Physiographic features

This site occurs on volcanic cones or crater landscapes. They formed in gently sloping to hilly cinder deposits. Slopes range from 0 to 50 percent and are on all aspects. Mean annual precipitation is about 18 to 20 inches. Mean annual temperature is about 41 degrees F. Elevation ranges from 6,900 to 9,000 feet above sea level.

Table 2. Representative physiographic features

Climatic features

The climate of this area can be classified as “semi-arid continental”.

Precipitation averages 14 to 16 inches. Seventy seven percent of the year’s moisture normally falls during the period of May through October. Practically all of it is brought by brief afternoon and evening thunderstorms. In July and August, normally the wettest months of the year, one can expect about one day in five when rainfall exceeds one-tenth inch. Early spring precipitation in May benefits the cool-season plants. Winter precipitation, supplying 24 percent of the year’s moisture, normally has no more than two days a month with as much as one-tenth inch of moisture. Much of the winter precipitation falls as snow.

Air temperatures vary from a monthly mean of 20 degrees F in January to 69 degrees F in July. Daily high temperatures average in the 80’s and low 90’s during the summer. Winter low temperatures fall below the freezing mark much of the time from November through March with minimum temperatures approaching 25 degrees F below zero. Dates of the last killing frost may vary from May 9th through May 17th, and the first killing frost from September 27th to October 8th. The frost-free season ranges from 141 days to 153 days from early May to early October.

Wind velocities for the area average 10 to 12 miles per hour and prevail from the south and southwest. Generally, March is the windiest month. Strong winds during the spring cause rapid drying of the soil surface.

Nearby mountains to the west intercept much of the precipitation from the Pacific storms coming through this area during the winter. About 70 percent of the 14 to 16 inches of annual precipitation falls in the form of rainfall during the frost-free season. About 40 percent of the annual precipitation benefits cool-season plants, 50 percent benefits warm-season plants and 10 percent falls during the season of plant dormancy. Relative humidity is moderately low. The sun shines approximately 75 percent of the time.

Climate data was obtained from http://www.wrcc.sage.dri.edu/summary/climsmnm.html web site using 50 percent probability for freeze-free and frost-free seasons using 28.5 degrees F and 32.5 degrees F respectively.

Table 3. Representative climatic features

Influencing water features

This site is not influenced by water from a wetland or stream.

Soil features

Soils are moderately deep to deep. Surface texture gravelly loam or silt loam. Subsurface texture is gravelly loam or loose cinders. Permeability is rapid. Available water-holding capacity is low. Effective rooting depth is 20 to 40 inches. These soils are droughty. The gravel in these soils is volcanic cinder range from 70 to 90 percent cinders.

Minimum and maximum values listed below represent the characteristic soils for this site.

Characteristic soils:

Bandera

Table 4. Representative soil features

Animal community

Habitat for Wildlife:

This site provides habitats which support a resident animal community that is characterized by mule deer, spotted skunk, desert cottontail, rock squirrel, great horned owl, scrub jay, rufous-sided towhee, garter snake, and fence lizard.

There is seasonal use by the blue grouse, turkey, and mountain lion. Band-tailed pigeons will flock to these habitats during years of high mast production.

Hydrological functions

The runoff curve numbers are determined by field investigations using hydrologic cover conditions and hydrologic soil groups.

Hydrologic Interpretations
Soil Series ---Hydrologic Group
Bandera -------B
Cinders -------B

Recreational uses

This site has good aesthetic appeal because of its association with volcanic cones and the uniqueness within the area in which the site occurs. Its large variety of plants blooms from early spring to fall. It is fair for camping and picnicking. The site provides poor hiking because of small cinder gravel surface. Hunting is poor to fair for deer, rabbits, and upland game birds.

Wood products

This site produces no significant wood production except fuel for campfires.

Other products

Grazing:

This site can be used all season of the year. Because of this site’s potential to green up early, it is better suited for early spring grazing when grazing is not in successive years. Site is best suited for cattle and horses. Steer and young heifers could best utilize the site because of the cinder on the soil surface and slope. Approximately 80 percent of the total annual yield are from species that furnish forage for livestock. Continuous grazing during the growing season will cause the more desirable forage plants such as little bluestem, big bluestem, Arizona fescue, mountain muhly and mountain mahogany to decrease. Species most likely to invade the site are ring muhly and broom snakeweed. Species most likely to increase are blue grama, threeawn, oak brush, oneseed juniper, and annual forbs. A system of deferred grazing, which varies the time of grazing and rest in a pasture during successive years, is needed to maintain or improve the plant community. Rest during April, May, and June allows species such as Arizona fescue, green needlegrass, and prairie junegrass to grow and reproduce. Late spring and early summer rest is beneficial to big bluestem and little bluestem.

Other information

Guide to Suggested Initial Stocking Rate Acres per Animal Unit Month

Similarity Index ------Ac/AUM
100 - 76 --------------2.5 – 2.9
75 – 51 ---------------2.8 – 5.0
50 – 26 ---------------4.9 – 9.8
25 – 0 ----------------9.8+

Type locality

Contributors

Christine Bishop
Don Sylvester
Elizabeth Wright
John Tunberg

Approval

Kendra Moseley, 9/12/2023