Understory

The Falls Canyon Research Natural Area is distinguished by the presence of bigcone Douglas-fir-canyon live oak forest, which is generally restricted to the Transverse and Peninsular ranges. Other plant communities include mixed montane chaparral and an herbaceous "ridge flora."The area is underlain by one continuous Mesozoic granitic rock type, and similarly, soils are mostly of one family: the Stukel-Sur-Winthrop complex.

The Horse Meadow Research Natural Area (HMRNA) is distinguished by its well-developed white fir forest, and Southern California subalpine forest. Located in the Transverse Ranges of California, the area represents one of the southernmost examples of these vegetation types. The area is contained within the Upper San Gorgonio Mountains Subsection of the Southern California Mountains and Valleys Section Ecological Units. It is underlain by mostly glaciated granodiorite rocks which form steep terrain. Moraine deposits are also present, but the most striking feature of the landscape are avalanche c...

San Emigdio Mesa Research Natural Area (SEMRNA) is distinguished by its broad, gently sloping mesa, steep mesa edges, and alluvial fans and washes. Most of the RNA is a large alluvial fan formed by ancient stream flow from the region of Mt. Pinos. SEMRNA supports an excellent example of pinon-juniper woodland and has extensive stands of regenerating single-leaf pinon pines (Pinus monophylla). It supports a variety of plants including many desert species outside their normal ranges. The value of this RNA is enhanced by its location in a rich archaeological area that is highly regarded.

For estimating suspended sediment concentration (SSC) in rivers, turbidity is potentially a much better predictor than water discharge. Since about 1990, it has been feasible to automatically collect high frequency turbidity data at remote sites using battery-powered turbidity probes that are properly mounted in the river or stream. With sensors calibrated to give a linear response to formazine standards, turbidity and sediment concentration should have a linear correlation close to unity for a given size and composition of suspended particles (Gippel,1995; Foster et al., 1992). For events of ...

The Devils Rock-Hosselkus Research Natural Area occupies the upper Brock Mountain peninsula to the east of Lake Shasta. The area is bisected by a prominent ridge of rugged, resistant gray limestone that stretches in a north to south direction for approximately five miles (8 km). This limestone rises above 3000 ft (914 m) in several locations but is deeply cut by the canyon of Low Pass Creek in the northern portion of the area. The area to the east of the limestone is more gentle topography, underlain primarily by shale, and is dominated by the valleys of Flat and Ripgut creeks. The upper slope...

Spawning surveys were conducted in portions of three streams located in Mendocino County. These three coastal streams were the Ten Mile River, Caspar Creek and Garcia River. Spawning population estimates were derived with four separate estimation procedures using carcass mark-recapture techniques, area-under-the-curve live fish counts and two redd based methodologies. Indices of steelhead abundance are also developed for these areas. Coho spawning populations were estimated to be between 105 and 351 in the portions of the Ten Mile River surveyed but the most likely ranges was estimated to be b...

Located on the southeast slope of Mt. Shasta, which was formed by periodic volcanic activity over the last 100,000 years, Red Butte - Red Fir Ridge Research Natural Area displays many unique geologic features. Red Butte at 8377 ft (2553 m) elevation is the dominant feature in the western portion of the RNA. It is a cinder cone of relatively recent origin, rising more than 400 ft (122 m) above the surrounding terrain. Red Butte is flanked by a smaller cinder cone to the southeast.

Wilder Ridge on the western border of Wilder Ridge Research Natural Area (WRRNA) is the dominant feature. It runs north-south and the elevational range is approximately 800 ft (244 m). The WRRNA is predominantly east-facing with moderately steep slopes ranging from 30 to 50 percent (16-26°). Several steep draws and intermittent stream courses incised the slope creating a topography with very broken relief.Chamise chaparral is the dominant botanical feature occupying most of the area. The eastern edge of the RNA contains scattered blue oak and oak-savannah grasslands. Some of the ephemeral cree...

This article was authored by John K. Francis, research forester, and Salvador Alemañy, botanist, from the U.S. Forest Service International Institute of Tropical Forestry to raise awareness and promote citizen participation in the Puerto Rico Champion Tree Project.

The southwest summit of the Twin Sisters Mountain (5916 ft [1803 m]), the large pristine watershed, and the diversity of vegetation types are the principal distinguishing features of the Manzanita Creek Research Natural Area. At least eight SAF forest types are included in the RNA. Taylor and Teare classified the vegetation cover into seventeen plant associations after extensive sampling of the area. These include riparian types as well as forest types ranging from foothill (or gray) pine (Pinus sabiniana) to montane white fir (Abies concolor).