Research Project Summary: Early postfire response of southern Appalachian Table Mountain-pitch pine stands to prescribed fires in North Carolina and Virginia



RESEARCH PROJECT SUMMARY CITATION:
Gucker, Corey, compiler. 2007. Research Project Summary: Early postfire response of southern Appalachian Table Mountain-pitch pine stands to prescribed fires in North Carolina and Virginia. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: http://www.fs.fed.us/database/feis/ [].

Sources:
Unless otherwise indicated, the information in this Research Project Summary comes from the following references:

Turrill, Nicole Leigh. 1998. Using prescribed fire to regenerate Pinus echinata, P. pungens, P. rigida forests in the southern Appalachian Mountains. Knoxville, TN: University of Tennessee. 148 p. Dissertation. [4].

Welch, N. T.; Waldrop, T. A.; Buckner, E. R. 2000. Response of southern Appalachian table mountain pine (Pinus pungens) and pitch pine (Pinus rigida) stands to prescribed burning. Forest Ecology and Management. 136(1-3): 185-197. [5].

SPECIES INCLUDED IN THE SUMMARY:
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.

STUDY LOCATION:
Burned stands occurred on the Warm Springs Ranger District of the George Washington and Jefferson National Forests in Virginia and on the Grandfather Ranger District of the Pisgah National Forest in North Carolina.

SITE DESCRIPTION:
In the southern Appalachians, Table mountain pine and pitch pine occupy dry, south to southwest slopes with shallow, acidic, nutrient-poor soils.

PREFIRE PLANT COMMUNITY:
Pitch pine was the canopy dominant of the 60-year-old Warm Springs stands. Table mountain pine and pitch pine shared the canopy in 77-year-old Grandfather stands. Associated canopy species included chestnut oak and scarlet oak, and species common in the midstory were blackgum and sourwood. Understory species included mountain-laurel, blueberries, and huckleberries. None of the stands were harvested or burned since the late 1930s or early 1940s.

Historic fire regime characteristics for southern Appalachian Table Mountain-pitch pine communities are summarized 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 Potential Natural Vegetation Group listed below.
Vegetation Community (Potential Natural Vegetation Group) Fire severity* Fire regime characteristics

Percent of fires

Mean interval
(years)
Table Mountain-pitch pine Replacement 5% 100
Mixed 3% 160
Surface or low 92% 5
*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].

PLANT PHENOLOGY
Phenology of the vegetation before the spring and fall fires was not described, but vegetation was likely actively growing before the spring fire and beginning to senesce at the time of the fall fire.

FIRE SEASON/SEVERITY CLASSIFICATION:

Fire season Fire severity
fall low
spring low

FIRE DESCRIPTION:
The objective of prescribed burning was to encourage pine regeneration and decrease hardwood dominance in the mid- and understories. Researchers expected to better understand if spring or fall fires would accomplish these goals.

Both fall and spring prescription fires burned in pitch pine-dominated stands on the Warm Spring Ranger District. The fall fire was set using a ring firing technique in mid-October. Air temperature was 22 C and relative humidity was 30% to 40% at the time of the fire. Flame lengths reached 1 to 3 m. The spring fire in mid-May was also ignited using the ring firing technique. Air temperature and relative humidity at the time of the fire were 26 C and 40% to 60%, respectively. The fire produced flame lengths of 1 to 6 m. Char heights averaged 2 m for the spring and fall Warm Springs fires. Ring and head firing techniques were used to start the spring fire in Table Mountain pine-pitch pine stands on the Grandfather Ranger District. At the time of the fire, the air temperature was 27 C, and relative humidity was 36% to 46%. Flame lengths ranged from 12 to 46 m, but char height averaged 4 m. Canopy scorch averaged 20%.

FIRE EFFECTS ON PLANT COMMUNITY:
Postfire effects were studied almost 1 year after the fall fire and approximately 3 months after the spring fires. Pre- and postfire species differences were not statistically analyzed.

Pitch pine and scarlet oak were the canopy (stems ≥10 cm DBH) dominants before and after the fall fire on the Warm Springs Ranger District. Canopy basal area and density of black oak and blackjack oak were reduced by the fire. Most species in the midstory (stems 9.9-2.5 cm DBH) were top-killed by the fall fire. For most species of hardwoods, sprout (stems <2.5 cm DBH) density was much greater after the fall fire; the exception was blackjack oak, which decreased in this size class. Researchers noted sassafras, pitch pine, and black oak seedlings in the postfire surface vegetation. Pre- and postfire vegetation is summarized by size class below.

Pre- and postfire vegetation in Warm Springs pitch pine-dominated stands burned in the fall
 

Prefire

Postfire (~1 year)

Overstory canopy
(stems ≥10 cm DBH)
Basal area
(m/ha)
Density
(# stems/ha)
Basal area
(m/ha)
Density
(# stems/ha)
blackjack oak 0.6 56.3 0.2 12.5
black oak 0.8 62.5 0.2 12.5
black tupelo 1.6 93.8 1.5 87.5
chestnut oak 1.5 93.8 1.2 75.0
pitch pine 11.3 206.3 9.6 168.8
scarlet oak 3.9 193.8 3.8 187.5
white oak 0 0 0.1 6.3
Midstory
(stems 2.5-10 cm DBH)
Basal area
(m/ha)
Density
(# stems/ha)
Basal area
(m/ha)
Density
(# stems/ha)
blackjack oak 1.7 400.0 0 0
black oak 0.6 143.8 0 0
black tupelo 0.5 112.5 0.2 37.5
chestnut oak 0.4 62.5 0.1 18.8
downy serviceberry 0.1 12.5 0 0
pitch pine 0 6.3 0 0
red maple 0 6.3 0 0
sassafras 0.1 31.3 0 0
scarlet oak 0.2 37.5 0.1 18.8
white oak 0.1 6.3 0 0
Saplings, sprouts, and shrubs
(stems <2.5 cm DBH)
Density
(# stems/ha)
Height
(m)
Density
(# stems/ha)
Height
(m)
blackjack oak 43.8 0.8 81.3 0.7
black oak 0 0 381.3 0.6
black tupelo 0 0 75.0 0.4
chestnut oak 0 0 56.3 0.6
huckleberry 18.8 1.0 0 0
mountain-laurel 325.0 0.9 575.0 0.4
red maple 0 0 12.5 0.4
rhododendron 6.3 1.5 0 0
sassafras 406.3 2.2 1,537.4 0.5
scarlet oak 312.5 1.2 193.8 0.5
Ground layer (≤1 m tall) Cover
(%/m)
Frequency
(%)
Cover
(%/m)
Frequency
(%)
blackjack oak 1.7 12.5 0 0
black oak 0 0 3.9 8.3
black tupelo 0 0 0.1 3.1
blueberry 13.7 62.5 13.5 81.3
common greenbrier 0.0 3.1 0.1 3.1
dwarf crested iris 0 0 0.1 3.1
huckleberry 45.1 81.3 17.0 56.3
mountain-laurel 7.9 18.8 3.8 12.2
panicgrass 0.2 3.1 0.1 3.1
pitch pine 0 0 1.5 3.1
red maple 0.0 3.1 0 0
sassafras 3.9 28.1 3.7 46.9
scarlet oak 0.3 9.4 0.0 3.1
vetch 0.1 3.1 0 0
western bracken fern 4.0 81.3 3.9 56.3

Pitch pine and scarlet oak dominated the overstory before the spring fire on the Warm Springs Ranger District. The spring fire top-killed chestnut oak, white oak, sassafras, and red maple and reduced the basal areas and densities of scarlet oak, black oak, and black tupelo in the canopy. The midstory was dominated by blackjack oak and sassafras before the fire and by black tupelo and chestnut oak after the fire. Blackjack oak, scarlet oak, black oak, red maple, and hickory in the midstory were top-killed. However, most of these species (all but blackjack oak and hickory) sprouted and were present with increased density in the sapling size class (stems <2.5 cm DBH). Sassafras sprouts dominated the understory after the fire, and huckleberry dominated both the pre- and postfire ground layer (<1 m tall).

Pre- and postfire vegetation in Warm Springs pitch pine-dominated stands burned in the spring
  Prefire Postfire (~3 months)
Overstory canopy
(≥10 cm DBH)
Basal area
(m/ha)
Density
(# stems/ha)
Basal area
(m/ha)
Density
(# stems/ha)
black oak 0.8 43.8 0.3 6.3
black tupelo 0.3 25.0 0.1 12.5
chestnut oak 1.8 112.5 0 0
pitch pine 14.4 200.0 13.9 181.3
red maple 0.2 6.3 0 0
sassafras 0.2 1,838 0 0
scarlet oak 6.5 262.5 1.4 62.5
white oak 0.3 18.8 0 0
Midstory
(2.5-10 cm DBH)
Basal area
(m/ha)
Density
(# stems/ha)
Basal area
(m/ha)
Density
(# stems/ha)
blackjack oak 1.1 306.3 0 0
black oak 0.3 50.0 0 0
black tupelo 0.2 50.0 0.1 18.8
chestnut oak 0.5 106.3 0.1 18.8
hickory 0.0 6.3 0 0
red maple 0.0 6.3 0 0
sassafras 0.6 243.8 0.0 6.3
scarlet oak 0.5 81.3 0 0
Saplings, sprouts, and shrubs
(<2.5 cm DBH)
Density
(# stems/ha)
Height
(m)
Density
(# stems/ha)
Height
(m)
American chestnut 0 0 6.3 0.4
blackjack oak 6.3 0.7 0 0
black oak 0 0 231.3 0.4
black tupelo 0 0 25.0 0.4
chestnut oak 0 0 56.3 0.4
huckleberry 1,006.3 0.8 0 0
mountain-laurel 193.8 2.3 143.8 0.4
red maple 12.5 0.7 6.3 0.4
sassafras 537.5 1.0 2,675.0 0.5
scarlet oak 31.3 0.7 106.3 0.4
Ground layer
(≤1 m tall)
Cover
(%/m)
Frequency
(%)
Cover
(%/m)
Frequency
(%)
blackjack oak 0.3 2.6 0 0
black oak 0 0 0.1 3.1
black tupelo 0 0 0.0 3.1
blueberry 10.5 59.4 0.5 3.1
huckleberry 49.2 78.1 11.1 96.9
mountain-laurel 1.3 15.6 0.8 15.6
red maple 0.1 3.1 0 0
sassafras 6.5 37.5 5.1 65.6
scarlet oak 0.2 9.4 0.3 9.4
western bracken fern 1.2 28.1 1.1 31.3
wintergreen 0.1 6.3 0.0 3.1

Table Mountain pine and pitch pine dominated the pre- and postfire canopy following the spring fire on the Grandfather Ranger District. Basal areas of black tupelo, Virginia pine, and red maple were not reduced by the fire. Basal areas and stem densities of all midstory species were reduced after the fire. Witch-hazel, chestnut oak, scarlet oak, sassafras, and eastern white pine were killed or top-killed in the midstory. Black tupelo dominated the midstory before and after the fire. Sourwood, red maple, black tupelo, and mountain-laurel sprouts (<2.5 cm DBH) were common in the understory after fire. Mountain-laurel and blueberry dominated the postfire ground layer (<1 m tall).

Pre- and postfire vegetation in Grandfather Table Mountain pine-pitch pine stands burned in the spring

  Prefire Postfire (~3 months)
Overstory canopy
(≥10 cm DBH)
Basal area
(m/ha)
Density
(# stems/ha)
Basal area
(m/ha)
Density
(# stems/ha)
black tupelo 1.4 106.3 1.3 81.3
chestnut oak 0.9 56.3 0.4 18.8
pitch pine 9.0 256.3 5.3 137.5
red maple 1.1 68.8 0.9 50.0
scarlet oak 1.8 68.8 0.6 25.0
sourwood 0.7 56.3 0.3 18.8
Table Mountain pine 12.0 225.0 13.8 287.5
Virginia pine 2.2 62.5 2.4 56.3
Midstory
(2.5-10 cm DBH)
Basal area
(m/ha)
Density
(# stems/ha)
Basal area
(m/ha)
Density
(# stems/ha)
black tupelo 1.3 375.0 0.5 93.8
chestnut oak 0.2 37.5 0 0
downy serviceberry 0.0 12.5 0 0
eastern white pine 0.0 6.3 0 0
pitch pine 0.2 43.8 0.1 12.5
red maple 0.5 150.0 0.2 68.8
sassafras 0.0 6.3 0 0
scarlet oak 0.1 43.8 0 0
sourwood 0.6 168.8 0.1 37.5
Virginia pine 0.1 12.5 0 0
witch-hazel 0.1 93.8 0 0
Saplings, sprouts, and shrubs
(<2.5 cm DBH)
Density
(# stems/ha)
Height
(m)
Density
(# stems/ha)
Height
(m)
black tupelo 0 0 552.5 12.9
blueberry 12.5 1.5 0 0
chestnut oak 6.3 2.9 26.0 4.7
common sweetleaf 12.5 4.0 195.0 8.2
eastern white pine 12.5 3.3 0 0
mountain-laurel 1,581.3 2.8 975.0 147.5
red maple 12.5 1.8 344.5 10.7
rhododendron 0 0 6.5 0.5
scarlet oak 12.5 2.9 19.5 5.1
sourwood 31.3 2.8 156.0 6.0
witch-hazel 31.3 2.8 19.5 4.5
Ground layer
(≤1 m tall)
Cover
(%/m)
Frequency
(%)
Cover
(%/m)
Frequency
(%)
black tupelo 0.1 1.6 0.0 3.1
blueberry 36.5 67.2 1.7 28.1
common greenbrier 2.3 45.3 0.1 9.4
common sweetleaf 0 0 0.0 3.1
eastern white pine 0.2 1.6 0 0
galax 3.9 4.7 0.1 3.1
huckleberry 0 0 2.7 40.7
mountain-laurel 18.2 68.8 4.7 62.5
panicgrass 0.5 3.1 0 0
red maple 0.3 7.8 0.8 6.3
rhododendron 0 0 0.0 3.1
scarlet oak 0.4 7.8 0.9 9.4
sourwood 0.3 1.6 0 0
Table Mountain pine 0 0 0.1 3.1
western bracken fern 0.4 4.7 0 0

The average basal area and density of the canopy was significantly (P<0.05) lower on all sites after burning. Fire reduced the density of stems less than 25 cm DBH on all sites, and very few trees with stems larger than 20 cm DBH were top-killed. Stem density in the understory, however, was significantly (P<0.05) greater after the fires. Ground layer cover was significantly (P<0.05) lower after the fire. Litter depths were significantly (P<0.05) lower on postfire than prefire sites, but duff depths were only significantly (P<0.05) lower than prefire levels on the fall burned site. There were 15,000 pitch pine seedlings/ha after the fall fire and 8,000 pitch pine seedlings/ha after the spring fire on the Grandfather Ranger District.

FIRE MANAGEMENT IMPLICATIONS:
The spring and fall prescribed fires in the southern Appalachians "were ineffective at opening the forest canopy". Trees with stems over 20 cm DBH were not killed, and the canopy "remained fairly intact". Postfire sprouting of hardwoods increased the density of hardwood stems in the understory on all 3 burned sites. Whether or not pine regeneration in the burned stands will be enough to maintain future pine dominance is unknown. The researchers predicted that many pine seedlings will not survive beneath the associated vegetation canopy.

The researchers suggested that prescribed fires that open both the canopy and the understory would produce conditions more conducive to pine seedling establishment and survival. However, they did not suggest the fire intensity and/or firing method that would open both the canopy and understory.
SPECIES INCLUDED IN THE SUMMARY:
This Research Project Summary contains fire response information on the following species. For further information, follow the highlighted links to the FEIS reviews for those species.

Appendix

Common name Scientific name
red maple Acer rubrum
downy serviceberry Amelanchier arborea
hickory Carya spp.
American chestnut Castanea dentata
galax Galax urceolata
wintergreen Gaultheria procumbens
huckleberry Gaylussacia spp.
witch-hazel Hamamelis virginiana
dwarf crested iris Iris cristata
mountain-laurel Kalmia latifolia
black tupelo Nyssa sylvatica
sourwood Oxydendrum arboreum
panicgrass Panicum spp.
Table Mountain pine Pinus pungens
pitch pine Pinus rigida
eastern white pine Pinus strobus
Virginia pine Pinus virginiana
western bracken fern Pteridium aquilinum
white oak Quercus alba
scarlet oak Quercus coccinea
blackjack oak Quercus marilandica
chestnut oak Quercus prinus
black oak Quercus velutina
rhododendron Rhododendron spp.
sassafras Sassafras albidum
common greenbrier Smilax rotundifolia
common sweetleaf Symplocos tinctoria
blueberry Vaccinium spp.
vetch Vicia spp.

REFERENCES:


1. Hann, Wendel; Havlina, Doug; Shlisky, Ayn; [and others]. 2005. Interagency fire regime condition class guidebook. Version 1.2, [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). Variously paginated [+ appendices]. Available: http://www.frcc.gov/docs/1.2.2.2/Complete_Guidebook_V1.2.pdf [2007, May 23]. [66734]
2. 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]
3. LANDFIRE Rapid Assessment. 2007. Rapid assessment reference condition models. In: LANDFIRE. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Lab; U.S. Geological Survey; The Nature Conservancy (Producers). Available: http://www.landfire.gov/models_EW.php [66533]
4. Turrill, Nicole Leigh. 1998. Using prescribed fire to regenerate Pinus echinata, P. pungens, P. rigida forests in the southern Appalachian Mountains. Knoxville, TN: University of Tennessee. 148 p. Dissertation. [66835]
5. Welch, N. T.; Waldrop, T. A.; Buckner, E. R. 2000. Response of southern Appalachian table mountain pine (Pinus pungens) and pitch pine (Pinus rigida) stands to prescribed burning. Forest Ecology and Management. 136(1-3): 185-197. [65618]

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