Treesearch

Grazing crested wheatgrass during spring only, fall only, and spring and fall to a 1-inch stubble height for 10 years had little effect on vegetative characteristics of the seeded stands. Invasion of the stands by other species was greater with spring or spring-fall use than with fall use. Litter decreased with all seasonal treatments, but decreased most under spring-fall use. Drought and growing-season moisture were the critical factors in determining forage yields. The spring-fall pastures produced more forage, provided more days of grazing, and gave the highest average beef production,...

Individual herbaceous and shrubby species can be identified most accurately on large scale (1: 600-1: 1,100) colour infra-red aerial photographs. There was no apparent advantage of this film type as compared with normal colour film for identifying non-vegetation characteristics in herbaceous and shrubby plant communities. Site delineation, as inferred by the plant community, can be equally well defined on either film type at a scale of 1:4,200. Species density and foliar cover can be estimated from this type of aerial photography within acceptable error limits. Colour infra-red photographs...

Butcher paper, surveyor stakes, lath strips, plastic letter-number codes, paper plates, and drop-panel markers were all useful for marking range ground features, providing strict flightline control, and interpreting resultant aerial photographs. All markers were both highly detectable and resolvable at the largest scale of 1:600. All markers remained visible, yet some became less resolvable, at the smaller scales of 1:2400 and 1:4600.

Apollo 11, the first manned flight to the surface of the moon, was a spectacular feat. A major reason the flight was so successful was that Apollo 11 had already made the trip a great many times - theoretically in a computer. What a mess the first flights must have been! But, they were made without loss of astronauts, resources, or time. The technique used by NASA is available to, and being used by, managers and scientists in many fields. It has, however, had only limited use so far in land management. This valuable tool is the study of a system in a computer through simulation of changes...

New remote sensing techniques will be widely used in wild land research and management in the years ahead. A review of our initial efforts with one facet of remote sensing - large-scale 70-mm. color aerial photography - will stimulate appreciation of its vast potential. This potential can be categorized into possibly valuable applications with unique advantages. This system can ultimately be related to more powerful sensor systems, whose efficient use awaits only research and development.

Important range-shrub species were identified at acceptable levels of accuracy on large-scale (1:600 to 1:1,500) 70 mm color and color infrared aerial photographs (positive transparencies). Identification of individual shrubs was significantly higher, however, on color infrared. Eight of 11 species were identified correctly more than 80 percent of the time on color infrared and two species were correctly identified 100 percent of the time. Six species were identified more than 80 percent correctly on color photographs but none were identified 100 percent correctly. Photoscales smaller than...

Valleys of open grassland parks interspersed among the mountains of the ponderosa pine zone of Colorado are suitable for the production of livestock. Unfortunately, during the late 1800's and early 1900's many of these grassland parks were cultivated and attempts made to raise row crops or hay. Soil often too infertile to produce adequate yields, short growing season, erratic moisture, and the depressed economic conditions of the 1930's combined to cause many farming ventures to fail. As a result, many cultivated areas were abandoned. On others overgrazing by livestock depleted the native...

Ponderosa pine trees from 19 geographic sources planted on a test area in northern Idaho have been measured 12, 20, 40, and 50 years after outplanting. From the 12th through the 50th years after outplanting, trees from one nonlocal source have been tallest. Trees from the local source now rank second in height, having risen from sixth during the last 10 years. In general, trees from sources close to the test area have performed better than those from more distant sources.

Heights of 31 progenies of western white pines from four geographic localities and four crosses between localities were assessed on 14-year-old trees at two sites. Differences in height among individual progenies were detected but could not be related to localities or crosses between localities. Although differential effects of sites on tree height became apparent after age 9, differences among progenies were similar on both sites.

Between 1950 and 1955 hybrid progenies of lodgepole pine (Pinus contorta Dougl.) X jack pine (Pinus banksiana Lamb.) were tested to determine whether adaptation and performance in Montana and Idaho justified improvement of lodgepole pine by hybridization. Average heights, diameters, and survival rates of hybrids, of jack pines native to the Lake States, and of lodgepole pines native to Montana and Idaho were similar after 15 to 20 years of field tests. Poor growth and survival characterized progenies of California lodgepole pines, which represented the maternal parents of several hybrid...