March 2017

Protect Your Trees and Shrubs from “Mower Blight”

Each year a large number of treesand woody shrubs in local

landscapes are severely injured anddie from wounds caused by contactfrom lawn maintenance equipment.When the stem of a tree or shrub isstruck by a lawn mower or stringtrimmer, a wound is created thatdisrupts the flow of energy throughoutthe tree. The damage is irreversibleand even small wounds make the

plant vulnerable to attacks by decayfungi and other harmful insects anddiseases. Critical energy is thentaken away from the plant’s normalfunctions in order to close thesewounds. Once mechanical woundsexist around the entire trunk, the plantbecomes girdled and subsequentlydeclines and dies.This damage is so common in thegreen industry that professionalshave coined names for it like “mowerblight” and “string trimmer wilt”. Theseare phony disease names as this is ahuman caused condition. Damage iscompletely preventable by simplykeeping lawn mowers, stringtrimmers, and other power equipmentaway from the stems of trees andwoody shrubs. If you hire someoneelse to mow your lawn, talk to them

about protecting your trees andshrubs. Ensure the equipmentoperators are aware of theproblem and hold themaccountable for damage.The best protection for yourtrees and shrubs from lawn

maintenance equipment is toremove the grass around the trunk

and install a tree well. Tree wells aregrass-free, ring-shaped areas aroundthe trunk that create visual cues forlawn equipment operators to avoid

those areas. They can be as narrowas a few inches or as wide as severalfeet. Ideally they are filled with 2-4inches of quality mulch, compost, ortopsoil. Be careful not to pile it directlyagainst trunks as this can do moreharm than good.Another less effective preventativeoption is tree guards. Plastic andmetal guards can absorb the impactof string trimmers. Keep in mind thatthey will need to be replaced and/oradjusted regularly to prevent girdlingthe tree themselves.If you notice mower blight on yourtrees, contact us to evaluate thedamage and develop a solution toprevent further injury. We can installand maintain customized trees wellsfor the long term health of your treesand shrubs.

• Saving Trees & Views

• Wood Decay Diseases of Aspen

• Growing Trees That Attract Birds• Noxious Weed Alert

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In This Issue…

Serving Sun Valley and Beyond Since 1997Plant Health Care Programs, Tree Removal and Pruning, Pest &Disease Management, Lawn Care, Soil Health, and Consulting.

Visit our website for a listing of all of our services.

FUN TREE FACTS■ Wind-blown cottonwoodseeds can stay airborne for daysbefore they land. In fact, theycan fly longer than any otherkind of tree seeds.

■ Despite common belief, treesgrow from the top. A branch'slocation on a tree will onlymove up the trunk a few inchesin 1000 years.

Topping is the indiscriminate cuttingof tree branches to stubs or to lateralbranches that are not large enough to

assume the terminal role. Oncetopped, your blocked view is nowreplaced by the ugly remnant of aonce fully developed tree. A dense

mass of suckers and shoots willreplace each cut branch, ultimatelycreating a broader, thicker top thanyou had previously. Topping createsdangerous trees that develop heavytops and weak branch attachments

with decay points. It should bepointed out that topping is very

different from crown reductions cuts.Crown reduction cuts are completed

by a Certified Arborist with a fullunderstanding of how the tree will

respond and heal. They are alsoinspected and re-pruned on a regular

basis to mitigate the risk of failure.

Why Topping Isn’t the Answer

Be a Good Neighbor with Respect to View Conflicts● Make sure the tree you are having pruned or removed is on your

property. If not, get permission to do the work from the treeowner in writing including the specifics of the work and who willpay for it. Keep in mind, your neighbor is completely in theirown right to refuse having their trees pruned or removed for thebenefit of your view. Consider what effect this work will have ontheir views and privacy and respect their decision.

● Research the ordinances your community (city, county, HOA)may have regarding preserving or improving existing views thatmay prevent or limit you from completing the work. If required,make sure you have the proper permits in place prior to thescheduled work date. Contact us and we can supply informationregarding permits in your particular location.

Saving Trees and Views

Communities throughout the nation are finding that tree lovers are increasingly at odds with view seekers. Living inthe mountains lends itself to spectacular views and so this is an issue we deal with routinely. Unfortunately the

most common compromise is to “top” trees. Many people are realizing rather than saving the trees and views, toppingeventually ruins both (See sidebar - Why topping isn’t the answer). In many cases tree owners and their neighbors

can find ways to make views and trees work together. Most of the solutions involve theskilled/specialized pruning methods discussed below. Contact our Certified Arborists forrecommendations to enhance your view corridors!

Thinning – Trees can be trimmed in order to see through them. This requires reducing thefoliage evenly throughout the canopy. The actual amount of foliage that can be removed dependson the species. As a general rule removing no more than a quarter of the total leaf area isrecommended. Properly thinned trees will retain their shape and structure and their naturalbeauty will be enhanced. This method will only work in situationswhere a screened view is acceptable.

Windowing – This method works best when the subject is a large, close-in tree that isblocking your view. By carefully selecting branches to thin or remove, you can open awindow in the tree that gives you a fully framed view of whatever lies beyond. Like mostpruning there is a certain amount of art involved in this method. When you window atree on one side, you may want to balance it with some pruning on the opposite side.

Skirting – This method works best for trees located ata mid-range distance from your viewpoint. Dependingon your perspective, you may be able to open up a viewby removing the lower limbs of a tree. As a general ruledon’t skirt up more than one third of the tree’s visibleheight. If the tree looks top-heavy after skirting, the restof the tree may need to be thinned. A tree should stilllook like a tree and not like a flag. But beware; toomuch skirting can result in increased risk of tree failuredue to top-heavy trees with an altered wind flow.

Selective Removals – Sometimes the best method involves removingwhole trees that block portions of the view. It is best however to leave treeson the edges of your view, directing your vision and framing the outlook.This method is particularly useful with aspen stands and other grove specieswhere views can be created by removing the taller trees within the stand.

Seasonal Views – This method needs to be considered before plantingnew trees within view corridors. Deciduous trees are particularly valuable forview management because they offer different seasonal views whilepreserving the environmental benefits of trees. In other words, you can haveprivacy and plant color in your summer view and mountains or water in thewinter view.

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Wood Decay Diseases of Aspen

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White Mottled Root RotWhite mottled root rot is caused bythe fungus Ganoderma applanatum. Itcan affect many tree species (oftendead trees) across the northernhemisphere. It occurs primarily onliving aspen in the Rocky Mountainsand is the most serious and prevalentroot disease of aspen in the west.The fungus causes extensive decayof the roots and buttress of the tree.Infected trees usually fail while aliveand appearing healthy. The diseaseis associated with about 90% of liveaspen trees that fail due to wind (USForest Service 2011 statistics). This isparticularly important in developedsites such as landscapes as itcontributes to hazardous trees thatfail in high use areas.Infection may occur from airbornespores or from contact with infectedroots of neighboring trees. Thefruiting body is a white woody shelffungus or “conk”. Billions ofmicroscopic, airborne spores arereleased from the underside of theconk.Currently there are no effectivemethods for preventing or reducingthe incidence of white mottled rootrot. Conks are the only usefulindicator of infection in live, standingtrees. In developed sites with aspen,trees should be monitored for conksand trees with conks should promptlybe removed. Due to these risks,experts recommend considering otherspecies of trees for developedsites.

Aspen Trunk RotAspen trunk rot is caused by a funguscalled Phellinus tremulae that causesheartwood decay. It exclusivelyaffects living aspen trees and diessoon after the host tree dies. Theinfection occurs at existing wounds,branch stubs, or small dead branchesand eventually grows into theheartwood of the tree.The fruiting body is a brownish conk.It produces microscopic spores thattravel long distances to a suitableinfection site.Aspen trunk rot conks are usefulindicators for detecting and estimatingdecay and risk associated with aspentrees. Infected stems can have up to70% decayed wood (USFS 2011).Tree failure and breakage is ofparticular concern in developed sites.Landscapes with aspens should bemonitored regularly for the presenceof conks and trees removed promptlyif infected.

Cytospora cankerCytospora canker is an abscesscaused by various species of thefungus Cytospora. These pathogensaffect many species of trees in Idahoincluding poplar, apple, cherry,peach, plum, birch, willow, honeylocust, mountain ash, silver maple,spruce, and elm.The fungus attacks trees that areinjured or in a weak or stressedcondition. Drought stress and oxygenstarvation of roots by over-wateredsoil are the two most commonreasons that predispose trees toCytospora. Mechanical woundscaused by lawnmowers and weedtrimmers are also susceptiblelocations for infection.Cytospora infection causes cankerson branches and stems. The cankersare irregular, slightly sunken, orange-brown colored areas of the bark. Thecanker eventually causes girdling ofthe plant tissue, killing the branch orpart of the stem above the canker.Because this canker disease usuallyoccurs on a weakened host, theprimary method of control is toprevent and/or reduce stress on thetree. To help trees resist infection,use resistant plants when possible,provide appropriate care before andafter planting, remove infected limbs,and make proper pruning cuts.

From left: White Mottled Root Rot conk at base of aspen tree, Aspen Trunk Rot conk emerging from aspen stem, Cross-sectionof aspen stem showing heartwood decay due to aspen trunk rot infection, Cytospora canker on aspen trunk, Masses of bright

orange spores ooze out of the Cytospora canker in thread-like spore tendrils.

Growing Trees That Attract Birds

Not all trees are created equalwhen it comes to attracting birds

and other wildlife. But if you carefullyselect the ones you plant,you can feed a varietyof birds and provideshelter and nestingareas. Differentspecies of treesflower and pro-duce food at dif-ferent times ofthe year, so themore types of treesyou have, the moreenticing your yard willbe.In spring, lilacs and fruit trees offerinsects and tender buds for birds toeat. Mountain ash, crabapple, apple,pear, plum, cherry, and hawthorn pro-vide fall fruit.

Birds that favor seeds are attractedto seed-producing deciduous treessuch as alders, willows, poplars,

maples, and birch. Our local ever-greens offer excellent year-

round shelter and produceseed-filled cones.Even sap from trees likebirch and maple can bea feast for some birds,and any insects attract-ed to the sap may be-

come a meal forinsectivores.

As you can see, there aremany options of trees to attract

birds to your landscape. Diversity isthe key to extend the season by of-fering both evergreen and decidu-ous trees with overlapping bloomingand fruiting cycles. Happy Birding!

Dalmatian toadflax, Linaria dalmatica is a close cousin of yellowtoadflax that is widespread throughout North America. It was imported

to North America from the Mediterranean region of Europe as an ornamen-tal and is currently found in 34 states in the U.S. and most of Canada. It ismost widely distributed in the western U.S., where it has significantly re-duced livestock production on infested pastures and rangeland. It has novalue as food, crowds out valuable forage for na-tive animals and livestock, and can be harmful ifingested.It is a perennial weed that grows up to 3 feet talland spreads by seed and lateral roots. Matureplants can produce up to 500,000 seeds whichremain viable in the soil for up to 10 years. Theextensive root system can grow 6 feet deep andout 10 feet or more from the plant.Dalmatian toadflax is very difficult to control onceestablished. Maintaining a healthy stand ofgrasses and other plant species can help preventestablishment. Contact us to help identify noxiousweeds, turf weeds, or other native area weeds onyour property and create a management plan forthis coming season.

Noxious Weed Alert: Dalmatian Toadflax

Seth Gates is now an ISA Certified Arborist! Seth has beena team member since spring of 2016. He’s originally fromMaine and holds a Bachelor of Science from Colorado StateUniversity. ISA Certified Arborists are professionals who haveachieved a high level of education and on-the-job experience inthe tree care industry and who have successfully completed anextensive exam developed by the International Society ofArboriculture.

Congratulations to Seth Gates!

PO Box 397, Hailey, ID 83333(208) 788-1611

SunValleyTree.com

Registered Consulting ArboristBill Josey RCA #566

Board Certified Master ArboristBill Josey RM-0715BT

Certified ArboristsJeff Beacham PN-5864ANick Chickrell PN-6472AManny Austin PN-7705AArt Adamiec PN-8097ASeth Gates RM-7062A

Tree Worker/Climber SpecialistBill Josey RM-0715BTNick Chickrell PN-6472A

Tree Risk Assessment QualifiedBill Josey RM-0715BTJeff Beacham PN-5864A

ISDA Licensed ApplicatorJohn Olson Manny AustinNate Baumann Tim EnglandJeff Beacham Nick ChickrellBill Josey Art Adamiec