Response of herbaceous vegetation to winter burning in Texas oak savanna
Smith, Jane Kapler, comp. 2010. Research Project Summary: Response of herbaceous vegetation to winter burning in Texas oak savanna. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: https://research.fs.usda.gov/feis/fire-studies/hutcheson-et-al-2010
| Abbreviation | Common Name | Scientific Name | Classification | Status |
|---|---|---|---|---|
| ABUINC | pelotazo | Abutilon incanum | Kingdom: Plantae Class: Dicot Order: Malvales Family: Malvaceae Genus: Abutilon | Fed. Protected: No Nativity: Native Invasiveness: Noninvasive |
| BOTEDW | Edwards Plateau beardgrass | Bothriochloa edwardsiana | Kingdom: Plantae Class: Monocot Order: Cyperales Family: Poaceae Genus: Bothriochloa | Fed. Protected: No Nativity: Native Invasiveness: Noninvasive |
| RHYTEX | Texas snoutbean | Rhynchosia texana | Kingdom: Plantae Class: Dicot Order: Euphorbiales Family: Phyllanthaceae Genus: Phyllanthus | Fed. Protected: No Nativity: Native Invasiveness: Noninvasive |
| Plants | ||||
| BOTBAR | cane bluestem | Bothriochloa barbinodis | Life Form: Plants/Graminoid Kingdom: Plantae Class: Monocot Order: Cyperales Family: Poaceae Genus: Bothriochloa | Fed. Protected: No Nativity: Native Invasiveness: Noninvasive |
| DESVEL | velvet bundleflower | Desmanthus velutinus | Life Form: Plants/Forb Kingdom: Plantae Class: Dicot Order: Fabales Family: Fabaceae Genus: Desmanthus | Fed. Protected: No Nativity: Native Invasiveness: Noninvasive |
| DIGCOG | fall witchgrass | Digitaria cognata | Life Form: Plants/Graminoid Kingdom: Plantae Class: Monocot Order: Cyperales Family: Poaceae Genus: Leptoloma | Fed. Protected: No Nativity: Native Invasiveness: Noninvasive |
| ELYVIR | Virginia wildrye | Elymus virginicus | Life Form: Plants/Graminoid Kingdom: Plantae Class: Monocot Order: Cyperales Family: Poaceae Genus: Elymus | Fed. Protected: No Nativity: Native Invasiveness: Noninvasive |
| ERAINT | plains lovegrass | Eragrostis intermedia | Life Form: Plants/Graminoid Kingdom: Plantae Class: Monocot Order: Cyperales Family: Poaceae Genus: Eragrostis | Fed. Protected: No Nativity: Native Invasiveness: Noninvasive |
| ERISER | Texas cupgrass | Eriochloa sericea | Life Form: Plants/Graminoid Kingdom: Plantae Class: Monocot Order: Cyperales Family: Poaceae Genus: Eriochloa | Fed. Protected: No Nativity: Native Invasiveness: Noninvasive |
| HILBEL | curly-mesquite | Hilaria belangeri | Life Form: Plants/Graminoid Kingdom: Plantae Class: Monocot Order: Cyperales Family: Poaceae Genus: Hilaria | Fed. Protected: No Nativity: Native Invasiveness: Noninvasive |
| LESPRO | trailing lespedeza | Lespedeza procumbens | Life Form: Plants/Forb Kingdom: Plantae Class: Dicot Order: Fabales Family: Fabaceae Genus: Lespedeza | Fed. Protected: No Nativity: Native Invasiveness: Noninvasive |
| NASLEU | Texas wintergrass | Nassella leucotricha | Life Form: Plants/Graminoid Kingdom: Plantae Class: Monocot Order: Cyperales Family: Poaceae Genus: Nassella | Fed. Protected: No Nativity: Native Invasiveness: Noninvasive |
| OXADIL | yellow woodsorrel | Oxalis dillenii | Life Form: Plants/Forb Kingdom: Plantae Class: Dicot Order: Geraniales Family: Oxalidaceae Genus: Oxalis | Fed. Protected: No Nativity: Native Invasiveness: Noninvasive |
| PANHAL | Hall's panicgrass | Panicum hallii | Life Form: Plants/Graminoid Kingdom: Plantae Class: Monocot Order: Cyperales Family: Poaceae Genus: Panicum | Fed. Protected: No Nativity: Native Invasiveness: Noninvasive |
| PANOBT | vine-mesquite | Panicum obtusum | Life Form: Plants/Graminoid Kingdom: Plantae Class: Monocot Order: Cyperales Family: Poaceae Genus: Panicum | Fed. Protected: No Nativity: Native Invasiveness: Noninvasive |
| PHYPOL | smartweed leaf-flower | Phyllanthus polygonoides | Life Form: Plants/Forb, Plants/Subshrub Kingdom: Plantae Class: Dicot Order: Euphorbiales Family: Phyllanthaceae Genus: Phyllanthus | Fed. Protected: No Nativity: Native Invasiveness: Noninvasive |
| SCHSCO | little bluestem | Schizachyrium scoparium | Life Form: Plants/Graminoid Kingdom: Plantae Class: Monocot Order: Cyperales Family: Poaceae Genus: Schizachyrium | Fed. Protected: No Nativity: Native Invasiveness: Noninvasive |
| SMIBON | saw greenbrier | Smilax bona-nox | Life Form: Plants/Shrub, Plants/Vine or Liana Kingdom: Plantae Class: Monocot Order: Liliales Family: Smilacaceae Genus: Smilax | Fed. Protected: No Nativity: Native Invasiveness: Noninvasive |
| SPOCOM | composite dropseed | Sporobolus compositus | Life Form: Plants/Graminoid Kingdom: Plantae Class: Monocot Order: Cyperales Family: Poaceae Genus: Sporobolus | Fed. Protected: No Nativity: Native Invasiveness: Noninvasive |
| TORARV | spreading hedgeparsley | Torilis arvensis | Life Form: Plants/Forb Kingdom: Plantae Class: Dicot Order: Apiales Family: Apiaceae Genus: Torilis | Fed. Protected: No Nativity: Nonnative Invasiveness: Invasive |
| TRANEP | noseburn | Tragia nepetaefolia | Life Form: Plants/Forb Kingdom: Plantae Class: Dicot Order: Euphorbiales Family: Euphorbiaceae Genus: Tragia | Fed. Protected: No Nativity: Native Invasiveness: Noninvasive |
Unless otherwise indicated, the information in this Research Project Summary comes from the following paper:
- Hutcheson, Ann-Marie; Baccus, John T.; McClean, Terry M.; Fonteyn, Paul J. 1989. Response of herbaceous vegetation to prescribed burning in the Hill Country of Texas. Texas Journal of Agriculture and Natural Resources. 3:42-47 [2].
Common names are used throughout this summary. For a complete list of the common and scientific names of species discussed in this summary, see the Appendix or the Species in this Study section.
This study was conducted in a bastard oak-post oak (Quercus fusiformis-Q. stellata) savanna at the Kerr Wildlife Management Area in Kerr County, Texas. Site and soil characteristics were not described.
The prefire plant community was dominated by grasses, with a very open oak overstory. The study measured abundance of herbaceous vegetation surrounding individual plateau oaks and post oaks. Fuels were measured before and after burning. Species-specific productivity was measured on burned and paired, unburned plots in the first summer after burning (~6 months after fire).
Plant Phenology
Herbaceous vegetation was dormant when burned in February; postfire vegetation was measured in the growing season after burning (July and early August).
This research was designed to determine responses of forbs and grasses in a Texas oak savanna to prescribed burning in winter.
Study sites were burned with a strip headfire pattern between 1230 and 1315 on 1 February 1982. At the time of ignition, air temperature was 55 °F (13 °C), relative humidity was between 42% and 48%, and wind speed ranged from 10 to 32 mi/h (16-51 km/h). Fuel moisture averaged 20% at the time of burning, and the quantity of herbaceous vegetation averaged 988 lb/ac. Fuels were most abundant at the base of trees, less at the edge of the canopy, and even less in open grassland (table 2):
| Location | Fuel load (SD) (lb/ac) | ||
|---|---|---|---|
| Base of tree | Canopy edge | Open grassland* | |
| Plateau oak | 1,937 (1,256) | 724 (179) | 435 (132) |
| Post oak | 2,005 (437) | 897 (313) | 544 (310) |
| *Measured at twice the canopy radius from the tree base | |||
Burning consumed approximately half of the herbaceous fuel, 455 lb/ac on plateau oak plots and 587 lb/ac on post oak plots. A lower proportion of fuel was consumed at the bases of trees than at other positions, probably because the fire front split at the bases of trees, leaving small unburned patches on the downwind sides.
Maximum temperatures were highest at the litter surface. On plateau oak plots, the average maximum temperature at the litter surface ranged from 138 °F (59 °C) at the tree base to 300 °F (150 °C) in the grassland. On post oak plots, the average maximum temperature at the litter surface was approximately 400 °F (200 °C) and varied little with respect to distance from the tree base. Maximum temperatures at the soil surface averaged 20 to 40 °F (10-20 °C) lower than at the litter surface. Mean temperatures above the litter dropped off "dramatically". At a height of 3 ft (1 m) above the litter surface, average temperatures remained less than 100 °F (38 °C) in plateau oak plots and less than 150 °F (66°C) in post oak plots.
Fire Season and Severity Classification
Winter, low severity
Species richness was lower in burned than unburned plots, with burned plots containing 5% to 20% fewer herb species than unburned plots (table 2). Trailing lespedeza was the only species present near both tree species (post oak and plateau oak) in unburned plots and lacking near both species in burned plots.
| Dominant tree species | Plateau oak | Post oak | ||||
|---|---|---|---|---|---|---|
| Treatment | Unburned | Burned | % change | Unburned | Burned | % change |
| Forbs | 22 | 18 | -18 | 25 | 20 | -20 |
| Grasses | 20 | 16 | -20 | 21 | 20 | -5 |
Winter burning increased forb biomass without substantially altering grass biomass. Total forb biomass was 48% to 78% greater on burned than unburned plots (table 3), mainly due to increases in velvet bundleflower and saw greenbrier. Many species were less abundant on burned than unburned plots near one tree species but more abundant near the other species.
| Dominant tree species | Plateau oak | Post oak | ||||
|---|---|---|---|---|---|---|
| Treatment | Unburned | Burned | % difference | Unburned | Burned | % difference |
| velvet bundleflower | 4.12 | 9.5 | 130.58 | 5.45 | 9.05 | 66.06 |
| catnip noseburn | 2.19 | 1.8 | -17.81 | 1.16 | 1.21 | 4.31 |
| saw greenbrier | 0.71 | 2.85 | 301.41 | 0.07 | 3.19 | 4457.14 |
| Texas snoutbean | 0.20 | 0.00 | -100.00 | 0.68 | 3.54 | 420.59 |
| spreading hedgeparlsey | 0.01 | 0.05 | 400.00 | 0.00 | 1.35 | N/A |
| pelotazo | 0.06 | 0.00 | -100.00 | 0.57 | 1.18 | 107.02 |
| smartweed leaf-flower | 0.69 | 0.22 | -68.12 | 0.15 | 0.00 | -100.00 |
| slender yellow woodsorrel | 0.08 | 0.03 | -62.5 | 0.07 | 0.04 | -42.86 |
| trailing lespedeza | 0.54 | 0.00 | -100.00 | 0.50 | 0.00 | -100.00 |
| Other forbs (12 species) | 0.97 | 1.68 | 73.20 | 0.72 | 1.22 | 69.44 |
| Sedge species | 3.32 | 3.01 | -9.34 | 4.33 | 3.68 | -15.01 |
| Total live forb and sedge biomass | 12.95 | 19.14 | 47.80 | 13.74 | 24.51 | 78.38 |
Many grass species were less abundant on burned than unburned plots near one tree species and more abundant near the other (table 4). Total grass biomass was 28% less on burned than unburned plateau oak plots, with differences mainly due to lower productivity of little bluestem and Texas wintergrass. Vine-mesquite and cane bluestem had substantially greater productivity on burned than unburned plots. On post oak plots, total biomass was virtually the same in burned and unburned plots.
| Dominant tree species | Plateau oak | Post oak | ||||
|---|---|---|---|---|---|---|
| Treatment | Unburned | Burned | % difference | Unburned | Burned | % difference |
| little bluestem | 55.54 | 41.53 | -25.23 | 62.90 | 46.71 | -25.74 |
| Texas wintergrass | 40.21 | 22.87 | -43.12 | 25.80 | 31.18 | 20.85 |
| composite dropseed | 6.86 | 8.60 | 25.36 | 28.54 | 29.34 | 2.80 |
| threeawn species | 8.80 | 11.34 | 28.86 | 7.86 | 4.57 | -41.86 |
| grama species | 11.98 | 7.49 | -37.48 | 7.86 | 16.74 | 112.98 |
| Edwards Plateau beardgrass | 14.72 | 2.55 | -82.68 | 9.36 | 9.49 | 1.39 |
| plains lovegrass | 10.08 | 3.97 | -60.62 | 5.95 | 5.43 | -8.74 |
| Texas cupgrass | 0.81 | 0.63 | -22.22 | 16.48 | 19.89 | 20.69 |
| vine-mesquite | 2.95 | 6.85 | 132.2 | 6.76 | 7.31 | 8.14 |
| curly-mesquite | 4.73 | 1.69 | -64.27 | 0.60 | 0.42 | -30.00 |
| cane bluestem | 1.25 | 7.60 | 508.00 | 1.51 | 1.26 | -16.56 |
| fall witchgrass | 1.34 | 0.58 | -56.72 | 0.31 | 0.15 | -51.61 |
| Hall's panicgrass | 3.56 | 0.46 | -87.08 | 1.20 | 0.43 | -64.17 |
| Virginia wildrye | 0.00 | 0.00 | 0.00 | 2.14 | 4.77 | 122.90 |
| Other grasses (4 species) | 1.57 | 1.51 | -3.82 | 1.19 | 4.96 | 316.81 |
| Total live grass biomass | 164.47 | 117.75 | -28.41 | 178.57 | 182.74 | 2.34 |
Standing dead biomass was 3 to 4 times greater in unburned than burned plots, comprising more than 40% of total standing biomass in unburned plots and less than 32% in burned plots (table 5).
| Dominant tree species | Plateau oak | Post oak | ||
|---|---|---|---|---|
| Treatment | Unburned | Burned | Unburned | Burned |
| Live biomass (lb/ac) | 177.42 | 136.89 | 192.31 | 207.25 |
| Dead biomass (lb/ac) | 225.60 | 61.12 | 145.38 | 43.68 |
| Percent dead of standing biomass | 56% | 31% | 43% | 17% |
Winter burning may increase forb productivity without adversely affecting grass production, which may improve habitat for deer. The authors speculate that a reduction in standing dead biomass caused by winter fire may increase forb productivity by reducing cover (thus increasing insolation) and by increasing available nutrients in the soil.
| Biophysical Setting | Mean Fire Interval (years) | Fire Severity Percent (%) | ||||||
|---|---|---|---|---|---|---|---|---|
| Code | Fire Regime Group | Low | Mixed | Replacement | All | Low | Mixed | Replacement |
| Series 15190 - East-Central Texas Plains Post Oak Savanna and Woodland | ||||||||
| 15190_32_35_36_37 | I-A | 5 | 53 | 57 | 4 | 84 | 8 | 8 |
| Summary | ||||||||
| Minimum | 5 | 53 | 57 | 4 | 84 | 8 | 8 | |
| Maximum | 5 | 53 | 57 | 4 | 84 | 8 | 8 | |
| Mean | 5 | 53 | 57 | 4 | 84 | 8 | 8 | |
| Median | 5 | 53 | 57 | 4 | 84 | 8 | 8 | |
| Percentage of fires in 3 fire severity classes, derived from LANDFIRE succession modeling. Replacement-severity fires cause >75% kill or top-kill of the upper canopy layer; mixed-severity fires cause 26%-75%; low-severity fires cause <26%. | ||||||||
| LANDFIRE. 2020. Biophysical settings models and descriptions, [Online]. Washington, DC: U.S. Department of Agriculture, Forest Service; U.S. Department of the Interior; U.S. Geological Survey; Arlington, VA: The Nature Conservancy, (Producers). Available: https://www.landfirereview.org/search.php [96496] | ||||||||
Table A1: Common and scientific names of species mentioned in this summary.
| Common name | Scientific name |
|---|---|
| cane bluestem | Bothriochloa barbinodis |
| catnip noseburn | Tragia nepetifolia (Tragia neptaefolia)* |
| curly-mesquite | Hilaria belangeri |
| Edwards Plateau beardgrass | Bothriochloa edwardsiana |
| fall witchgrass | Digitaria cognata (Leptoloma cognatum) |
| grama species | Bouteloua spp. |
| Hall's panicgrass | Panicum hallii |
| little bluestem | Schizachyrium scoparium |
| pelotazo | Abutilon incanum |
| plains lovegrass | Eragrostis intermedia |
| composite dropseed | Sporobolus compositus (Sporobolus asper) |
| saw greenbrier | Smilax bona-nox (Smilax bonanox) |
| sedge species | Carex spp. |
| slender yellow woodsorrel | Oxalis dillenii |
| smartweed leaf-flower | Phyllanthus polygonoides |
| spreading hedgeparlsey | Torilis arvensis |
| Texas cupgrass | Eriochloa sericea |
| Texas snoutbean | Rhynchosia texana |
| Texas wintergrass | Nassella leucotricha (Stipa leucotricha) |
| threeawn species | Aristida spp. |
| trailing lespedeza | Lespedeza procumbens |
| velvet bundleflower | Desmanthus velutinus |
| vine-mesquite | Panicum obtusum |
| Virginia wildrye | Elymus virginicus |
| *For species that have undergone scientific name changes, names in parentheses are those used in this Sumary. | |
1. Hann, Wendel; Havlina, Doug; Shlisky, Ayn; [and others]. 2008. Interagency fire regime condition class guidebook. Version 1.3, [Online]. In: Interagency fire regime condition class website. U.S. Department of Agriculture, Forest Service; U.S. Department of the Interior; The Nature Conservancy; Systems for Environmental Management (Producer). 119 p. Available: http://frames.nbii.gov/frcc/documents/FRCC_Guidebook_2008.07.10.pdf [2010, May 3]. [70966]
2. Hutcheson, Ann-Marie; Baccus, John T.; McClean, Terry M.; Fonteyn, Paul J. 1989. Response of herbaceous vegetation to prescribed burning in the Hill Country of Texas. Texas Journal of Agriculture and Natural Resources. 3: 42-47. [17777]
3. LANDFIRE Rapid Assessment. 2005. Reference condition modeling manual (Version 2.1), [Online]. In: LANDFIRE. Cooperative Agreement 04-CA-11132543-189. Boulder, CO: The Nature Conservancy; U.S. Department of Agriculture, Forest Service; U.S. Department of the Interior (Producers). 72 p. Available: http://www.landfire.gov/downloadfile.php?file=RA_Modeling_Manual_v2_1.pdf [2007, May 24]. [66741]