Many indicators and criteria have been proposed to assess the sustainable management of
forests but their scientific validity remains uncertain. Because the effects of forest disturbances
(such as logging) are often specific to particular species, sites, landscapes, regions
and forest types, management ‘‘shortcuts’’ such as indicator species, focal species and...
Rice, maize, sorghum, wheat, barley and the other
major crop grasses from the family Poaceae
(Gramineae) are mankind’s most important source
of calories and contribute tens of billions of dollars
annually to the world economy (FAO 1999, http://www.fao.org; USDA 1997, http://www.usda.gov).
Continued improvement of Poaceae crops is necessary
in order...
Stem sinuosity is a highly visible stem-form trait in the leaders of fast-growing Douglas-fir (Pseudotsuga menziesii var. (Mirb.) Franco) trees, yet its cause is unknown. We tested the hypotheses that sinuous stems have longer expanses of primary growth than nonsinuous stems (putting the leader at higher risk curvature, induction of...
Soil respiration is a major pathway for carbon cycling in terrestrial ecosystems yet little is known about its response to natural and
anthropogenic disturbances. This study examined soil respiration response to prescribed burning and thinning treatments in an old-growth, mixedconifer
forest on the western slope of the Sierra Nevada Mountains....
Even after 140 years without a fire, mixed-conifer forest such as Teakettle’s Experimental Forest has a
distinct patch pattern and complex structure. Researcher Malcolm North and colleagues examined the
structure and function of these ecosystems and their response to widely used restoration treatments.
Collectively the studies found fire was essential...
Seasonal alkenone concentrations, production rates, and unsaturation patterns (U₃₇ᴷ') were measured at station ALOHA in the oligotrophic subtropical North Pacific. Highest alkenone concentration and production rates were found in (winter and fall) or just below (summer) the surface mixed layer. Lowest alkenone concentration and production rates were found within the...
This report describes the results of semiquantitative analysis of clay mineral composition by X-ray diffraction. The samples consist of hemipelagic mud and mudstone cored from Hydrate Ridge during Leg 204 of the Ocean Drilling Program. We analyzed oriented aggregates of the clay-sized fractions (<2 μm) to estimate relative percentages of...
The exchange of waters between the Pacific and the Southern Oceans occurs along the eastern boundary of the South Pacific. Because water masses of the Antarctic provide a connection among the world's ocean basins, these water masses maintain the ability to influence changes in ocean circulation and climate (Lynch-Stieglitz et...
The effect of disturbance on the resistant propagule community (RPC) of ectomycorrhizal
fungi has been given relatively little attention. In this study we investigate the effects of
heat, one important factor of fire disturbances, on the ability of ectomycorrhizal RPC fungi
to colonize Pinus jeffreyi seedlings in greenhouse bioassays. Prior...
The stable nocturnal boundary layer is commonly viewed or modelled as a balance between the temperature tendency (cooling) and vertical heat-flux divergence. Sometimes the radiative-flux divergence is also included. This perspective has dictated the design of field experiments for investigating stable nocturnal boundary layers. Tower-based micrometeorological data from three field...