Treesearch

The daily activity of some predators is correlated with the activity pattern of their prey. If capture efficiency varies as a function of prey activity, a predator that synchronizes its foraging activity with the time of day that prey are most vulnerable should capture more prey, and at lower cost, than a predator that initiates foraging at random. Mink, Mustela vison, and weasels, M. erminea and M. nivalis, were presented with an opportunity to maximize their intake in similar circumstances in the laboratory. An animal's ability to synchronize its foraging activity with the time of day...

Larvai of Lacinipolia patalis (Grote) (Lepidoptera: Noctuidae) were discovered in Douglas-fir (Pseudotsuga menziessi [Mirb.} Franco) cones collected from the Louisiana-Pacific Corporation's Little River Seed Orchard near Trinidad Head in Humboldt County, CA (elevation 91 m) during the fall of 1985. Previous surveys have not reported this noctuid from Douglas-fir cones (Keen 1958; Tietz 1972; Furniss and Carolin 1977; Hedline et al. 1980; Ruth 1980; Schowalter et al. 1985). Its usual hosts are blackberry and loganberry (Rubus spp.) and roses (Rosa spp.); it normally feeds on foliage and, to...

Mixed-conifer forests are the largest vegetation type in California, covering more than 13 million acres (Barbour and Major 1977). This type, the Sierra Nevada Mixed Conifer (Society of American Foresters Forest cover type 243, Tappeiner 1980) dominates mid-elevations of the Sierra Nevada's western slopes. The extent of the mixed-conifer type and the amount of timber harvested from the west slopes of the Sierra Nevada emphasize the need for accurate growth and yield prediction methods for this area.

Estimates of forest growth (increment) are used for evaluating productivity of land and to project growing stock into the future. Since volume is the accepted parameter for measuring forest growth (Spurr 1952), estimates of periodic volume increment for individual trees on inventory plots form the basis for appraising the productivity of the land and timber.

Economic efficiency and risk have long been considered during the selection of fire management programs and the design of fire management polices. The risk considerations was largely subjective, however, and efficiency has only recently been calculated for selected portions of the fire management program. The highly stochastic behavior of the fire system and the high degree of interaction among its components make it difficult to model analytically. Without fairly advance quantitative models, estimating the risk and efficiency consequences of fire management alternative was impossible.

Abstract - A programmable calculator is connected to a pumping sampler by an interface circuit board. The calculator has a sediment sampling program stored therein and includes a timer to periodically wake up the calculator. Sediment collection is controlled by a Selection At List Time (SALT) scheme in which the probability of taking a sample is proportional to its estimated contribution to total sediment discharge, or according to accumulated predicted sediment weight. Stage height is also measured and is recorded according to a set scheme.

Readers of this Newsletter are aware that CDF and the USFS, through its Pacific Southwest Forest and Range Experiment Stationa at Arcata (PSW), are carrying out a long term cooperative watershed experiment in JDSF's Caspar Creek drainage.