Urban and Community Forestry Agriculture & Natural Resources TIMELY INFORMATION Post Storm Tree Assessment; Guide to evaluating trees

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1 Urban and Community Forestry Agriculture & Natural Resources TIMELY INFORMATION Post Storm Tree Assessment; Guide to evaluating trees Post Storm Assessment: To assess trees in the aftermath of storms it is important to understand the types of damage that are likely to occur. Trees are made up of four primary components; roots, trunk, limbs, and crown. Each of these components are subject to damage that have varying impacts on tree s health, structural integrity, and the eventual decision to keep or remove the tree. This document will review common post storm damage and help guide the decision of whether to remove or repair the damaged tree. This document is laid our in four stages to help the homeowner better understand the assessment process. This document provides some recommendations, however, it must be noted that every tree and situation is different so good decision will require reviewing all the available information and may require the help of a professional arborist. Step 1: Targets: Trees in forest settings have a low risk factor as there are no structures and few people. Trees in yards or in playgrounds on the other hand need to be evaluated more harshly. Homes and other urban structures, power lines, roadways and most importantly people are potential targets. Another factor is frequency of use of the area under the tree in questions. Rarely visited portions of a yard or park present less of a risk as trees over frequently used patios or playgrounds. The harshness with which trees are assessed and evaluated is largely based on the threat to human safety and welfare. Step 2: Tree Species: First, identify the tree species. Some species of trees are more susceptible to disease, decay, or structural problems than others. For example water oaks are fast growing and often become hollow, riddled with decay, and structurally unsafe as they become mature. This becomes important to the future health of certain trees when large broken branches are pruned. For some species that are mature or over mature large pruning cuts are not recommended due to future safety concern as a result of decay. Trees of Concern are over mature: Water Oak, Laurel Oak, Willow Oak and Maples Step 3: Consider Tree Age The younger the tree the easier it will be to repair damage and expect full recovery. Like people young trees are more resilient and are far easier to correctively pruning. Small broken branches pruned off trees will heal quickly with few lasting signs. However, as trees mature the loss of large branches and the corresponding canopy increase incidents of decay and future structural problems as well as tree decline from loss of leaves. Additionally, root problems such as leaning trees and broken roots are more common in larger trees. These problems in smaller trees can be easily corrected by staking with little risk to safety and homes. Large leaning trees, however, are very dangerous and cannot simply be propped up. Unfortunately there is no clear delineation that separates young trees from mature trees. However the following rules of thumb can be applied to trees needing storm pruning or lean correction. Trees less that 5 years success Trees between ages of 6 15 years Moderate success Trees between Moderate to poor

2 Step 4: Assess Root damage Some of the most damaging injuries can occur below ground in the root system. These problems are often hidden and careful examination is needed to identify problems. winds often cause trees to rock causing the severing of roots and in extreme cases whole tree failure. The most prominent sign of root failure are leaning trees. A good indicator of a problematic leaning tree is a soil mound at the base of the tree on the opposite side of the lean (Pictures 1). On the inside of the lean there may be an indentation in the soil. Cracks in the soil on the opposite side of the lean especially when combined with mounding are a serious hazard. Leaning trees with mounding often indicates broken and damaged roots, and should be examined by a professional immediately and usually require removal. However, trees may also have a lean due to the trees natural growth patterns. Examples include trees leaning out towards sources of light or leaning as a result of prevailing winds. Naturally leaning trees will often have branches or tree tops that have adjusted to the lean (Pictures 3, 4). In such cases the branches will be growing towards the light even if the tree is leaning away. Call a Certified Arborist if you see any of Lean Recommended Maintenance Likelihood of surviving With mounding Immediately Remove Soil Cracks Hire Certified Arborist for further assessment Mounding & Soil Crack Immediate remove Lean with no mounds or Cracks Hire Certified Arborist for further assessment Danger Moderate Picture 1 (This tree is dangerous) Picture 2 (This tree is dangerous) Picture 3 (Correction illustrates an old lean) Picture 4 (upward branches illustrate an old lean)

3 Step5:AssesstheTrunk Thetrunkofthetreeisprimarystembetweentherootsandthelimbsandfoliageabove.Thetrunk servesastheconductorofwaterandnutrientsandsupportsthetotalabovegroundweightofthetree makingitanimportantcomponentinanytree.damageoccurringonthemainstemortrunkisoften structuralinnatureandcanbeexceedinglydamaginganddangerous.windswilloftenpush,bend, andtwiststemscausingwholetrunkfailures,cracks,splits,orbarkripping.step5willoutlinethesedam agesinmoredetailinthesectionsbelow: a.crackedtrunkorbranches: Duringstormeventstreesaretwistedandbentandinsomecasescandevelopcracks.Thesecracksmay beinthecrotchofaco dominantstemorinextremecasesinthemiddleofthetrunk.allcracksareama jorproblemandwillrequireimmediateattention.treeswithcrackscanfailatanytimeandwilldevelop decaycompoundingtheproblem.inmanycasesthesetreeswillneedtoberemoved.contactacertified arboristifyouobservethefollowing: (Picture1 Verticalcrackverydangerous) (Picture2 BranchCrackmoderatelydangerous) (Picture3 Crackbetweenforkedtree) Crackscanleadtofailureandshouldberemoved

4 CrackRecommendations: Crack RecommendedMainte nance Likelihoodof surviving Danger Other Considerations Verticalcrackon maintrunk ImmediatelyRemove andreplant These cracks are common and will generally require full tree removal. Horizontalcrackon maintrunk ImmediatelyRemove treeandreplant Horizontal cracks are rare but very dangerous and often times hard to spot due to the bark. Moderate Mightconsiderwhole treeremovalifthe crackedbranchislarge andthetreespecies doesnotrespondwell topruning;suchas waterorlaureloak. OnBranch PruneBranchtoISA standards b.brokenorsplittrunk: Startbycarefullywalkingaroundthetreelookingforcracks(seeprevioussection),twistedwoodspiraling aroundthetree,tornorrippedbark,orbreaks.notetheseverityofthedamagetoprovidetheproper managementtechnique.belowisacharttohelpquantifydamageandreceivecorrespondingmanage mentrecommendations. Splitsoccurasaresultoflargebranchesbreakingawayfromthetree.Theseusuallycauselarge woundsthatwillallowdecaytoenterthetreeandcausestructuralproblemslater(pictures1&2) LargesplitsorbrokenstubsasinPictures1&2willrequireremovalbecausetheyexceed50%ofthe diameter. Smallersplitsorbrokenlimbsfromthetrunkasinpicture3below,areeasierforthetreetoseal. Thesewoodsarestillriskyandwillrequiremonitoring. (Picture1 Severalbranchessplit remove) (Picture2 Forkedtreesplitsaway remove)

5 Broken or stubbed trunks even in hardwoods will require that the tree be removed. Even if lower limbs remain the loss of the top of the tree is a major concern (Picture 5). If the loss occurs in the lower 2/3rds of a mature tree removal will be required. Loss in the upper will need further assessment. (Picture 4 Top of the lost) (Picture 3 Branch lass less than 50% of trunk diameter) (Picture 5 Top of the lost) Trunk damage Recommended Maintenance Likelihood of surviving Broken or stubbed trunk Remove and Replant Split or broken limb causes damage to less than 30% of the diameter of the stem Prune away stubs and monitor Split or broken limb between 30 to 50% of the trunk diameter Split or broken limbs greater than 30% of the stem diameter Broken or Split Trunk Recommendations: Prune away stubs and monitor/or remove Remove and Replant Moderate Pine trunk broken anywhere Remove and replant Hardwood trunk broken in the top 1/3 of the tree Hardwood trunk broken from the ground to 2/3rds up Prune away damage and monitor Remove and replant Moderate

6 c. Twisted or Bent Trees: When high winds twist or bend trees it is important to look for any cracks or broken tops. Mature trees will seldom twist or bend without either cracking or breaking. Also trees that have bent or twisted near the ground should be examined for broken roots or any mounding that will indicate a lean. Young trees however are still flexible and can sometimes be bent without breaking. In the case of young trees that are twisted and bent stake tree trees to their upright position and monitor their progress (Pictures 1 & 2) (Picture 1 leaning/bent young tree. Image source Ed Gilman, Univ. Of FL) (Picture 2 Staking methods for young trees Image source ISA Arborist) Trunk damage Recommended Maintenance Likelihood of surviving Twisted young tree Stake and monitor Moderate Bent young tree roots unaffected Bent Young tree Roots appear broken or mounding is evident Twisted or Bent Tree Recommendations: Stake and monitor Remove and Replant Comments If not broken wood fibers evident these trees should recover. Their shape may be altered in the future. Unless the tree has been in the landscape for less than 2 years broken roots on young trees will cause the tree to repeatedly fall over during any wind event and will likely always need support.

7 d.barkrippingonthetrunk: Barkrippingoftenresultsfromalimbpartiallybreaking.Thepartiallybrokenlimbasiffallwillripthe barkdownthesideofthetreeexposingthewoodbeneath.thisdamageisnotinitiallystructuralinna turebutrathercangirdlethetreeorallowdecayandinsectproblemsinthefuture. Belowarerecommendationsbasedonthepercentageofthetrunkdiameterthatisaffected. Photoby:DennisDrenner/AmericanRedCross BarkRippingRecommendations %ofstrippedbark RecommendedMaintenance Likelihoodofsurviving 25%orless Trimthebark 25 50% Trimthebarkandmonitor Moderate 50%ormore Removeandreplant

8 Step6:AssessingtheCrown: Followingseverestormeventsitisnotunusualtoseebrokenbranchesandtreesstrippedoftheirleaves. Thelossofleavesisusuallynotaproblemastreewillsproutnewleavesintheweeksfollowingthestorm. Thisdamagecanbeeasilycounteredbywateringthetreeregularlytohelpitregeneratehealthyfoliage. Brokenlimbs,however,aremoreseriousbecausetheyrequirepruningtoinsureminimalincidencesof decayandinsectattacks.treeswithonlyacouplebrokenlimbsareseldomaproblem.however,trees thathavelostlargelimbsorseverallimbsneedtobeassessedwithathoughttothefuturestructureand likelydecaytooccurasaresultofthedamage.decaywillweakentreesinthefutureandcausedanger oussituationsastheweightoftheremaininglimbscausesdecayweakenedareastopossiblyfail. Belowareseveraldiagramstohelpgaugewhetherpruningorwholetreeremovalisnecessary: Arbor Day Foundation Illustrations Photoby:BradNelson BrokenBranchRecommendations %oftreewithbrokenbark RecommendedMaintenance Likelihoodofsurviving Maintrunkbrokenoff SeeTrunkSectionpart B LargeBrokenLimb Prunebranchfromtree Moderate 50%ormoreofbranchesbroken Removeandreplant 30%to50%oflimbsbrokenfrom Prunebrokenlimbsandmonitor tree Lessthat30%ofthelimbsbroken Prunebrokenlimbs Moderate