The Coconino sun., 1920-09-03
THE COCONINO SUN

1n 1916 an investigation known as
 the study of forest types was initiated;
 the immediate object of the study was
 to secure an accurate knowledge of
 the physical conditions prevailing in
 the various forest types or forest as-
 sociations. Having obtained this in- formation it will be possible to form
 a close estimate of the soil and climat-
 ic requirements of different species
 and particularly the factors limiting
 their distribution. Since the occur
 renee of given tree species or asso-
 citation of species is indicative of phys
 ical conditions corresponding to their
 requirements, trees may be used as
 indicators" of soil and climate. From
 November, 1916, to January l, 1920,
 series of six instrument stations
 was maintained at various attitudes,
 extending from the woodland at 5100
 feet to timber line at II 800 feet. Con-
 tinuous records of air temperature,
 soil temperature, precipitation, evap-
 oration and wind were secured mainly
 by means of self recording instru-
 ments. These stations were visited
 weekly summer and winter through
 out three years. Studies have also
 been made of the moisture content
 and other properties of soils, and the
 relative moisture requirements of diff
 fferent tree species in the seeding
 stage. This investigation, which is
 still in progress, is expected to yield
 valuable fundamental data of direct
 or indirect application to many forest
 problems.
 "The problem which is of most inn mediate importance, and which, un-
 fortunately, has proven to be the most
 perplexing and time consuming, is that of securing natural reproduction of western yellow pine. A general survey of the situation in 1908 result ed in establishing certain broad con- clusions. It was found that, contrary to prevailing opinions, considerable numbers of seed trees were necessary; that large crops of seedlings had be- come established under unusually fla vorable combinations of seed produc- tion and rainfall; and that under cer- tain conditions excessive damage was done by grazing. Later investigations substantiated the above conclusions and developed additional facts. Rec ords during a period of 12 years on the permanent sample plots previously | described have shown that as a rule seed crops are borne only every other | year and that good seed crops have oc- cured only at intervals of about five | years; that the seed sometimes fails l to germinate for lack of moisture and | that in some years when moisture | conditions are favorable there is no seed; that of the seedlings which do | germinate rarely more than to per cent survive; that despite this great | few seedlings survive from almost every seed crop, so that as a result of this slow but reasonably cer- tain cumulative process, areas which are we'll provided with seed trees and protected against fires and grazing may be expected to fully restock in about 20 years. At irregular intervals often longer than 25 years single heavy seed crop fol- lowed by two or more years of favor able moisture conditions may result in the establishment of seedlings in suf- ficient numbers to completely restock an area. Such occurrences are, how ever, too uncertain to be relied upon, and therefore, to be sure of reproduc- ton, the few seedlings which become every two or three years must be conserved. The heavy seed crop on the Colorado plateau in 1918 by the extremely wet year of 1919 gave promise of recurrence of feat 25 years ago when large areas became fully stocked as result of a single seed crop; but the dry sum- mer of 1920 has already taken heavy toll from the splendid seeding crop of 1919, and therefore, the outcome still hangs in the balance. It has requiredi nearly 12 years to establish these facts and others pertaining to reproduction of yellow pine. Administrative details remain to be worked out, but the sci