This description covers characteristics that may be relevant to fire ecology and is not meant for identification. Keys for identification are available (e.g., [31,59]).
Deerbrush is a native, drought-deciduous shrub reaching 3 to 18 feet (1-6 m) in height at maturity. It is loosely branched and spreading in form. Flowers are borne in compound clusters. The fruit is a sticky capsule containing small, obovoid seeds [31,59]. Nitrogen-fixing actinomycetes form nodules in deerbrush roots [17,25].
Deerbrush stems, excluding the root crown, live about 35 years. The stem of one specimen has been aged at 47 years. Maximum age attained by roots and root crowns has not been determined, but life span of these organs can be more than 35 years if periodic top-kill occurs [22].
Deerbrush grows on well-drained soils of all textures [22]. Slope varies from gentle to steep [15]. In California, deerbrush occurs primarily on the west slope of the Cascade-Sierra Nevada crest [22,33]. In Oregon, deerbrush occurs on both sides of the Cascade Range [80].
Elevational ranges of deerbrush are as follows:
Arizona 3,500 to 7,000 feet (1,100-2,100 m) [40]Deerbrush provides high-quality, palatable, and often abundant forage for livestock and wildlife, especially deer [1,22,66]. On Arizona chaparral of the Tonto National Forest, deerbrush was one of three principle browse species used by white-tailed deer in fall [51]. In California, deerbrush is the most important summer browse species for mule deer and livestock in the ponderosa pine belt. Mule deer also make moderate to heavy use of it on California's winter ranges [22,49].
Porcupine browse deerbrush stems. Gambel quail have been observed eating large quantities of the seed [13].
Palatability and nutritional value: Deerbrush is highly palatable to ungulates [66,73].
Deerbrush leaves are high in protein, and calcium levels are high in both leaves and twigs. However, based on the nutritional standard for lactating cows, deerbrush provides inadequate levels of phosphorus and digestible energy. Overall, browse quality decreases from late spring to late summer. On the Sierra National Forest, nutritional quality of deerbrush browse varied significantly by year, but not by shrub age or degree of overstory canopy closure. Average nutritional content of deer brush, collected every 2 weeks from June 1 to September 8, 1982 and 1983, follows. Data are means (standard errors) [43].
Variable Year Leaves Twigs Neutral-detergent fiber (%) 1982 33.66 (1.92) 65.48*(2.25) 1983 25.38 (1.39) 53.17*(1.05) Acid-detergent fiber (%) 1982 19.85*(1.71) 48.42*(2.02) 1983 14.65*(0.89) 38.95*(0.88) In-vitro digestible dry matter 1982 53.93*(3.64) 33.49 (1.70) 1983 63.60*(1.38) 35.14 (1.40) Digestible energy (kcal/g) 1982 2.42*(0.18) 1.48 (0.08) 1983 2.93*(0.06) 1.56 (0.06) Crude protein (%) 1982 18.15*(0.43) 8.22*(0.34) 1983 16.92*(0.30) 7.77*(0.23) Calcium (%) 1982 3.66*(0.47) 1.27*(0.10) 1983 2.33*(0.10) 1.07*(0.05) Phosphorus (%) 1982 0.18 (0.01) 0.16*(0.01) 1983 0.19 (0.01) 0.12*(0.01) *Significant (P<0.05) difference with respect to year of collection.Average protein content of deerbrush collected from various California locations varied seasonally as follows [11]:
April August October 25.2 % 13.7 % 8.9 %Cover value: No information was available on this topic as of 1997.
Deerbrush has attractive white, lilac, or pink flowers and is planted as an ornamental [47]. It is also a valuable honey plant [73].
Miwok Indians of California made baskets from deerbrush branches [5].
Deerbrush reproduces from seed and by sprouting from the root crown and/or stem [22]. It occasionally layers where branches contact soil [14].
Seed reproduction: Deerbrush first produces seed at about 4 years of age [21]. Ripe seed is forcibly ejected from the capsule when the capsule dries and splits [64]. Deerbrush is a seed banking species. Seed is stored in extremely high densities in duff and the upper few centimeters of mineral soil. Anderson [4] estimated that the deerbrush seed population in a mixed coniferous forest in northern California was greater than 2 million seeds per hectare. Viability of the seed averaged 90.6 percent in the laboratory [4]. Similarly, Kauffman and Martin [37,38] reported a range of 60 to 90 percent viability of deer brush seed from three northern California mixed-conifer forests. Viability of deerbrush seed is generally high, and the seed is long-lived. Quick and Quick [62] reported 90 percent viability of 24-year-old seed. Other researchers have suggested that deerbrush seed remains viable for well over 100 years [4,22,62].
Seed is dormant until the hard seedcoat is scarified by fire or mechanical disturbance such as logging [19,22]. Optimal temperatures for scarification range from 170 to 195 degrees Fahrenheit (77-90 deg C) [39]. High-consumptive fire (> 90% of duff burned) kills most seed in duff, but most seed in mineral soil survives. Anderson [4] found that following one high-consumptive fire, 12.5 percent of seed in duff and 52.4 percent of seed in mineral soil was viable. Seed requires stratification follow scarification, and usually germinates in spring [39]. Keeley [41] reported that light inhibited germination, an unusual response, and that charate (charred wood powder) had no effect on germination.
Best establishment occurs with seed in bare mineral soil [7,22]. In a greenhouse study, seeds planted at one-half inch (1 cm) when in shade and at 1 inch (2.5 cm) when in sun showed better seedling emergence than seeds planted at greater or lesser depths. Emergence did not occur with seeds planted on the soil surface [1]. Nearly all seedling establishment occurs in the first postfire spring; establishment after the second postfire year is rare [22]. Plants typically average 3 to 4 inches (8-18 cm) in height at the end of their first growing season and 8 inches (20 cm) in height at the end of the second growing season [21,22,77].
Vegetative reproduction: Sprouts grow more rapidly than seedlings, reaching a height of 30 or more inches (76 cm) in their first year [22]. Age at which deerbrush sprouts first produce seed is undocumented; however, sprouts of most Ceanothus species produce seed after 3 to 6 years [21]. When deerbrush plants are top-killed before they become decadent, roots remain alive, and root crowns retain the ability to sprout for years beyond the 35-year life expectancy of other stem tissue. Without periodic top-kill, root systems and root crowns of decadent plants die [22].
Ceanothus integerrimus, known by the common name deer brush, is a species of woody shrub in the family Rhamnaceae, native to the western United States in Arizona, New Mexico, California, Oregon, and Washington. It grows in montane chaparral and woodlands regions, in hardwood forests, and in fir, spruce, and Ponderosa pine plant communities, being most abundant in the California chaparral and woodlands and Sierra Nevada.[2][3]
Ceanothus integerrimus is a deciduous shrub from 1–4 metres (3.3–13.1 ft) tall with an open ascending to erect branch habit.[3] It is a drought-tolerant phanerophyte. Nitrogen-fixing actinomycete bacteria form root nodules on Ceanothus roots.[4][5] Its stems are round yellow to pale green in color with either small soft to straight stiff sharp hairs parallel to or in contact with the surface of the stem,.[3][6]
The leaves are glossy, deciduous and 2.5–8 cm long. Leaves grow alternately on stems. The leaf petioles are less than 15 mm in length and the stipules are also deciduous. The leaf blade is lanceolate, elliptical or oblong to widely ovate in shape. Leaves can have one to two ribs from the base; they are also generally thin and have an acute to obtuse tip. Leaf margins are either entire or slightly dentate, more so towards the leaf tip. Leaf surfaces are light green and are ciliate or contain hairs visible only by magnification. The lower leaves are also hairy and lighter in color.[3]
The flowers are white or blue and rarely pink in color. They are produced in raceme clusters of 15 centimeters or less and contain both male and female organs. The fruit is a sticky valved capsule about 4–5 mm in diameter with a slight crest; the seed is ejected from the capsule after splitting.[3]
It regenerates by seed, shoot formation from the crown and stem, and also by layering when branches come in contact with soil.[5][7] It has been suggested that some Ceanothus species do not resprout from the root after the crown has burned as a result of fire where most other species are able to regenerate.[8] Pollination of flowers is primarily by bees.
Seed production occurs after about four years of age. High densities of seeds occur in the upper soil of Ceanothus communities. Seeds remain viable up to 24 years or more. Seed dormancy is broken by the removal of the seed coat by fire scarification or physical disturbance.[5][7] Seeds germinate best at about 1 inch soil depth in shady areas in the spring following fire scarification.[5][7]
There are four weakly defined varieties of Ceanothus integerrimus. Identification is primarily by leaf morphology and flower color:[3][5][7]
Ceanothus integerrimus hybridizes with Ceanothus tomentosus (Lemmon's ceanothus) and Ceanothus cordulatus (mountain whitethorn).
C. integerrimus is an important part of forest regeneration after wildfires by providing nitrogen.[12] It does this by creating nitrogen rich patches in the soil. The nitrogen source is created by its root association with nitrogen fixing bacteria.[2]
Deer and specifically mule deer feed on C. integerrimus. Porcupines and quail have also been observed eating the stems and seeds.[13] Nutritionally leaves are a good source of protein and stems and leaves also contain high levels of calcium. However, nutritional quality of leaves is seasonal and appears to be best from fall to early spring.[5]
Indigenous peoples of California use the branches to treat women after childbirth.[14] The Miwok Indians of Northern California also use the branches of this plant in weaving complex baskets.[5] The Concow tribe call the tree hē′-bē (Konkow language).[15]
Cattle ranchers will claim that cattle do immensely well on this plant during their seasonal grazing.
Ceanothus integerrimus, known by the common name deer brush, is a species of woody shrub in the family Rhamnaceae, native to the western United States in Arizona, New Mexico, California, Oregon, and Washington. It grows in montane chaparral and woodlands regions, in hardwood forests, and in fir, spruce, and Ponderosa pine plant communities, being most abundant in the California chaparral and woodlands and Sierra Nevada.
