The density here is often determined by crown competition for light rather than by root struggle for moisture. The average yield is about 18,000 B. F. per acre. Reproduction is mainly fir, occurring in groups beneath the large trees; jeffrey pine reproduction, on the other hand, comes in only in openings but it outgrows fir in the seedling stage.

Management in the jeffrey pine type aims to favor jeffrey pine within the limits of the best growth. A modified shelter-wood system is used with the aim of providing adequate pine reproduction, conserving the factors of site and securing a second cut in thirty years. It is not advisable to open up the stand heavily on account of deficient soil moisture and the competition of brush.

The general

Red Fir Type. - Red fir is the chief species. altitudinal range of the type is from 7,500 feet on south exposures, and from 6,500 feet on north slopes up to the summits. Although red fir sometimes occurs pure, it is more often associated with white pine (Pinus monticola), white fir, black hemlock (Tsuga mertensiana) and lodgepole pine, in various mixtures and proportions, forming several more or less definite sub-types. White fir generally predominates at the lower limits of the type but is less numerous at higher altitudes. The stand is a selection forest, with a tendency toward grouping of age classes. The average stand is about 25,000 B. F. per acre, but the yield shows a wide variation in accordance with local conditions. The maximum stand is about 125,000 B. F. Such large yields occur, however, only under the most favorable conditions and on restricted areas. Red fir reaches its best development on deep moist soil in sheltered situations.

The chief consideration in marking is protection of the remaining stand from damage by wind. A group selection system is used in management, favoring red fir. Watershed protection is an important consideration in marking.

Both the red and white firs are of great value as pulp material. A sale of 5,500 cords of these two species was made last year on this Forest to a company which uses 28,000 cords of red and white fir timber per year. The products are a high grade of wrapping paper and tissue paper.

Lodgepole Pine Type. This type, which generally consists of pure lodgepole pine, is governed in distribution by soil moisture. It occurs only around the edges of mountain meadows, along the banks of streams, and in moist pockets in the side hills. The average stand is about 5,000 B. F. per acre. Mixtures of lodgepole pine with red fir, white fir and hemlock are frequently found. Black Hemlock Type. Pure hemlock occurs only on high peaks at altitudes from 7,500 feet to the summits. The average stand is 12,000 B. F. to the acre. The type is at present of little value commercially but is valuable as a protection forest.

The Forests of the West Slope. - Forest conditions on the west slope at elevations from 3,000 to 5,000 feet, where reconnoissance is being carried on this winter, offer a strong contrast to conditions on the east slope where the above described types are found. The west slope of the Sierras in the region covered by the Tahoe National Forest is the richest gold producing locality in the state. The mining boom which followed the discovery of gold in 1849 was followed by a period of settlement which brought with it the exploitation of a large amount of the virgin yellow pine, sugar pine, douglas fir, white fir, and incense cedar, which originally covered a large part of this country.

Reproduction, chiefly of yellow pine, came in quickly on the cut-over areas and growth is extremely rapid on account of favorable soil and moisture conditions. Consequently we have a combination of virgin stands of high yield with many scattered second growth even-aged stands from thirty-five to fifty years old which compare favorably in density, quality, and rate of growth with the even-aged douglas fir stands on the western foothills of the Cascade Mountains in Washington and Oregon.

The party last season consisted of four field assistants, a packercook and a forest assistant. A second forest assistant and a ranger, who were engaged in timber sale work and silvical studies, joined the party at intervals. The method used was the strip system which was followed throughout the district. A strip one chain wide in dense timber and two chains wide in more open stands was run through the centre of each "forty." This gives an estimate based upon five or ten per cent of the area. In most cases distances could be obtained with sufficient accuracy by pacing but the chain.

was frequently used in locating corners and running difficult lines. The Forest Service standard staff compass was employed. The compassman ran out the line for each strip, tallied the distance covered, took necessary field notes, mapped topography and types on a scale of four inches to the mile, and noted elevations, which he obtained from aneroid readings. The estimator recorded the DBH and the number of sixteen foot logs of all the trees on the strip, and took silvical notes.

Frequent checks of diameter and height estimates were made by means of the hypsometer and diameter tape. For each forty the per cent of cull for defects in each species was noted and a correction factor was applied when, in the estimator's judgment, the strip did not represent average conditions on the forty.

All trees twelve inches and over in diameter were included in the estimate of the total stand. Trees six to twelve inches D B H were tallied by diameter classes and recorded by number of each species. Trees between six inches DBH and five feet in height were described as saplings; trees below five feet in height were classed as seedlings. These two classes were estimated by the total number per acre and the percentage of each species. The silvical data noted for each forty covered the following points: rock, soil, ground cover, underbrush, condition of timber (in detail by species), average age, factors aiding or hindering logging, adaptability of land.

When a section was completed, a brief forest description was written, summarizing the points on the forty sheets, and including a description of the timber by species, according to size, quality, and condition. No attempt was made to work up the estimates in the field, but the map work was kept up-to-date. The types were colored on the maps in accordance with a legend used throughout the district. From these section maps township maps on the scale of two inches to the mile were later made in the office.

The work was entirely in surveyed land and in most cases little difficulty was experienced in finding the old Land Office corners, most of which were set from thirty-five to fifty years ago. Copies of the original field notes were of great value in retracing the work of the old surveyors. As a rule only two miles of exterior lines were run and blazed for each section estimated.

These

were sufficient to establish points to which the strips could be tied. All forest boundary lines within reach of camp were run out, blazed, and posted.

The total area covered was 28,500 acres; the cost per acre was $0.057. The amount estimated was 269,155,000 B. F.; the cost per M. was $0.0067.

THE ART OF PACING

E. I. TERRY, B.S.F. 1907

PACING is one of the roughest methods of measuring distance and cannot be used where a high degree of accuracy is required, but within its limitations it has a wide and extremely serviceable field of usefulness for many kinds of forest work. With a hand or staff compass the woodsman may employ it to advantage in finding section corners or other marks from known points, in tracing old lines and in cruising timber. It is the cheapest and quickest method of making forest and topographic maps, and it is the mainstay of reconnoissance work on the National Forests. The older method of running strip surveys by dragging a chain attached to the compassman's belt has been almost entirely superseded by pacing. It is therefore important, in fact often essential, for the student of forestry to become proficient in the art of pacing. To do this he must have much practice, but there are certain underlying principles which one must understand and apply in order to do consistently accurate work.

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For one thing, it is much better and easier to count every double расе, that is, every time the same foot is put forward — than it is to count with both feet as most novices and even some experienced pacers do. Our word pace is derived from the Latin passus, and that itself meant a double pace. A thousand passus made the Roman mile, which was approximately 5000 feet, so the average double pace of the Roman soldier was about five feet. In counting paces with a tally-register to which I will refer later it is much easier to record double than single paces.

Again, most beginners try to take an artificial step, such as a three-foot stride. That is exactly the wrong way to pace. The right way is to determine the length of one's natural stride by pacing several times over a measured line which should be at least a quarter of a mile in length. Pacing between section-corners where the lines are clearly blazed and the corners are known to be