Forest health


Forest Insect and Disease Newsletter February 2015

PlayCleanGo: Stop Invasive Species In Your Tracks

Screen Shot of partners logos from PlayCleanGo webpagePlayCleanGo produced a bumper crop year of new partners in 2014, more than doubling the number of organizations actively participating in the outreach campaign to disrupt the link between outdoor recreation and the spread of terrestrial invasive species. The most significant development occurred last, when the North American Invasive Species Management Association (NAISMA) adopted PlayCleanGo as their national campaign and invited all of their participating organizations to join PlayCleanGo as well. Visit our partner webpage to see who all is now involved in spreading the word.

Launched in 2012, the outreach campaign has grown in leaps and bounds. At the end of 2013, the campaign had enlisted 38 partners in using PCG branded materials. In 2014, that number jumped to 107 organizations, covering a large portion of the U.S. and Canada. During January 2015, another six organizations joined the effort. With a look that is modern, fun and accessible, like-minded organizations have found the materials flexible and well suited to their outreach needs. As a result the campaign is well on its way to becoming a national success.

Summary of Key 2014 Activities

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Quarantined forest pests

 

Gypsy Moth Program Overview of 2014 and plans for 2015

2014 Gypsy moth survey results
2014 Gypsy moth survey results map. Click to enlarge.

This year's cool wet spring followed by an abnormally warm Memorial Day weekend affected treatment timing and operations that were originally targeted for late June. The first Btk applications was scheduled to begin on Thurs. June 12 but due to rain was postponed until Friday, June 13, which turned out to be perfect for an early morning application (low winds, high humidity and cool temps 40-60 degrees). The second application of Btk was targeted for Thurs. June 19 but was delayed numerous times due to heavy fog, high winds and rain that persisted in the area for several days coupled with Grandma's marathon which eliminated the option to treat over the weekend due to public perceptions of aerial applications. The second application finally occurred on June 23 in the late afternoon beginning at 5:30 p.m. only to have to shut down operations before the block was completed due to heavy fog that moved into the area causing it to be hazardous for aerial applications, leaving just under 100 acres left untreated. These final acres were completed on Thurs. June 26, concluding our Btk applications for the year. Full article This is a PDF file. You will need Adobe Acrobat Reader to download it.

 

Status of Emerald ash borer in Minnesota

Emerald ash borer (EAB) was discovered in two new counties (Olmsted and Dakota) in Minnesota during 2014, bringing the total number of known EAB-infested counties to six. The initial Olmsted County find south of Rochester was made in August after a report to MN DNR of declining ash trees. Shortly after that find was reported another confirmation of EAB was made 5 miles to the north and just outside Rochester city limits. The initial find in Dakota County occurred in late December and was located across the Mississippi River from another infestation in Hennepin County. These finds resulted in emergency quarantines for EAB declared around Olmsted County and Dakota County by the Minnesota Department of Agriculture (MDA). After a comment period and public hearing, the emergency quarantines are expected to become part of the formal state quarantine for EAB that already includes Hennepin, Houston, Ramsey and Winona Counties in early January 2015. Full article This is a PDF file. You will need Adobe Acrobat Reader to download it.

 

Thousand cankers disease of walnut: External quarantine report for 2014

Thousand canker disease of Walnut
Thousand canker disease of Walnut map. Click to enlarge.

Thousand Cankers Disease of Walnut (TCD) had killed hundreds of eastern black walnut trees (Juglans nigra L.) planted outside their native range, in western and southwestern U. S., prior to the first report of the disease in its native range in 2010. In July 2010, TCD was confirmed for the first time on black walnut in Knoxville, TN. Since that time, TCD has been found in five eastern states within its native range, mostly in urban landscapes and also in Europe. TCD has not been found in MN.

The native range of black walnut extends into southern Minnesota, where it is an important resource of wood, nuts, wildlife, and habitat. The wood is highly prized by artisans, having a dark-colored, true hardwood that is durable, yet is easy to work with. Movement of walnut wood by hobbyists is one way that TCD is introduced into new areas. Full article This is a PDF file. You will need Adobe Acrobat Reader to download it.

 

Mountain pine beetle: External quarantine implemented January 1, 2015

An emerging concern in Minnesota and elsewhere throughout the Great Lakes region is the possible introduction of pests from western forests. Despite sharing a continent, there are insects, pathogens and plants that occur in western North America that could cause problems if they were introduced to eastern North America. This differentiation is due primarily to the separation of eastern and western forest ecosystems by the buffer area of the Great Plains. As a result, there are pests in western North America that may be just as foreign to trees in Minnesota as pests from other continents. Full article This is a PDF file. You will need Adobe Acrobat Reader to download it.


Terrestrial invasive species

 

Addressing Invasive Plants on State Forest Lands

There have been lots happening in the last year or so relative to invasive plant management on state forest lands. The changes move the division toward a more proactive approach to invasive plant management and lay the structural foundation necessary for effective management in the future, making these exciting times. As we move into 2015, there will be a number of new projects that build on these changes. So stay tuned as the program evolves.


Extra Funds for Field Projects

Three sources of funding support invasive species management on state forest lands: Outdoor Heritage funds from the Fish and Game fund, grants from the Division of Ecological and Water Resources (EWR) and grants from the U.S. Forest service. Management projects got an extra boost in 2014 with a one-time influx of general funds. As a result, forestry field staff took on a large number of field projects to address invasive species concerns. A total of 9 projects were funded with EWR dollars and 15 projects were funded with general fund dollars. The largest of these projects were the knapweed project discussed below, treatment of a large number of gravel pits to help minimize the spread of invasive plants in material used for road grating, and control of woody plants invading the blow down area of the St. Croix State Forest. Buckthorn, spotted knapweed, tansy and wild parsnip were among the targets of the smaller projects scattered around the state, as were gates to limit the spread of invasive plants associated with the activity of off-road vehicles.


Buckthorn Detection Project

Buckthorn Detection Project Map.
Buckthorn Detection Project Map. Click to enlarge.

To address the apparent leading edge of buckthorn invasion, DNR received a federal grant in 2012. As per statewide data in the DNR data deli, the southern portion of the state is thoroughly infested with buckthorn. North of a diagonal line running through Morrison, Todd and Otter Tail counties, the number and density of reported observations of buckthorn drop off sharply. While buckthorn has been reported in just about every Minnesota county, the incidence is quite low north of that line. So the purpose of the project was three-fold: 1) test aerial detection methods at a large scale, 2) detect likely buckthorn infestations ahead of the apparent leading edge of infestation and 3) provide managers the means to prioritize key infestations on state managed lands.

In the late fall of the first two years of the project, full-color aerial photography was taken on over 600K acres of state managed lands stretching from Sand Stone west to Detroit Lakes and north to Mahnomen. To detect buckthorn, photographs are taken after leaf drop for oak, but before leaf color change for buckthorn, so the residual green can be easily spotted from the air. Using stereo paired photographs interpreters were able to see three-dimensional stand structures, allowing them to pick out buckthorn in the understory 4' or greater in size. They mapped 397 polygons as suspected buckthorn, 217 of which were on private lands within state land boundaries. The data was then digitized and distributed to state land managers. Five percent of the polygons mapped on state lands as suspected buckthorn were ground truthed in 2013.

In 2014 another 43 percent of the polygons on state lands were ground truthed. Additional ground truthing will be conducted the summer of 2015 in an attempt to check the remaining state land sites. Treatments began on selected stands in the fall of 2013 and will continue as funding allows.

On the sites visited to date, very little buckthorn was found. Forty four of the 87 sites checked had no buckthorn present. Thirty one of the positive sites had small scattered buckthorn seedlings 2-6' tall. Mature plants were found scattered on 12 of the 43 positive sites. Nowhere was buckthorn present as the kind of thicket prevalent in southern Minnesota.

Almost all of the false positives were lowland hardwood swamps. Once that pattern was established, hydrological maps were used to set aside the remaining lowlands for future consideration. Ground inspections during the summer were prohibitively time consuming. However, because glossy buckthorn can thrive under these conditions, these sites can't be ignored. Future monitoring will rely on winter inspections.


Knapweed Biocontrol

The division of forestry had not been particularly involved in biological control of invasive plants in the past. Any biocontrol work implemented was due to the diligence of a few individuals. However, it can be a cost effective way to limit both the reproduction and spread of invasive plants. To kick off more active participation, two workshops were organized in 2014 for state land managers. The first was held at General Andrews and focused on how to establish a new biological control program for spotted knapweed. The second was held near Crookston and focused on how to monitor and maintain an established program. Included was how to survey for, collect and distribute root and flower weevils specific to spotted knapweed.

The tiny flower or seed-head weevils are common and disperse readily on their own. They feed on the seed and can thus greatly reduce viable seed production. While small they can be easily found because of their habit of perching on top of knapweed flowers.

The root weevils on the other hand are difficult to spot. They are large and lumbering. But they hang out on knapweed bracts where they are well camouflaged with their speckled coloring. They also tend to drop immediately to the ground if someone or something comes near the plant. Because they do not disperse well, it is best to purchase them from the collectors out west. Arriving in boxes of 100, releasing the lumbering beasts can be quite entertaining. 5000 root weevils were released on state forest lands and the sites recorded for future monitoring. A few of the sites at the General Andrews nursery will likely serve as good insectaries providing weevils for future release on other sites.


Occurrence Data Management

All information technology (IT) in now organized under a single department, Minnesota IT or MNIT for short. In a pilot project to explore data governance among state agencies, MNIT is currently involved in a scoping process to address how best to integrate invasive species occurrence data across divisions and genera, and ultimately across state agencies. Once complete the system will facilitate observation data collection, reporting, verification and management such that state employees, partners and clients have ready access to reliable observation data.

System requirements have been identified, so the next step is to determine which portions can be bought off the shelf and which can be built in-house. Project completion dates are in one to two years.


2015 Plans

2015 ushered in a number of changes within the DNR Division of Forestry that will help lay the foundation for a proactive approach to invasive plant management on state forest lands.

For the first time, annual work targets were established for each forestry area for both invasive plant survey and control work. These targets formalize our commitment to managing invasive species in order to ensure forest sustainability and setting an example for other landowners. While we have a long way to go towards those goals, our best foot is now forward and on the move.

Invasive plant survey work will be integrated into all summer field work. Planned activities that will now include invasive plant survey work include ground-based regeneration checks, native plant community determinations, summer stand exams done in preparation for future harvesting and site visits related to contract administration. Invasive plant occurrences will be reported and added to the geo-referenced layers on the DNR data deli and our internal Quick Themes geographic data library. Along with the occurrence data, field staff will determine treatment needs and integrate those recommendations into our annual work and budget planning processes. That will provide a systematic approach to prioritize and tackle those projects likely to make the greatest impact.


Management Team

Also for the first time this year, representatives from each region and from each forestry area were identified to serve as an invasive species team. The region staff will provide coordination across areas and the area staff will provide coordination across forestry programs. Invasive species touches almost all forestry programs, so coordination at the area level will be critical to ensure all field staff are observing the appropriate prevention measures and reporting infestations as they are discovered. Both area and region staff will be involved in making sure invasive species are addressed as needed in all future contracts, leaves and permits.

One of the first team projects will be to outline a system of prioritization that allows area staff to effectively utilize limited resources to survey for and control infestations capable of impacting long-term forest sustainability. The second team project will be to review and update the division's invasive species prevention guidelines. It is through these guidelines that the division is working to create a "safety" culture among the all staff. The third team project will be to tackle the gravel pits managed by the division. Invasive species protocols are needed for both active and inactive gravel pits. While guidelines exist to help make sure material taken from active gravel pits is weed seed free, the guidelines do not effectively address the full range of sites on state forest lands. Treatment regimens have been too sporadic to prevent the build-up of a large seed bank in many of our gravel pits. Space to scrape off and store infested material isn't always available. Methods to protect clean material from reinfestation have not been fully explored. These and other concerns will keep the team busy for some time to come.

 

New Year, New Weeds?

By Laura Van Riper, DNR

When people think of noxious weeds, often the first thing they think of is Canada thistle. However, there are a number of other species on Minnesota's Noxious Weed list and a robust process for adding and removing species.

The Minnesota Department of Agriculture (MDA) has regulatory authority over noxious weeds and the law is enforced by county agricultural inspectors. The Noxious Weeds Advisory Committee (NWAC) exists to advise the commissioner of the Minnesota Department of Agriculture as to which species should be regulated as noxious weeds. NWAC consists of 16 members covering a variety of stakeholder groups listed in state statute. This includes state agencies, the University of Minnesota, and agricultural, forestry, horticultural, and conservation organizations.

NWAC uses a formal risk assessment process to evaluate species and produce a recommendation. The committee then discusses the recommendations and votes on an outcome. The committee's final recommendation is then passed on to the MDA commissioner who can decide whether or not to accept the recommendations.

Since NWAC was founded in 2010 they have reviewed species that were already on the noxious weed list along with a number of new species. This has resulted in Minnesota having an up-to-date noxious weed list with strong supporting evidence for the species that are listed. Every three years, NWAC reviews all species on the noxious weed list to determine if anything needs to be re-categorized or removed from the list. If you have a species you think should be evaluated by NWAC, you may contact the MDA to fill out a petition form.

Healthy oaks in Glacial
Japanese barberry in a forest understory in Houston County, MN.
Photo by: Laura Van Riper, DNR

One change coming in 2015 is the beginning of a three year phase-out of the sale of the 25 highest seed-producing cultivars of Japanese barberry (Berberis thunbergii) and the parent species. Japanese barberry is popular shrub that can become invasive in woodlands and forms a thick shrub layer that out-competes other vegetation. The sale will be phased out from 2015 through 2017. Starting January 1, 2018 the sale of these plants will not be allowed. The sale of cultivars that produce less seed will continue. Landowners will not be required to remove Japanese barberry on their land.

Healthy oaks in Glacial
Palmer amaranth growing in a crop field in Wisconsin.
Photo by: Ross Recker, University of Wisconsin-Madison, bugwood.org

Each year since 2010 NWAC has evaluated species and there have been subsequent changes to the noxious weed list. The last update was January of 2014. Due to concerns about the list changing too frequently, there will not be additional changes to the list until January 2017 except in cases of emergency.

In 2014, NWAC evaluated a number of species. The table below lists the species evaluated and the category recommended for that species. If the MDA commissioner accepts the recommendations, they would go into place in 2017, except for Palmer amaranth which was recommended as an emergency addition to the list to go into effect in 2015. Palmer amaranth is resistant to multiple herbicides and can cause large economic impacts to the agriculture industry. It has not been found in Minnesota at this time.

Table: Species reviewed by the Noxious Weed Advisory Committee in 2014 and their listing recommendation.

species reviewed by the Noxious Weed table

The current noxious weed list is found on the MDA website along with definitions of the several categories of noxious weeds.

Species on the Prohibited Noxious Weed: Eradicate list are the high priority species that are not known to be widely distributed in Minnesota. Through early detection and rapid response to these species we hope to prevent these species from becoming widespread and having negative impacts on Minnesota's ecology, economy, and human health. These species may be less familiar to you, but they are important to know. If you find them, it is a big help for control efforts. Species in this category include Grecian foxglove, Oriental bittersweet, and giant hogweed.

Species on the Prohibited Noxious Weed: Control list are more widely distributed in the state than species on the eradicate list. Landowners must control these species on their lands to prevent spread. This is where some of the most familiar noxious weeds are categorized, such as Canada thistle, leafy spurge, wild parsnip, and purple loosestrife.

Restricted Noxious Weeds are species that are banned from sale and transport of propagating parts, but landowners aren't required to control the plants that are on their land. This prevents the introduction of additional plants, but recognizes financial and logistical constraints that can prevent landowners from controlling these species. Common and glossy buckthorn, multi-flora rose, non-native common reed, and garlic mustard are on restricted noxious weeds.

Specially regulated plants are plants that may be native species or have demonstrated economic value, but also have the potential to cause harm in non-controlled environments. These plants each have specific regulations that apply in their case. For example, Japanese and giant knotweed cannot be sold without a label indicating that it is unadvisable to plant this species within 100 feet of a water body or its designated flood plain.

Finally, county noxious weeds are plants that are listed as noxious within a county, but are not listed as noxious at a statewide level. This gives counties the flexibility to add species of local concern. For example, houndstongue is listed as noxious in Becker County.

Healthy oaks in Glacial
Cutleaf teasel is on the cover of the Minnesota Noxious Weeds booklet by the Minnesota Department of Transportation.

A great resource for identification and management of noxious of weeds is the Minnesota Noxious Weeds booklet by the Minnesota Department of Transportation. This booklet includes photos of noxious weeds and their look-a-likes along with management recommendations including the best times of year for management. By learning to identify noxious weeds, you can address weed problems on your own property quickly and help others to identify noxious weeds.