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Defoliation by larch casebearers

By Linda Williams, forest health specialist, Woodruff, (Linda.Williams@wisconsin.gov), 715-356-5211 x232

The two cigar-shaped, tan objects sticking to the newly expanding needles of this tamarack tree are larch casebearer caterpillars, feeding on the foliage.

The two cigar-shaped, tan objects sticking to the newly expanding needles of this tamarack tree are larch casebearer caterpillars, feeding on the foliage. Photo: Linda Williams

As tamarack needles begin to appear, so do some tiny caterpillars that feed on them. Larch casebearers defoliate tamarack trees early in the season, first causing the trees to look pale green or yellowish, or even brown if defoliation is severe. This year I have been able to find larch casebearers wherever I look, but so far, I haven’t found any high populations of the insect. Continue reading “Defoliation by larch casebearers”

Tree mortality in low areas

Trees have grown in this low area for many years, but high-water levels and constant rainfall in 2017 was too much for them. The larger trees have already died, and the small white pine are not doing well at all.

Trees have grown in this low area for many years, but high-water levels and constant rainfall in 2017 was too much for them. The larger trees have already died, and the small white pine are not doing well at all. Photo: Linda Williams

By Linda Williams, forest health specialist, Woodruff. Linda.Williams@wisconsin.gov; 715-356-5211 x232

I continue to get calls about dying trees that are a direct result of all the rainfall we got throughout last year’s growing season. When the ground is saturated so many times throughout the growing season as we saw last year, trees are put under significant stress. Even trees that typically grow well in seasonally wet areas may not do well when the ground is wet for extended periods. Under these conditions, roots start to die due to lack of oxygen, and the crown of the tree will also die back.  Continue reading “Tree mortality in low areas”

Region-wide needle tip browning on red pine

Typical appearance of needle tip browning on lower portion of red pine crowns

Red pine with needle tip browning on the lower crown. Photo: Paul Cigan

By Paul Cigan, forest health specialist, Hayward.  Paul.Cigan@wisconsin.gov; 715-416-4920

Although no tree mortality is associated with the condition, widespread needle tip browning on red pine has been observed for the second consecutive year across much of the upper Great Lakes region. The condition is heavier in some places than others, but once in a stand or location, tends to be evenly distributed. Needle tip browning is common on the lower half of mature red pine crowns. On two- to three-year-old needles, the outer half to three-quarters of the needles appear reddish brown to straw-colored while needle bases remain green. Black or dark brown necrotic bands and spots are often present on symptomatic needle tips. Lower crown thinning is also common on symptomatic pine. Newly impacted needles will gradually lighten in color from reddish brown to straw-colored as dead needle tips dry out through the growing season. Continue reading “Region-wide needle tip browning on red pine”

Rhizosphaera needle cast disease on spruce

Spruce trees affected by rhizosphaera needle cast disease will have thin foliage in the lower parts of the tree, and branches may die in severe cases. Some trees are more susceptible, like the tree on the far left and the tree on the far right.

Spruce trees affected by rhizosphaera needle cast disease will have thin foliage in the lower parts of the tree, and branches may die in severe cases. Some trees are more susceptible, like the tree on the far left and the tree on the far right. Photo: Bethany and J.R. Pulham

By Linda Williams, forest health specialist, Woodruff.  Linda.Williams@wisconsin.gov; 715-356-5211 x232

 Are the lower branches of your spruce tree suddenly looking very thin? Rhizosphaera needle cast disease, caused by a fungal pathogen, can severely impact spruce, killing needles and causing them to drop prematurely. Wet years such as 2017 are great for the fungus, but bad for trees. Spring 2016 was also unusually wet, allowing the fungus to start to build up. With all the rain and wet conditions of 2017, the disease exploded. Continue reading “Rhizosphaera needle cast disease on spruce”

Results of survey of Forest Health News subscribers

By Jodie Ellis, communications specialist, Madison. Jodie.Ellis@wisconsin.gov; 608-843-3506

Thanks to all of you who participated in our recent reader survey. About one-fifth of subscribers (336 out of 1,741) took part, providing valuable information which will help us develop better ways to serve all of our readers. The survey was completed April 15, 2018.

Following are some of the things we learned.

Numbers are rounded to the nearest whole number. Some participants chose to skip some questions. Questions are presented below with the total number of respondents indicated in parentheses.

  1. Do you live in Wisconsin (336)?    Yes – 93%       No – 8%
  2. Do you work in Wisconsin (335)   Yes – 87%       No – 13%
  3. Do you own forested land in Wisconsin? (336)  Yes – 54%       No – 46%
  4. How many acres of forested land in Wisconsin do you own? (180)

        Less than 5 acres                    13%

        5 – 10 acres                               14%

        11 – 100 acres                          54%

        More than 100 acres             19%

  1. Where do you own forested land in Wisconsin? (179)

Northeast zone             30%

East central zone          18%

Northwest zone            18%

West central zone          5%

Central zone                 21%

South central zone      12%

Southeast zone               4%    MAP

  1. I am most interested in articles concerning the following zones (refer to older map) (319).

Northeast zone           26%

East central zone        15%

Northwest zone           19%

West central zone       10%

Central zone                 21%

South central zone      11%

Southeast zone           10%

Not interested                 1%

   How often do you read Forest Health News? (318)

Each time I receive an e-mail notification     74%

More than half the time                                     20%

Less than half the time                                         4%

Seldom or never                                                  1%       

 How would you rate the overall content of Forest Health News? (319)

Excellent                                    43%

Good                                           52%

Neither good nor poor              5%

Poor                                             n/a

Terrible                                       n/a

  1. How often do you find information that you can use in your work? (317)

Always                   22%

Usually                  44%

Sometimes           28%

Seldom                   5%

Never                      1%

  1. In general, how interesting or not interesting are topic in Forest Health News to you? (318)

Very interesting                                             31%

Mostly interesting                                          62%

Neither interesting or uninteresting             6%

Mostly uninteresting                                        1%

Very uninteresting                                         < 1%

  1. Are you satisfied or dissatisfied with the timeliness of the information in Forest Health News? (318)

Extremely satisfied                              30%

Usually satisfied                                   58%

Neither satisfied or dissatisfied         11%

Usually dissatisfied                              n/a

Extremely dissatisfied                          n/a

  1. Do you agree or disagree that Forest Health News is useful to you? (318)

Completely agree                        71%

Somewhat agree                         25%

Neither agree nor disagree         3%

Somewhat disagree                       1%

Completely disagree                   n/a

  1. What types of articles do you usually read in Forest Health News? (318)

I read all articles.                                                                        33%

I read only articles specific to my zone(s).                            12%

I read only articles designated as statewide.                         n/a

I read a mix of articles, from both the statewide category and articles in specific zones categories.     55%

  1. Is it currently easy or difficult to move from article to article online? (316)

Easy                                                 65%

Neither easy nor difficult            28%

Difficult                                          7%

  1. Please indicate how each of the four categories below is relevant to your work.
Category Extremely relevant Mostly relevant Neither relevant nor irrelevant Mostly irrelevant Extremely irrelevant
Information about quarantines and other regulatory concerns (314)

 

46% 32% 14% 5% 3%
Current pest and disease observations and management information (313) 59% 30% 6% 3% 2%
General education information about invasive plants and pests (313)

 

49% 38% 8% 3% 2%
Management and regulation of invasive species (312)

 

49% 36% 10% 4% 2%
  1. From the list of four categories above, which is the most important to your work or interests? (314)

Information about quarantines and other regulatory concerns                          12%

Current pest and disease observations and management information              60%

General educational information about invasive plants and pests                     15%

Management and regulation of invasive plants                                                      13%

  1. How often would you like to receive Forest Health News? (317)

Once a month all year round.                                                                         38%

Once every two months all year round.                                                        19%

Monthly during the growing season; less frequently during winter.      19%

The frequency is not important to me.                                                          24%

  1. What is your age? (317)

Under 20 years old           n/a

20-25 years old                 3%

26-35 years old                 14%

36-45 years old                 19%

46-55 years old                 25%

Older than 55 years          40%

  1. How would you rate the speed of internet service in your area? (316)

Fast                     39%

Adequate            48%

Slow                     13%

  1. Which category best describes you? (318)

Forester                                                 48%

Land manager                                         7%

Logger                                                   < 1%

Mill employee                                        n/a

Craftsman                                             < 1%

Scientist/researcher                               3%

Student                                                  < 1%

Policymaker                                          < 1%

Education/outreach professional        4%

Professional/business services             7%

Landowner                                              19%

Other                                                        11%

  1. If you are reading Forest Health News for information pertaining to your job, who is your employer? (268)

Federal agency                                        3%

State agency                                          49%

County agency                                         8%

Municipal agency                                    7%

Private sector                                        16%

Tribal government or business               1%

Non-profit organization                          2%

Academic institution                               2%

Other                                                        13%

  1. What federal agency do you work for? (9)

USDA                             n/a

APHIS                            n/a

US Forest Service       44%

Other                             56% (none specified)

  1. Which state agency do you work for? (133)

WI DNR             92%

WI DATCP         <1%

Other                   7%

New “Tick App” available

Ticks pose increasing health threats throughout North America

Ticks pose increasing health threats throughout North America. Photo: WI DNR

from the May 2018 edition of RECReport, for the WI DNR Bureau of Parks and Recreation Management

The University of Wisconsin-Madison, a partner in the Midwest Center of Excellence (Center) in Vector-Borne Diseases, has announced that “Tick App” is now available for download. Tick App is a phone application that is part research tool and part educational tool with the goal to transition towards a preventative tool over time.

The Center would like to enroll people, by the app, in their study to determine the risk for tick encounters, assess the success/failure of self-reported prevention strategies, and educate people at the same time. Participation is entirely voluntary. When people download the app, they will go through a sign-up process—and about 5 minutes of questions—so the researchers can assess risk factors for tick exposure.

When people are in the app they can complete daily tick diaries (asking about activities and tick exposure) and can report a tick. Users can even send in an image for identification after the report is completed. For more information on the Tick App, visit http://www.thetickapp.org or tickapp@wisc.edu.

Browning on spruce and other conifers due to winter drying

Deep snow during the winter covered the lower branches, protecting them from the drying effects of dry air, wind, and sun throughout the winter, while the top of the tree experienced significant winter desiccation and browning.

Deep snow during the winter covered the lower branches, protecting them from the drying effects of dry air, wind, and sun throughout the winter, while the top of the tree experienced significant winter desiccation and browning. Photo: Bill Ruff

By Linda Williams, forest health specialist, Woodruff. Linda.Williams@wisconsin.gov; 715-356-5211 x232

Recently, several reports of evergreens turning brown have come in from around the state. Spruce trees seem to be the most commonly reported species, as well as being the most severely impacted. We’re also seeing this on white pine, balsam fir, and white cedar, with some areas more heavily impacted than others. Forest health specialists in northeast, central, and southern Wisconsin have received many reports, with reports being submitted in other areas of the state as well. This appears to be a widespread problem: a recent article from the Minnesota Department of Natural Resources’ Forest Health unit outlined the same issue. Continue reading “Browning on spruce and other conifers due to winter drying”

White pine blister rust

On this white pine, you can see on the lower left a branch recently killed by blister rust; on the lower right is a branch that is slightly off-color. The off-color branch also had a canker but it had not yet completely girdled the branch.

On this white pine, you can see on the lower left a branch recently killed by blister rust; on the lower right is a branch that is slightly off-color. The off-color branch also had a canker but it had not yet completely girdled the branch. Photo: Linda Williams

By Linda Williams, forest health specialist, Woodruff. Linda.Williams@wisconsin.gov; 715-356-5211 x232

White pine blister rust is a fungus that causes cankers on white pine. The cankers can girdle and kill branches or the main stem of the tree. White pine blister rust infections create “dead spots” or cankers that continue to expand each year on the branches or main stem. Eventually, orange pustules develop which erupt around the edges of the canker; this is how the fungus reproduces. Continue reading “White pine blister rust”

White pine weevil – old and new damage

By Linda Williams, forest health specialist, Woodruff. Linda.Williams@wisconsin.gov; 715-356-5211 x232

The terminal leader of this young white pine was killed by white pine weevil.

The terminal leader of this young white pine was killed by white pine weevil. Photo: Linda Williams

White pine weevil is an insect that can attack and kill the terminal leader on white pine, jack pine, and spruce trees. Terminal leaders killed last year may remain on the tree until spring, although they commonly break off during winter. Adult weevils are now out laying eggs on terminal leaders, just below the expanding buds. After the eggs hatch, the larvae will bore just under the bark of the terminal and feed, moving downward as they progress. As buds expand this spring, they will quickly run out of water and food due to damage caused by larval feeding, and the terminal leader will begin to wilt, curl, and die. Continue reading “White pine weevil – old and new damage”

Porcupine and squirrel damage on trees

By Linda Williams, forest health specialist (Woodruff). Linda.Williams@wisconsin.gov; 715-356-5211, x232

During winter and early spring, damage to trees caused by porcupines and squirrels is evident in some areas. As spring arrives, new green leaves will mask the destruction.

This red pine had the bark stripped off it by a porcupine, which has wider incisors than a squirrel.

This red pine had the bark stripped off it by a porcupine, which has wider incisors than a squirrel.

Porcupine and squirrels feed on the bark of trees, stripping it from branches and main stems. Stripping bark can girdle trees, resulting in branch dieback which shows up the year following the damage. If the branch isn’t completely girdled, it will start to grow callus tissue over damaged areas in an attempt to recover.

This maple bark was eaten by a squirrel. You can see where the tiny incisors scraped the bark down to the wood.

This maple bark was eaten by a squirrel. You can see where the tiny incisors scraped the bark down to the wood.

Both porcupines and squirrels feed on bark in the crowns of trees, so how can you tell which one is doing the damage if you don’t catch them in the act? The size of the teeth marks left in the wood is one clue. A gray squirrel’s incisors leave marks between 1.3 to 1.7 mm wide, while a porcupine’s teeth marks are nearly triple that, from 3.6 to 4.8 mm wide. You should also consider the species of tree being debarked: squirrels prefer maples while porcupines will feed on oak, pine, maple, and even spruce, as well as other species.

Rabbits, mice, and voles can cause similar damage to that caused by squirrels and porcupines, but damage will be located near the base of the tree instead of in the crown.

Another type of tree damage seen in late spring is when squirrels clip 4 to 6 inches off the tips of spruce branches, apparently to consume tasty buds. They drop the remainder of the branches to the forest floor, leaving a carpet of branch tips under spruce trees. I have yet to observe squirrels doing this, but the carpet of branch tips they leave prompts calls from concerned landowners each spring.

Spruce branch tips litter the ground where squirrels dropped them after clipping them from the tree. Although it can look alarming it rarely does enough damage to affect the overall health of the tree.

Spruce branch tips litter the ground where squirrels dropped them after clipping them from the tree. Although it can look alarming it rarely does enough damage to affect the overall health of the tree.

UW Extension offers a brochure about squirrels, including control options to share with landowners having trouble with these critters.