Shade Tree Advocate - Winter 2010

ADVOCATE • Winter 2010 11

The Minnesota Shade Tree Advisory Committee’s mission is to advance Minnesota’s commitment to the health, care, and future of all community forests.

Inside ThIs Issue2 The Year of emerald Ash Borer

4 Measuring Canopy Cover

6 Turning Over the umbrella

9 Mystery Tree

12 Winter Damage to Trees and shrubs

15 Board Member Bio

16 Arbor Month

Visit MnSTAC on the Web at www.mnstac.org

COMMUNITY FOREST PROFILE

VOl. 12, NO. 1

TBy Kathleen Preece and Jerry Stensing

his is a story about partnerships. And it’s about a lot of the details that go into

making Minnesota—Minnesota.

It’s about planting red and white pine trees, and maples, aspens, and oaks. And it’s about generous people like Jack Strowbridge who donated trees, and foresters like Jerry Stensing who walked the extra mile (and planted the extra tree). And it’s about the students in the J.W. Smith Elementary School of Beltrami County’s Independent School District #31 who took part in the creation of the Minnesota Biomes Project, right in their Beltrami County located school’s back yard.

Okay, let’s begin with Chapter 1 of the story of the Bemidji Biome Project. The setting is J.W. Smith Elementary, a 300-body student population, and one of six public elementary schools serving the Bemidji area. J.W. Smith is located in a highly urbanized setting just north of downtown Bemidji, adjacent to resi-dential and light commercial zoning, and a few blocks to the west of the Bemidji State University campus which—all combined—results in very limited opportunities for a child’s first-hand contact with nature.

Chapter Two (and Three and Four and Five…): Enter character Jerry Stensing. As

a forester with the Beltrami Soil and Water Conservation District (SWCD), Jerry knows trees, and really likes young people. Jerry dreamed of a project whose purpose was to provide increased environmental science opportunities to the J.W. Smith school’s students. His plan? Create an outdoor classroom—but not just any classroom. This one would be shaped as the state of Minnesota, with trails that followed major river courses and forest cover that geo graph ically represented the vege-tation of Minnesota’s biomes. The Minnesota Biomes Project would enhance environmental education by creating a representation of Minnesota’s forests and prairie lands.

As the story unfolded, the restoration included vegetative representation of Ontario, Manitoba, Wisconsin, Iowa,

Where Biomes Gather… continued on p. 10

Minnesota Biomes Project Let All Biomes Gather in One Community

Winter 2010 • ADVOCATE22

W

Figure 2

Figure 1

uRBAN FOResT heALTh

e knew it was coming. We just didn’t know when. Many of us in state and federal

agencies were hoping that a few more years would elapse before we had to engage our emerald ash borer (EAB) response plans.

EAB was found in Minnesota when our “backs were turned.” Here’s what happened: On April 6, an EAB infestation was discovered in Victory, Wisconsin, across the Mississippi River from the corner of southeast Minnesota bluff country (Fig. 1). All attention turned to Houston County, where

EAB surveys were being conducted, traps and trap trees were being set up, quar-antine regulations were being planned, news releases were being created and inter-agency relationships were being forged.

A few weeks later on May 13, an EAB population was found in St. Paul when a tree care worker was doing some routine tree inspections. He noticed a symptom of EAB in an ash tree: a thinning crown. When he peeled back the bark, he saw characteristic S-shaped galleries, and contacted the Minnesota Department of Agriculture (MDA) with his find. EAB was discovered when we least expected it, but not where we least expected it; according to a risk map produced by

MDA in 2003, the Twin Cities area had a very high risk of EAB introduction (Fig. 2).

The day after the St. Paul discovery, a quaran-tine was enacted in the Twin Cities’ counties of Hennepin and Ramsey (Fig. 3). In an intensive, short-duration delimiting survey of the discov-ery area of St. Anthony Park in St. Paul (Fig. 4), 68 ash trees were found to be infested and were

2009: The Year of Emerald Ash Borer

Figure 3

Source: Minnesota Department of Agriculture

Source: Minnesota Department of AgricultureSource: Minnesota Department of Agriculture


subsequently removed and chipped by the City of St. Paul and brought to St. Paul’s District Energy for incineration. Twenty suspect trees were girdled (stripped of trunk bark) near the infestation to attract any adult EAB in the area. The suspect trees were removed in the fall; some of these trees were found to be infested as well.

The Minnesota Department of Agriculture and agency partners deployed nearly 700 purple panel traps within a 4-mile radius of the discovery, which captured only four EAB adults between the end of May and October. One of the adults was found in a trap a ½-mile from the discovery site, and two were found on one trap 1 mile north of the site, on the St. Paul campus of the University of Minnesota.

Results from dendrochronological studies of EAB-infested trees indicate that the St. Paul infes-tation dates back to 2006, making this one of the quickest discoveries of an EAB infestation.

An Incident Command System was initiated to facilitate communication about EAB events, outreach, and planning, with unified command representatives from the Minnesota Department of Natural Resources (DNR), the MDA, and USDA APHIS Plant Protection and Quarantine.

The state has developed a readiness plan to mini-mize the impact of emerald ash borer in the state of Minnesota and specific to urban and rural

forests, the econ-omy, citizens, and natural resources. Planning and detection plans have been developed collab-oratively by the MDA, DNR, and University of Minnesota. Through the foresight and collective approach of these agencies, strate-gies have been outlined as to the “who does

what” as Minnesota deals with both the pend-ing and realized threats of EAB across its forests. The DNR is currently developing guidelines for forest managers, for ash utilization, and black ash management.

Ash makes up 50 percent of the lowland hard-wood forest cover type in Minnesota, and Minnesota has the third highest volume of ash in the U.S. Based on a survey in 2006, there are over 3 million ash trees that are publicly owned in municipalities across the state.

The DNR is continuing its efforts to limit introductions of exotic forest pests onto state-administered lands by enforcing recent firewood legislation. Firewood from over 900 vendors has been approved by DNR-Forestry for use in Minnesota State Parks. Since EAB was found inside Minnesota and three counties are now quarantined, additional firewood vendor restrictions were added in 2009: all hardwood firewood from quarantined counties or their bordering counties can only be used in those counties. Public outreach campaigns continue.

Figure 4

Source: Minnesota Department of Agriculture

“Have you missed us? No, you are not losing your mind! You did lose two issues of the Advocate. That emerald green bug has tripped us up and grabbed all of our attention. However, we are back on track to face EAB, AND to keep the Shade Tree Advocate coming to your mailboxes!”


uRBAN FOResT heALTh

any U.S. cities are turning to canopy assessments to

identify areas that need more tree cover. Aerial photographs or satel-lite images provide the perspective needed to determine how much of the city is currently covered by tree canopy (see figure 1). The results are then used as a basis for setting an urban tree canopy goal, either for the entire city or for individual sections of the city.

There are many different ways to analyze tree canopy and deter-mine realistic goals. The approach described below was developed by the U.S. Forest Service, University of Vermont, and several state forestry agencies. There are five basic steps:

1) Complete an urban tree canopy assessment to determine how much canopy cover currently exists and where there are opportunities for more,

2) set a goal to increase canopy cover based on the assessment,

3) create a plan to achieve the goal, 4) implement the plan; and 5) evaluate successes and challenges, adjusting

the plan as necessary to meet the goal.

Most communities will need help with the first step, the assessment. But the other parts of the process can be completed internally if there is an urban forester on staff. The details of each step are outlined below.

Urban Tree Canopy AssessmentsThe assessment determines how much canopy a community currently has, called “Existing” canopy, how much is “Possible,” and then depend-ing on the specific interests of the community, where canopy is most “Desired.” These assess-ments require high resolution aerial photographs or satellite images and experts called remote sens-ing specialists to analyze them.

The first step is for the specialist to create a land cover map from the aerial photographs or satellite images. At a minimum, the final map should show where existing tree canopy is located. But it is very helpful if the pavement, grass/shrubs, and water are also identified (see figure 2). Once the existing canopy is mapped, the next step is to determine where it’s possible to add canopy. Because trees cannot be planted on top of build-ings, in the middle of roads, or in water, these areas are blocked out. What is left is a map show-ing where it is biophysically possible to plant trees.

The final step involves integrating specific interests of the community. Social and other environmental concerns can be incorporated so increases in canopy cover address multiple issues. For exam-ple, one city wanted to plant trees in low-income neighborhoods. So the map of “Desired Canopy” highlighted those low-income neighborhoods that had the least amount of canopy.

Setting a Canopy GoalThe big question is always, “How much is enough?” Unfortunately there is no clear answer. The national non-profit organization, American Forests, has developed some guidelines from their experience analyzing tree cover in U.S. cities.

Measuring Canopy Cover: What Should My City’s Canopy Cover Be?by Jill Johnson

Jill Johnson is Coordinator, Midwest Center for Urban and Community Forestry, U.S. Forest Service

Figure 1: The tree canopy covers roughly 20% of the total area seen in this photo.

©Me

tropo

litan

Des

ign Ce

nter,

Reg

ents

of th

e Univ

ersit

y of M

innes

ota

M

ADVOCATE • Winter 2010 5Tree Canopy Cover continued on p. 8

These are as follows:• Averagetreecoverfortheentirecity 40%• Suburbanresidentialzones 50%• Urbanresidentialzones 25%• Centralbusinessdistricts 15%

These are just guidelines; every community should consider its own needs and set realistic and achievable goals. The canopy cover of U.S. cities completedtodaterangesfrom12%inFrederick,Marylandto39%inBurlington,Vermont.Sodeciding on an acceptable goal depends signifi-cantly on the community’s current situation.

When setting a goal, be specific about the geographic boundaries. Most communities have a city-wide goal, but many have identified sepa-rate goals for different neighborhoods or land use types. The goal should be to increase canopy cover. However, considerations for wide-scale losses due to insect or disease outbreaks should be noted. Specify the timeline for achieving the goal, and be sure that it is endorsed by local officials.

Make a PlanThe plan should include activities that will both protect existing canopy as well as create new canopy by planting. It is difficult to achieve increases in canopy within a 10 to 30 year timeline by planting new trees and ignoring the existing ones. The plan needs to incorporate activities for both. This includes measures to design adequate above- and below-ground growing space for trees, protecting high quality trees already in the landscape, providing quality tree care, and managing the population with

practices that minimize the impacts of storms and insect or disease outbreaks.

Because the greatest potential for increasing canopy often exists on private property, some parts of the plan may include initiatives to fund or assist with private tree planting and regulations for private tree protection. Implementation of the PlanAll action items in the plan should be completed in the given timeframe.

Evaluation and RevisionFinally, it is advised that a subsequent canopy cover assessment be completed every 5-10 years. The follow-up assessment may only need to exam-ine existing canopy to determine how successful the efforts have been and identify necessary changes to the plan (or goal).

Goal Setting in MinnesotaThe cities of Woodbury and Minneapolis have recently received grant funds to set Urban Tree Canopy goals. Both are working with the University of Minnesota‘s remote sensing special-ists for the analysis.

Canopy Cover Assessments versus Tree InventoriesTree canopy assessments should not replace community tree inventories. Their purposes and value are different. A public tree inventory provides information about the species, size, condition, and maintenance needs of individual

Figure 2: Land Cover

Canopy

Grass/Shrubs

Impervious(roofs and pavement)


eelings of foolishness flooded over me. Unpacking my umbrella, I overheard the

local weather man make reference to the ongo-ing drought. The low flow faucet and showerhead, disposable plastic cups, and instruction card on reusing towels were all water saving measures implemented by the hotel.

How could I have forgotten? Out of sight, out of mind, I suppose. I had just arrived in Atlanta for the 2008 Partners in Community Forestry National Conference.

Leveraging trees as stormwater management tools increases their value, building on the “Trees Pay Us Back” program completed by the USDA Forest Service. Maximizing their value by leveraging trees to the greatest extent practicable, and with a focus on stormwater applications, was a primary topic of the concurrent (education) session that I, along with colleagues Janette Monear (Texas Trees Foundation) and Randy Neprash (Bonestroo), presented.

While flying in, I studied the urban forest canopy, or the lack thereof. I recalled a Wall Street Journal article, “Loss of Trees Compounds Pollution in Cities” that claimed a temperature increase of 5 to 8 degrees in Atlanta apparently followed decades of development that had “…bulldozed wooded areas.”

Could the loss of trees (and natural watersheds) be responsible, at least in part, for the drought? Given the extent of development, how could the urban tree canopy be expanded to act as, and provide the benefits of green infrastructure? The severity of the drought underscored the need for change. It highlighted the need for green infra-structure and especially for partnering trees and stormwater. Over the next three days, I would find answers to these and other questions as a broad based group gathered to identify ways to work in partnership for community forestry.

Trees as Green InfrastructureThe conference theme: promoting trees as green infrastructure while building healthier, livable commu-nities, was apparent from the opening general

session. “Greening of our Nation’s Urban Places” was presented by Dan Burden, a nationally recog-nized authority on bicycle and pedestrian facilities and programs—who, incidentally, earned a B.S. in Forestry at the University of Montana.

He straightforwardly walked us through what makes a livable and ‘walkable’ community and the vital role trees play. Trees contribute heart-ily, providing benefits ranging from economic, environmental, and social. Creating the backbone of green infrastructure, trees can, and should, be integrated with gray infrastructure. The City of Red Wing has accomplished this with its compre-hensive Asset Management Plan. This innovative program is providing the city with new perspec-tive on the value of, and a renewed commitment to its public trees. This allows it to prioritize and facilitate improvements for its trees, such as incor-porating stormwater.

Turning the Umbrella Upside DownSo what does it mean to integrate trees and storm-water? My otherwise useless umbrella will help illustrate. Right side up, its function is similar to traditional stormwater (gray) infrastructure. It directs water away. In this scenario water is considered a liability and efficiently removed.

Let’s turn the umbrella upside down. It now captures water and directs it toward the center. A tree and stormwater BMP functions as the latter. It captures, directs, and stores rainwater above or below grade for use by trees. Through filtra-tion and infiltration it also prevents rainwater from immediately leaving the site.

Stormwater management seeks to achieve inter-ception (rate control), evapotranspiration (quantity control), filtration (quality), and infiltration (recharge). And integrated tree and stormwater BMPs, when properly designed and installed, can achieve all four.

Trees–and Stormwater–Pay Us Back as Existing Vertical RaingardensTrees, especially large canopy trees, transpire far more water than a traditional rain garden. Due to their unique relationship to the ground plane,

Turning Over the Umbrella: The Role of Trees in Storm Water ManagementBy Loren W. Culver

F

ADVOCATE • Winter 2010 7Continued on next page

trees can be used where rain gardens cannot (i.e., parking lots, along streets, etc.) In general, as compared to traditional rain gardens, trees live longer and costs for maintenance and replacement are less, giving them a supreme advantage.

Leveraging trees as stormwater management tools is a simple concept. It increases their value, build-ing on the “Trees Pay Us Back” program completed by the USDA Forest Service. Maximizing their value by leveraging trees to the greatest extent practicable, and with a focus on stormwater appli-cations, was a primary topic of the concurrent (education) session that I, along with colleagues Janette Monear and Randy Neprash presented.

The concept is simple. Use trees as vertical rain-gardens. Implementing it can be a bit more difficult. Generally, as urban density increases, so too does the design’s complexity. However, the resulting benefits increase exponentially and trees more completely pay us back and in several ways not fully realized initially. First, supple-mental water can be significantly reduced or eliminated as well as the associated costs. Second, trees will have a better chance of establishment and survival. Third, and of growing significance, stormwater fees can be vastly reduced or elimi-nated entirely using a smartly designed system. The advantages will increase dramatically over time as water and stormwater fees reflect true costs. Eventually, equilibrium will be reached between implementing tree and stormwater BMPs and the resulting cost savings.

An Important Partnership–Trees and StormwaterThere was an abundance of informa-tion about the important partnership between trees and stormwater at the conference. The case for “Connecting Trees to Water Quality and Stormwater Management” (also the session’s title), was made by Vincent Cotrone, an urban forester with Penn State Cooperative Extension. He discussed the role of trees and forests in healthy watersheds and how they manage stormwater, reduce flooding, and improve water quality.

It also stands to reason that healthy watersheds contain healthy trees. In “Advanced Green Infra structure in Compact Green Developments,” Dan Staley, an

urban planner from Aurora, Colorado, discussed prioritizing code to allow/capture comprehensive sustainable benefits. We have been so successful in building what we thought to be highly efficient systems that we now need to engineer trees back into the urban fabric and our lives.

Integrating trees and stormwater BMPs provide effective sustainable solutions that are mutually beneficial to trees and in meeting many stormwa-ter requirements—done either through preserving existing trees and tree stands or innovative design solutions.

Managing Stormwater for Urban Sustainability Using Trees and Structural Soils is a synthesis of research by Virginia Tech, Cornell University, and the University of California Davis. It presents a new space-saving infiltration BMP that mitigates runoff using pervious surfaces and structured soils, and one that could benefit Atlanta’s parched trees.

Combating Global Climate Change–One Tree at a TimeLarger Opportunities to Use Trees In “Our Evolving Understanding of Climate Change and Weather,” Stu Ostro from The Weather Channel presented ongoing research indicating how global warming is responsible for unpredictable weather patterns. Urban forests and tree planting are a strong part of the solution to global climate change. Sustainable expansion of the urban forest canopy can assist in mitigating increasingly erratic weather conditions.

Figure: Virginia Tech College of Natural Resources, Susan Day


trees—information critical for managing the population.

ChallengesThere are a few challenges associated with canopy goals. First is the cost of obtaining high-quality imagery. Second is the cost of hiring specialists to analyze the imagery. Third is that most of the opportunities for increasing canopy cover exist on private property. And finally, it is difficult to ascer-tain the difference between high and low quality tree canopy. For example, the widespread tree

cover in a park may be buckthorn. It is impera-tive that any community considering an urban tree canopy goal understand these challenges and limitations.

Where to Get More InformationTo learn more about measuring urban tree canopy or view reports from communities who have set goals, visit the U.S. Forest Service Web site at www.nrs.fs.fed.us/urban/utc.

Or visit the American Forests’ Web site at: www.americanforests.org/resources/urbanforests/treedeficit.php.

Measuring Canopy Cover continued from p. 5

Turning Over the Umbrella continued from p. 7

During a media panel we also learned how Atlanta’s prolonged drought had unexpectedconsequences. Sudden tree drop was a current symptom and had recently claimed a victim. To prevent the resulting dendrophobia from spread-ing like wildfire, local foresters had to perform the combined roles of spokesperson and therapist to assuage fears. As the voice of reason, they were required to instantaneously respond and provide relevant information to prevent clear cutting of the urban forest. Lessons learned? First, always be prepared to advocate for trees!

Second, sustaining trees with rainwater through integrated stormwater BMPs makes sense–small quantities of water take on increased importance during times of drought.

Community Trees–Expanding PartnershipsDeveloping and maintaining effective partnerships are critical to expanding the reach of commu-nity forestry. Conference social events, informal breaks, and the product expo provided ideal networking opportunities to discuss and explore partnerships among diverse professionals. These partnerships are key to identifying mutually bene-ficial goals and possible funding opportunities among agencies along with facilitating the imple-mentation of innovative programs.

Partners in Community Forestry was an extremely well organized conference presented by The Home Depot Foundation and Arbor Day

Foundation. For information about this years conference consult the Arbor Day Foundations website for updates.

Useful links for additional information:• PartnersInCommunityForestryNational

Conference–Photos and Presentations 2008 http://www.arborday.org/shopping/conferences/photos/pcf/2008/

• BeltLine:AtlantaConnectedwww.BeltLine.org• Trees Atlanta www.treesatlanta.org• Managing Stormwater for Urban Sustainability

Using Trees and Structural Soils http://www.cnr.vt.edu/urbanforestry/stormwater/

• DanBurden’sWalkable Communities website; For “22 Benefits of Urban Street Trees” go to www.walkable.org click on resources, then articles

• RedWingAssetManagementPlan:http://www.red-wing.org/images/content/files/departments/planning/openspace.pdf

Lorin Culver is a LEED AP and Landscape Architect licensed in MN and CA. He has worked on projects with a national scope. As the recently selected National Park Foundation Transportation Scholar, he is helping to develop an Alternative Transportation Plan for the Mississippi National River and Recreation Area within the Twin Cities. His professional profile can be viewed at: www.linkedin/in/lorinculver He can be reached at [email protected]

Answer on p. 14


Mys

tery

Tre

e...

by Kathleen Preece

This shrub or small tree (up to 5 meters in height) has some very distinct and unique characteristics. Its leaves are opposite, compound with three leaflets with serrated/fine-toothed edges. The branches of older trees/shrubs have bark that is streaked with white.

In the spring, small, pendant white flowers are produced. They mature to highly-distinctive, inflated, papery capsules containing several large seeds. At maturity, the capsules can be induced to “rattle” by shaking the fruit. The capsules themselves are relatively large, ranging from 1 to 2 inches in length.

Flowers are clustered at the end of twigs and appear in April–May, with fruits maturing mid-August through September.

In summary, your clues are the following: drooping clusters of cream, bell-shaped flowers; attractive, dark-green, trifoliate leaves; greenish bark textured with white cracks; and interesting fruit. The fruit, which changes from green to yellow to brown, is a three-chambered bladder.

(PS) Speak French? Here’s a real clue: Staphylier à trois folioles

Kathleen Preece is a writer in natural resource communications.

Phot

o: St

even

J. B

aska

uf

Bark Fruit

Leaves

Phot

o: St

even

J. B

aska

ufPh

oto:

Stev

en J.

Bas

kauf


Kathleen Preece is a writer in

natural resource communications; Jerry Stensing is

a forester with the Bemidji

Soil and Water Conservation

District

North and South Dakota. Handicap accessible trails are planned to follow the major river courses of Minnesota and provide access to each biome. The site covers almost 61,000 square feet.

According to Jerry, it is a “coming together place,” where tree orphans from new development sites have been collected and saved along with the diversity in shrubs and ground covers. Trees were inspected for insect and disease before coming to the site, and were selected by form and quality. For every tree selected, two other candidates were rejected. One pine site was completely rejected due to the discovery of an emerging needle blight tree health issue. A private landowner came to the rescue and donated eight trees needed to fulfill the plan for the biome.

Within moments of completing installation of the first 20 trees, the SWCD received word that the City of Bemidji and Menard Inc., had final-ized negotiations to use the project for off-site tree replacement to fulfill tree mitigation requirements on a proposed building site for a new Menards in the community. (The City of Bemidji Tree Ordinance requires replacement trees to offset tree removal impacts on commercial construction sites.

Designed in the shape of Minnesota and surround-ing states and provinces, it contains primary representations of natural landscapes in geographi-cally correct placement. The unique capacities of the SWCD to bring together multiple partners and provide planning and implementation was the foundation for the growing of this Minnesota biome. Funding came from multiple sources that included public, private and corporate contributions.

The SWCD will provide 2 years of maintenance to ensure the biomes have ‘taken’ to their Minnesota locations next to J.W. Smith.

This is a story of partnerships and bringing together available resources to build a living classroom that reflects both simple and complex interactions within the natural environment. The legacy created will last for generations and provides an outdoor learn-ing experience for students and the community’s residents. Additionally, the completed project will integrate solutions to site-specific environmental issues such as storm water management, green space, and bio-diversity.

Jerry points out that—thanks to the integration of stakeholders, including community, educational system, private landowners, county government, and civic groups—the Bemidji Biome Project might be called “community-urban forest management at its best.”

The story is still being written. The trees were installed during the fall of 2008, with storm water survey and detailed topographic mapping completed in the fall of 2009. Design and engi-neering of a storm water bio-retention system is scheduled for construction during 2010. And then there’s the prairie chapter to write.

“Flying into Bemidji?” Jerry asks. “Look down as the airplane makes its approach. You will see all of Minnesota: a land of prairies, red and white pines, maples, aspens, and oaks.” When you’ve landed and you want to walk among all the biomes of Minnesota, find Jerry at www.beltramiswcd.org. He will have a few more chapters written, and will tell you more about the main characters (and maybe even what the sequel is).

• IndependentSchoolDistrict#31—Vision,Support,andBiomesGrant

• JointPlanningBoard—BemidjiTreeOrdinance

• CityofBemidji—SupportandAssistance

• BemidjiRegionalAirport—TreeDonations

• JackStrowbridge—TreeDonations

• BeltramiCountyandMinnesotaDNR—SuppliesDonations

• MinnesotaDepartmentofAgriculture—TreeHealthConsultation

• MenardInc.—FinancialContributionandTreeDonations

• BeltramiSWCD—FinancialContribution

• USDANaturalResourcesConservationService—TechnicalAssistance

• BemidjiAviationInc.—As-builtPhotoFlight

• CollinsOakgrove—TraditionalBlessings

The Bemidji Biomes Partners

Where Biomes Gather from on p. 1


Collins Oakgrove, an educator for over 30 years, is a Red Lake Band of Chippewa Tribal Elder/Spiritual Leader. He provides a traditional spiritual blessing at the site of the first tree. Forester Jerry Stensing lights the match.

Northland Tree Service uses the 80-inch tree spade to install the first of 145 trees. Here, Northland is bringing in a nice red oak.

“And, on the second day, the birds returned.”

—Jerry Stensing

Aerial photo of the biomes in January 2009.

Jamie is a student from an area school whose curiosity, interest, and inquisitiveness fostered a friendship with the tree planting crew. Jamie showed up regularly to the delight of the field and planning crews.

Students began using the outdoor classroom, even as construction was underway.

Minnesota Biomes tree locations as built November 2008.

Phot

o: Je

rry St

ensin

g

Phot

o: Je

rry St

ensin

g

Phot

o: R

uth

Trask

Phot

o: Je

rry St

ensin

g

Phot

o: Je

rry St

ensin

g

Phot

o: Je

rry St

ensin

g


Most plants that chronically suffer winter damage and die are usually health stressed plants that would have died from something else. Keeping trees and shrubs healthy enough to survive the stresses of winter usually moder-ates the exact type of damage when possible.

Types of winter damage. Winter damage usually falls into one of four major categories: mechanical, desiccation, cold temperatures, or chemical injury.

Mechanical damage is usually the most common and includes animal feeding damage, heavy snow and ice loads that break branches, and snow blower or plow damage. Preventing or mitigating mechanical damage relies on some sort of physical protection, either for the tree trunk or the buds and twigs. Stem protectors that soften the blow of ice and gravel from snow blow-ers can be as simple as corrugated plastic stem protectors. If the winter damage is primarily from animals, protec-tion needs to be more exclusionary, such as hardware cloth.

Desiccation (drying of living tissues) damage occurs very commonly on plants that have evergreen foliage or large buds. The drying winter winds on fully exposed landscape sites constantly dry out evergreen foliage tissues and large flower buds, especially on more sensi-tive evergreens (yews, arborvitae, hemlock). Desiccation may also happen to plants exposed to the bright southern sun of winter that warms

up buds and foliage, causing the tissues to lose too much moisture as they transpire.

Most desiccation injury doesn’t kill plants, but it often makes you wish they would die. Most commonly, the evergreen foli-age “scorches” or turns brown from the lack of moisture, but is replaced by new needles during the following growing season.

Cold temperatures do occasionally cause damage. True frost cracks (cracks through the wood of a stem) are partially due to cold temperatures. Unusually early autumn frosts and unusually late spring frosts can kill plant tissues either before or after they are safely in full dormancy. Plants that are hardy to -30° F temperatures when they are fully dormant can be damaged by temperatures as “warm” as 25° F when they are not dormant. Severe cold temperatures can go beyond the scorched foliage damage from desiccation injury and actually kill buds and branches, and this type of damage is difficult to prevent. Choosing plants

Winter Damage to Trees and Shrubs—It’s Much More Than Cold Temperatures

FOResT heALTh

Figure 2: “Scorched” or desiccated foliage such as this will be replaced by new needles during the next growing season… as long as the buds are still alive and healthy.

Figure 3: Frost cracks extend into the trunk of trees and are the beginning of internal decay in many cases. This is a cross-section of a tree with a frost crack that extended up 20 feet from the ground. Within a few years, the tree would have been removed due to extensive decay.

By Gary Johnson, Department of Forest Resources, University of Minnesota

Phot

o: G

ary J

ohns

on

Phot

o: G

ary J

ohns

on

Figure 1: Crabapple stem girdled by rabbit feeding off the bark.

Phot

o: D

ave H

anso

n


that in a healthy state can tolerate extremely low temperatures is the only “fail-safe” way of moderating extremely cold temperature damage.

Frost cracks can be minimized, however. True, one of the ingredients for damage is cold temperatures, but two other factors must be present for frost cracks to become common… otherwise, every tree would frost crack. The second factor that encourages frost cracks is the presence of a wound on the stem. Avoid stem wounding and frost crack frequency will be lessened. Finally, trees entering winter in a water-stressed condition will be more prone to frost cracks. Water trees regularly until the ground freezes, mulch over the root system to keep the soil moist, avoid or minimize any wounds to the stem and frost cracking will be kept to a minimum.

Finally, chemical injury from deicing salt spray drift or run-off may be the defining damage to plants. Plants within 60 feet of a busy high-way or street are most at-risk to this type of damage. Most of the time, salt spray damages foliage and buds, disfiguring the plant but not killing it. Salt run-off that accumulates in the soil can become very toxic and eventually kill plants. Avoid these “kill-zone” areas completely or only use highly tolerant plants, such as

Figure 5: Deicing salt run-off from this parking lot killed all of this grass. Imagine the fate of trees whose root systems would be in this “kill zone.”

Phot

o: D

ave H

anso

n

Figure 4: Spray salt has accumulated on the needles of this pine and will cause them to turn brown and die. Unsightly, but rarely does it kill the tree.

Four “Easy Steps” to minimize winter damage:

1. Keep plants healthy, especially well-watered until the ground freezes. Moist soil freezes slower and stays warmer than dry soil.

2. Mechanical injury requires physical protection: hardware cloth, snow fencing, deer netting.

3. Rely on mulch rather than snow. Four inches of organic mulch is as effective as a good snow cover for keeping soil warmer and roots healthy.

4. Don’t plant closer than 60 feet from highways and 30 feet from streets that use a lot of deicing salt.

honeylocust or Black Hill’s spruce in areas that receive spray or run-off salt. Occasionally, if there is enough space, a snow fence placed between the road and the plant materials can minimize the damage from spray salt drift, but there needs to be at least 20 feet of clear-ance between the 4-foot tall snow fence and the plants for it to be effective.

Phot

o: G

ary J

ohns

on


Thinking of Spring?Think of energy conservation planting strategies

Mystery Tree Answer: Bladdernut Staphylea trifolia

West is bestShade west and east windows to most effectively reduce air conditioning use:

• Givehighestprioritytoplantingshadetreesnext to west windows.

• Planttreesnexttoeastwindowsasasecondpriority.

• Selectatreethatcanbeplantedwithin20feetof a window and will grow at least 10 feet taller than the window.

• Selecttreesthatarestrong,resistanttodisease,pests and dam age from storms; and that will grow vigorously under local site conditions.

• Selectatreewithdensefoliage,asbroadinform as space permits.

Let the sun shine in• Avoidshadingsouthwindows.• Iftreesalreadyexistsouthofwindowsremove

their lower branches to let more winter sun under the limbs.

• Ifyoudowantatreesoutheastorsouthwestof a window: Use a “solar friendly” tree that has moderately dense foliage during the hottest times of the year, loses its leaves early in the fall as the heating season begins, and has sparse winter branches.

Remember: Take advantage of the free solar energy coming in through the south windows in the winter. The worst place to have a tree is in the yard south of a home, since the sun’s angles cause the shadow of the tree to miss the home during the summer months and always fall on the home during the winter months.

The more the merrierMaximize tree canopy cover throughout the neigh-borhood to maximize environmental benefits.

Up and overWhere winters are long and windy, the most valu-able way to reduce annual energy use is to create windbreaks. Tall trees will guide wind up and over an area to a point downwind at least 10 times the height of the windbreak.

Learn more details on these strategies at: http://www.dnr.state.mn.us/treecare/energy/strategies.html

MN D

NR


sTAC INFO & NeWs

For handy up-to-date links to Web sites of interest, be sure to visit www.mnstac.org

About MnsTACThe Minnesota Shade Tree Advisory Committee (MnSTAC) was established in 1974 by a group of concerned citizens to address the health and well being of community forests. MnSTAC is recognized throughout Minnesota and the country for its expertise, advice, coordination, and support for community trees. It is an organization of diverse individuals who represent a broad spectrum of tree-related interests. It fosters and supports local community tree programs across the state so healthy community forests are fully integrated into community development, infrastructure, education, and management.

MnSTAC BoArd of direCTorS

Katie Himanga PresidentSteve Nicholson Vice President, Private Consultants – S&S TreeSteven Shimek MN Dept. of Agriculture Tina Markeson MN Dept. of Transportation Alan Ek University of Minnesota Dave Epperly MN DNR Forestry Jeffrey Gillman Univ. of MN Extension Service Glen Hambleton Tree Care Advisor Kit Richardson Local Tree Board Member – Minneapolis Larry Westerberg Society of American Foresters Steve Roos American Society of Landscape Architects Jim Vaugha MN Society of Arboriculture Dave Kleinhuizen MN Nursery & Landscape Assoc. Barb Spears MN Forestry Association Anne Oldakowski Soil and Water Conservation Districts Craig Johnson League of MN Cities Emily Barbeau City Forester–City of Minnetonka Kameron Kytonen City Forester–City of Andover Dave Auchter Utilities–East Central Power Deborah Karasov Non-profits–Great River Greening John Ingleman MN Corporation–Hutchinson Technologies Stephen Schott Student–University of Minnesota Ron Norenberg Citizen–DNR Region 1 – Park RapidsJames Lemmerman Citizen–DNR Region 2 – Duluth Dave Moehnke Citizen–DNR Region 3 – Rochester

Meet A MnStac V.I.P. Robert “Bob” Fitch

It’s really not fair to categorize folks from “the Dakotas” as coming from a treeless environment that does not foster advocates for a green world. Robert “Bob” Fitch is a shining example of why it isn’t!

Bob grew up in the Sioux Falls/Yankton area of South Dakota. His early career was focused on “words”—as a reporter, writer, and editor. His career path brought him to management of differing non-profit associations, none of which were “green.” That is, until Bob joined up with the Minnesota Nursery and Landscape Association (MNLA) now serving as its executive director.

He admits, “I really have a passion for everything green,” particu-larly as his 13-year tenure with the MNLA grows.

As the state’s oldest and largest green industry trade organization, MNLA (it began in 1925 as the Minnesota Nurserymen’s Association), represents and serves nursery and greenhouse growers, garden centers, irrigation contractors, industry suppliers, and a wide range of landscape professionals. The association aims to help these members operate their businesses more successfully by providing education, networking, legislative and regulatory representation, public relations, and financial benefits through group purchasing, and other member services.

Four full-time, three part-time, and a number of independent contractors handle the core of the association’s work, with over 150 individuals actively volunteering on the MNLA’s 20 active committees.

Education programs and government affairs are the two corner-stones of the association. Bob suggests that a high priority in the months ahead will be finding support for tree removal and replace-ment in light of the pending spread of the emerald ash borer.

“While dealing with EAB is going to be a significant and serious challenge,” Bob attests, “the MNLA’s connection to, and working relationship with the Minnesota Shade Tree Committee will provide a forceful front in facing what lies ahead for Minnesota’s community trees.”

Robert Fitch

Phot

o:

Winter 2010 • ADVOCATE

Presorted Standard

U.S. Postage

PAID

Permit No. 171

St. Paul, MN

Minnesota Shade Tree Advocate

A quarterly newsletter published by the Minnesota Shade Tree Advisory Committee.

Managing Editorial Group: Ken Holman, Gary R. Johnson, Rebecca Koetter, Karl Mueller, Lara Newberger, Jacob Ryg, Stephen Schott, and Mark Stennes.

Editor-in-Chief: Kathleen Preece

Design: Creative Services Unit, MNDNR

Material in this newsletter is not copyrighted. Reproduction for educational purposes is encouraged. Subscriptions are free. Articles, news items, photos, and videos are welcome.

This publication was produced with the support of the USDA Forest Service, Northeastern Area; State and Private Forestry.

Address inquiries to:

Minnesota DNRDivision of Forestry500 Lafayette RoadSt. Paul, MN 55155

Printed on recycled paperusing soy-based inks.

Minnesota Shade Tree Advocate500 Lafayette RoadSt. Paul, MN 55155-4044RETURN SERVICE REQUESTED

ay is Arbor Month in Minnesota and Arbor Day, Friday, April 30,

marks the beginning of an entire month of celebrating trees.

For Arbor Month 2010, the Minnesota Department of Natural Resources has reissued and added content to the 2002 Arbor Month poster titled From Small Seeds Grow Big Dreams. The idea behind this year’s Arbor Month theme is to demonstrate that seeds are packed with everything for a new life.

A packet of red pine seeds will accompany the poster to encourage seed germination experiments and the planting of Minnesota’s state tree.

M

Shade Tree Advocate - Winter 2010

Documents

Transcript of Shade Tree Advocate - Winter 2010