Treesearch

Due primarily to alteration of riparian vegetation and nest parasitism by brown-headed cowbirds (Molothrus ater), the least Bell's vireo (Vireo bellii pusillus) has under-gone a tremendous decline in range and numbers since the 1920's. In 1987, we sampled vegetation at 32 nest sites to characterize nesting habitat of least Bell's vireos in the Santa Ynez River drainage. Most next (59.4%) were located in willows (Salix spp.) or mugwort (Artemisia douglasiana) at heights of less than 1 m. Vireos selected sites with relatively dense vegetative cover in the vicinity of the nests. Herbaceous...

Managing and restoring watersheds often involves recreation of riparian habitats. The natural functions of riparian forest natural to slow flood water, stabilize stream banks and trap sediments can be used in restoring disturbed creek systems. The State Coastal Conservancy's wetland enhancement program is preserving wetlands on the California coast through repair and management of watersheds. Examples from rural and urban areas illustrate how riparian restoration can be integrated into watershed projects.

After the Wheeler Fire in southern California in July 1985, we monitored sediment deposition and vegetation recovery in a section of the severely burned chaparral riparian zone of the North Fork of Matilija Creek, near Ojai, California. Increased runoff was accompanied by low magnitude debris flows and fluvial transport of gravel, most of which was added to the channel and nearby hillslopes by post-fire dry ravel. The preburn riparian forest was dominated by white alder, California sycamore, and coast live oak. Regeneration of these species was entirely by resprouting, due to the absence...

Certain floodplain systems in southern California sustain a unique scrub vegetation rather than riparian woodlands due to a lack of perennial water. Alluvial scrub occurs on outwash fans and riverine deposits along the coastal side of major mountains of southern California. This vegetation type is adapted to severe floods and erosion, nutrient-poor substrates, and the presence of subsurface moisture. Ten major stands were sampled by line intercepts to determine their species composition, community structure, and successional status. Plant ecology and successional dynamics of these stands...

Constituent loads in small streams are often estimated poorly. This is especially true for discharge-related constituents like sediment, since their flux is highly variable and mainly occurs during infrequent high-flow events. One reason for low-quality estimates is that most prevailing data collection methods ignore sampling probabilities and only partly account for variations in constituent flow

The California Wildlife-Habitat Relationship (WHR) system was tested for birds breeding in the Valley-Foothill Riparian habitat along California's Sacramento and South Fork Kern rivers. The model performed poorly with 33 pct and 21 pct correct predictions respectively at the two locations. Changes to the model for 60 species on the Sacramento River and 66 species on the Kern River are recommended. Special problems, such as differences in habitat suitability among study areas and how the model treats threatened and endangered species, are discussed and solutions are suggested.

Chronic surface and mass erosion from recent landslides often prevents the recovery of productive stream habitats following initial mass failure events. Low-cost methods that can accelerate recovery and stabilization processes have been employed on numerous failed slopes in the Six Rivers National Forest in the northwest corner of California, with notable success. Two treatment methods, toe erosion control and revegetation have wide applicability in situations where funding is scarce.

Monitoring human impact on outdoor recreation sites and view landscapes is necessary to evaluate influences which may require corrective action and to determine if management is achieving desired goals. An inexpensive method to monitor environmental change is to establish camera points and use repeat color slides. Successful monitoring from slides requires the observer to determine if there are increases or decreases of trees, shrubs, or herbaceous plants; bare ground or duff; screening by trees; and soil erosion. Illustrated guidelines are given for land managers who must monitor human...

Logistic regression equations predicting the probability that a tree will die from natural causes--insects, diseases, intertree competition--within 10 years have been developed for California red fir (Abies magnifica) and white fir (A. concolor). The equations, like those with a 5-year prediction period already developed for these species, are based on analysis of crown and bole characteristics of trees, and are readily programmed into pocket calculators for field use. For user convenience, the equations are formulated into Award-Penalty Point Systems, in which a tree is awarded or...