. The number of each tree rolled is recorded, and these numbers also turned in to the spotters each evening.

The records, as mentioned, are kept by the spotting crew. After each number in the original record, a check is placed when that number is turned in by the Fallers and later by the Rolling crew. This system checks up on trees missed.

A daily report is prepared as to total trees spotted, cut, and rolled, and these figures complete a final report. These final reports are useful in planning work for future years, in estimating future costs, and by comparison with previous years, in determining on the basis of percentage the effectiveness of the work.

A system of tags has been suggested to avoid duplication of numbers, misreading of numbers of other normal errors. Each tag would have three stubs, one stub to be retained when the tree was spotted, one when felled, and one when rolled.

In conclusion a few facts will be given concerning the work actually done during the two years in which appropriations have been available.

Volcanic Bombs of Mt. Mazama
By Clyde E. Gilbert, Ranger Naturalist

The name volcanic "bomb" is applied to fragments thrown out by an active volcano in a liquid or partially liquid state. Their form is wholly or partly determined during flight through the air, while in a liquid state.

Bombs naturally fall into two classes. Those which start as liquid masses, acquire some symetrical form during flight and retain this form upon landing. These forms are very characteristic, usually symmetrical and unless broken after falling, show fracture surface.

A second class of these bombs starts as a solid angular fragment which has either been reheated in the volcano hearth until the surface has melted or has been dipped in molten lava in the course of its upward movement through the crater. Such a bomb may have any form, depending upon the shape of the original fragment, and the coating may have any thickness.

The bombs of either of the classes may be breadcrusted. The first type presumably by the quick cooling during flight which produces a solid shell around the liquid nucleus. The sudden contraction causes the solid surface to crack while the central liquid portion remains intact, giving an appearance of "breadcrust".

A solid fragment which becomes molten on the surface because of the intense heat to which it is subjected.

The size of volcanic bombs (both classes) varies from 10 or 12 feet in diameter down to indefinitely small fragments. The very small ones are commonly called lapilli. Very large ones are rare, for the obvious reason that the large sizes do not fly and if they did the crust acquired in flight would not be strong enough to hold them together after landing. Most of the bombs found on Wizard Island are under two feet in diameter, while the largest ones found on Mt. Mazama are about four feet in diameter.

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