This week, about 22 people from a variety of organizations gathered to conduct a prescribed fire at The Niobrara Valley Preserve. The 900 acre burn unit was on the north side of the Niobrara River. Before a big wildfire in the summer of 2012, the area was covered with mixed-grass and tallgrass prairie, bur oak savanna, and ponderosa pine/eastern redcedar savanna/woodland.

That wildfire swept across more then 70,000 acres, including more than 30,000 acres of the Preserve. North of the river, it wiped out the vast majority of the ponderosa pine and eastern redcedar trees and top-killed many of the bur oaks, though the oaks resprouted from their bases. Where the pines and cedars had been, smooth sumac quickly filled in, spreading quickly across much of the area and forming large clones that now cover hundreds of acres (and are still spreading).

Remember to click on photos to see bigger/sharper versions. If you’re reading this in your email, you’ll have to click on the post’s title to open it online so you can click photos.

This area has been the subject of countless hours of discussion about how we should guide it into its next ecological phase. We could just let the sumac spread unimpeded, creating a huge shrubland. Unfortunately, eastern redcedars are reinvading that area too. Letting sumac spread ahead of that invasion would suppress grass growth, and without grass we’d be unable able to use prescribed fire to control the cedars. Since we know dense stands of eastern redcedar provide poor habitat for wildlife and suppress the diversity of plants and other species, we want to avoid that.

We’d be glad to have some ponderosa pines come back, but they are notoriously slow to re-seed themselves after a ‘stand-replacing fire’, especially when there aren’t mature trees around to drop pine cones. We can plant some (and the Nebraska Forest Service has already planted a fair number for us on the steeper slopes), but any fire hot enough to kill young eastern redcedars would kill pines too, unless we plant them in steep rocky areas where there’s insufficient grass to carry fire. Of course, those are the same places where it’s difficult for trees to establish because the ground, such as it is, is dry and hard.

The consensus reached among stewardship staff was that we needed to get a fire through the area, both to remove a lot of the downed wood (making it easier to access the area) and to kill the numerous invading cedar trees. It would be nice not to kill the small pines, but controlling the cedar invasion is a bigger priority right now. One fire won’t suppress the sumac much, but staff might be able to mow or otherwise treat those sumac stems in the year following the fire to amplify the suppression effect.

Deciding to burn the area was relatively easy compared to the task of figuring out the logistics and prepping the site. Firebreak routes had to be found on the steep slopes between the flat above the ridge and the river below. Huge numbers of dead pine and cedar skeletons – some standing, some on the ground – had to be cleared away from those firebreaks to give us a chance to control the fire along those boundaries. Chad Bladow, fire manager and burn boss for the fire, had to figure out how to get crews, water, and vehicles into places where the terrain made that difficult.

Eventually, though, everything came together and we assembled this week to make it happen. My role was pretty small. I showed up and did as I was told. The crew at the Niobrara Valley Preserve had already put in tremendous effort getting the site ready, coordinating the crew and their needs, working with local fire departments to get permission and support, and doing all the little things that go into making a big event happen.

We had help from some nearby ranchers, Nebraska Game and Parks Commission, Northern Prairies Land Trust, Central Platte Natural Resources District, the Bureau of Indian Affairs Pine Ridge Agency, and others. There was a lot of expertise and experience among crew members, as well as some people who were still relatively new to prescribed fire. Even for many of us with quite a bit of experience, this would be a more complex burn than we’re used to. Fortunately, Chad Bladow and several others on the crew were very capable leaders, and the fire was pulled off smoothly and effectively.

We started by burning a big flat area above the ridge, but the line I was on quickly started working down some very steep slopes, igniting as we went. Getting water to those slopes so we could control the fire took a lot of planning and equipment. A big tank was set up above the ridge and a very long hose was connected to it and stretched downslope. A pump charged up the hose with water so the crew could spray the edges of the firebreak and keep the fire contained.

Once our crew made it off the steeper slopes and down to the relatively flat areas at the bottom, everything moved much more quickly. We ignited all the way down to the river, which then acted as the south boundary for the fire. Meanwhile, the other half of the crew worked west along the top and then came down the slopes on the west side until they also hooked into the river. From there, it was a matter of lighting off everything in the interior before it got dark and temperatures dropped and relative humidity rose.

That interior ignition was partially accomplished by people with drop torches – directed by others who stood on vantage points and guided them down the slopes via radio directions. Additional ignition, especially in really steep areas, was done with a specialized flare gun. Even with all that effort, the difficult terrain and the short period of daylight at this time of year meant that the sun went down before everything could be ignited. (A subset of the crew went out the following day and lit off the remainder.)

As the sun went down, many of us had little to do besides watch the fire spread across the interior of the site and patrol the outer edges. With permission, I grabbed my camera and took advantage of the late day light and smoke to get some ‘mood shots’.

I also did some (relatively) close-up photography of small patches of fire. I love the way flames look when captured in still photos.

As darkness settled in, the remnants of the fire kept burning. We knew the bigger logs and standing dead trees would burn through the night, but we had wide bands of blackened ground around the perimeter to contain the fire. The overnight forecast was also favorable, with high humidity and temperatures well below freezing, which would keep the fire from spreading. After assuring the perimeter was secure, the crew retreated to the Preserve headquarters just across the river to watch from there while putting away equipment, grabbing some food, and reviewing the day’s events.

Ecologically speaking, the 900 acres we burned this week is a very small portion of the 56,000 acre Niobrara Valley Preserve, and neighboring properties contain similar habitat that stretches in all directions for miles. We’re hoping to learn what we can from this fire and any follow-up treatments so we can apply that to other areas of the Preserve. More importantly, we hope our experiences will be helpful to our neighbors, who are dealing with very similar issues in terms of sumac expansion, eastern redcedar invasion, and slow recruitment of ponderosa pine.

If you’re interested, you can look back at some of my old blog posts to see what this site looked like immediately after the wildfire and during the next couple of years. The grasslands on Conservancy land and neighboring properties bounced back from the summer wildfire quickly, as grasslands do. The woodland and savanna areas, though, were a bigger question mark for us because there is less collective wisdom about how those kind of sites respond to a big fire like that.

Since summer wildfires in sites invaded by eastern redcedar are becoming more common, we all need to work together to figure out what kind of land stewardship is most helpful after an area burns. Hopefully, this week’s fire and its impacts will be educational for us and others. In the meantime, it sure felt good to be able to pull off a burn we’ve been talking about for a very long time.

On behalf of all our staff at the Niobrara Valley Preserve – thank you to everyone who helped with the fire this week!