Fire in combination with herbicide treatments boost effectiveness

By: Adam Throckmorton

Sweat equity. As a manager attempting to corral sumac invasions at George Washington Carver National Monument (GWCA) in Diamond, MO, I have put a lot of sweat equity into this task. I have spent days in the cold and windy winter, the heat and ticks of summer, and long days burning at GWCA to corral sumac invasions and I have seen the positive results of our strategy first hand.

Prescribed fire at George Washington Carver National Monument, 2012

Prescribed fire at George Washington Carver National Monument, 2012

When I took the job as crew lead for the Heartland Exotic Plant Management Team (EPMT) in 2011, I was asked to tackle the invasion of sumac into the restored prairie at GWCA, specifically the “view shed” area which could be seen from an observation deck on the second floor of the Visitor’s Center. We discussed the dual-management strategy of fire plus herbicide treatments for this effort. For a long-time exotic plant control worker, such a big project can be bewildering at first, but seeing results in the end is worth the sweat in the beginning.

Sumac resprouts following prescribed fire at George Washington Carver National Monument in 2012

Sumac resprouts following prescribed fire at George Washington Carver National Monument in 2012

Thanks to a prescribed burn in March 2012, the amount of plant cover in the unit adjacent to the Visitor’s Center was reduced enough that the EPMT could walk into the unit for treatment purposes. In April 2012, with the early fire and early green-up we were able to foliar spray small plants just beginning to leaf out with a broadleaf-specific herbicide (typically triclopyr). We treated this area again in June of 2012 with a 9-person crew, who spent all day foliar spraying broadleaf-specific herbicide (again, triclopyr) in 14-acres of the 240-acre prairie. The triclopyr herbicide had shown reduction in woody plants, specifically sumac, at other locations at GWCA, so we knew, with a little bit of sweat, it would work.

The Heartland Exotic Plant Management Team treats sumac at George Washington Carver National Monument. Plants begin turning red after treatment giving a fall like appearance.

The Heartland Exotic Plant Management Team treats sumac at George Washington Carver National Monument. Plants begin turning red after treatment giving a fall like appearance.

When we visited with a similar-sized crew in June of 2013, our task had been reduced to about an hour of work cleaning up what we had missed the previous year. The compliments from GWCA staff plus my own eyes confirmed our dual-management strategy had worked. Fire can make herbicide treatments from efficient and the double wammy provides additional stress on the target plants to work towards reaching our goal.  Belt transect monitoring this coming summer will quantify our observations and hopefully lend support to this strategy.

Pre-burn monitoring photopoint image shows the abundance of sumac in the restored prairie at George Washington Carver National Monument.

Pre-burn monitoring photopoint image shows the abundance of sumac in the restored prairie at George Washington Carver National Monument.

Pre-burn monitoring in 2014 shows the success of previous treatments with reduced sumac stems. Intern David Londe holds the indicator sign for photopoint monitoring.

Pre-burn monitoring in 2014 shows the success of previous treatments with reduced sumac stems. Intern David Londe holds the indicator sign for photopoint monitoring.