wildland fire - marylandwildland fuel types & fire behavior in maryland hardwood litter fires...
TRANSCRIPT
Wild iresareacommonoccurrencein Maryland. In an average year, theMarylandForestServicerespondsto500wild ires, which burn more than 4,000acresof land. Firedepartmentsrespondtoover5,000wild ireincidentsperyear. While some wild ires in Marylandcanburnhundredsoreventhousandsofacres, most are smaller in size, burningless than 10 acres. Even these smallerwild irescanthreatenlives,homes,otherstructures, and our natural resources.Each year hundreds of homes andstructures are threatened, and dozensaredamagedordestroyedbywild ires.
Wild ires occur in every month inMaryland,butpeakinthespringandfall.During these seasons the leaves are offthe deciduous trees, allowing sunlightand wind to reach the forest loor anddry the forest fuels. The relativehumidity of the air is also drier and,combined with a breeze, creates theconditionsforwild irestospreadrapidly.
Theonlynatural causeofwild iresis lightning, and this accounts for only3%ofthewild ireignitionsinMaryland.The remaining 97% of wild ires arecaused by humans. Maryland’s leadingcause of wild ires is improper debris oroutdoor burning that ignites an average
of29%ofthe ireseachyear.Arson,thesecond leading cause, accounts foraround 25% of ignitions. Other causesinclude:equipmentuse, childrenplayingwith ire, smoking, camp ires, railroads,and other miscellaneous ignitions fromsources such as downed power lines,discardedashes,and ireworks.
WILDLAND FIRE
IN MARYLAND
Larry Hogan, Governor Boyd Rutherford, Lt. Governor
Mark Belton, Secretary
Maryland Department of Natural Resources Forest Service
580 Taylor Avenue, E-1 Annapolis, MD 21401
Donald VanHassent, Director/State Forester Monte Mitchell, State Fire Supervisor
Phone: 410-260-8531 or 877-620-8DNR x8531
TTY via Maryland Relay—711 (within MD) or 800-735-2258 (Out of State)
The facilities and services of the Maryland Department of Natural Resources are available to all without regard to race, color, religion, sex, sexual orientation, age, national origin, or physical or mental disability.
This document is available in alternative format upon request from a qualified individual.
A wild ire is an even greaterchallenge when it threatens homes andotherstructures.ThezonewherehomesarebuiltinorneartheforestiscalledtheWildland‐Urban Interface (WUI). Thenumber of homes built in the WUI inMaryland has increased dramatically inrecentyears.
Since 97% of wild ires are causedby people, wild ire ignitions are alsomore common in these Wildland‐UrbanInterface zones. Considering all factors,wild ires can be a signi icant threat inMaryland. Homes and other structuresintermixed with wildland fuels are atrisk, and WUI residents need to takeactions to protect themselves and theirproperty.
For more information, call the Firewise Maryland program, at
301-791-4010 or
Contact your county Forest Service office:
or visit:
Allegany 301-777-2027 Anne Arundel 410-360-8421 Baltimore 410-665-5820 Calvert 410-535-1303 Caroline 410-479-1623 Carroll 410-848-9290 Cecil 410-287-5777 Charles 301-934-2543 Dorchester 410-228-1861 Frederick 301-473-8417 Garrett 301-334-3296 Harford 410-692-5172
Howard 410-442-2080 Kent 410-819-4120 Montgomery 301-854-6060 Prince Georges 410-360-8421 Queen Anne 410-819-4120 St. Mary’s 301-880-2745 Somerset 410-651-2004 Talbot 410-479-1623 Washington 301-791-4733 Wicomico 410-543-1950 Worcester 410-632-5499
Pub. #: 02-292012-553 November, 2017
Publication funding provided by the USDA Forest Service
Most wild ires in Maryland aresurface ires, which burn fallen leaves,twigs, anddebris on the ground. Underthis fallen debris is often a layer ofpartiallydecomposed leavesandhumus,called “duff.” During dry periods, irescanburnunderground in thisduff layer,andbeverydif iculttoextinguish.Theseduff ires can burn for weeks, or evenmonths,andcausesmokeissues.
The intensityofwild ires increasesgreatly in areasofdense ine fuels, suchas grasses, ordense resinous fuels, suchas mountain laurel shrubs or evergreentrees. In these areas, wild ires canspread rapidly and burn with amazingintensity. Maryland rarely experiencesactivecrown ires‐wild iresthatburninthe tree canopy. However, crown irescan occur in dense stands of evergreentreesduringtimesofverydryandwindyweather.
The three factors that controlwild irebehaviorare fuels,weather,andtopography.Inallfueltypestheintensityandrate‐of‐spreadofa irewill increaseas slope increases, wind increases, andrelativehumiditydecreases.
Prescribed ires, or ires ignitedunder controlled conditions by ireprofessionals,canbebene icialtoreduceforestfuels,improvewildlifehabitat,andpreparesitesfortreeplanting.
WILDLAND FUEL TYPES & FIRE BEHAVIOR IN MARYLAND
HardwoodLitterFires typically burn the surfaceleaves and debris, with lamelengths of 1‐4 feet. Residualground iresmaysmolderinthedufflayer.Inareaswithadenselayer of shrubs, or a largeaccumulation of woody debris,ireintensityandrate‐of‐spreadcanincreasesubstantially.
TallGrassWhengrassiscuredandbrown,theabundanceof inefuelleadsto ires that burn hot and fast.Flame lengths can reach 12‐18feet, andunder the in luenceofa strongwind, ires can spreadataveryfastrate.
EvergreenLitterThebuild‐upofpineneedlesonthe forest loor are easilyignited and allow for rapid irespread. Flame lengths of 1‐6feetcanbeexpected.
MarshDespitebeingsurroundedbywater,marsheshave a large amount of ine fuel that canreadilyburn. Firesspreadrapidlyandburnintensely,with lamelengthsof20ftormore.
EvergreenOverstoryIn stands of dense pine andother evergreen trees, surfaceires can spread into the treecanopy. This usually results inthe “torching” of individualtrees, but under the rightconditions, sustained crowniresarepossible.
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