Prescribed burns: Expert explains the what, when, why, where and how of controlled burning

There’s been an increased interest over the past few years in how prescribed burning can decrease risks of forest fires and help with conservation efforts.

The Register-Guard talked with an expert to untangle some of the confusion around prescribed burns.

Amanda Rau, prescribed fire coordinator for Oregon Department of Forestry, said there’s a lot of factors that go into planning for a prescribed burn.

“It's slightly mystified. It's conflated with wildfire, frequently, and there's a lot of differences," Rau said. "When you use prescribed fire, you have the opportunity to manipulate it, and we're working with it. There's an art to it. It's not like you're just putting fire down."

What is a prescribed burn?

Rau said there are two main types of prescribed fire: pile burning and broadcast/understory burning.

For pile burning, piles of woody debris are burned, with the intention to keep fire in a footprint of one pile.

“Pile burning is the most common,” she said. “I would say that most folks don't think about burning of piles as a form of prescribed fire ... but when you think about a bunch of piles on the landscape, which does occur, there will be a large-scale thinning project where there's piles all over the forest, those piles all have to get burned. When you do that, it's a little bit more than a backyard (fire)."

Broadcast/understory burning intends to carry fire across a pre-identified area on a landscape. More specifically, broadcast burning is where you intend to consume everything in a given area, while understory burning is carrying fire underneath the canopy, without the intention of burning down those trees.

Rau said understory burning is intended to reduce the fields on the forest floor for forest health and wildfire hazard reduction.

Controlling the burn

Rau said the process of controlling a prescribed fire has a lot of similar components to controlling a wildfire.

They use similar equipment and tactics, such as fire engines and control lines.

One of the first steps is identifying control lines. With prescribed burns, there are often pre-existing barriers, like roads, water features, rocks or anything that doesn't burn. Sometimes a burn team will wet vegetation or mow and wet grass, but most of the time, a non-flammable bare mineral soil will be exposed in advance.

"When you're fighting fire, you're getting right up on the fire, or you're getting a little bit off of it, and putting in line and then sometimes burning off that line to connect to the fire to stop it," Rau said. "On a prescribed fire, we're doing that ahead of time and then lighting the fire."

Burn teams will also use water on heavy stumps or large logs that can release embers that could blow over the line.

Cultural history of controlled burning

Controlled burning has a long history across the country. In Oregon, there is clear evidence that Indigenous populations used these methods to tend the land. Rau said the Willamette Valley is considered a "cultural fire hotspot."

Cultural burning is an Indigenous practice that historically lowered damage during fire seasons, created paths, increased plant growth and helped wildlife. The practice also has cultural significance for many Indigenous tribes and nations.

"(Prescribed burning today) is mimicking some of the effects of historical cultural fire that Indigenous peoples and tribes have used since time immemorial," Rau said.

However, cultural fires have been suppressed and prohibited for generations after colonization by European settlers. Rau said there are efforts to revive those cultural practices. Although limits have loosened, Oregon House Bill 2986 is an attempt to expand even further.

The bill, which was not voted on by the end of the 2023 legislative session, would create a $5 million Prescribed Fire Capacity Fund, intended to award grants to local governments, federally recognized tribes and other groups to help fund prescribed and cultural burns.

Slash burning became more popular for Oregon agencies in the '60s and '70s, but in other parts of the country like the southern U.S., prescribed burning has been ongoing for 200 years on national forests.

"Prescribed fire has been more recognized as important in recent years," Rau said. "I would not say that's associated with an increase in prescribed fire, but there is an attempt to get more on the ground. The (U.S.) Forest Service is putting a lot of money and energy into that space."

When is prescribed burning used and what is the goal?

When determining whether a prescribed fire is viable, ODF or fire departments look at temperature, humidity and wind speeds to help determine what kind of fire behavior could happen and make sure there's no risk of dangerous fire behavior.

Rau said the reasons for burning are broad and varied.

"It's generally for forest health and wildfire hazard reduction, as well as wildlife habitat enhancement or creation," Rau said. "Many times when you're using it for range land purposes, it's to improve conditions for grazing animals. When it's being used in agriculture, it's generally to prepare an area to be planted, or to remove pests or something that's causing some harm to what's being planted and can reduce the amount of herbicides and tilling used."

Rau added there's a lot of plants and animals that depend on fire.

"It's really taking material that's not very useful, because it's dead, and it's accumulating, and it turns it into something useful, (like) meaningful nutrients for the soil," Rau said.

Who is in charge of a prescribed burn?

Rau compared a prescribed burn to an orchestra. There's a burn boss, the main coordinator or conductor; a holding boss, who's in charge of engines and personnel; people in charge of ignition; people in charge of controlling; meteorologists to provide forecasting and predict smoke behavior; and sometimes even more specialized roles depending on the project.

"All these people doing different things so that they don't interfere with each other, so that they're complimentary as opposed to competing," Rau said. "There's a lot of notifications and working with partners to make sure everybody's on the same page."

Where are prescribed burns allowed in Oregon?

Rau said that permissions vary across the state. She said landowners should start by reaching out to either ODF or their local fire department to ask about permits in their area.

She added ODF is preparing to launch the Certified Burn Manager Program later this summer to provide education and training for those who want to learn about the practice.

"I would not recommend that anyone do a prescribed burn without any prior experience," Rau said. "When you're lighting the land on fire, there's a pretty high level of consequence of failure from a liability perspective, and actual harm, potentially."

Miranda Cyr reports on education for The Register-Guard. You can contact her at mcyr@registerguard.com or find her on Twitter @mirandabcyr.

This article originally appeared on Register-Guard: Prescribed burns: What to know about controlled burning in Oregon