Treesearch

Quaking or trembling aspen (Populus tremuloides Michx.) is the only aspen in western North America. Therefore, in this part of the continent, it is commonly and correctly referred to simply as "aspen". Throughout much of the interior West, it is the only upland hardwood. Aspen occupies millions of acres, and, in some states, it is the most widespread forest type.

Aspen forests provide important habitat for many species of wildlife (Gullion 1977b), especially in the West (see the appendix to this chapter). In the coniferous forests of the interior West, aspen groves may be the only source of abundant forage; in the grasslands they may be the sole source of cover. A primary value of the aspen ecosystem in the West during the past century has been production of forage for both wildlife and domestic livestock (see the FORAGE chapter).

Presents classifications of successional community types on four major forest habitat types in western Montana. Classifications show the sequences of seral community types developing after stand-replacing wildfire and clearcutting with broadcast burning, mechanical scarification, or no followup treatment. Information is provided for associating vegetational response to treatments.

A land classification system based upon potential natural vegetation is presented for the coniferous forests of northern Utah. The classification and descriptions are based on reconnaissance data from over 1,000 stands. A total of 8 climax series and 36 habitat types are described. A diagnostic key, utilizing conspicuous indicator species, provides for field identification of the types.

Successful natural regeneration of Engelmann spruce in small clearcut openings depends on weather and aspect and is modified by cultural treatments. Small clearcut openings (1-2 ha) can be successfully regenerated on north aspects with mineral soil seedbeds and shade. On south aspects, shade is absolutely essential for any survival. However, successful natural regeneration is not likely regardless of cultural treatments. Drought is the most serious cause of mortality; but clipping by birds, frost heaving (north aspect), heat girdle (south aspect), and snowmold (north aspect) caused...

Differential scanning calorimetry has been applied to three woody laboratory fuels studied in current wild/and fire modeling research. The heat required to increase a fuel's temperature to ignition is an important modeling parameter affecting the rate of fire spread. Below 200° C, ground fuel-stick samples had similar heat requirements, but above 200° C the heat of preignition varied up to 19 percent among fuels. Therefore, these variations can affect fire spread rates similarly to variations in moisture content. A consistent set of data is provided for calculating the heat of preignition....

This proceedings, second in a series of publications of wildland shrub symposia, brings together current knowledge of plants belonging to the chenopod family. Topics addressed by the 46 papers include distribution, systematics, genetics, ecological relationships, physiology, seed technology, animal relationships, and revegetation techniques.

The mountain pine beetle, Dendroctonus ponderosae Hopkins, exhibits variations in morphology, behavior, and physiology over its extensive range. Morphological variation is seen in size differences in beetles from different localities and in the surface sculpturing of various body parts. There are also apparent differences in host selection among populations. While this insect attacks most species of pines in western North America, beetle populations in mixed pine stands may concentrate on one host species (Barker et al. 1971, Wood 1963). This diversity is reflected in the taxonomic history...

During a 2-year study of the fish and macroinvertebrates of a third-order montane stream, a severe drought in the first year resulted in a temporary cessation of surface flow. Flow was continuous during the second year. Some taxa (e.g. Ophiogomphus severus) exhibited higher density during the drought year, others declined in abundance during low flow (e.g. Baelis spp.), whereas a few (e.g. Tricorythodes minuius) appeared unaffected. Total macroinvertebrate density decreased by 50% during the low flow year compared to the normal flow year. Mayflies were most severely affected, but also...

This report summarizes information on distribution, botanical description, habitat conditions, life history, special uses, and genetics of Engelmann spruce.