Where there is smoke, there is fire, is the old adage. This fall, at Lubrecht Experimental Forest, the fire was there precisely for the smoke. On three different days, UM FireCenter staff and UM students ignited their drip torches and implemented small, prescribed burns with the production of smoke as the main goal. The first burn was completed on October 1st just east of Jones Pond and measured only 1/10 of an acre. The fuels consumed by the flames consisted mainly of pine needles, small diameter sticks, and some grass and brush. The burn unit was designed with smoke sampling in mind, so access for the ‘super van’ was located in the forecasted downwind direction. Even though the winds were light and variable that day, the van was able to collect and analyze a good amount of smoke.
The next week another burn window opened up, and a second prescribed fire was ignited. Besides producing smoke, these burns provide great opportunities for workforce development. Even though the units are small, the students who participate see all phases of a prescribed fire in just a short amount of time, and they are heavily involved in the ignition, holding and mop-up of the fire. They also help with documenting weather and fire behavior observations, as well as describing the fuel conditions, i.e. the moisture-content of fuels in various size-classes. Being involved in fire operations as well as the data collection for science enhances the academic experience for the students. During the burn, the smoke van drove around the unit, following changes in wind direction, to take advantage of as much smoke as possible.
After the success of these very small burns, a 20-acre unit was on the docket. On October 30th the weather and fuel conditions where right and students, staff and researchers convened for a briefing, followed by a test-fire, and then burned the unit. Earlier that day FireCenter staff had used a Remote Piloted Aerial System (RPAS, or drone) to collect Lidar data and aerial imagery of the whole unit. This allowed for the creation of a pre-fire, 3-D model of the forest, including the surface fuels and the small Douglas-fir trees, which later were turned into smoke by the fire. This data collection flight was repeated a week after the burn, once the smoke had settled, to visualize which fuels were consumed. This burn unit also contained several large stumps that smoldered for days, and the smoke generated created a longer-duration collection opportunity.
Collecting data pre-fire, during-fire, and post-fire on fuels, weather, fire behavior, and smoke, creates unique datasets for the SMART FIRES project and beyond. Additional benefits of these burns include wildfire risk mitigation through fuels reduction and reintroducing fire as a natural process in the dry Ponderosa pine ecosystem. Having access to Lubrecht Experimental Forest allows us to design burns of different sizes, that meet multiple objectives and that are located on the landscape in a variety of topographical situations, so that they can be implemented under a variety of weather conditions. This increases the number of observations for the researchers by taking advantage of more prescribed burn windows.
Because of SMART FIRES, the smoke, which is usually a less-than-desirable side-effect of prescribed burning, has become one of the main objectives for our burns. This spring we will try to increase the size and number of burns and provide more opportunities for scientific collaboration.