The Coconino sun., 1921-09-16

plots it is possible to maintain an ac- curate record of what actually takes place in the forest, so that after 10, 20 or 30 years complete and authen- tic history of areas under observa- tion becomes available.
 From 1909 to 1913, AZ plots having a total area of 1886 acres were es- tablished on six national forests in Arizona and New Mexico. Each plot lis mapped to scale, showing the exact location of every tree, group of seed lings, stumps, logs, brush piles and other features. The diameter, height and full description of every tree is recorded by number.
 Periodic measurements show the rate of growth as well as death or in- jury from lightning, windfall, insects, disease and other agencies. Annual examinations on number of plots furnish record of the occurrence of seed crops, germination and survival of seedlings under various conditions. These plots, the oldest of which were established II years ago, are already yielding a mass of information ob- tainable by no other means, but the records become more valuable each year and it is only after 20 or more years that anything approaching full returns will be realized.
 Forest Reduces Wind.
 Records in the forest and in ad- joining open areas have shown that the forest greatly reduces wind and evaporation, and modifies the exa tremes of temperature, particularly low temperature. Snow melts more rapidly in the forest than in the open during the winter, but less rapidly in the spring. The result is less tor rential but more sustained surface runoff and less erosion on forested than on nonforested areas.
 "In 1916 an investigation known as the study of forest types was initiated, the immediate object of the study be- ing to secure an accurate knowledge of the physical conditions prevailing in the various forest types or forest tree associations. Having obtained this information it will be possible to form a close estimate of the soil and climatic requirements of different spe- cies and particularly the factors lim- itpg their distribution.
 "Since the occurrence of given tree species or association of species is indicative of physical conditions corresponding to their requirements, trees may be used as indicators of soil and climate.
 From November, 1916, to January 1, 1920, series of six instrument sta tions was maintained at various alti- tudes extending from the woodland at 5, 100 feet to timber line at II ,500 feet. Continuous records of air tempera- ture, soil temperature, precipitations, evaporation and wind were secured mainly by means of self recording in- struments. These stations were wis., ited weekly, summer and winter throughout the three years.
 Studies of Moisture.
 Studies have also been made of the moisture content and other properties of soils, and the relative moisture re- quirements of different tree species, in the seeding stage This investi- gation, which is still in progress, is expected to yield valuable fundamen- tai data of direct or indirect applica- tion to many forest problems.
 "The problem which is of most i'm mediate importance and which, un- fortunately, has proven to be the most perplexing and time consuming is that of obtaining natural reproduction of western yellow pine. A general sur vey of the situation in 1908 resulted in establishing certain broad conclu- sions. It was found that contrary to prevailing opinions, considerable num- bers of seed trees were necessary; that large crops of seedlings had be- come established only under unusually favorable combinations of seed pro- duction and rainfall, and that under certain conditions excessive damage