Inside This Issue2 President’s Column

4 Salt, Sand andVegetation

6 Green Economics

7 Urban Forest Survey

11 Living Snow Fences

12 Frost Cracks & Sunscald

14 STAC Info

15 Tree Potpourri

16 Conservationist Award

VOL. 4, NO. 1 • WINTER 2001

1MnSTAC has a NEW WEB ADDRESS! Visit us there at http://www.mnstac.org

Winter

2001◆

The Minnesota Shade TreeAdvisory Committee’s mission is to advance

Minnesota’s commitment to the

health, care and future of all

community forests.

ommunities are growingrapidly and we must lis-

ten to the whispers in thewind, for the voices seem tosay “remember as you grow,please speak for us, the trees.”There are ripples in the waterand the voices seem to say,“remember as you grow, pleasespeak for us, the fishes.” Thereare whispers beneath our feetand the voices seem to say,“remember as you grow, please speak for us, the soil.” As we moveahead into the 21st Century, it is a time for us to step forward andspeak for all of those things that cannot speak for themselves: thetrees, wetlands, prairies, woodlands, rivers and our future generations.But, how do we speak for all the voiceless and keep a balance? How do we grow smart, and what is the role of Community Forestry inSmart Growth?

Community Forestry now is much more integrated than in previ-ous times. In the old days City Foresters just had to deal with treeplanting and maintenance. That is no longer true. Mark Schnobrich,Forester for the City of Hutchinson, says, “Community Forestry is theintegration of people, trees, environment and the continual change ofhow they interact with one another. It used to be about planting trees,removing dead ones and pruning existing ones. It is now a multi-disci-plinary connection of communities and how they perceive their physicalsurroundings: development/greenspace/conservation/infrastructure.Community Forestry has evolved to a point of necessity. It has moved

C

Community ForestrySpeaks for Smart Growth

By Janette Monear

MINN

ESOT

A TR

EE TR

UST

Smart Growth to p. 2

Actively engagingyoung citizens inCommunity Forestrybroadens its base ofsupport.◆ ◆ ◆

UrbanForestHealthSurvey

page 7

Winter 2001 • ADVOCATE2

PRESIDENT’S CORNER

A New BeginningWhen we start a new calendar we look back at

the “old” pages, but we also look ahead-to seewhere the holidays fall and what day of the weekour birthdays falls upon. MnSTAC is 26+ years oldand has had a wonderful life. I am thankful tohave had a part in that history. Many have steppedforward to lead and work for the common goal ofimproving Community Forestry; quite a few formost of the quarter century, some from the begin-ning.

MnSTAC has been recognized for meetingchallenges. Community Forestry continues to offeradditional provocations to our mettle. Natural ene-mies of the forest—DED, OW, Two-Lined ChestnutBorer, ALB, Buckthorn—are familiar and we canrespond with scientific vigor.

It is the political arena that causes us thegreatest difficulties. Here we see funding forMnReleaf dropped. The DNR Community Forestryprogram is proposed to be cut 50%. Forest Servicefunding allocation is reduced so that our own needsare shorted.

What are we doing to meet challenges? We areseeking Legislative assistance, working towardfunding MnReleaf. A Task Force is looking atwhether it may be advisable to seek 501 (c) (3)status as an aid in funding our own needs. We arekeeping up on the Farm Bill process—a “bill” that provides funding for the Forest Service; i.e.Community Forestry.

What’s the “New Beginning”? For me it’s get-ting ready for retirement—cleanup the office, studythe finances, think about after-career activities,etc. For you, if you are not active in MnSTAC, stepup and volunteer your efforts to the cause. Those ofyou who have been carrying the load need to pullin interested/committed individuals that canrelease you from duty when the time comes. Foryour commitment andeffort, I THANK YOU !

Note: Glen Shirley steppeddown from his position asMnSTAC President at theend of 2000. On behalf ofeveryone in the organiza-tion, thank you, Glen. Yourleadership and your many hours of “speaking for the trees” over the years have done much to promotecommunity forestry. We wish you a happy and healthyretirement whenever that time comes, and want you toknow you’re always welcome anytime the “STACers”get together!

Growing greener isgrowing smarter!

COUR

TESY

MN

DNR

MELV

IN B

AUGH

MAN

If we are to “speak for the trees,”

then protection andplanning must include

the trees as well asall our natural

resources.

Smart Growthis an integrated

approach togrowth.◆ ◆ ◆

Community involvementand planning are keys toSmart Growth.◆ ◆ ◆

ADVOCATE • Winter 2001 3

beyond the preconceived notion of being a luxuryin communities. More is still needed, however, ifwe are to make Community Forestry a part ofevery community’s budget and comprehensiveplan.”

It has taken many years for most people tounderstand the role of Community Forestry.Community Forestry is taking care of the greeninfrastructure and helping to incorporate the grayinfrastructure in a way that protects, preservesand enhances our natural environment. The chal-lenge in doing this must and can be met in manyways. The most important are through educationand policy. There is wetland protection policy inplace, but then construction moves to the wood-lands and this makes the woodlands “at risk.”Many communities still do not have tree protec-tion ordinances in their comprehensive plans.Since most developers and builders use the com-prehensive plan1 as their development guidelines,it is necessary to clearly state what can and can-not be done in terms of protection, restoration andreplanting. If we are to “speak for the trees,” thenprotection and planning must include the trees aswell as all our natural resources.

So, how do we reach a balance in CommunityForestry? And how do we help with SmartGrowth?

✔ Put tree protection and preservation inlocal plans and ordinances that set stan-dards for more creative development design.

✔ Implement Best Management Practices2

in woodland areas. The BMP guidebook pro-vides communities with a better understand-ing and appreciation of the economic, socialand environmental benefits of wooded areasand individual trees.

✔ Integrate thinking to include all areas ofconcern. This means that a natural resourceinventory must be done in every communityas well as at the county and/or watershedlevels.

✔ Integrate different groups, agencies andorganizations at the beginning of the plan-ning process so a broad focus is attained andgreater resources are available.

✔ Engage citizens in the planning process andproject implementation. This broadens thebase of support and empowers the public forlong-term community sustainability.

✔ Provide education that integrates thinkingand identifies options for better choices tolink the gray and the green infrastructuresthat make communities desirable places tolive.

✔ Speak out! Speak for the trees, for the treeshave no tongues; speak for the waters eventhough they have a mouth; speak for the soileven though it’s older than dirt; and mostimportantly speak for our future generations!

Tree Trust is one resourcefor promoting Smart Growth. Aprivate non-profit organizationfocused on Community Forestry,it provides educational andhands-on opportunities that foster individual responsibility.Programs like Ecosystem BasedManagement, Best ManagementPractices, EnvironmentalPlanning and Zoning and theSchool Environmental Programprovide information and techni-cal resources to change para-digms that change actions abouthow to grow smart. Integratingcurriculum into school and com-munity education brings a bet-ter understanding about howeverything is interrelated andhow one action affects another. We are but onevoice, an integrated green voice, and a CommunityForestry voice. Together, with your voice andexpertise, we can help Minnesota grow smarter.Growing greener is smarter!

Janette Monear is Director of Outreach at Tree Trust.

1 Results from open forums for smart growth—Creative Development Through Communication,Tree Trust, Minnesota Land Trust and MN Dept.of Natural Resources. Supported by AmericanPlanners Assn., Builders Assn. of Minnesota,Minnesota Dept. of Agriculture and theMinnesota Design Team.2 Conserving Wooded Areas in DevelopingCommunities—Best Management Practices inMinnesota was produced by the MinnesotaDepart-ment of Natural Resources in cooperationwith many organizations. For a copy, call JeanMouelle at DNR: 651/772-7567.

Community Forestry istaking care of the

green infrastructureand helping to

incorporate the grayinfrastructure in a way

that protects, preserves and

enhances our naturalenvironment.

Smart Growth, from p. 1

New TechnologyFascinating tech-

nology is being appliedto solving ice problemson the I-35 bridge overthe Mississippi. A hightraffic area susceptibleto black ice, the bridgeis equipped withrecessed nozzle headsin the deck and a 3,000gallon storage tank.Potassium acetate iscurrently being testedin this system. Whenicy conditions develop,the bridge is de-icedwith its own built-insystem!

MnDOT isconstantlyexploringalternatives for creatingsafer winter road condi-tions. Shown in MnDOTDistrict 1B on Highway53 is a tandem-axlestandard sanding truck. ◆ ◆ ◆

Salt, Sand and Vegetation:Striving for Best Practices

s we moved through the second cold-est and snowiest December onrecord, snowplows and sanding units

were a welcome sight throughout the state.No one questions that public safety must be the priority on icy and snow-packedhighways, but “green” advocates often wonder what the deicing materials aredoing to the vegetation.

Salt and sand are important tools increating safer winter road conditions, butrunoff or spray can affect nearby soil,groundwater and vegetation. Knowledge ofwhich materials to use, how and where toapply them, and matching proper materialsto the road surface temperatures andweather conditions helps minimize environ-mental impact.

Three deicing materials are commonlyused in Minnesota: Sodium chloride (salt),magnesium chloride and calcium chloride.They are effective at different temperaturesand different road conditions. Ideal man-agement would involve using two or threedifferent de-icing materials matched to theconditions. In the real world, however, deci-sions are often based on cost. Because it’srelatively inexpensive (5 cents a gallon forsalt brine and $25 per ton for rock salt) andreadily available, sodium chloride is mostwidely used. Calcium chloride, available asgranules or flakes, is easier on plants andthe environment, but it is also most expen-sive of the three and consequently used

A less. A biodegradable de-icer, potassiumacetate, is highly effective to –50°F, but at$5.00 a gallon, few use it. It is used at MSPairport.

MnDOT and many local communitiesfollow industry recommendations in storageand field use of road salt. But since localsupervisors generally make de-icing deci-sions, many communities (and their vegeta-tion) would benefit from further education.

To limit use of road salt, MnDOT pre-wets the sand/salt mix to help it stick tothe road and stay in place. A salt brinesolution is sprayed on roads before snowand ice arrive to prevent ice buildup onroad surfaces. Many sanding trucks areequipped with electronic road sensors tomonitor the precise temperature of the roadsurface, indicating the optimal sand/saltmix to meet the conditions. An on-going“Salt Solutions” program trains supervisorsand snowplow operators in the most effec-tive and efficient use of salt. MnDOT alsocontinues to experiment with various de-icing methods and alternative chemicals inits commitment to gain best public safetywith minimal environmental impact.

How can we tell if our plants are beinginjured by de-icers? Most salt injury pat-terns follow what we might logically expect:

■ Damage increases as traffic increases.

■ Damage decreases with distance fromthe road (most injury occurs within 60feet of the road).

Winter 2001 • ADVOCATE4

COUR

TESY

MND

OT

ADVOCATE • Winter 2001 5

■ Injury is more severe on the side facing theroad, so plants are often one-sided due tobranch dieback.

■ Branches covered by snow or above thespray-drift zone are less likely to suffer damage.

■ Salt spray penetrates only a short distanceinto dense plants.

■ Plants in sheltered locations generally avoid injury.

■ Plants that are less winter-hardy may beinjured more severely.

■ Plants damaged over several years can losevitality and decline, becoming more vulnera-ble to secondary diseases and insect damage.

■ Spray injury to conifers can be seen in latewinter, but injury to deciduous plants isn’tevident until leaves emerge.

Reducing DamageFor local decision-makers and city foresters,

the following guidelines can help reduce salt dam-age to trees and shrubs in urban areas:

➠ Avoid de-icing salts as much as possible, orreduce quantities by pre-wetting the saltwith a liquid such as salt brine, or by mixingthe salt with abrasives such as sand, cindersand ash.

➠ Improve the structure and drainage of poorlydrained soils. Reduce sodium. Add organicmatter, activated charcoal or gypsum andthoroughly leach the soil.

➠ Protect susceptible plants. Place physicalbarriers made of plastic, burlap or snowfenc-ing between the pavement and the plants.

➠ Avoid planting trees and shrubs in high saltsites, or use only plants sufficiently tolerantof exposure to salt.

➠ Keep plants healthy. Appropriate water,mulch, pruning, soil amendment to correctnutrient deficiencies and control of diseaseand pests help roadside trees and shrubsmaintain the vibrancy they need to resistweakening due to salt injury.

Salt-Tolerant SpeciesAlthough salt-tolerant species are available,

there are relatively few of them. If only tolerantspecies are planted, however, there are few

On Highway 169 near Virginia,MN, a MnDOT sanding truckbattles winter road conditions.This truck has an integratedpre-wetting tailgate tank.◆ ◆ ◆

Salt Tolerance ofSome Common Streetand LandscapeTreesTolerant of bothspray and soil salt

✔ horse chestnut✔ Russian olive✔ white ash✔ ginkgo✔ honey locust✔ Black Hills spruce✔ jack pine✔ white poplar✔ black locust✔ mountain ash✔ Norway maple*✔ Ohio buckeye*(*Evaluations are based on a single parameterand more data is needed.)

Sensitive to salt✗ sugar maple✗ hawthorne✗ Norway spruce✗ Norway pine✗ white pine✗ eastern pin oak✗ yew✗ American linden✗ Canada hemlock

Sensitive to spraysalt, but tolerantof soil salt

~ black walnut~ black cherry~ white oak~ northern red oak

A MnDOT MetroDivision plowtruckwith inbox pre-wet-ting tank restsbetween tasks.◆ ◆ ◆

COUR

TESY

MND

OTCO

URTE

SY M

NDOT

Salt, Sand to p.6

Winter 2001 • ADVOCATE6

Salt, Sand, from p.. 5

opportunities to match tree species with soil characteristics,and the risks increase for a single disease or tree pestdestroying large numbers of trees. No species is completelytolerant of salt injury; even salt tolerant species have limitson the amount of salt they can accept before they weakenand become vulnerable to other problems. Some species cantolerate spray salt, but will not necessarily tolerate soil salt.

Common street and landscape trees tolerant to bothspray and soil salt include horse chestnut, Russian olive,white ash, ginkgo, honey locust, Black Hills spruce, jack pine,white poplar, black locust and mountain ash. Norway mapleand Ohio buckeye are also possibilities, but evaluations ofthese two species are based on a single parameter and moredata is needed.

What are some of the most salt-sensitive species toboth spray and soil salt? You’ll find many of them liningboulevards and roadways in the state: sugar maple,hawthorne, Norway spruce, Norway pine, white pine, east-ern pin oak, yew, American linden and Canada hemlock.While sensitive to spray salt, black walnut, black cherry,white oak and northern red oak can tolerate soil salt rela-tively well.

Information for this article was provided by Paul Walvatne,Minnesota Department of Transportation Office of EnvironmentalServices, St. Paul; by Edward Fleege, Road Weather InformationSystem Project Advisor, located in Duluth; and through excerptsfrom MnDOT printed material and Minnesota Extension Servicepublication FO-1413-S, Minimizing De-Icing Salt Injury toTrees by Gary R. Johnson and Ed Sucoff.

Spring Celebrations and GrSpring Celebrations and GreeneenEconomics: Natural ParEconomics: Natural Par tnerstners

Many communities are well intoplanning spring planting and ArborDay celebrations. Most will involvecivic leaders and school children,park or city staff and local media.

Bruce Bacon, City of RamseyForester and a lead organizer ofRamsey’s Green EnvironmentalExpo (See City of Ramsey, page 10Minnesota Shade Tree Advocate Vol.2, No. 1, Winter ’99), urges commu-nities to go a step farther and createspecific opportunities to involvelocal green businesses and promotetheir economic development.

These local venders are keyplayers in green infrastructuredevelopment throughout the com-munity all year long. Creating part-nerships with them in spring cele-brations builds their visibility,enhances their role as environmen-tal and information resources andgenerates income opportunities.

Ramsey’s Green EnvironmentalExpo, held the Saturday following

Arbor Day each year, includes treeand plant sales. Local vendors setup booths, determine the mix ofproducts, provide planting and careinformation and offer special dis-count prices on selected items. It’s awinning situation for everyone.Stock often sells out, buyers go ontheir way newly enthused aboutplanting and all those trees, bushesand plants become part of Ramsey’sgreen infrastructure.

Bruce believes economic ele-ments are too often omitted fromenvironmental education and com-munity programs. He is excitedabout a proposedreal-life demon-stration projectthat would helpprofessionals andthe public learn toapply ecologicaland green econom-ic stewardship.

The Kunde Company, theMinnesota Historical Society and itsOliver H. Kelley farm near ElkRiver are in the planning and pro-posal stages of creating a CertifiedStewardship Forest at the Kelleyfarm. This sustainable woods man-agement plan would educate visitorsabout site planning, planting trees,native vegetation, management formultiple goals including supplemen-tal income, and sustainable prac-tices with growing examples. Watchfor more information in futureAdvocate issues.

Think Spring!Mark your calendar now and look for-

ward to a fun-filled open house at theMinnesota Historical Society’s Oliver H.Kelley Farm this year! The date isSunday, April 29 from noon to 5 PM.Call 763-441-6896 for more information.

ADVOCATE • Winter 2001 7

The University of Minnesota, Forest Resources Extension Department has been contracted by the U.S.D.A. Forest Service,Midwestern Center for Urban and Community Forestry, to conduct a research and education needs assessment. This surveywill aid in the allocation of technology transfer funds as well as define major areas of research and education for severalyears. Your input is critical. You have the option of accessing and submitting the form on line by visiting:http://www.cnr.umn.edu/FR/extension/survey/survey.htm. If you have any questions concerning the survey please e-mailextfor@forestry.umn.edu or call 612-624-3020. To return the survey please fold into thirds, staple, place a stamp on the out-side, and return to the address on the last page.

1. You are:

❑ Private urban forestry professional ❑ Volunteer

❑ University/agency urban forestry professional ❑ Advocate of urban forestry issues

2. What is your assessment of the general health and condition of the urban forests in your state or city? (Health can bedefined as the general state of vitality, free of insect and disease. Condition can be defined as structural integrity as inlack of decay and pruned regularly. Please rate on a scale of 1-5 with 5 being excellent and 1 being poor.

_____ Health _____ Condition

3. Do you need assistance in the survey, detection, or evaluation of urban forest health and conditionproblems or pests within your state or city? If so, please check all that apply:

❑ Consultants ❑ Training Workshops

❑ Fact Sheets ❑ Color “How To” Publications

❑ Don’t Know ❑ Other (please specify)

4. Is preserving the health and condition of urban forests currently an integral component of the Urban and CommunityForestry programs in your city or state?

❑ Very Integral ❑ Somewhat Integral ❑ Minimally Integral ❑ Don’t Know

5. I interact with the following Urban Forestry clients or partners (O) often, (S) sometimes, (R) rarely, (N) never. Pleaseplace a letter designator before each client category.

_____ State Department of Natural Resources _____ USDA Cooperative Extension Service

_____ State University Staff and Programs _____ Community Groups

_____ USDA Forest Service _____ State and Regional Tree Advisory Councils

_____ International Society of Arboriculture _____ State Department of Agriculture

_____ Nursery/Garden Centers _____ Private Tree Care Companies

_____ Homeowners _____ City Foresters/Parks Personnel

_____ City Planners _____ Landscape Architects

_____ Builders/Developers _____ Emergency Management Contacts

_____ Other – Who?

Urban Forest Health and Condition Needs Assessment Survey

Winter 2001 • ADVOCATE8

6a. How would you rate the following urban forest management practices for preserving the health and condition of yoururban forest/s? Please rate on a scale of 0-5 with 5 being very critical, 1 being rarely critical, and 0 being no opinion.

Tree Health Monitoring: 0 1 2 3 4 5

Disease Management and Control: 0 1 2 3 4 5

Insect Management and Control: 0 1 2 3 4 5

Non-infectious Disorders: 0 1 2 3 4 5(e.g. drought, deicing salt damage, flooding)

Tree Risk Evaluation and Management: 0 1 2 3 4 5

(i.e. likelihood of failure)

Proper Tree Pruning Techniques: 0 1 2 3 4 5

Fertilization Needs: 0 1 2 3 4 5

Watering Needs: 0 1 2 3 4 5

Minimizing Construction Damage: 0 1 2 3 4 5

Site Analysis and Tree Selection: 0 1 2 3 4 5

Natural Disaster Planning and Mitigation: 0 1 2 3 4 5

Identification and Collaboration with Local Groups Concerned with Community Forestry Issues:(e.g. non-governmental organizations) 0 1 2 3 4 5

Funding: Where to get it, How to apply, Tips: 0 1 2 3 4 5

6b. When managing your urban forest, what other factors do you consider besides tree health and condition?

7a. Please indicate if it would be useful to you to receive printed information and/or training in the following long-term treecare/maintenance subject areas. Please rate on a scale of 0-5 with 5 being very useful, 1 being rarely useful, and 0 beingno opinion. Also please indicate whether you would prefer printed information or training.

Tree Health Monitoring: 0 1 2 3 4 5 ❑ Printed information ❑ Training

Disease Management and Control: 0 1 2 3 4 5 ❑ Printed information ❑ Training

Insect Management and Control: 0 1 2 3 4 5 ❑ Printed information ❑ Training

Non-infectious Disorders: 0 1 2 3 4 5 ❑ Printed information ❑ Training(e.g. drought, deicing salt damage, flooding)

Tree Risk Evaluation: 0 1 2 3 4 5 ❑ Printed information ❑ Training(i.e. likelihood of failure)

Proper Tree Pruning Techniques: 0 1 2 3 4 5 ❑ Printed information ❑ Training

Proper Fertilization Techniques: 0 1 2 3 4 5 ❑ Printed information ❑ Training

Proper Watering Techniques: 0 1 2 3 4 5 ❑ Printed information ❑ Training

Minimizing Construction Injury: 0 1 2 3 4 5 ❑ Printed information ❑ Training

Site Analysis and Tree Selection: 0 1 2 3 4 5 ❑ Printed information ❑ Training

Natural Disaster Planning and Mitigation: 0 1 2 3 4 5 ❑ Printed information ❑ Training

ADVOCATE • Winter 2001 9

7b. If you indicated in question 7a that you would like to receive printed information and/or training within a particularsubject area, please list specific topics (e.g. Sycamore anthracnose, cold-hardy trees, Asian long-horned beetle).

8. The following are effective information transfer tools. Please circle the appropriateresponse on a scale of 0-5 with 5 being strongly agree, 1 being strongly disagree and 0 being no opinion.

“How To” Informational Brochures: 0 1 2 3 4 5

Fact Sheets: 0 1 2 3 4 5

Pest Alerts: 0 1 2 3 4 5

Press Releases: 0 1 2 3 4 5

Posters: 0 1 2 3 4 5

Popular Magazine Articles: 0 1 2 3 4 5

Slide Sets: 0 1 2 3 4 5

Reference Handbooks: 0 1 2 3 4 5

Videos: 0 1 2 3 4 5

Internet (computer on-line networks): 0 1 2 3 4 5

Workshops (hands on): 0 1 2 3 4 5

State Conferences: 0 1 2 3 4 5

Regional Conferences: 0 1 2 3 4 5

Other Methods (please specify)

_______________________________________ 0 1 2 3 4 5

_______________________________________ 0 1 2 3 4 5

_______________________________________ 0 1 2 3 4 5

_______________________________________ 0 1 2 3 4 5

9. For information pieces, it is often most effective to produce two versions, one tailored for homeownersand another more technically oriented for professionals. Please check the appropriate response.

❑ strongly agree ❑ agree ❑ no opinion ❑ disagree ❑ strongly disagree

10. When seeking information where do you search? Please rank responses with 1 being the most importantand 5 being the least important.

_____ Websites _____ Local Extension Office

_____ Professional Associations (ISA, NAA, others) _____ Local Forest Service Personnel

_____ Other—Who?

11. There seems to be a growing dependence on the internet for information transfer. If you use the internet regularly pleaselist specific websites you visit to get information or where you refer others to.

12a.Do you feel you are aware of all the places to access information?

❑ Yes ❑ No

12b.If you answered No, what is the most beneficial way for the information to get to you?

13. The last survey of this kind was sent out in 1995. Do you think the quantity and quality of informationavailable has improved and adjusted to changing needs? ❑ Yes ❑ No

Forest Resources Extension Office115 Green Hall1530 Cleveland Ave. NorthSt. Paul, MN 55108

PlaceStampHere

ADVOCATE • Winter 2001 11

iving snow fences are plantings of trees,shrubs, native grasses and sometimes

standing rows of corn that trap blowing anddrifting snow. Strategically placed, these barriershelp keep roadways clear and prevent big driftsthat lead to stranded motorists. But that’s not allthey do.

■ Living snow fences save lives. According to the Federal Emergency

Management Administration, the number onenatural disaster that claims the most lives inMinnesota is winter weather. From 1984 throughthe spring of 2000, 265 motorists were killed onMinnesota roads as a result of snow and blowingsnow. During the decade of 1990 to 2000, in theMankato-Windom area alone, there were 1,411vehicle crashes due to snow, 917 crashes due toblowing snow, and 86 crashes resulting fromcross winds. With living snow fences, driver visibility is improved and vehicle accidents arereduced.

■ Living snow fences savemoney.

According to Standard andPoor’s financial information services, economic disruption ofhaving to shut down the highwaysfor one day in Minnesota would

Living Snow Fences:The NaturalSolution

cost $66 million in lost wages and $27 million inlost sales. Living snow fences help keep roadsopen and reduce shipping delays for goods andservices. They are cost-effective to create, andhelp make better use of public money by reduc-ing the need for plowing.

■ Living snow fences look good. These natural, live-material barriers are

aesthetically pleasing year round. They provide

L

Windbreaks and ShelterbeltsWith the rising energy costs we

are experiencing this winter, manycommunities and homesites across thestate would benefit from having shel-terbelts. In her Energy SavingLandscapes publication dated April1993, DNR’s Peggy Sand states well-placed windbreaks could reduce annu-al fuel bills by up to 10-20%.

Farmers with livestock can tellyou that a farmstead shelterbelt helpsreduce winter feed costs. That’sbecause animals do not have to eat asmuch food to maintain their body heat.The shelterbelts stop the fierce winterwinds and create a more liveable envi-ronment for both humans and animals.

This snow-sweptaerial photo showsa honeysuckleshrub living snowfence protecting aroad and farm (prevailing windsfrom lower left).◆ ◆ ◆

Above: An accident causedby snow.

Left: Mechanical snowremoval can be difficultand costly.◆ ◆ ◆

RON

TABL

ER

DAN

GULL

ICKSO

N

DAN

GULL

ICKSO

N

Living Snow Fence to p. 12

Winter 2001 • ADVOCATE12

Frost Cracks andSunscald: BadWeather or BadManagement?by Dr. Robert W. Miller

e associate frost cracks with coldweather and sunscald with late wintersun damage to the south and south-

west side of trees. Frost cracks split open onvery cold nights, leading us to conclude thatwhen a warm trunk chills rapidly the outsidelayers cool and shrink faster than the insidecreating physical stresses that result in the treecracking open. Likewise we speculate that inlate winter the sun thaws the cambium on thesouth side of trees and rapid cooling at night re-freezes these tissues resulting in their damage.Sounds logical, but if weather is the sole sourceof these problems, then all trees would havecracks and sunscald. There is more to it thanthe weather.

For the past decade I have been teaching acourse titled “Tree Structure and Function”where students and I learn about trees throughdissection. We dissect small parts of trees andlook at them under the microscope, and later inthe term we go to the woods and do the samething to larger parts with a chain saw. We payparticular attention to trees with obviousdefects, including cracks, cavities, decay andsunscald.

Frost CracksHalf of what we say about cracks is true.

They do happen when it gets very cold, veryfast, late at night. We hear them crack and wesee the results. But since most trees do notcrack, there must reasons that some do. Mystudents and I have dissected hundreds of treeswith frost cracks, and we are always able tofollow the crack into an internal defect wherethe problem originates. The defects are many,but generally fall into three categories: trunkinjuries, broken or torn branches and flush

W

Dispel a Myth

visual cues, or land marks, to help drivers find their way.

■ Living snow fences are an environmental-ly sound solution to improve snow manage-ment.

They provide shelter for wildlife, create oxygen,absorb carbon dioxide and help reduce soil erosionfrom wind and water. Less salt, fewer plow and trucktrips and less fuel are required to keep the roadwaysclear.

Mn/DOT, with a $2.5 million grant from FEMAand the participation of landowners and local govern-ments, is increasing its investment in the living snowfence program. By June 2001. between 50 and 60 newliving snow fences will be planted statewide.

The information for this article was provided by DanGullickson, Forester, Minnesota Department ofTransportation Office of Environmental Services. For moreinformation, you can reach Dan at (651) 284-3763 ordan.gullickson@dot.state.mn.us

Above: A farmstead shelterbelt protect-ing livestock.◆ ◆ ◆

Living Snow Fences, from p. 11

Wendell community shelterbelt (prevailingwinds from upper right of photo).◆ ◆ ◆

DAN

GULL

ICKSO

N

DAN

GULL

ICKSO

N

DAN

GULL

ICKSO

N

Below: A new generation shrubliving snow fence

with native grasses.◆ ◆ ◆

ADVOCATE • Winter 2001 13

pruning wounds, all of which havebeen covered with new wood.

As these kinds of injuries closeover with woundwood, the callus tissue making thewoundwood fuses together and seals over the injury.However, areas of structural weakness typically formwhere the woundwood joins together over the injury,and at the edges of the original wound, especially ifthe woundwood rolls over the edge of the wound.Years may pass until all evidence of the injury isburied under new wood. But as the tree warms byday and cools by night, physical stresses start theprocess of splitting the wood from weak areas at theoriginal injury towards the surface. Slowly the crackworks its way to the surface until finally on a coldnight the tree splits open. Sometimes more than onecrack will form from the same injury, one from thecenter and one or more from the edges. Arboristsused to bolt cracks closed, but often this would mere-ly transfer the stress from one area of the trunk toanother, resulting in a new crack at another location.

What can be done about cracks? They can be pre-vented by avoiding trunk injuries and by properpruning. There isn’t much that can be done once theproblem materializes, but the tree should be evaluat-ed for any risk it might pose. A healthy tree with atrunk crack that has compartmentalized the injurywill likely pose little risk, but cracks associated withcavities, decay and/or large branches should be evalu-ated for potential removal, and monitored on anannual basis if the tree is not removed. There are dif-ferences between species relative to their ability tocompartmentalize and the strength of their wood.Likewise, healthy trees compartmentalize better thanunhealthy trees.

SunscaldMy former graduate student Don

Roppolo and I recently completed aresearch project in an attempt to bet-ter understand the source of sun-scald injuries. Scientists and practi-tioners have noted that sunscaldmay be associated with flush prun-ing, trunk and/or root injuries, trans-planting and deep planting. In acooperative project with the City ofMilwaukee Forestry Division, we didall of these to transplanted Norwaymaples in the city nursery and oncity streets. We also planted some ofthe trees following commonly accept-ed procedures. A second phase of this

project involved dissecting and microscopically examiningtrees from the Milwaukee nursery and Johnson’s Nurserywith apparent sunscald injury to determine the source ofthat injury. In both phases of the study we were surprisedby what we found.

Trees in all of our treatments developed sunscald, buttrees planted on city streets and deep-planted trees hadsignificantly fewer sunscald injuries. Of the trees thatdeveloped sunscald, 77% had flat-headed borer(Buprestidae spp.) damage associated with these injuries.The borers attacked the tree at the graft union on thesouth side of the tree, and the sunscald spread upwardone to three feet from the attack site. These borers arenoted for attacking the south side of trees, especiallystressed trees. Trees grown in the nursery are deep-plant-ed to avoid staking, but when out-planted the soil isremoved from the top of the ball and the root collar set atgrade. We speculate that transplanted trees are stressed,and trunk tissue exposed to direct sunlight for the firsttime in several years may be further stressed, making thegraft union an ideal site for borer infestation. Deep-plant-ed trees had no borer damage, and the graft tissue wasburied. This is not to suggest deep planting as a way toavoid borer damage and associated sunscald. Long-termproblems associated with stem girdling roots make deepplanting a poor remedy for managing sunscald.

The trees planted on city streets were watered atplanting and watered by most adjacent property ownersthroughout the first summer, while the trees in the nurs-ery were not ever watered in spite of a prolonged dry peri-od in mid summer. This suggests a relationship betweensunscald and stress, as a primary stress following trans-

Flush-cut pruning (a) sets trees up to develop frost cracks (b). Frost cracks in treesoriginate through injuries, such as trunk wounds, broken or torn branches and flush-cutpruning, that result in internal structural weakness. Physical stresses such as wintercooling complete the process of splitting wood from the weak area to the surface.◆ ◆ ◆

Frost Cracks and Sunscald, to p. 14

RICH

HAU

ER

RICH

HAU

ER

a

b

Sunscald often results from improp-er pruning or establishment-inducedstress. Newly transplanted treesrequire frequent watering during establishment. Water deficits can leavethem susceptible to invasion by borer insects [note flatheaded borer exitholes and larval galleries on so-called sunscald-damaged Norway mapletrees] or canker-forming pathogens such as coral spot nectria canker.◆ ◆ ◆

Winter 2001 • ADVOCATE14

STAC INFO & NEWS

About MnSTACThe Minnesota Shade Tree Advisory

Committee (MnSTAC) was established in 1974by a group of concerned citizens to address thehealth and well being of community forests.MnSTAC is recognized throughout Minnesotaand the country for its expertise, advice, coor-dination and support for community trees. Itis an organization of diverse individuals whorepresent a broad spectrum of tree-relatedinterests. It fosters and supports local commu-nity tree programs across the state so healthycommunity forests are fully integrated intocommunity development, infrastructure, edu-cation and management.

MNSTAC BOARD OF DIRECTORSPresident: Position currently openVice President: Mike Max, EnvironMentor Systems, Inc.

—763/753-5505Kirk Brown, Tree Trust—952/920-9326Ken Holman, DNR Forestry—651/772-7565Gary Johnson, U of M Forest Resources—612/625-3765Janet Larson, consulting arborist—952/941-6876Rich Hauer, MN Dept. of Agriculture—651/296-0592Bob Slater, MN Dept. of Transportation —651/779-5104Mark Stennes, Top Notch Treecare—952/922-3239

Regional MnSTAC CommitteesSoutheast STACChair: Henry Sorensen

651/388-3625 or 651/385-3674Sec./Treas.: Katie Himanga, Heartwood Forestry, Lake City

651/345-4976

Headwaters-Agassiz STAC (HASTAC)Chair: John Johnson

City Forester, City of Thief River Falls 218/681-1835Sec./Treas.: Jeff Edmonds

DNR Forestry, Bemidji 218/755-2891

West Central STACChair: Bob Fogel

Director of Parks, City of Moorhead 218/299-5340Sec./Treas.: Dave Johnson

DNR Forestry, Detroit Lakes 218/847-1596

Northeast STACChair: Kelly Morris

City Forester, City of Grand Rapids 218/326-7600Secretary/Treasurer/Technical Advisor: Dan Jordan

IRRR–Mineland Reclamation 218/254-3369Coordinator: Kathleen Preece

Minnesota BetterFORESTS magazine 218/326-0403 e-mail kathleen@uslink.net.

planting is the inability of a much-reduced root system tomeet water demands of the tree.

Dissection of trees with apparent sunscald yielded unex-pected results. Some specimens with what appeared to besunscald actually had frost cracks with dieback of the cambi-um at the margins of the crack. Subsequent woundwoodgrowing over the dead cambium had the appearance of sun-scald but it was not until these trees were dissected that thesource of the injury became apparent. We were able to tracethe origin of the stem cracks back to improper pruning ofvery young trees in the nursery. Other injuries thatappeared to be sunscald were actually cankers, likely coralspot nectria canker (Nectria cinnabarina). These cankerscommonly attack the cambium after it has been injured orstressed by transplanting.

It appears the primary predisposing factor to sunscald istransplanting stress, especially water stress. It is also evi-dent that what is commonly called sunscald is more complexthan cambial death related to a single causal agent. Borersand cankers are biotic factors that take advantage of stress,resulting in what appears to be sunscald. Likewise stemcracks and associated cambial dieback on young trees givethe appearance of what is called sunscald.

What can the manager do to reduce the incidence ofsunscald? It may be as simple as providing adequate waterthe first growing season after transplanting. Since some ofwhat we call sunscald is really from stem cracks, properpruning in the nursery and after transplanting can reducethis problem as well.

Dr. Robert W. Miller is Professor of Urban Forestry at theUniversity of Wisconsin—Stevens Point.

Frost Cracks andSunscald, from p. 13

RICH

HAU

ER

RICH

HAU

ER

c

d

GARY

JOHN

SON

ADVOCATE • Winter 2001 15

EventsMarch 6-8—Social Issues and

the Environment NationalConference, Lied Confer-ence Center, Nebraska City,NE. Contact National ArborDay Foundation 888/488-7337 or www.arborday.org/socialissues

March 20-21—Shade TreeShort Course, BethelCollege, St. Paul. ContactTracey Benson, U of MN,612/624-3708 or 800/367-5363.

March 26-28—Building WithTrees National Confer-ence, Lied ConferenceCenter, Nebraska City, NE.Contact National Arbor DayFoundation 888/448-7337.

March 27—New TreeInspector Workshop,Lamberton. Contact RichHauer, 651-296-0592.

March 28—Northwest UrbanForestry Conference,University of Minnesota–Crookston. Contact PhilBaird, 218/281-8130.

March 31—New TreeInspector Workshop, St.Paul. Contact Rich Hauer,651/296-0592.

April 4—New Tree InspectorWorkshop, Rochester.Contact Rich Hauer, 651/296-0592.

April 12—New Tree InspectorWorkshop, Alexandria.Contact Rich Hauer, 651/-296-0592.

April 27—Arbor Day inMinnesota.

May 5-11—Minnesota ArborMonth Trail of TreesBicycle Tour. Kick-off atState Capitol followed bysites around the state.Contact Don Mueller,651/772-6148.

May 6-8—Tree Structure andMechanics: How TreesHold Together and Fall

Apart, Savannah, GA.Contact Dr. Kim Coder, 4-432School of Forest Resources, Uof GA, Athens, GA, 30602.

July 26 -27—VegetationManagement Associationof Minnesota 5th AnnualConference, Breezy PointResort, Brainerd. ContactJennifer Hildebrand 612/760-4186 or Brad Williams651/458-4473.

August 5—Tour des TreesKick-off, Minneapolis.

August 12-15 InternationalSociety of ArboricultureNational Conference,Milwaukee, WI. Contacthttp://www.isa-arbor.com

Sept. 5-8—National UrbanForestry Conference:Investing Natural Capitolin Urban Spaces,Washington DC. Contact Cheryl Kollin,American Forests;www.americanforests.org

New PublicationsConserving Wooded Areas inDeveloping Communities: BestManagement Practices inMinnesota. Contact MN DNRForestry at 651/772-7925.

Storm Damage to LandscapeTrees: Prediction, Prevention,Treatment. Gary R. Johnson andBen Johnson, 1999. FO-7415.University of MinnesotaExtension Service Distribution

Center, 20 Coffey Hall, 1420Eckles Ave., St. Paul, MN55108-6069; 800/865-8636. Refer to publication numberwhen ordering.

The Big Woods Heritage Forestpamphlet. Contact MinnesotaDNR-Forestry at 651/772-7925.

Tree and Shrub Handbook:Selection, Care, Pests, Diseases.This handbook from the MortonArboretum provides a widerange of information on treeselection, planting and care in athree-ring notebook format.Purchase by calling 630/ 719-2465. (Caution: Some plants rec-ommended in the manual arenot considered hardy in Zone 4,and some of the insect and dis-ease problems listed are notfound at significant levels, if atall, in Minnesota.)

Tree Pests of the Midwest poster.Produced by Morton Arboretumand Ohio State UniversityExtension. Contact DNR Urbanand Community Forest Office at651/772-6148.

Woody Plants in North America.The two-CD set contains infor-mation on 470 native and intro-duced woody species commonlyfound in North America. Thereare leaf and twig keys to helpidentify plants and printablefact sheets for each species. TheCDs include nearly 10,000 colorphotos and interactive quizzes totest how much you’ve learned.Contact DNR Urban andCommunity Forestry Office at651/772-6148.

Tree PotpourriInternet◆ Center for Urban

Horticulture, University ofWashington (research ofhuman dimensions of urbanforestry): www.cfr.washington.edu/enviro-mind

◆ Hazard Tree Web Page,USDA Forest Service, Stateand Private Forestry St. PaulField Office:willow.ncfes.umn.edu/Hazard/hazard.htm

◆ International Society ofArboriculture:www.ag.uiuc.edu/~isa

◆ Livable Communities:www.livablecommunities.gov

◆ Minnesota Department ofNatural Resources:www.dnr.state.mn.us

◆ NEW! MnSTAC:www.mnstac.org

◆ NEW! Minnesota Society of Arboriculture: www.isa-msa.org

◆ National Arbor DayFoundation:www.arborday.org

◆ National Tree Trust: www. nationaltreetrust.org

◆ National Urban andCommunity Forest AdvisoryCouncil:www.treelink.org/connect/orgs/nufac/index.htm

◆ The Simple Act of Planting aTree: www.treelink.org/simpleact/index.htm

◆ Traffic Calming: www.grounds-mag.com/planting.htm

◆ Tree Climbing: www.treeclimbing.com

◆ Tree Climbers DiscussionGroup:spectre.ag.uiuc.edu/archives/isa/treeclimbers

◆ Tree Link: www.treelink.org◆ University of Minnesota

Forest Resources Extension: www.cnr.umn.edu/FR/extension/pages

URBAN AND COMMUNITY FORESTRY CALENDAR

Presorted Standard

U.S. Postage

PAID

Permit No. 171

St. Paul, MN

Minnesota Shade Tree Advocate115 Green Hall1530 Cleveland Ave. N.St. Paul, MN 55108

RETURN SERVICE REQUESTED

Minnesota Shade TreeAdvocate

A quarterly newsletter pub-lished by the MinnesotaShade Tree AdvisoryCommittee.

Managing Editorial Group:MnSTAC EducationCommittee (Cindy Ash, RichHauer, Gary Johnson, JanetLarson, Don Mueller, JeffRick, Gail Steinman)

Editor-in-Chief: Jan Hoppe

Design: Jim Kiehne

Material in this newsletter isnot copyrighted.Reproduction for educationalpurposes is encouraged.Subscriptions are free.Articles, news items, photosand videos are welcome.

This publication was pro-duced with the support ofthe U.S.D.A. Forest Service,Northeastern Area; Stateand Private Forestry.

Address inquiries to:

Jan HoppeMinnesota Shade Tree

Advocate115 Green Hall1530 Cleveland Ave. N.St. Paul, MN 55108

Printed on recycledpaper using soy-basedinks.

2000 OutstandingConservationist: Bruce Bacon

Bruce Bacon of Ramsey has been select-ed as Anoka County’s 2000 OutstandingConservationist! With this honor Bruce hasalso been nominated for Minnesota’sOutstanding Conservationist Award. Hisefforts to develop farming methods that areenvironmentally sound and economicallyviable for urban fringe farms are the embodi-ment of land stewardship. Through his efforts,there is real hope that farming efforts can beidentified that will allow the preservation ofthe family farm within a rapidly urbanizingenvironment. Bruce’s approach provides acomprehensive set of landscape design princi-ples for integrating energetics, biology andorganic cycling into a meaningful local eco-nomic framework.

Bruce’s colleagues in MnSTAC have longrecognized him as one of the leading and creative thinkers of our region as he inte-grates principles of conservation, ecology andeco-nomic viability. Congratulations, Bruce, onthis honor!