Treesearch

We examined fire and weather records for areas of the western United States for the period 1970-1984 to determine the effects of simultaneous wildfire occurrence on fire suppression efforts. Burning conditions were accounted for by use of short strings of fires which involved simultaneous suppression efforts. These strings were matched with closely preceding isolated fires to form matched sets, which were used to examine the relative effects of simultaneous fire occurrence. Fires were predominantly lightning-caused, and within matched sets they showed little difference in burning conditions...

Yap is a high island with a mean annual rainfall of 3040 mm and considerable potential for erosion. The island once supported a dense population with a nature-intensive technology. The traditional food production system incorporated tree gardens which mimic natural forests in intercepting rainfall and holding the soil, and taro patch system which mimic swamp forests as s silt trap. Trails were stone-paved and drained by stone-lined ditches. In wild forests, the canopy is removed during the dry season and mixture of crops cover the still by the time the heavy rains arrive. The system...

Ohia lehua (Metrosideros polymorpha) is the most abundant and widespread tree in Hawaii. This slow growing native hardwood seeds freely and often starts as an epiphyte in fern forests. It is the first tree to appear on new lava flows where it offers watershed protection. The wood is of fine even texture and takes a good polish. It is used for flooring, fenceposts, and fuel. This tree provides important habitat to native birds, several endangered.

Airborne measurements of 13 trace gases from seven forest fires in North America are used to determine their average emission factors. The emission factors are then used to estimate the contributions of biomass burning to the worldwide fluxes of these gases. The estimate for NH3 (˜7 Tg N yr-1) is about 50% of the global emissions of this gas. Combined NH3 and NH4 emissions from biomass burning could be the most important component of the NH3 cycle. N2 0 from biomass burning (˜2 Tg N yr-1) is also significant worldwide. The estimate for NOx from biomass burning worldwide (˜19 Tg N yr-1),...

William B. Critchfield died July 11, 1989. He left a legacy unparalleled in forest genetics. Bill made major contributions to understanding genetic variation, hybridization, growth and development, biogeography, paleobotany, systematics, and taxonomy of forest trees, especially pines. In each of these fields, Bill's pioneering work earned him the position of world authority. These studies were mainly spinoffs from groundwork Bill was meticulously laying for his primary interest: unraveling the evolutionary history of conifers. And it is his evolutionary syntheses that best reveal Bill's...

Pacific madrone (Arbutus menziesii) is one of the most widely distributed tree species native to the Pacific coast. Named for its discoverer, Archibald Menzies, a 19th century Scottish physician and naturalist, the species is called arbutus in Canada, and madrone, madroña, or madroño in the United States. The latter name is ascribed to Father Juan Crespi, chronicler of the 1769 Portola expedition. Although examples of fine furniture and attractive veneer from madrone are common, utilization is far below potential and management is almost nil.

Tanoak (Lithocarpus densiflorus), also called tanbark-oak, is an evergreen hardwood that, with other species in the genus, is considered a link between the chestnut, Castanea, and the oak, Quercus (19). Tanoak has flowers like the chestnut and acorns like the oak. This medium-sized tree grows best on the humid moist slopes of the seaward coastal ranges. It usually occurs in a complex mixture with conifers and other hardwoods, but often forms pure even-aged stands. The wood is hard, strong, and fine-grained. Tanoak is designated a commercial species in California. Current major uses are for...

The hardwood component of young loblolly pine (Pinus taeda L.) plantations was simulated for use in a sampling study of competing vegetation. Spatial arrangement, total height, and crown area of hardwood rootstocks in 19 plantations 3 to 6 years old in Alabama and Georgia were used to develop the simulator. Rootstock arrangement ranged from uniform to clumped. A two parameter, left- and right-truncated Weibull function modelled height distribution. Total rootstock height conditionally determined crown area. The simulator was used to evaluate 42 sampling estimators of competing hardwood...

Called "the most princely of the genus" by its discoverer, David Douglas, sugar pine (Pinus lambertiana) is the tallest and largest of all pines, commonly reaching heights of 53 to 61 m (175 to 200 ft) and d.b.h. of 91 to 152 cm (36 to 60 in). Old trees occasionally exceed 500 years and, among associated species, are second only to giant sequoia in volume. For products requiring large, clear pieces or high dimensional stability, sugar pine's soft, evengrained, satin-textured wood is unsurpassed in quality and value. The huge, asymmetrical branches high in the crowns of veteran trees, bent...