Forest Insect and Disease Newsletter

DNR Forestry's Invasive Plant Program First Four Years

With funds from the Heritage Enhancement account, a position was created and a program begun in late 2007. The first task was to complete division guidelines for invasive species as directed by operations order 113. From there, the task was a large one – develop a program where there hadn't been one before; fill in the massive gaps in our understanding of where invasive species occurs on state forest land, and the factors that influence their spread; and then begin a prioritized approach to invasive plant management across the state.

map: Invasive Plant Occurences surveyed by DNR Forestry

Grant funds awarded through the division of Ecological and Water Resources were a great addition to the effort. With those funds, three large projects and a number of smaller projects were begun. The first project was to develop a set of survey and training protocols, and implement a survey of invasive plants found on rights-of-ways along all maintained roads within state forest boundaries. Both public and private roads were included because of the potential for invasive plants on those rights-of-ways to move into adjacent forest lands. Over 87,000 invasive plant occurrences were reported in the first three years of the program. For several plant species it was the first good look at their distribution across the state. For instance, wild parsnip was thought to occur mostly in southeast Minnesota. Our surveys indicated that large pockets also occur in far northern Minnesota.

map: showing DNR locations of administrered gravel pits

The next big project was to survey all gravel pits managed by the DNR to determine the risk of spreading invasive plants during road maintenance operations. A total of 258 gravel pits were surveyed from top to bottom. The survey was then followed by a large management project to treat invasive plants found in those gravel pits being actively used. Treatment efforts were completed in FY2010 with post-treatment monitoring to follow for several years.

The third large project was to develop aerial detection protocols for common and glossy buckthorn. There is a narrow window of opportunity in the fall after most hardwood tree species have dropped their leaves and buckthorn is still bright green. During that time, even small individual plants show up well on color photography when interpreted using stereo paired photographs. Photographs at a 1:22,000 scale (taken with two cameras, a 25MB color and a 16 MB color infrared camera) were first used on an experimental basis to survey the Hay Creek day-use area of the image: Aerial view of Invasive buckthorn the fall)Dorer state forest and Frontenac state park. Then to test the methods at an operational scale, all state forest lands were flown in Pine County. In both cases, a subset of the data points was ground truthed to determine the accuracy of the data. And then management practices were implemented on the highest priority infestations. Photo interpretations were pushed so as to avoid missing any buckthorn. That meant the likelihood of false positives increased. Interestingly, we found the false positives varied by region. In southeast Minnesota most false positives were either black locust or honey suckle – both invasive plants that could be controlled during operations to remove the buckthorn. However, in Pine County to the north, the false positives were almost all native alder. Using elevation models in that area, the accuracy of the invasive plant occurrence data could be enhanced by pulling out the sites at lowest elevation where alder was much more likely to occur. In FY2011, the methods were used again to survey state lands in Sherburne and Carlton Counties.

A total of 29 smaller projects were implemented across the state during the first four years of the program. These ranged from noxious weed management projects on DNR managed rights-of-ways, to buckthorn control during regeneration operations, to trials testing the efficacy of goats at controlling woody invasive plants. Combining state funds, a total of $730,770.00 was spent on invasive plant inventory and management over the four years.

graphic: Project dollars chart, not including staff labor


In additional to the project work, 32 power washers were purchased to support operations order 113 goals and division objectives. These were purchased and stationed such that all forestry staff had access to wash station. Many of these locations were at multi-discipline sites, so other division staff benefitted as well. Several small backpack sprayers and an extra water bucket to be used in aerial fire suppression when working in areas with infested waters were purchased using state funds.

In addition to the state funds spent in Forestry's program, a grant of $100,000.00 was awarded for outreach and education specifically aimed at Minnesota recreationists. The goal was to disrupt the link between recreational activities and the spread of terrestrial invasive species by changing public behavior. Project objectives were to establish a baseline of understanding of recreationists and develop an education plan that built on the science or social marketing. Nine focus groups were held and a phone survey of 1200 participants was completed to describe current recreationists knowledge, behaviors and attitudes. Besides informing the education plan, survey results can be used as a baseline to measure the success of future outreach efforts With state FY2012 funds, a brand identity for the education campaign is being developed (plans are to launch it in FY2013) that will parallel the national Stop Aquatic Hitchhikers program.

With all of this work, the biggest accomplishment of the four years is the increased understanding of the issues among our foresters and vendor-partners. The division went from being largely oblivious of the concern beyond county-enforced noxious weed laws, to grasping the potential future impact of invasive species on the long term sustainability of our forest resources. Most field staff now have a working understanding of the species that occur in their area and can identify those most likely to harm people or the forests under their care. They are familiar with management practices that can help prevent the accidental introduction or spread of invasive species. And there are now extensive tools, materials and references available to support them in their management efforts.

So, while the road is long and we're just beginning, we have a strong foundation on which to build. May the next four years be as productive.