There’s a new version of the old game, Pick-up Sticks, to be played in New England farm woodlots. While the risk of forest fire is relatively low in the Northeast, it still pays to take steps to protect woodlots from fire damage.
Extensive study has gone into the science of fire. One thing we know about fire is called the fire triangle.
According to research sponsored by the U.S. Forest Service, there are three ingredients necessary for fire: heat, oxygen and fuel. Limiting the availability of one or more of these ingredients is the key to controlling fire. In fact, there is no other way to stop a forest, brush or grass fire.
As Smokey Bear reminds us constantly, prevention is key to avoiding forest or woodlot fires.
Simple preventive steps
Picking up sticks and other debris (including trash often dropped by careless passers-by or that blows in from the road) is a good place to start to control things. It removes a source of fuel. Fuel is anything combustible. Its moisture content determines how quickly it burns.
Light, fast-burning fuels like dead leaves, tree needles, brush and small trees cause rapid spread of fires. They serve as kindling material for heavier branches and, eventually, whole trees. Fires in heavy fuel usually spread more slowly than fires in light fuel, unless it is windy. However, those heavy fuels throw off enormous amounts of heat when dry.
Along with wind, heat causes a woodland fire to spread. Heat removes moisture from fuel, preheats it and warms the surrounding air. It is an increasing spiral. The hotter the fire gets, the more the moisture is removed from the surrounding trees, bushes and other fuel sources, and the hotter it gets. Hot days, when the temperatures are in the 90s, simply add to the problem. Wood debris that is pre-heated by the sun will burn quickly. So will wood on the warm ground.
Twenty-one percent of air is oxygen. Fires generally require just 16 percent oxygen to burn. When fire burns, it reacts with surrounding oxygen to produce heat, gas and embers in a process called oxidation.
Throwing dirt or water on a fire will help smother it. Keep in mind that water, while it will cool a fire and stop its spread, is only half the game. A fire will not be under control until fuel is removed from its path. Again, picking up sticks will remove much of the problem before it starts.
While fire statistics on private woodlands are difficult to find, over the past 10 years, an average of 3,500 human-caused wildfires have burned an average of approximately 400,000 acres of U.S. National Forest System land annually.
We start fires
Jonathan Kays is a University of Maryland natural resource extension specialist who was a fire warden in Virginia before joining the cooperative extension service. “Most fires are started by people burning trash or debris,” Kays said.
People assume autumn is the highest risk season for fire, but Kays said spring and late summer months are the two highest risk seasons for fire. “In spring, with no leaves on the trees, the wind can be a real factor in spreading fire out of control, especially when burning debris.”
Woodlot owners can take precautions to reduce risk of fire. Constructing fire breaks is always a good idea to protect buildings. Cutting brush and trees back to a 30-foot margin will greatly help reduce fire risk to structures.
Kays said cutting grass on access roads and meadows in the woods is also helpful.
“It’s not uncommon for parked vehicles to spark grass fires from their engine heat,” he said. Hot catalytic converters have been known to start fires as well.
Cutting grass along roadsides also is beneficial. Lots of fires start from cigarettes being thrown from careless smokers in passing cars.
Equipping tools and vehicles with spark arrestors will greatly reduce the risk of fire around farms. Spark arrestors usually consist of a mesh screens designed to capture carbon particles before they are exhausted by an engine.
There are two kinds of spark arrestors available. One is designed specifically for handheld tools, such as chainsaws and leaf blowers. A second type is intended for vehicles such as tractors and ATVs. It can also be a good idea to attach spark arrestors to chimney flues.
Dry hydrants are non-pressurized pipes that extend from a water source – a pond, stream or lake – to a roadside that are equipped with fittings to allow fire trucks to draw water into their tanks.
Pipes are embedded into embankments and extended into the water source at a minimum depth of 2 feet below the surface. With appropriate hoses and equipment, water pulled from dry hydrants can be directly applied to fires as much as 1,000 feet from the source.
Kays said federal and state forestry services are always looking for farms with pond or creek access to encourage dry hydrant construction. The U.S. Forest Service offers a matching grant to cover half the construction cost if local funding covers 25 percent.
Since so many fires are started by farmers or landowners, it is a good idea to take precautions when burning trash or debris. Spend a couple of minutes planning the burn before setting a brush pile ablaze.
Contacting your fire department is the first step toward safe trash burning. “Following the local fire regulations usually begins with getting a burn permit,” Kays said.
Seeking a burn permit usually results in determining whether burning is allowed, and if it is, at what time of day. “In Maryland, burning is generally limited to after 4 p.m.,” he said. The local fire department will know what the fire risk is for the local area, as well as whether weather will be a factor.
Choose a safe burn site well away from power lines, equipment, overhanging limbs and structures.
There are several rules of thumb to help you determine if the fire is lit in a safe burn site. First, check vertical clearance. Vertical clearance should be at least three times the height of the burn pile.
Horizontal clearance should be twice the height of the burn pile.
Look at the area that will be under the burn pile, too. The surface area should consist of either gravel or bare soil. It takes only a couple of minutes to run a box scraper or blade on the ground where the fire will be lit. Keep the immediate area – approximately 10 feet in all directions – wetted down before and during burning.
Burn barrels are a good idea for containing fires. Burn barrels should be all metal and not be rusty. They should be vented with three, 3-inch square vents spaced evenly around the rim of the barrel at ground level.
Back each vent with a metal screen and have a metal top screen constructed of a mesh size no larger than 1/4 inch. That top screen will cut down on flying, flaming trash.
Stay with the fire until it is out and all of the burnable materials have been consumed. Once the fire is out, drown it with water. If the fire was on the ground, turn the area over with a shovel and drown the remainder again.
Return to check the site, especially when the weather is windy, dry and warm.
Breaking the triangle
In closing, the key to woodlot fire protection is prevention and ready access: access roads and access to water.
In addition, having good firebreaks to keep vegetation well away from structures and keeping meadows and roadsides mowed are all good strategies to prevent the fire triangle from forming.
Raised on a farm in Southeastern Pennsylvania, David Weinstock is a freelance journalist specializing in agriculture and animal sciences. He is a graduate of Penn State University.
Curt Harler, who has a B.S. in agriculture from Penn State University and an M.S. in AG from Ohio State University, is a full-time freelance writer specializing in green topics.
Cover photo: HandmadePictures/istock