Treesearch

Annosus root disease is widely distributed in the northern Rocky Mountains. Stump infection often results in tree mortality occurring in progressively expanding root disease centers, in groups of various sizes, and as scattered individuals.

The impact of precommercial thinning of western hemlock (Tsuga heterophylla) on the development of Annosus root and butt rot (caused by Heterobasidion annosum) in coastal Washington has been followed for more than 20 years. Infection of stumps and wounds was high following thinning and there was a high probability of residual tree infection. Eleven years after precommercial thinning tree infection was high, but after 20 years levels of infection were low in both thinned and unthinned stands (averaging

Annosus root disease is mainly a concern in pines and true firs in California. It is most serious on the east side of the Sierra Nevada and Cascade crest, in the mountains of southern California, and in higher elevation fir forests. Symptoms caused by the disease include crown decline and decay and resinosis of roots. Several signs of the fungus may be found. Conks are most common in stumps. Mycelial sheets on the inner bark and popcorn conks on thin-barked roots are diagnostic. Declining trees or recent mortality are best for diagnosis. Wood samples should be symptomatic but not well...

Ammonium-based fire retardants are important in managing wildfires, but their use can adversely affect water quality. Their entry, fate, and impact were studied in five forest streams. Initial retardant concentrations in water approached levels which could damage fish, but no distressed fish were found. Concentrations decreased sharply with time after application and distance downstream, and there was no long-term entry. The numbers and kinds of stream insects were not affected. Simulations of retardant dispersal in streams showed fish mortality might occur from zero to more than 10,000 m...

Adjacent headwater streams were monitored for postfire shade, summer streamflow and maximum water temperature following the 40,000 ha Silver Complex fire in southern Oregon. Average postfire shade (30 percent) for the three streams was considerably less than prefire shade (est.>90 percent). Dramatic increases in direct solar radiation resulted in large but variable increase in maximum water temperature. Increase was greatest in Stream C where temperature increased 10.0°C. Stream B increased 6.2°C. Stream A increased 3.3°C.

SAC88 is a major revision of the Sacramento Model, which was developed in 1969 with minor revisions through 1973. Two of many 1988 changes make it possible to estimate hydrologic effects of a fire in a watershed where pre-fire parameters can be calibrated or estimated: (1) Evapotranspiration, treated as extracted from six root-zone layers under pre-fire conditions, may be limited to one to five layers in the burned area; (2) An infiltration-rate limiting value, large for an unburned area, may be substantially reduced for an area where high soil temperatures and ash are thought to have...

Effects of brush fire on hydrologic characteristics of chaparral watersheds were analyzed. An unburned chaparral produces moderate surface runoff. The vegetation promotes infiltration by retarding the runoff and providing temporary storage during intense rainfall. The hydrologic characteristics of chaparral watershed, however, are drastically changed by fires. The high rate of runoff following brush fires may result from the combined effects of denudation and formation of a water-repellent soil layer beneath the ground surface. This layer greatly decreases infiltration rates and reduces...

Wildfires and prescribed burns are common throughout Arizona and California chaparral. Predicting fire effects requires understanding fire behavior, estimating soil heating, and predicting changes in soil properties. Substantial quantities of some nutrients, particularly nitrogen and phosphorus, are lost directly during combustion. Highly available nutrients released during a fire are deposited on the soil surface where they are immobilized or lost by erosion. Information on the effect of fire on physical, chemical, and biological soil properties provides a basis for discussing short- and...

The Angel Fire of September, 1987 caused extensive damage to second growth forest in the south fork drainage of Cow Creek, 55 km northeast of Grant's Pass, Oregon, USA. The fire was characterized by a high-intensity burn over areas of steep topography. The areal distribution of soil hydraulic properties in a small, tributary watershed following high-intensity wildfire is examined using tests of infiltration capacity, saturated hydraulic conductivity, and soil moisture characteristics. Also, measures of soil water-repellency are determined. Soil hydraulic properties are evaluated for logged...

Recognizing annosus root disease affecting conifers in northwestern United States forests is discussed. Field diagnosis can bemade by observing characteristic stand patterns, wood stain and decay, ectotrophic mycelium, and sporophores. Most seriously affected trees include hemlocks, grand fir, white fir and Pacific silver fir. Ponderosa pine and other true firs may also be damaged. Wounded trees, especially hemlocks and true firs, are readily colonized by Heterobasidion annosum and wounds can be used as an indicator of infection. Laboratory analysis can be used to confirm field diagnosis.