Horizontal Roll Vortices and Crown Fires

Haines, Donald A.

doi:10.1175/1520-0450(1982)021<0751:hrvacf>2.0.co;2

Cited by 46 publications

(33 citation statements)

References 16 publications

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“…Within a given fire, severity and intensity are typically quite variable as a result of fire-created wind patterns such as horizontal roll vortices (Haines, 1982), and ''fire shadows'' downwind of partial firebreaks. An unusual phenomena-crown stripes-occur as linear islands of surviving vegetation in areas blackened by crown fires (Haines, 1982). Trees and other plants in crown stripes and fire shadows often escape top-killing, and provide a seed source for nearby burned over land.…”

Section: Spatial Patternsmentioning

confidence: 99%

Conceptual ecological models for the Long Island pitch pine barrens: implications for managing rare plant communities

Jordan

Patterson

Windisch

2003

Forest Ecology and Management

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Fire dependent pitch pine (Pinus rigida Mill.) and scrub oak (Quercus ilicifolia Wang.) barrens are found on coarse-textured, droughty soils in the northeastern United States. These communities are globablly rare and, in many areas, dependent on active management to sustain them. We used historic and recent aerial photographs of the Central Pine Barrens in New York to develop transition matrices and trajectories of vegetation change. A vegetation map for 1990 provided pre-burn cover type information for a 1,200 ha area burned by an extremely severe wildfire in August 1995. Geographic information system analyses, a firehistory study, post-wildfire research and existing literature provided additional information for development of three conceptual models that describe our understanding of vegetation change in response to fire and land clearing. A simulation model was then used to predict the amount of each cover type in 2046. The reasonableness of the prediction was assessed based on our understanding of pine barrens vegetation dynamics.In 1938, following a period of frequent, intense wildfires of the region, 90% of vegetation in the study area was open canopy barrens (including dwarf pine plains, pitch pine-scrub oak woodland, heath, pine-heath woodland, and scrub oak shrubland). Between 1938 and 1994, wildfires decreased in size, the average area burned per year generally declined, and there were no fires in 70% of the study area. As a result, barrens decreased to $45% of study area vegetation. In August 1995, an unusually severe summer wildfire converted 810 ha of woodland and forest into scrub oak shrubland, and increased barrens to 60% of study area vegetation. Most areas of heath and pine-heath, which comprised 24% of barrens vegetation in 1996, are successional types that developed on formerly cleared land. In the absence of extensive burning, we expect barrens vegetation to be converted to closedcanopy forest as coppice trees and new seedlings mature. Recent changes in fire regimes are likely to result in a loss of barrens vegetation that exceeds predictions of the simulation model. Careful use of prescribed fire and/or mechanical treatments to simulate the effects of fire are recommended for future restoration and maintenance of pitch pine barrens, and for protection of human life and property. #

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Section: Spatial Patternsmentioning

confidence: 99%

Conceptual ecological models for the Long Island pitch pine barrens: implications for managing rare plant communities

Jordan

Patterson

Windisch

2003

Forest Ecology and Management

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“…This convention has been most recently championed by Forthofer and Goodrick (2011) in their comprehensive review of vortices associated with wildland fire. Haines (1982) referred to the phenomenon as horizontal roll vortices (HRVs) and the Glossary of Meteorology (Glickman 2000) defines both HCRs and HRVs as acceptable terms for the spectrum of thermal-kinematic-driven horizontal circulations within the PBL.…”

Section: Conceptual Model Of Low-level Horizontal Vorticesmentioning

confidence: 99%

“…An explanation of strengthened debris plume in association with an HLV Haines (1982) pointed out that for an eastwardmoving (southward-moving) fire, a left flank or north side (east side) counter-clockwise circulation produces a fire-induced vortex. It is the alignment, or phasing, of the fire's convectively driven circulation and the ambient HLV that is considered as a means of augmenting the debris plume of the BCW between 2306 and 2329 UTC.…”

Section: A Radar Analysis Of the Debris Plumementioning

confidence: 99%

“…Haines (1982) provided observational evidence from analyses of nine crown fires that suggests low-level horizontal vortices are a major mechanism that contribute to the induction of crown fires. Haines' study hypothesized that although strong downward motion of air along the parallel cloudless streets of horizontal vortices initially suppresses crown fires within the zone of strongest subsidence, these downdrafts enhance entrainment of dry, warm air and intensify lateral spread.…”

Section: Post-fire Evidence Of Crown Fire and Crown Streetsmentioning

confidence: 99%

“…Influences of meso-β (20-200 km) convective outflow boundaries on wind speed and direction historically have proven to be especially dangerous in the near-fire environment. Historic examples of such convective mesoscale influences resulting in firefighting tragedies include In addition to thunderstorms, other convective processes (ambient and fire-generated), such as lowlevel horizontally oriented vortices, have been shown to influence the character of wildland fire (Haines 1982;Forthofer and Goodrick 2011). In this study, the formation and evolution of fire-scale phasing of horizontal vortices is briefly reviewed, including the various descriptive terms of similar atmospheric vortices and their potential influence on wildland fire.…”

Section: Introductionmentioning

confidence: 99%

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