Annotated Bibliography Sarah Brown

The Yellowstone Fires of 1988 Seminar 1998

Clark, James S., 1988. Effect of climate change on fire regimes in northwestern Minnesota, Nature v334, p233-235.

This study investigates the relationship between climate change and forest fire frequency and intensity. Petrographic thin sections of varved lake sediments from Deming Lake, MN were used to count charcoal grains and create a record for the last 750 years. This charcoal abundance record was compared to existing climate data from the northern Great Plains. Charcoal is most abundant during the warm, dry 15th and 16th centuries, and decreases dramatically with the onset of the 'little ice age' (1600). It is suggested that fire regimes are controlled by the 22-yr drought cycle for the region and the availability of fuel (forest succession dynamics). It is noted that the warm, dry 20th century climate would be more fire prone in the absence of fire suppression policies.

Landmark study in climate/fire regimes. Neat study and interpretation; well written paper. Good background for climate/fire link in recent sediments.

Christensen, Norman L. et al., 1989. Interpreting the Yellowstone Fires of 1988, BioScience v39, p678-685.

This is a summary of the final report of the scientists assembled to consider the ecological consequences of the 1988 Yellowstone fires. 11% of the Greater Yellowstone Area, and 45% of Yellowstone National Park burned. 1988 was the last year in a decade of below average rainfall, the driest year on record, with drought conditions beginning in June and continuing through September. Lightning and human induced fires began in July, increasing in size and strength to a climax in August and September. From 1886 - 1968 there was a policy of total fire suppression, modified to exclude small natural fires in 1968 and revised again in 1972. All forest age and types were affected by the 1988 fires. The fires are thought to be "natural" in scale and size despite controversies over accumulation of fuel due to complete fire suppression policies. The ecological impacts are summarized under soils, aquatics and vegetation and call for little intervention. Further scientific research of the ecological effects and re-evaluation of management processes is urged.

Good basic summary of the state of the forest after the fire. Excellent before and after color pictures of the fire damage. More policy than science.

La Marche, Valmore C. Jr., 1974. Paleoclimatic Inferences from Long Tree-Ring Records Science v183, p1043-1048.

This paper is a reassessment of the usefulness of tree-ring chronologies and their interpretation and application to paleoclimate studies. Bristlecone pines in the White Mountains of Eastern California have been studied since the 1950's, resulting in an 8200 yr chronology of ring-width. This study has used a portion of that record (1100 yrs) from the southern forest border and developed a longer record (5405 yrs) for the upper tree line. In addition to the traditional tree ring width record, the records were statistically analyzed for correlation, sensitivity and their associated standard deviations. The relationships between ring width properties and climate were found to be as follows; 1) enhanced climatic sensitivity is found at both the upper and lower forest limits, 2) at the lower limit the most important variable is soil moisture, evapotranspiration is negatively correlated with ring width, 3) at the upper tree line, high temperatures are most important for limiting tree growth, and 4) overall, ring width variations over several hundred years seem closely dependent on warm-season temperatures. In addition, the two climate regimes of the White Mountains, the fall-spring cyclonic storms of the Pacific, and the summer Pacific high, were compared to the findings. By using two correlated records from different locations, and modern circulation patterns, inferences were made about paleoclimate patterns and tree ring chronologies for the last 1100 yrs.

Referenced often as a background paper for tree-ring studies, and for paleoclimate information for the region. Gives a very thorough look at tree-ring correlation and analysis techniques (circa 1974) and makes a strong link between climate fluctuations and tree growth.

Meyer, Grant A., Wells, Stephen G., Balling, Robert C. Jr., and Jull, Timothy A.J., 1992. Response of alluvial systems to fire and climate change in Yellowstone National Park, Nature v357 p147-150.

Debris-flow and stream-flow deposits produced by post-1988 fire-related sedimentation in Yellowstone National Park were used to interpret the paleo-emplacement of alluvial fan sequences and fire history in northeastern Yellowstone. Charcoal rich deposits and overlying streamflow units (with little charcoal) are interpreted to be fire-related and make up over 30% of the late Holocene alluvial fan materials. The record covers 3500 yrs and identifies 18 debris flow events and 17 sedimentation events each with charcoal 14-C dates. Clustering of fire-related events seems to indicate maximum activity during drought-dominated periods (Mediaeval Warm Period 900-1300), and periods of high variability in climate (recent fires). The last large fire event is hypothesized to be around 1700. Alluvial systems are dissected and floodplains aggrade during low fire activity periods.

Meyer, Grant A., Wells, Stephen G., and Jull, Timothy A.J., 1995. Fire and alluvial chronology in Yellowstone National Park: Climatic and intrinsic controls on Holocene geomorphic processes, GSA Bulletin v107, p1211-1230.

Fire-related deposits from the 1988 Yellowstone fires are used as an analog for interpretation of the fire-history of the northern Yellowstone area. 50 14-C ages of charcoal within alluvial fan deposits show 8 clusters of fire-related sedimentation events since 7500 yr BP, including one coinciding with the Medieval Warm Period (1050-1200). Historic climate data suggest the intensity and variability of summer precipitation is greater during warm periods increasing the chance of drought and forest fires. Cut-fill terrace deposits from accumulation of overbank sediments alternate with periods of fire-related sedimentation, and suggest cooler, wetter conditions. Provides evidence for "small-scale" climate fluctuations during the Holocene as important controls on fire-frequency and thus geomorphic development of the landscape.

Longer, more intense version of Nature article with pictures, data and great diagrams to illustrate points.

Romme, William H. and Despain, Don G., 1989. Historical Perspective on the Yellowstone Fires of 1988, BioScience v39 p695-699.

The 250yr fire history of south-central Yellowstone is reconstructed from the current forest mosaic and is compared to the 1988 fires and fire suppression polices of the past. The current forest was categorized by stand development (mostly lodgepole pine) which is related to amount of fuel available to burn. Increment cores were taken to determine tree ages, and the presence of fire scars noted. The last significant burn before 1988 was circa 1700. It is hypothesized that the low level of fire activity between the two fires was due to stand age (young) and lack of dry, windy weather conditions, as the age of the stand should have supported a burn after 1930; this was however, during fire-suppression. They conclude that the 1988 fires were "normal" and not unduly influenced by human fire-suppression.

Wells, Stephen G., and Harvey, Adrian M., 1987. Sedimentologic and geomorphic variations in storm-generated alluvial fans, Howgill Fells, northwest England, GSA Bulletin v98, p182-198.

Alluvial fan deposits from northwest England are used to analyze the sediment transport dynamics of a 1982 storm event. Sediment accumulation and erosion was determined by the sediment to water ratio over time. Initial debris flow caused aggradation on the alluvial fans and subsequent streamflow dissected the fans and aggraded the floodplains. Large basins tended to be dominated by streamflow, small basins by alluvial fan sedimentation. Traditional analysis of both the alluvial fans and floodplains had suggested they were products of long term climate change; this study suggest they are primarily controlled by geomorphic "event" thresholds associated with watershed topography, available sediment and the storm dynamics.

Background paper on alluvial fan sedimentation and storm deposit dynamics. Referenced by Yellowstone researches for large basin/small basin comparison. Supports the idea of geomorphic "threshold events" for changing landscape features.

Whitlock, Cathy, and Bartlein, Patrick, J., 1993. Spatial Variations of Holocene Climate Change in the Yellowstone Region, Quaternary Research v39, p231-238.

Interpreting paleoecologic records in the Rocky Mountains has traditionally been best explained by local topographic variability, but here is modeled using large-scale climate variations in moisture and temperature. This study uses fossil-pollen data from Yellowstone region to illustrate the indirect effects of changes in summer radiation, and thus, the length of the summer monsoon and the intensity of the Pacific high-pressure system, in two distinct climate regimes. The boundary between these regimes is topographically fixed. In the early Holocene, northern Yellowstone became wetter through increased precipitation from strengthened monsoonal flow (overwhelming increases in ET) and southern Yellowstone became drier due to increases in evapotranspiration due to higher temperatures, unaffected by the monsoonal currents.

Gives a climate change record for the Holocene (<14,000 yr BP), and precipitation and circulation data for the west coast. Illustrates the complexity of the vegetative and climatic variability of the Yellowstone Region.

Vaughan, Andrew, and Nichols, Gary, 1995. Controls on the deposition of charcoal: Implications for sedimentary accumulations of fusain, Journal of Sedimentary Research vA65 p129-135.

This study investigated the effect of variations in charcoal formation, particle size and transport and settling medium on the sedimentation of charcoal particles (fusain). Laboratory experiments were performed to create, transport and settle charcoal particles. Settling rates are determined by the rate at which the fragments become waterlogged, which is controlled by the temperature of formation. The size of the fragments is also an important control on settling rates. The salinity of the water, suspended material, and the presence of a clay or sandy substrate, has little to no effect on settling rates. Researchers are cautioned in estimating the size, intensity, and temperatures of wildfires from fusain deposits, as much of the charcoal produced at temperatures from 250-300 C may not be preserved in the sediment record.

Interesting background on charcoal formation; gives insight into the limitations of using charcoal as a paleoindicator.