Treesearch

Rains of 12 inches or more in 6 hours fell on the east slopes of the Black Hills the night of June 9, 1972. Resulting flash floods exacted a disastrous toll in human life and property. Rainfall and discharge so greatly exceeded previous records that recurrence intervals have been presented in terms of multiples of the estimated 50- or 100- year event. Quick runoff was produced in the heaviest rainfall areas regardless of hydrologic condition. Flood sources included all major geologic and soil types and practically all land uses in the Black Hills. The highest measured peak runoff per unit...

The accuracy of a BOD oxygen probe for field measurements of primary production by the light and dark bottle oxygen technique is analyzed. A figure is presented with which to estimate the number of replicate bottles needed to obtain a given accuracy in estimating photosynthetic rates.

This pictorial describes how western spruce budworm larvae feed on young western larch and the trees' responses to this damage. Larvae feed not only on the current year's foliage-their usual diet on most coniferous hosts-but also sever stems of current year's shoots. Multiple-topped, bushlike trees develop in direct response to the amount and type of damage. As a result, trees cannot maintain straight boles and good form. Sustained budworm damage could conceivably influence the management of western larch-one of the more important conifers in the northern Rockies.

A generalized, non-linear population dynamics model of an ecosystem is used to investigate the direction of selective pressures upon a mutant by studying the competition between parent and mutant populations. The model has the advantages of considering selection as operating on the phenotype, of retaining the interaction of the mutant population with the ecosystem as a whole, and of setting a reasonable balance between theoretical manageability and quantitative testability.

Five existing fire models, both experimental and theoretical, did not adequately predict rate-of-spread (ROS) when tested on single- and multiclump fires in oak chaparral in Arizona. A statistical model developed using essentially the same input variables but weighted differently accounted for 81 percent ofthe variation in ROS. A chemical coefficient that accounts for effects of fuel chemistry on ROS is applied to the model. The model provides usable guidelines for predicting fire spread in Arizona oak chaparral.

As a matter of policy and good forest resource management, the Forest Service will manage the timber resources on the National Forests to achieve the various multiple use objectives established for the respective management units. In so doing, we are not to be bound to any particular system of management as the primary system, but we are to prescribe and use the system of management and the cutting methods associated with that system which will best fit the resource conditions and needs of the situation at hand. Consequently, we must be prepared to prescribe and apply correctly uneven-aged...

Describes a set of computer programs for developing prognoses of the development of existing stand under alternative regimes of management. Calibration techniques, modeling procedures, and a procedure for including stochastic variation are described. Implementation of the system for lodgepole pine, including assessment of losses attributed to an infestation of mountain pine beetle, is described.

A provenance test of 49 origins of Scotch pine (Pinus sylvestris L.) from eastern Europe, Russia, and Siberia was established at three locations in North Dakota and one in Nebraska. After 10 years (7 in Nebraska), trees from 50º to 55º latitude and 20º to 40º longitude survived best, were taller, and had greener winter foliage. Several provenances appear to be well suited for planting in shelterbelts and for Christmas tree culture.

Recommendations are provided to aid the forest manager in regenerating Engelmann spruce by planting in the central and southern Rocky Mountains. Reforestation operations covered include storage, transportation, microsite selection, site preparation, planting, plantation protection, and recordkeeping. The physiological and silvicultural requirements of spruces are discussed with respect to the harsh environment of the spruce-fir zone so that planting principles can be better understood.

This field guide was prepared to provide the planter with the techniques needed to establish Engelmann spruce seedlings successfully. Planting principles are discussed in detail in USDA Forest Service Research Paper RM-89, “Planting Engelmann Spruce” which emphasizes the relationship between the physiological and silvicultural requirements of spruces and the environmental conditions to which seedlings are exposed.