1998 Forest Health Highlights, Wisconsin
The Forest Health Protection Unit and Regional Forest Pest Specialists provided a wide variety of programs and information on forest pests, and continued to teach integrated pest management principles to DNR foresters, industrial foresters, and private woodland owners. They successfully educated about 4,500 individuals at 79 different training sessions. At the same time, insect and disease detection surveys were conducted on approximately 9.6 million acres, and evaluation surveys on 1.8 million acres.

The Resource
The area of forest land in Wisconsin has been steadily increasing in recent decades and currently stands at almost 16.0 million acres, representing 46 percent of the total land area. The state now has the most forest land than it has had at any time since the first forest inventory in 1936. Wisconsin's forests are predominately hardwoods, with 84 percent of the total timberland area classified as hardwood forest types. The primary hardwood forest type in the state is maple-basswood, which makes up 5.3 million acres (34%) of Wisconsin's timberland area. Conifer types represent 16 percent of the total timberland area (pine forests - 8%, spruce-fir - 6%, and swamp conifers - 2%).

Forests are important to the economy of Wisconsin, not only in the form of wood products, but also in the form of recreation and tourism. The primary and secondary wood products industry is the second largest employer in the state and puts Wisconsin first in the nation in the production of fine paper, sanitary paper products, children's furniture, and millwork. The value of shipment of these products annually exceeds $19.7 billion. Forest and water resources in Wisconsin are a primary tourism attraction for both residents and visitors. The variety of Wisconsin's forest ecosystems support a great diversity of wildlife species, while recreational use of the forests continues to grow and expand.

Major Forest Types - Wisconsin

Special Issues
This year, the gypsy moth spray program treated 61 sites, for a total of 34, 711 acres in 20 counties. The bacterial insecticide, Btk was applied twice, at one week intervals, to all sites in mid May. The majority of the acreage sprayed was in Portage, Wood, and Waushara counties. In late June, two more sites in Jefferson and Sauk counties were treated to slow the spread of the gypsy moth. Instead of Btk, however, flakes containing the female pheromone were distributed by plane over parts of Devil's Lake State Park and the Southern Unit of Kettle Moraine State Park.

Results from this year's trapping season revealed a total of 108,704 moths trapped from approximately 45,000 delta traps throughout the state. The total number of moths caught is a reflection of both DATCP and cooperator data.

Introductions of biological controls made in October 1997 were followed up this summer. The fungus Entomophaga maimaiga was introduced into 22 sites in eastern WI. It has been confirmed that E. maimaiga has become established at an introduction site in Oconto, WI. At three sites in northeastern WI, the parasitic wasp Cotesia melanoscela was released.

No change was observed in the county distribution of oak wilt in 1998. Surveys were conducted in northeastern Wisconsin in Marathon, Marinette, Menominee, and Shawano counties. No significant movement north was noted but new pockets in all of these counties were observed. On a similar note, oak twig girdler was widespread on northern pin oak and black oak in Northwest and Central Wisconsin this August. Damage from this pest was often confused for oak wilt symptoms. The jumping oak gall caused injury to buds of burr oak and white oak in Southern Wisconsin in May. Trees failed to leaf out in late May and early June, but did refoliate two to three weeks later.

The fourth year of a five-year survey of oak wilt was conducted to determine the relationship between pruning of oak conducted by Allient (formally Wisconsin Power & Light) and the overland spread of oak wilt. Surveys were concentrated in Columbia County. This project will continue in 1999 and a summary report will be written at the survey's conclusion.

A committee entitled Oak Wilt Management in Communities, composed of private citizens and individuals in local and state government and private business worked together to create a model ordinance for oak wilt control. Copies of the model ordinance will be available in 1999 through DNR urban forestry specialists and forest health specialists. The committee is also developing a web site for oak wilt, which will be maintained by the USDA Forest Service.

A cooperative project between the USDA Forest Service, University of Wisconsin and WI, MI and MN DNR's was initiated to determine the current health status of basswood in selected areas of the state. The project was initiated in response to an observed change in the crown density and dieback of basswood in Michigan. Efforts in 1998 concentrated on sampling basswood for various insect pests. Data was also collected on crown health, and the presence of any other damaging agents were noted. This project will continue through 1999 and possible through the year 2000. Introduced basswood thrips caused moderate defoliation in Northwestern Wisconsin in 1998. Damage covered approximately 9,700 acres in Bayfield, Polk, Rusk, Sawyer, and Washburn counties.

Efforts on butternut canker continued to be focused on collection of scion wood from potentially disease resistant butternuts. Scions were collected from a stand in Rock County and one in Winnebago County. Scions were sent to the USDA Forest Service for grafting to the root stock of black walnut seedlings. Seedlings were planted into orchards in MN and WI and will be tested for their ability to resist infection.

On May 31, a "derecho" or widespread, straight-line wind event moved through parts of southcentral and southeast Wisconsin - the most damaging straight-line wind event to hit Wisconsin in 100 years. Hurricane-like winds, with gusts up to 100 mph, ripped through 12 counties in that part of the state. Thousands of large trees were uprooted, twisted, broken off, and downed by the winds.

Again, on June 27, high winds ripped through Monroe, Trempealeau, and Jackson counties, damaging nearly 100,00 acres of forested land. About 3,000 acres of previously thinned red pine plantations were snapped off, flattened, or bent. Oaks and other hardwoods were tipped or broken off. Cleanup and salvage operations began in July and DNR foresters still continue to deal with the storm damage. The Ips bark beetle moved in rapidly and attacked damaged pines in early July.

Other Issues
The Columbian timber beetle was found in Dane County on bur oak in September 1998. While it may have previously existed here at low numbers, it has never been recorded in Wisconsin before. It attacks a variety of hardwood species, especially silver and red maple and oak in some areas. Damage is limited to the staining of wood in characteristic patterns, which causes a reduction in the grade of hardwood lumber. Gallery entrances heal over and decay fungi seldom enter. Because the beetle attacks healthy trees, mortality is seldom associated with outbreaks.

The lesser maple spanworm, which defoliates red maple in late spring, occurs in the eastern United States and Canada. This inchworm is native to Wisconsin, but before 1998 it had not been reported to cause noticeable defoliation. This year in Sauk County, understory saplings were often completely defoliated, while mature trees were lightly to heavily defoliated. The defoliation pattern was spotty, with individual trees heavily defoliated and adjacent trees nearly untouched. Pockets of heavily defoliated trees often occurred near the center of the outbreak area between Plain and Natural Bridge State Park.

Asian long-horned beetle (ALHB) infestations have recently been reported in Illinois, and have generated considerable interest in Wisconsin. Three locations have been quarantined in the Chicago area since the first infestation was reported in early July. USDA - APHIS suspects that the beetles were transported from Asia in shipments that use wooden crates and pallets. In southern Wisconsin, a beetle found inside a warehouse three years ago was identified as ALHB. Currently, no infestation on trees in Wisconsin has been reported, although the beetle could pose a serious threat since many Asian goods are coming into Wisconsin.

Unlike most native long-horned beetles, Asian long-horned beetles can attack and kill healthy, mature hardwood trees. Known hosts are maple (especially silver and Norway maples), boxelder, horsechestnut, willow, poplar, birch, rose of Sharon, and ash. At this point, the control strategy in Wisconsin is to conduct a thorough search for symptoms, but to avoid disturbing adult beetles, which might cause them to disperse. Trees with symptoms will be cut, chipped, and burned during the dormant season.

A recently discovered pitch midge on white pine Christmas trees has the potential to become a pest, but the severity of the problem in Wisconsin is not predictable. This white pine pitch midge is native to North America and has probably been in Wisconsin all along, but never numerous enough to be noticed. The biology and potential damage of this pitch midge is largely unknown. They appear to inhabit pitch masses that ooze from wounds caused by physical damage. It is unclear whether they can initiate a wound or if they cause increased pitch flow in existing wounds. Currently, the only confirmed location of white pine pitch midge in Wisconsin is in Jackson County.

Various broadleaf defoliators were observed in Northern Wisconsin in 1998. Aspen blotch miner caused moderate to severe damage in Langlade, Lincoln, and Oneida counties. Oak webworm defoliated 2,000 acres of oak in the Minong area in Washburn County, as well as in Oneida County. Trembling aspen was severely defoliated by large aspen tortrix in Oneida County. For the first time in several years, bruce spanworm defoliated sugar maple in Florence and Forest counties. The only previous outbreak in Wisconsin occurred from 1984-1987 in the same area - little maple damage resulted.

Conifer pests included: jack pine budworm defoliation in Adams and Juneau counties, spruce budworm defoliation of white spruce in Marathon County, pine spittlebug on jack and red pines in Oneida and Vilas counties, and red pine needle midge present on 1,500 acres in Burnett and Washburn counties.

Due to the mild winter, followed by the long growing season this year, there was an abundance of multicolored Asian lady beetles throughout the state. This swarm resulted in numerous calls about the beetles invading homes.

A survey of white pine in Wisconsin is currently underway to document the incidence of stem cankers due to white pine blister rust. The study focuses on pole and small sawtimber stands in Risk Zone 4 of Northern Wisconsin. The main objective is to evaluate the current status of older stands that may have undergone high infection as seedlings/saplings.

Regional Issues
Efforts to detect changes in forest health on a regional (Lake States) basis continues through data collection on permanent plots - 89 for Forest Health Monitoring (FHM) and 18 for North American Maple Project (NAMP). In addition to visiting all plots on the ground, all 18 NAMP plots were observed from the air in an attempt to detect major outbreaks of spring defoliators. No widespread defoliation of sugar maple was detected in 1997. Data for both of these plot programs centers on monitoring crown conditions, including dieback, foliage transparency, and crown density.
Forest Health Monitoring Plots & NAMP Plots - Wisconsin

For more information contact:

Gene Francisco,
State Forester
101 S. Webster St.
P.O. Box 7921
Madison, WI 53707
(608) 267-7494
Wisconsin DNR logo Forest Health Protection
USDA Forest Service
1992 Folwell Avenue
St. Paul, MN 55108
(612) 649-5261
Northeastern Area, S&PF logo
Updated: December 1998.......

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