Dr. Monica G.Turner
Department of Zoology
University of Wisconsin
430 Lincoln Dr.
Madison, WI 53706
Ecosystem and
Landscape Ecology Lab




  1. Data set identity: Prefire heterogeneity, fire severity, and early postfire plant reestablishment in subalpine forests of Yellowstone National Park, Wyoming
  2. Identification codes for relevant data sets: YNPgrid89_data.txt, YNPgrid90_data.txt, YNPgrid91_data.txt, YNPgrid92_data.txt
  3. Data set description
  4. Principal Investigators: Monica G. Turner, William H. Romme, and Robert H. Gardner. 

    Contact Information: Monica G. Turner, Department of Zoology, 432 Birge Hall, University of Wisconsin Madison, WI 53706. 608-262-2592. turnermg@wisc.edu. http://landscape.zoology.wisc.edu/index.html

    Citation: Turner, M. G., W. H. Romme, and R. H. Gardner.  1999.  Prefire heterogeneity, fire severity and plant reestablishment in subalpine forests of Yellowstone National Park, Wyoming. International Journal of Wildland Fire 9:21-36.

    Abstract: The 1988 fires in Yellowstone National Park provided an opportunity to study effects of a large infrequent disturbance on a natural community. This study addressed two questions: (1) How does prefire heterogeneity of the landscape affect postfire patterns of fire severity? and (2) How do postfire patterns of burn severity influence plant reestablishment? At three sites, 100 sampling points were distributed regularly in a 1-km x 1-km grid and sampled annually from 1989 to 1992. Information was recorded on fire severity (damage to trees, depth of ash and soil charring, and percent mineral soil exposed); pre-fire forest structure (forest successional stage; tree density; tree species; tree size; and evidence of pre-fire disturbance by mountain pine beetle [Dendroctonus ponderosae Hopk.] or mistletoe [Arceuthobium americanum Nutt. ex Engelm.]); postfire percent cover of graminoids, forbs, and low shrubs; number of lodgepole pine (Pinus contorta var. latifolia Engelm.) seedlings; and general topographic characteristics (slope and aspect).

  5. Key words: fire severity, heterogeneity, disturbance, landscape ecology, Yellowstone National Park, Rocky Mountains, Pinus contorta, Dendroctonus ponderosae, Arceuthobium americanum


  1. Overall project description
  2. Identity:Prefire heterogeneity, fire severity, and early postfire plant reestablishment in subalpine forests of Yellowstone National Park, Wyoming

    Originator: Monica G. Turner, William H. Romme, and Robert H. Gardner.

    Period of Study: 1989-1992

    Objectives: (a) Study how prefire heterogeneity affects postfire patterns of fire severity, (b) Study how postfire pattern of burn severity influences plant reestablishment

    Abstract: Same as above.

    Sources of funding: National Geographic Society (Grant No. 4284-90), National Science Foundation (BSR - 9016281 and BSR-90118381)

  3. Specific subproject description

    Site description/selection criteria: We selected three 1-km x 1-km study sites on the subalpine plateau of Yellowstone National Park, Wyoming in which a mosaic of fire severity was observed aerially (by MGT and WHR during helicopter flight in October 1998) and from the ground. Criteria for site selection included the presence of crown fire and unburned forest within each 1-km2 area, similarity in substrate (glacial till composed primarily of rhyolite) and elevation (2300-2400 m), and accessibility (within 5 km of a road). The two most important environmental features controlling vegetation on the plateau are related to elevation and geological substrate (Despain 1990), with moisture generally increasing with elevation and soil fertility lower on rhyolite than on andesite substrate. Our study sites represent the dry and infertile end of the major gradients in YNP. The Mallard and Heart sites were embedded within a larger burn mosaic, whereas the Mystic grid was located at the edge of a large burn, capturing the transition between unburned forest and crown fire.

    Site type: subalpine forested plateau

    Geography: UTM Coordinates of sampling points A1(SW corner)and J10 (NE corner) for each grid site:

    Mallard: A1: 514,750 E 4,922,750 N; J10: 515,750 E 4,923,300 N

    Mystic: A1: 509,450 E 4,925,750 N; J10: 510,450 E 4,926,750 N

    Heart: A1: 533,450 E 4,907,550 N; J10: 534,450 E 4,908,550 N

    Habitat: Coniferous forests dominated by lodgepole pine, although subalpine fir (Abies lasiocarpa (Hook.) Nutt.), Engelmann spruce (Picea engelmannii Parry), and whitebark pine (Pinus albicaulis Engelm.) may be locally abundant.

    Geology: Glacial till composed primarily of rhyolite

    Watersheds/hydrology: N/A

    Site history: The prior mountain pine beetle outbreak in YNP (Despain 1990) affected our study sites between 1971 and 1983. The summer of 1988 was the driest on record in YNP; precipitation in June, July and August was 20%, 79%, and 10%, respectively, of the 100-yr average (National Park Service 1988 Weather Station Data, Yellowstone National Park).

    Climate: The climate is generally cool and dry; on the plateau, mean January temperature is -11.4 ºC and mean July temperature is 10.8 ºC (Dirks and Martner 1982). Mean annual precipitation is 56.25 cm with relatively moist springs and dry summers (Dirks and Martner 1982).

    Sampling methods: Initial field sampling was conducted during July 1989.  A 100-m interval grid was established at each study site (yielding 100 sampling points in each 1-km2 grid) by locating the initial corner point at random.   Each grid was oriented toward true north, and the corners of each grid were permanently marked with rebar and located by triangulation. 
                The 1989 field sampling used the following procedures.  We established a 50-m2 circular area centered on each sampling point within each grid.  Within this circular plot, we recorded slope, aspect, prefire successional stage of the stand, burn severity, and number of trees (live + dead) taller than breast height (1.5 m) by species.  Trees that were dead prior to the 1988 fires were deeply charred in many places on the stem, were almost completely lacking bark, and had few or no small branches and twigs (< 2 cm diameter).  Trees that were alive prior to having burned in 1988 had no deep charring, generally retained their bark, and usually had at least some small twigs and branches. We also recorded visual estimates of prefire mountain pine beetle and mistletoe damage within the stand.
                The circular plot was then subdivided into four quadrants (northeast, northwest, southwest, and southeast).  Tree species, diameter at breast height (dbh), and damage level burn severity as indicated by tree damage were recorded for the two trees nearest to the center of each quadrant.  Occasionally there was one or no trees within a quadrant, in which case fewer than two trees were sampled.  Percent cover of graminoids, forbs, shrubs, litter, and exposed mineral soil were estimated visually within a 1-m2 plot in each of the four quadrants, and the number of lodgepole pine seedlings and the dominant species by cover recorded.  The depth of ash and depth to which the soil was charred were measured by excavating a small hole in the center of each 1-m2 plot.  Ash was recognizable by both color and texture, and charred soil was distinguishable by color.  Data collected at each sampling point (i.e., within the four quadrats) were aggregated to provide a single value for each variable at each 50-m2 circular plot. 
                The three grids were resampled during the summers of 1990, 1991, and 1992.  The four corners of each grid were permanently marked in 1989, but the individual sampling points within the grid were not.  Slope, aspect, prefire successional stage of the stand, and burn severity were recorded in 1990, 1991 and 1992 at each sampling point as described above for the 1989 sampling.  Measurements of tree density, tree size, bark beetle damage, and mistletoe infestation were not repeated.  Ground-layer vegetation was resampled, but a point-intercept method was used in place of the visual estimate of percent cover to assure consistency among individuals.  At each sampling point, an 8-m line was extended perpendicular to the main north-south transect such that the center of the 8-m line coincided with the sampling point.  Percent cover data were recorded within eight 0.25-m2 point-intercept frames spaced at 1-m intervals along this line. We used a 0.5-m x 0.5-m point-intercept frame containing a total of 25 points (a modification of the method used by Floyd and Anderson [1982, 1987]).  The plant species or cover type that occurred below each intercept point was recorded. Percent cover for each sampling point was determined by aggregating the data from the eight 0.25-m2 plots. 

    Taxonomy and systematics: Dorn, R. D. 1992.  Vascular plants of Wyoming. 2nd Edition. Mountain West Publishing, Cheyenne, Wyoming.


For internal use only


Data is divided into four datasets because variables recorded were not identical for each year. Click on year to view the corresponding variable information.


Despain, D. G. 1990.  Yellowstone Vegetation:  Consequences of Environment and History in a Natural Setting. Roberts Rinehart Publishing Co., Boulder, Colorado.

Dirks, R. A. and B. E. Martner.  1982.  The climate of Yellowstone and Grand Teton National Parks.  Occasional Paper No. 6, U. S. National Park Service, Washington, D. C.

Dorn, R. D. 1992.  Vascular plants of Wyoming. 2nd Edition. Mountain West Publishing, Cheyenne, Wyoming.

Floyd, D. A. and J. E. Anderson.  1982.  A new point interception frame for estimating cover of vegetation.  Vegetatio 50:185–186.

Floyd, D. A. and J. E. Anderson.  1987.  A comparison of three methods for estimating plant cover.  Journal of Ecology 75:221–228.