Seventeen million acres of forestland – both private and public – blanket Pennsylvania. Every year, some 7,000 acres are burned by wildfires.

During this time of year when periods of sun and mild temperatures drive out people out of the winter doldrums and into the outdoors, the risk of uncontrolled fires increases. Yard work and cleanups begin and, for many, this means burning leaves, brush and garbage.

Add in winds and sometimes drier days and you have a combination of risk factors that can increase the danger of fire.

March through May statistically are shown to be the spring wildfire season. The state Department of Conservation and Natural Resources notes that 85 percent of Pennsylvania’s wildfires occur during this time.

Ninety-eight percent of wildfires are started because of careless human activity.

“There have been 85 fires so far – 216 acres burned since the first of the year,” said Jacob Richards, forest fire specialist supervisor with DCNR’s Tiadaghton State Forest.

All of those 85 fires were caused by people, he added.

Last year across the United States, 45,918 fires burned 4.2 million acres.

In Pennsylvania, 662 fires burned 1,648 acres.

This time of year, officials such as Richards keep a wary eye on weather conditions. Fire can spread easily through dormant, dry vegetation – leaf litter, grasses, brush, shrubs and trees – under windy conditions.

“Within the past two weeks, we have had, on the average, nice temperatures, more sunlight and there have been over 30 brush and grass fires in Lycoming County,” Richards said on April 4. “Every nice day of the week you are averaging two to three brush and grass fires.”

On-and-off rain events haven’t really made the area damp enough to “green up” and subdue fire risks, Richards said.

“We have not have the higher temps either, to green up the fields and forest floor,” he added.

To “green up” means the fields filled with hay or an overgrown mixture of finer fuels such as grasses and shrubs are dead, in color. They have no green color, no blossoms.

“The grass is not greening up and the fine fuel is readily available for any spark to ignite,” Richards said.

Humidity plays a vital role in determining what types of fire conditions he will face in the field.

“Periods of sunny days and low humidity (and) cool, dry air from Canada is keeping the humidity down and that is what is causing all these numerous brush fires,” he said.

Low humidity impacts the finer fuels, those that serve as jumpstarters to any wildland or brush fire.

People who burn debris should pay attention to the humidity level, Richards said. Below 40 percent at this time of the year is asking for trouble.

“For instance, the humidity was down to 20 percent, which means there is a lot less moisture in the air, and that transfers to the fine fuel,” he said. Low humidity means a fuel will ignite readily.

Wind and sunny also can dry out fuels.

“A period of time without rain and constant low humidity will affect the heavy fuels like larger logs, dead trees and so on … that can become an intense fire,” he said.

What’s Richards’ advice?

Apply common sense. If you want to burn yard waste, brush piles or trash, pay attention to the weather. Is it windy? Is it too dry? Has there been rain lately? Check the humidity and if it’s below 40 percent, save your burning for another day.

If you do opt to fire up your trash barrel, pay close attention to what is burning and stay with it.

“Just think. Be prepared. Stay and watch the fire, and have the proper tools on hand … like water and a rake, in case

it gets away,” Richards said.

Turkey hunters, hikers, campers and anglers should fully extinguish any flames or cigarettes.

Never leave a campfire unattended and make sure it’s fully out before you move on.

In state forests, open fires are prohibited from March 1 to May 25, as well as any other time when the fire danger is listed as high, very high or extreme, unless authorized by district foresters.

Local volunteer fire companies usually fight grass and brush fires. Most use specialized equipment and vehicles, Richards said, such as brush trucks stocked with hand tools and other equipment.

When fires strike bigger tracts of woodland, it becomes a corporative effort between some of the men and women of the volunteer companies; the units of the Bureau of Forestry, who spearhead the effort; and forestry district crews who have specialized training.

The bureau maintains a fire-detection system and works with fire wardens and volunteer fire departments to ensure they are trained in the latest advances in fire prevention and suppression, according to DCNR.

If a fire is intense, Richards said forestry districts from across the state can be called in and even might lend air support. Five planes and two helicopters are available in Pennsylvania for use throughout the wildland fire season.