Sources: Unless otherwise indicated, the information in this Research Project Summary comes from the following papers:
Lathrop, Earl W.; Martin, Bradford D. 1982. Response of understory vegetation to prescribed burning in yellow pine forests of Cuyamaca Rancho State Park, California. Aliso. 10(2): 329-343 [4].
Martin, Bradford D. 1981. Vegetation responses to prescribed burning in a mixed-conifer woodland, Cuyamaca Rancho State Park, California. Loma Linda, CA: Loma Linda University. 112 p. Thesis [5].
Martin, Bradford D. 1982. Vegetation responses to prescribed burning in Cuyamaca Rancho State Park, California. In: Conrad, C. Eugene; Oechel, Walter C., technical coordinators. Proceedings of the symposium on dynamics and management of Mediterranean-type ecosystems; 1981 June 22-26; San Diego, CA. Gen. Tech. Rep. PSW-58. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experiment Station: 617 [6].
SPECIES INCLUDED IN THE SUMMARY:
See the Appendix.
STUDY LOCATION:
The study sites were in Cuyamaca Rancho State Park in eastern San Diego County,
California. Burning was conducted on the West Mesa and East Mesa areas of the
park [4,6]. There were 5 burn sites: 1 on West
Mesa at Paso Picacho, 2 on East Mesa at Granite Springs, and 2 on East Mesa
at Oakzanita [5].
SITE DESCRIPTION:
Elevations at the burn sites were: 1,493 m at Paso Picacho, 1,515 m at Granite
Springs, and 1,478 m at Oakzanita. Other site information was not provided.
PREFIRE PLANT COMMUNITY:
The Paso Picacho site was a mixed-conifer Jeffrey pine-California black oak (Pinus
jeffreyi-Quercus kelloggii) woodland with a chaparral understory.
Incense-cedar (Calocedrus decurrens) dominated the midstory, and pointleaf manzanita
(Arctostaphylos pungens) was the dominant
understory shrub. Burn size was approximately 6 ha [5].
The first of the 2 Granite Springs fires was conducted on a mixed-conifer Jeffrey pine-California black oak woodland with a chaparral shrub/deergrass (Muhlenbergia rigens) understory. Pointleaf manzanita was the dominant understory shrub. The burn was approximately 85 ha in size. The second fire was on a deergrass meadow and was 0.1 ha in size. Associated species in the deergrass meadow included American bird's-foot trefoil (Lotus unifoliolatus), common yarrow (Achillea millefolium), and California goldenrod (Solidago californica) [5].
The first of the 2 Oakzanita fires was also conducted on a mixed-conifer Jeffrey pine-California black oak woodland. The understory was chaparral shrubs, dominated by pointleaf manzanita. Eastern Mojave buckwheat (Eriogonum fasciculatum) and California buckthorn (Frangula californica) were common associates. The mixed-conifer burn was approximately 1.2 ha in size. The second fire was on a deergrass meadow and was 0.1 ha in size [5].
Study sites are classified in the following plant community and probably experienced the historic fire regime described below:
Fire regime information on the vegetation community studied in this Research Project Summary. Fire regime characteristics are taken from the LANDFIRE Rapid Assessment Vegetation Model [3]. This vegetation model was developed by local experts using available literature and expert opinion as documented in the .pdf file linked from the name of the Potential Natural Vegetation Group listed below. | ||||||
Vegetation Community (Potential Natural Vegetation Group) | Fire severity* | Fire regime characteristics | ||||
Percent of fires | Mean interval (years) |
Minimum interval (years) |
Maximum interval (years) |
|||
Mixed conifer (north slopes) | Replacement | 5% | 250 | |||
Mixed | 7% | 200 | ||||
Surface or low | 88% | 15 | 10 | 40 | ||
Mixed conifer (south slopes) | Replacement | 4% | 200 | |||
Mixed | 16% | 50 | ||||
Surface or low | 80% | 10 | ||||
California grassland | Replacement | 100% | 2 | 1 | 3 | |
Fire Severities: Replacement=Any fire that causes greater than 75% top removal of a vegetation-fuel type, resulting in general replacement of existing vegetation; may or may not cause a lethal effect on the plants. Surface or low=Any fire that causes less than 25% upper layer replacement and/or removal in a vegetation-fuel class but burns 5% or more of the area. Mixed=Any fire burning more than 5% of an area that does not qualify as a replacement, surface, or low-severity fire; includes mosaic and other fires that are intermediate in effects [1,2]. |
An adjacent, unburned control was used for comparison at each burn site. Conditions on burning days were [4,5]:
Dates and weather conditions during prescribed fires at Cuyamaca Rancho State Park | |||||
Site and community | Date | Air temperature (°C) | Relative humidity (%) | 10-hr fuelstick moisture content (%) | Windspeed (km/hr) |
Paso Picacho, mixed-conifer/chaparral fire | 24 Apr. 1978 | 18 | 30 | 9-12 | ≤16 |
Granite Springs, mixed-conifer/chaparral/deergrass and deergrass meadow fires | 11-15 Dec. 1978 | 13 | 17-37 | 7.5 | 4.0-9.6 |
Oakzanita, mixed-conifer fire | 3 Dec. 1979 | 18-25 | 18-25 | 6-8 | 0-6.4 |
Oakzanita, deergrass meadow fire | 16 Apr. 1980 | not measured | not measured | not measured | not measured |
Mean total density and relative dominance of shrubs and trees in 100-m² burned and control mixed-conifer plots in the summer of postfire year 2 at Paso Picacho, Granite Springs, and Oakzanita | ||||
Area | Density (plants/ha) | Relative dominance (%) | ||
Burn | Control | Burn | Control | |
Paso Picacho | ||||
shrubs | 43 | 480 | 2.96 | 16.42 |
trees | 1,039 | 1,165 | 97.04 | 83.59 |
Granite Springs | ||||
shrubs | 3 | 31 | 0.11 | 1.44 |
trees | 345 | 369 | 99.99 | 98.56 |
Oakzanita | ||||
shrubs | 240 | 3,529 | 12.45 | 54.28 |
trees | 407 | 374 | 87.55 | 46.40 |
Total | ||||
shrubs | 286 | 4,040 | 3.91 | 32.25 |
trees | 1,917 | 1,782 | 96.09 | 67.75 |
Mean density and relative dominance of large trees and shrubs (≥9 in. DBH) in 100-m² mixed-conifer plots in the summer of postfire year 2 at Paso Picacho, Granite Springs, and Oakzanita | ||||
Species | Density (plants/ha) | Relative dominance (%) | ||
Burn | Control | Burn | Control | |
Paso Picacho | ||||
white fir | 3 | 4 | 0.11 | 0.03 |
incense-cedar | 760 | 846 | 31.75 | 44.28 |
limber pine | 3 | ----* | 0.11 | ---- |
Jeffrey pine | 236 | 77 | 46.03 | 17.14 |
coast live oak | 43 | ---- | 2.06 | ---- |
canyon live oak | 30 | 77 | 1.11 | 4.14 |
California black oak | 47 | 35 | 15.87 | 18.00 |
pointleaf manzanita | 40 | ---- | 2.86 | ---- |
Palmer ceanothus | 3 | ---- | 0.05 | ---- |
oceanspray | ---- | 4 | ---- | <0.01 |
Granite Springs | ||||
Jeffrey pine | 218 | 169 | 48.89 | 50.00 |
coast live oak | ---- | 79 | ---- | 4.12 |
California black oak | 127 | 121 | 51.10 | 44.44 |
Eastwood manzanita | ---- | 7 | --- | 0.36 |
pointleaf manzanita | ---- | 24 | ---- | 1.08 |
birchleaf mountain-mahogany | 3 | ---- | 0.11 | ---- |
Oakzanita | ||||
Jeffrey pine | 107 | 209 | 24.22 | 17.50 |
coast live oak | 273 | 137 | 49.22 | 23.20 |
California scrub oak | ---- | 10 | ---- | 1.50 |
California black oak | 27 | 28 | 14.11 | 5.70 |
Eastwood manzanita | ---- | 28 | ---- | 1.00 |
pointleaf manzanita | 233 | 3,318 | 12.43 | 48.40 |
chaparral whitethorn | ---- | 18 | ---- | 0.20 |
Palmer ceanothus | ---- | 18 | ---- | 0.80 |
birchleaf mountain-mahogany | 7 | 9 | 0.02 | 0.08 |
eastern Mojave buckwheat | ---- | 73 | ---- | 0.20 |
California buckthorn | ---- | 55 | ---- | 2.10 |
*not present. |
Relative coverage by size class was [5]:
Basal area percentage of trees and shrubs by size class in 100-m² mixed-conifer plots at Paso Picacho and Granite Springs in the summer of postfire year 2. Data for Oakzanita were not reported. | |||||||||
Species | Size class (DBH in cm) | ||||||||
2-8 | 9-16 | 17-24 | 25-32 | 33-40 | 41-48 | 49-56 | 57+ | Total (%) | |
Paso Picacho, burn plots | |||||||||
white fir | ----* | 0.28 | ---- | ---- | ---- | ---- | ---- | ---- | 0.28 |
incense-cedar | 19.94 | 27.06 | 8.83 | 4.27 | 1.42 | 2.28 | 0.85 | 0.57 | 65.24 |
limber pine | ---- | 0.28 | ---- | ---- | ---- | ---- | ---- | ---- | 0.28 |
Jeffrey pine | 2.28 | 6.56 | 3.42 | 1.42 | 2.28 | ---- | 2.28 | 1.99 | 20.28 |
coast live oak | 1.71 | 0.28 | 0.57 | 0.85 | ---- | 0.28 | ---- | ---- | 3.70 |
canyon live oak | ---- | 0.85 | ---- | ---- | ---- | ---- | ---- | ---- | 2.56 |
California black oak | ---- | 0.57 | 0.28 | 0.28 | 0.28 | 1.14 | 0.85 | 0.57 | 3.99 |
pointleaf manzanita | 0.57 | 0.57 | 1.14 | 0.85 | ---- | ---- | 0.28 | ---- | 3.42 |
Palmer ceanothus | ---- | 0.28 | ---- | ---- | ---- | ---- | ---- | ---- | 0.28 |
Size class totals | 24.50 | 37.59 | 15.09 | 7.69 | 3.98 | 3.70 | 4.26 | 3.13 | |
Paso Picacho, control plots | |||||||||
white fir | 0.26 | ---- | ---- | ---- | ---- | ---- | ---- | ---- | 0.26 |
incense-cedar | 17.95 | 16.92 | 8.72 | 4.87 | 3.85 | 3.08 | 0.26 | 0.77 | 56.41 |
Jeffrey pine | 1.03 | 0.51 | 0.26 | 0.51 | 0.51 | 0.51 | 0.51 | 0.26 | 4.10 |
canyon live oak | 2.82 | 1.79 | ---- | 0.51 | ---- | ---- | ---- | ---- | 5.13 |
California black oak | ---- | 0.26 | ---- | -.26 | ---- | ---- | 1.03 | 0.77 | 2.31 |
pointleaf manzanita | 12.31 | 8.46 | 5.38 | 1.54 | 0.51 | 0.26 | ---- | 0.51 | 28.97 |
Palmer ceanothus | ---- | 0.77 | 0.51 | 0.77 | 0.51 | ---- | ---- | ---- | 2.56 |
oceanspray | 0.26 | ---- | ---- | ---- | ---- | ---- | ---- | ---- | 0.26 |
Size class totals | 34.63 | 28.71 | 14.87 | 8.46 | 5.38 | 3.85 | 1.80 | 2.31 | |
Granite Springs, burn plots | |||||||||
Jeffrey pine | ---- | 0.9 | ---- | ---- | ---- | ---- | ---- | 0.9 | |
coast live oak | ---- | ---- | ---- | ---- | ---- | ---- | ---- | ---- | |
California black oak | ---- | 0.9 | 3.5 | 7.0 | 4.3 | 8.7 | 4.3 | 7.8 | 36.5 |
Eastwood manzanita | ---- | ---- | ---- | ---- | ---- | ---- | ---- | ---- | |
pointleaf manzanita | ---- | ---- | ---- | ---- | ---- | ---- | ---- | ---- | |
birchleaf mountain-mahogany | ---- | 0.9 | ---- | ---- | ---- | ---- | ---- | ---- | 0.9 |
Granite Springs, control plots | |||||||||
Jeffrey pine | 7.8 | 2.6 | 6.0 | 6.0 | 5.2 | 6.0 | 5.2 | 3.5 | 42.3 |
coast live oak | 16.4 | 0.9 | ---- | ---- | 1.7 | ---- | 0.9 | ---- | 19.9 |
California black oak | 0.9 | 0.9 | 4.3 | 5.2 | 7.8 | 6.0 | 3.5 | 1.7 | 30.3 |
Eastwood manzanita | ---- | 0.9 | 0.9 | ---- | ---- | ---- | ---- | ---- | 1.8 |
pointleaf manzanita | 2.6 | 1.7 | 0.9 | 0.9 | ---- | ---- | ---- | ---- | 6.1 |
birchleaf mountain-mahogany | ---- | ---- | ---- | ---- | ---- | ---- | ---- | ---- | |
*not present. |
Sapling trees and shrubs—The fires significantly reduced total density of sapling trees and shrubs (2-8 inches DBH) compared to unburned controls [4,5,6]. Reduction of sapling trees and shrubs across sites was 94% in postfire year 2. Due to postfire sprouting, mean density of 2- to 8-cm coast live oak, canyon oak, and California black oak increased after burning on most sites, while conifer density was less on burned sites compared to controls [6]. At Paso Picacho, sapling density on 100-m² plots was reduced 90% on the burn compared to the unburned control (P<0.01) in postfire year 2. Incense-cedar saplings comprised over 89% of saplings in burn and control plots, and both incense-cedar and canyon live oak saplings showed significant (P<0.02) reductions in density on burned plots. At Granite Springs, total sapling density was significantly reduced (P<0.01), with Jeffrey pine showing greatest change in density. Jeffrey pines comprised 85% of total saplings on control plots. In postfire year 2, Jeffrey pine density was significantly reduced (P<0.01) on burned 100-m² plots compared to control plots. Total tree sapling reduction on 100-m² burn plots at Oakzanita was significant at P<0.05, even though total tree sapling density was low on control plots. At Oakzanita, 1-m² plots were used in addition to 100-m² plots. On 1-m² quadrats, total sapling density showed an 88% increase due to sprouting shrubs. Eastern Mojave buckwheat and skunkbush sumac were the only 2 species common to both burned and control plots, and both species increased on 1-m² burned plots compared to controls. Sapling tree and shrub density and relative dominance are shown in the 2 tables below [5].
Mean density and relative dominance (based on basal area) of sapling trees and shrubs (2-8 in. DBH) in 100-m² mixed-conifer plots in the summer of postfire year 2 at Paso Picacho, Granite Springs, and Oakzanita | ||||
Species | Density (plants/ha) | Relative dominance (%) | ||
Burn | Control | Burn | Control | |
Paso Picacho | ||||
white fir | ----* | 4 | ---- | 0.23 |
incense-cedar | 97 | 1,562 | 97.00 | 89.62 |
Jeffrey pine | ---- | 8 | ---- | 0.46 |
coast live oak | 3 | 15 | 3.00 | 0.86 |
canyon live oak | ---- | 104 | ---- | 5.96 |
California black oak | ---- | 27 | ---- | 1.55 |
Palmer ceanothus | ---- | 23 | ---- | 1.32 |
Granite Springs | ||||
Jeffrey pine | 3 | 72 | 50.00 | 84.71 |
coast live oak | ---- | 10 | ---- | 11.76 |
California black oak | ---- | 3 | ---- | 3.53 |
birchleaf mountain-mahogany | 3 | ---- | 50.00 | ---- |
Oakzanita | ||||
Jeffrey pine | ---- | 9 | ---- | 16.67 |
coast live oak | ---- | 36 | ---- | 66.67 |
California black oak | ---- | 9 | ---- | 16.67 |
birchleaf mountain-mahogany | 7 | ---- | 100.00 | ---- |
*not present. |
Mean density and relative dominance (based on basal area) of sapling tree and shrubs (2-8 in. DBH) in 1-m² mixed-conifer plots at Oakzanita (summer of postfire year 2) | ||||
Species | Density (plants/m²) | Relative dominance (%) | ||
Burn | Control | Burn | Control | |
Oakzanita | ||||
eastern Mojave buckwheat | 1.10 | 0.15 | 47.21 | 55.56 |
Wright's buckwheat | ----* | 0.05 | ---- | 18.52 |
southern honeysuckle | 0.02 | ---- | 0.86 | ---- |
California buckthorn | ---- | 0.05 | ---- | 18.52 |
skunkbush sumac | 0.10 | 0.02 | 4.29 | 7.41 |
California rose | 0.22 | ---- | 9.44 | ---- |
Parish's snowberry | 0.82 | ---- | 35.19 | ---- |
poison-oak | 0.07 | ---- | 3.00 | ---- |
*not present. |
Seedlings—Total tree and shrub seedling density decreased at Paso Picacho and Granite Springs compared to control plots, but total tree and shrub seedling density greatly increased at Oakzanita. Most of the reductions were from mortality of trees in the smallest size class, particularly incense-cedar. Total shrub seedling density increased on burned plots compared to unburned plots. At Paso Picacho, tree and shrub seedlings were reduced 62% on burned plots, with incense-cedar seedlings showing greatest reduction in density (P<0.01). Pointleaf manzanita and Palmer ceanothus seedling densities increased approximately 85% compared to control plots. Coast live oak and canyon live oak showed moderate increases in seedling density, while California black oak and Jeffrey pine seedling density slightly decreased compared to control plots. Birchleaf mountain-mahogany seedlings showed minor coverage in the Granite Springs postfire community. At Granite Springs, total tree and shrub seedling density was reduced 76% compared to controls. Jeffrey pine (P<0.02), California black oak (P<0.02), and coast live oak (P<0.01) seedling densities were significantly reduced on burn plots. At Oakzanita, there was no significant difference between total tree and shrub seedling density between burned and unburned 100-m² plots. On 1-m² plots, however, there was a substantial increase (41%) in total tree and shrub seedling density. Most of the increase was due to coast live oak seedling establishment. Pointleaf manzanita and Palmer ceanothus also showed density gains compared to unburned controls. In contrast to the Paso Picacho and Granite Springs sites, California black oak seedling density increased after burning at Oakzanita [5].
Mean density and relative dominance (based on basal area) of seedling trees and shrubs (< 2 in. DBH) in 100-m² mixed-conifer plots at Paso Picacho, Granite Springs, and Oakzanita (summer of postfire year 2) | ||||
Species | Density (plants/ha) | Relative dominance (%) | ||
Burn | Control | Burn | Control | |
Paso Picacho | ||||
incense-cedar | 287 | 3.096 | 17.89 | 72.90 |
Jeffrey pine | 3 | 8 | 0.18 | 0.19 |
coast live oak | 137 | 27 | 8.54 | 0.64 |
canyon live oak | 197 | 169 | 12.28 | 3.98 |
California black oak | 700 | 912 | 43.64 | 21.47 |
pointleaf manzanita | 30 | 4 | 1.87 | 0.09 |
Palmer ceanothus | 250 | 31 | 15.58 | 0.72 |
Granite Springs | ||||
Jeffrey pine | 9 | 48 | 2.02 | 2.66 |
coast live oak | 79 | 710 | 17.71 | 39.31 |
California black oak | 352 | 1,048 | 78.92 | 58.03 |
Palmer ceanothus | 6 | ----* | 1.35 | ---- |
Oakzanita | ||||
Jeffrey pine | ---- | 18 | ---- | 0.44 |
coast live oak | 5,375 | 3,909 | 62.87 | 95.34 |
California black oak | 3,075 | 91 | 35.96 | 2.22 |
pointleaf manzanita | 25 | 82 | 0.29 | 2.00 |
Palmer ceanothus | 75 | 0.88 | ||
*not present. |
Mean density and relative dominance (based on basal area) of seedling trees and shrubs (< 2 in. DBH) in 1-m² mixed-conifer plots at Oakzanita (summer of postfire year 2) | ||||
Species | Density (plants/m²) | Relative dominance (%) | ||
Burn | Control | Burn | Control | |
Oakzanita | ||||
Jeffrey pine | ---- | 0.02 | ---- | 1.72 |
coast live oak | 5.62 | 1.07 | 94.77 | 92.24 |
California black oak | 0.12 | 0.07 | 2.02 | 6.03 |
pointleaf manzanita | 0.02 | ---- | 0.34 | ---- |
eastern Mojave buckwheat | 0.07 | ---- | 1.18 | ---- |
Palmer ceanothus | 0.10 | ---- | 1.69 | ---- |
*not present. |
Herbaceous vegetation—The prescribed burns increased total herbaceous vegetation density at Paso Picacho but decreased total herb density at Oakzanita. At Paso Picacho, mean total herb density was 107.7% that of herb density on control plots in postfire year 2. At Oakzanita, total herb density decreased 22%, but total herb diversity increased. The decrease in density was mainly due to the dominance of California goldenrod on control plots. Fifty percent of total herb density on control plots was California goldenrod, and California goldenrod density was reduced 39% on burn plots compared to control plots [5]. Burn and control densities of herbs at Granite Springs were not compared. For herbs, species responses to fire were not measured on any of the mixed-conifer sites.
Deergrass meadow:
The prescribed fires removed nearly all standing vegetation on both meadow sites.
Approximately 50% of the standing deergrass biomass before the fires was dead foliage.
At Granite Springs, deergrass gained 145% live foliage cover 3 months after
prescribed burning compared to control plots [5,6]. At Oakzanita, deergrass showed a 51%
gain of live foliar cover at postfire month 15. Deergrass is a bunchgrass, and there were over 3 times more
deergrass clumps on the Oakzanita burn compared to the control. However, deergrass clumps
were about 5 times larger in the control compared to the burn. Pre- and postfire
herbaceous cover of plants at Oakzanita is shown below [5].
Mean dominance and relative dominance of herbaceous cover on Oakzanita deergrass meadows at postfire month 3 (16 July 1980) | ||||
Species | Dominance (% foliar cover) | Relative dominance (%) | ||
Burn | Control | Burn | Control | |
common yarrow | 1.00 | 2.67 | 1.48 | 3.11 |
Cuman ragweed | ----* | 1.00 | ---- | 1.20 |
attenuate Indian paintbrush | ---- | 0.33 | ---- | 0.38 |
winecup clarkia | 1.67 | 0.67 | 2.48 | 0.78 |
San Bernardino larkspur | 0.33 | 0.33 | 0.49 | 0.38 |
tall annual willowherb | 0.33 | 0.33 | 0.49 | 0.38 |
western marsh cudweed | 1.00 | 1.33 | 1.48 | 1.55 |
American bird's-foot trefoil | 4.66 | 5.67 | 6.92 | 6.62 |
dwarf checkerbloom | 3.66 | 1.67 | 5.43 | 1.95 |
California goldenrod | 7.67 | 2.33 | 11.39 | 2.72 |
notchleaf clover | 1.00 | ---- | 1.40 | ---- |
squirreltail | 1.00 | ---- | 1.48 | ---- |
smallflower melicgrass | 6.00 | ---- | 8.91 | ---- |
deergrass (live) | 15.33 | 30.33 | 22.70 | 35.49 |
deergrass (dead) | ---- | 28.00 | ---- | 32.69 |
Kentucky bluegrass | 1.67 | 5.67 | 2.49 | 6.62 |
Sandberg bluegrass | 1.67 | ---- | 2.49 | ---- |
rattail sixweeks grass | 20.33 | 4.33 | 30.19 | 5.05 |
*not present. |
Recovery of deergrass clumps is shown below [5].
Mean density of deergrass clumps on meadow sites at Granite Springs in postfire month 18 (11 June 1980) and at Oakzanita in postfire month 11 (12 March 1981). | ||||
Site | Clumps/plot | area/clump (m²) | Total basal area (m²) | Dominance (% basal area) |
Granite Springs | ||||
Burn | 593 | 0.014 | 8.04 | 5.39 |
Control | 194 | 0.060 | 11.72 | 7.82 |
Oakzanita | ||||
Burn | 12.93 | 0.003 | 0.48 | 3.2 |
Control | 4.13 | 0.017 | 1.05 | 7.0 |
This study further showed the ability of pole-sized and mature oaks and pines to withstand low-severity prescribed underburning. Frequent prescribed fire generally favors oak species over pointleaf manzanita. Martin [5] found that prescribed late fall fire reduced Jeffrey pine seedling density, so he recommended spring prescribed burning to increase Jeffrey pine seedling establishment. After fire, Jeffrey pine seedlings tend to establish in "hot spots" where fire temperatures cause plant mortality. Lack of vegetation reduces postfire growth interference from herbaceous species, and spring fires may create more hot spots than late fall fires, favoring Jeffrey pine.
The fires demonstrated the effectiveness of spring and late fall underburns in controlling young incense-cedars. Incense-cedar is a late-successional species which, with fire exclusion, eventually replaces oaks and pines . Incense-cedar seedlings and saplings were greatly reduced by the prescribed fires. Incense-cedar seedlings generally show little establishment on new burns, so their establishment would be slight with frequent prescribed fires [5].
Herbaceous species on the deergrass meadows recovered quickly after prescribed burning. Deergrass showed greatly increased productivity after burning, probably due in part to removal of dead material within its clumps. Additionally, blackened soil probably encouraged earlier spring growth on burned sites compared to controls. Although not quantified, deergrass apparently showed increased flower and seed production on burned sites compared to unburned controls. Due to relatively greater recovery of deergrass after the spring burn at Oakzanita compared to the late fall burn at Granite Springs, Martin [5] recommends spring prescribed burning to increase deergrass productivity.
Common name | Scientific name |
Trees | |
white fir | Abies concolor |
incense-cedar | Calocedrus decurrens |
limber pine | Pinus flexilis |
Jeffrey pine | Pinus jeffreyi |
coast live oak | Quercus agrifolia |
canyon live oak | Quercus chrysolepis |
California black oak | Quercus kelloggii |
Shrubs | |
Eastwood manzanita | Arctostaphylos glandulosa |
pointleaf manzanita | Arctostaphylos pungens |
Palmer ceanothus | Ceanothus palmeri |
chaparral whitethorn | Ceanothus leucodermis |
birchleaf mountain-mahogany | Cercocarpus montanus var. glaber (Cercocarpus betuloides)* |
eastern Mojave buckwheat | Eriogonum fasciculatum |
Wright's buckwheat | Eriogonum wrightii |
oceanspray | Holodiscus discolor |
southern honeysuckle | Lonicera subspicata |
California scrub oak | Quercus berberidifolia (Q. dumosa)* |
California buckthorn | Frangula californica |
skunkbush sumac | Rhus trilobata |
California rose | Rosa californica |
Parish's snowberry | Symphoricarpos parishii |
poison-oak | Toxicodendron diversilobum |
Forbs | |
common yarrow | Achillea millefolium |
Cuman ragweed | Ambrosia psilostachya |
attenuate Indian paintbrush | Castilleja attenuata (Orthocarpus attenuatus) |
winecup clarkia | Clarkia purpurea |
San Bernardino larkspur | Delphinium parryi |
tall annual willowherb | Epilobium brachycarpum (Epilobium paniculatum) |
western marsh cudweed | Gnaphalium palustre |
American bird's-foot trefoil | Lotus unifoliolatus (Lotus purshianus) |
dwarf checkerbloom | Sidalcea malviflora |
California goldenrod | Solidago californica |
notchleaf clover | Trifolium bifidum |
Grasses | |
squirreltail | Elymus elymoides (Sitanion hystrix) |
smallflower melicgrass | Melica imperfecta |
deergrass | Muhlenbergia rigens |
Kentucky bluegrass | Poa pratensis |
Sandberg bluegrass | Poa secunda (Poa scabrella) |
rattail sixweeks grass | Vulpia myuros |
*For species that have undergone scientific name changes, names in parentheses are those used in the research papers. |
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