Treesearch

The object of precipitation measurement, as stated by Brooks (1), is to obtain "a fair sample of the fall reaching the earth's surface over the area represented by the measurement." The area referred to is horizontal, or map area. Even when measured on a slope, precipitation is always expressed as depth of water on a horizontal area.

This article presents the results of a study to determine the place, time, and number of measurements that should be made to obtain dependable ratings of "average-bad" fire conditions without an excessive number of stations or observations. The author concludes that under the conditions prevailing in the Priest River Experimental Forest in northern Idaho a single measurement taken daily at noon at either a valley-bottom or a south-slope station is adequate for the rating of fire danger.

One of the most conspicuous features of the forested regions of northern Idaho is the small treeless areas which occupy portions of the southerly exposures of especially prominent peaks and ridges. These areas, sometimes referred to as parks or balds, begin at the summits of the prominences and extend down over the south-facing slopes sometimes as much as approximately 200 m. Each park is essentially an island of prairie-like vegetation surrounded by belts of shrubs and scattered trees, and then by dense forest. Few if any of the mountains of northern Idaho are high enough to have a...

The interception of rain and snow in the forest-canopy is a factor of sufficient magnitude to require its measurement in any complete study of the hydrology of forested watersheds. In experiments set up to measure the relations of watershed-runoff and infiltration to precipitation it is particularly essential to measure net rainfall reaching soil under the forest-canopy, rather than total precipitation, in order to estimate adequately the amounts of water available for runoff.

During 1939, stream-gaging stations were built to measure water yields from typical watersheds on the Manitou Experimental Forest in the Front Range (Missouri Gulch) and on the Fraser Experimental Forest in the Main Range (Fool Creek).

One of the many duties of the Forest Service of the U.S. Department of Agriculture is the investigation of watershed management. A phase of this subject is the measurement of the flow of mountain streams, which varies through a wide range. To measure and record these varying quantities, a type of gaging station, which combines a flume and two broad-crested weirs, has been developed at the Rocky Mountain Forest and Range Experiment Station at Fort Collins, Colorado. Mr. Wilm discusses the accuracy with which extremes of flow in flashy mountain streams may be measured by this type of...

For over a third of a century exploitation of the western white pine forests of northern Idaho has been based upon the harvesting of virgin timber. In recent years, however, with the end of this ready-made crop definitely in sight, interest in the growing of new timber crops has been increasing. Particularly within the last decade, large public investments, including expenditures for control of the white pine blister rust and for such forest-improvement measures as disposal of defective trees and thinnings have resulted in definite commitments toward growing timber on a long-time basis.

At Spokane, a month ago, Dr. Carl F. Taeusch of the Bureau of Agricultural Economics told us that for common understanding of any problem it is essential that we first establish the "framework of ideas within which we are trying to work out the problem." Walter B. Pitkin stresses the same point when he says: "The next task is to take some position toward the subject you propose to discuss ... When you take a position toward a field of fact or fantasy, you do something strangely like the choosing of a vantage point from which you view a valley. . . . Point of view and perspective determine...

The Forest Service type rain-gage was originated by W. B. Osborne of the Portland, Oreg., office of the U. S. Forest Service to meet a need for reliable rainfall measurements at low cost. Many hundreds of them, over 700 on the national forests of northern Idaho and western Montana alone, are now being used during the summer months as aids to forest-fire control management. They supply the only measurements of summer precipitation on millions of acres of forested mountain watersheds. Without low-cost gages such measurements could not be afforded at most of these stations.

The measurement of fire danger has progressed remarkably since the early days of measuring humidity alone, or humidity and wind, or humidity, wind, and rain at a few valley bottom stations scattered widely apart over a forest of a million acres or more. Measuring the moisture content of the fuels directly is now known to be more accurate than measuring humidity and rain and then estimating the fuel moisture and inflammability. Other factors, such as the shade of timber canopies of different densities, north-versus south-facing slopes, valley bottom versus ridge top or mountain top exposure,...