How to Care for rn’s Aesset es - Juneau · “Happy is the man to whom every tree ... indeed a...

WSH&G|Winter 2008/09|www.WSHomeAndGarden.com Copyright © WestSound Home & Garden Magazine/Wet Apple Media, Inc.

Between the time when we rake the lastof autumn’s confetti from our lawns andthe day we first glimpse the bright petalson the bare branches of the cherry, mostof us never give a single thought to trees.Meanwhile, arborists, professionalmaintenance crews and gardeners in theknow are concentrating more on treesthan on any other aspect of thelandscape.

Winter is the time of the year whenmuch of crucial tree care is performed formany reasons. The most obvious is that,denuded of leaves, the trunk and branchstructure of a deciduous tree is clear asday. But more importantly from aperspective of tree vigor, winter dormancyis the ideal time for pruning because fewinsect pests are active and the tree willrespond with hearty spring growth.

According to a Tree City USA Bulletinby Dr. James R. Fazio, tree specialistsnationwide rank improper pruning as theNo. 2 killer of street and park trees, justbehind construction damage. If only ourleafy friends could get up and run!

In this second article on tree care, MikeJuneau, Board Certified Master Arboristand owner of Juneau Trees andLandscape, shares more of his knowledgeof how trees respond to and recover frompruning. He hopes to set the recordstraight on which pruning practicespromote tree health and which are“killers.”

Location, Location, LocationHow well a tree suits a location is the

biggest indicator of the quantity and typeof pruning it will require. A thoughtfullyplaced tree will need some pruning in itsfirst 25 or so years for proper structure, butwon’t require drastic measures to keep itfrom blocking a vista, growing under theeaves of a house, obstructing views oftraffic or growing into power lines. Theposition of a tree is often out of our control,having been planted by a previousproperty owner or public agencyresponsible for maintaining easements.Thankfully, though, much of the time wedo have control and tree selection shouldbe taken seriously. Improper placement is

the No. 3 tree killer, and we can prevent it.In fact, Mike Juneau says the majority of

tree failures he sees are preventable.Risky pruning corrections arborists mustperform to save mature trees would havebeen routine if done in the tree’s youth.This is because trees are flexible andvigorous when young. Just as people’sbroken bones heal faster and with fewercomplications early in life, so can treesbest respond to damage when young.

The specific pruning guidelinesfollowed by International Society ofArboriculture (ISA) certified arboristsdictate removing no more than 25percent of the “green” of a healthy tree inone season, even less for mature orunhealthy trees. Arborists refer to thecapacity to bounce back from pruning asthe pruning budget and it is differentdepending on the species and age of atree. And while it may seem commonsense, Juneau reminds us to prune onlywhen there is a structural, safety or healthreason to do so. Shaping a tree into apleasing ball is not a valid reason and

TEXT AND PHOTOGRAPHY BY COLLEEN M IKO

How to Care forYour Garden’s AssetTrees

PART II

“Happy is the man to whom every treeis a friend...”

— John Muir

PHOTO COURTESY RICHARD A. BROWN, THE BLOEDEL RESERVE


only causes profuse, weak branching.Shortening a side branch that blocks thesidewalk is a valid pruning justification.

Trees don’t heal as we know it, theycompartmentalize. When a tree iswounded (and to a tree a pruning cut isindeed a wound), or when the bark on thetrunk is hit with a string trimmer, all sorts ofdiseases invade. Trees cannot regrowdamaged wood, they can only wall it off,or compartmentalize, in an attempt tokeep decay away from creeping into

sound wood. Some trees are better atcompartmentalizing than others, andthose that do so poorly require careful,well-timed pruning.

Bigleaf maple, birch, willow, hemlock,plums and cherries are trees that are poorcompartmentalizers and commonly failfrom damage that other trees can betterwithstand simply due to genetics. How is apoor compartmentalizer pruned? Juneaurecommends only very small andjudicious cuts at an early age. When

mature, though, arborists usesophisticated techniques, such aselaborate cabling systems to keep poorcompartmentalizers vital.

An Ounce of PreventionChoosing a tree that naturally has a

good trunk and branch structure is whatJuneau thinks would save homeowners themost heartache. He’s been called out tomany a 30-year-old Thundercloud Plumthat up and split down the middle withoutwarning to the owners. To an arborist,looking at the tree’s structure would haveset off warning bells years before. In thesecases, he laments that pruning when thetree was a youngster would haveprevented premature failure.Unfortunately, some of our most belovedornamental trees have what is referred toas weak branch attachment, an unstableangle where the branch forks from thetrunk. As the branch gets larger andheavier with age, it can tear away fromthe trunk, causing a fatal wound.

No need to stray away from Japanesemaples and others with less than ideal �

PHOTO COURTESY RICHARD A. BROWN, THE BLOEDEL RESERVE

Example of strong branch attachment on oakPHOTO COURTESY MIKE JUNEAU

Don’t damage atree’s bark.This tree mustcompartmentalizethe wound made bypower equipment inorder to stop decayfrom penetratinghealthy tissue.


branch structure, but understand that such trees require carefulpruning in youth when the pruning budget is greater. If you havea silver maple, willow, Lombardy poplar, Austrian pine or Deodarcedar, have it pruned carefully and consider locating it wherelarge branches or tops won’t cause harm if they do fail.

Even trees with better structure genetically can have faults.When browsing for a tree at the nursery, ask the certifiedprofessional horticulturist on staff to evaluate the branch structureon the tree being considered and to explain why one is preferredover the other. The correct planting technique is illustrated in partone of this article in the fall issue 2008 and summer issue 2008.After the second summer of watering regularly, hire an ISAcertified arborist to inspect that same tree and do any structuralpruning that will set it up for a robust maturity. It will protect yourinvestment, and a tree is a worthwhile investment that payshandsome dividends with age.

The Kindest CutHow a correct pruning cut is made on a tree is counterintuitive

and only in the past 20 years have scientists understood that bothflush cuts and leaving a stub cause decay. But, if you don’t leavea stub and you don’t cut the branch off flush with the trunk, whatelse is there? It’s a hard concept to visualize, even with the

Shaun Sears “windows” a large tree for a view of Hood Canal.

Ornamental plum that has been topped to avoid power lines suffersfrom disease, weak branches and ugly rampant growth that requiresconstant repruning.

The columnar form of Hornbeam (Carpinus) suits a narrow planting strip.

Crimson Sentry Norway Maple was chosen here to avoid powerlines, sidewalk and street. Its large surface roots might interfere withlawn and could lift sidewalk, however.

PHOTO COURTESY MIKE JUNEAU

illustration provided here. The best bet is, when you’re takingFido on his walk, to look at many different trees in yourneighborhood and notice the area where the branch meets upwith the trunk. All trees are different, and on some, it is moreobvious, but all trees have what is referred to as a branch collar.The branch collar is the slightly swollen or raised area where thetrunk wood grows around the branch wood. The branch wood


and trunk wood are different and thisexplains why knots fall out of lumber.

Never cut into the branch collar, whichis what is referred to as a flush cut.Alternatively, never leave a long stub ofbranch beyond the branch collar. Taketime to inspect the branch to be pruned inorder to locate the branch collar anddetermine the angle at which it meets thebranch. Then cut the branch off at thatangle just beyond the branch collar.Anything different can cause decay.

For more details on branch collars andproper pruning cuts, check out the ISAwebsite for images and diagrams or lookat any recent book on pruning. Anotheroption is to hire a consulting arborist —an ISA certified arborist who makes aliving giving homeowners sage advice onhow to care for their specific trees for areasonable hourly rate.

Don’t Top TreesOne of the most egregious, yet

common pruning mistakes is topping atree. Topping is shortening a tree bylopping off main trunks or branches to apredetermined height. The founder ofPlant Amnesty, in her best-selling book onpruning, “Cass Turnbull’s Guide toPruning,” likens tree topping to cuttingthe head off a human body. The onlydifference is how long it takes the tree todie. Juneau says this is often true, andrestricts such drastic cuts to a very smallpercentage of trees that would otherwisehave to be removed but for some reasonshould not or cannot be, such as wildlife �

This large weakly-attached branch (on left)on Thundercloud Plum will inflict a largewound when it fails. Note the branch’s acuteangle and large size relative to the maintrunk, both indicators of weak attachment.


habitat trees in greenbelt areas,overgrown hedges or trees under powerlines. Topping, whether occurringnaturally (as in a severe storm), ordeliberately, usually shortens the life of atree, he says, making it a high-maintenance tree forever thereafter.

If the tree survives the topping, decaywill enter at the wound and may spreadthrough the trunk to the base. Dependingon the tree’s size, species and vitality, aswell as the size of the topping cut, rot canmove down the trunk slowly or rapidly.The tree’s response to topping is to grownew tops and for large limbs below thecut to elongate and become unstable.Needless to say, a tree with a decayingtrunk and unstable branches is a majorsafety concern, especially near buildings,streets, playgrounds and parking lots.

Arborists like Juneau have alternativetactics with which to open up scenicpanoramas and clear branches frompower lines. While the best way to preventtopping is to site a tree where it hassufficient space, the reality is that theplanter had the best of intentions andprobably had no idea how large and howfast the tree would grow or perhapsMother Nature planted the tree. Crown-thinning is one of the techniques used toopen up the branch structure of a tree todeliver more light to a shady gardenbelow or to improve the view from a deck.Another topping alternative is windowing,

which involves removing severalbranches close together in order to opena window through which to admire awaterscape.

Watching arborists perform their artway up in a massive Douglas fir is aharrowing reminder of the importance of

hiring an ISA certified arborist with atleast $1 million in liability insurance.While it makes the average person’shands sweat, Juneau admits, when he’spruning high up in a tree, that’s whenhe’s having the most fun. �

Just about every cardinal sin of pruning has been performed on thismature Bigleaf maple: topping cuts and removing more than 25 percentof green from a poor compartmentalizing tree. In a few years only ashell of live trunk wood will remain to support heavy tops that regrow.

Mike Juneau with a decayed Bigleaf Maple trunk

QUICK GUIDE TO PROPER TREE

SELECTION AND PLACEMENT

Physical obstacles to avoid:

• Utility lines: above and underground

• Onsite sewage (septic) systems: tanks, lines and drain fields

• Building overhangs

• Streets, sidewalks and driveways

Site conditions to consider:

• Exposure: sun or shade, windy or sheltered

• Soil type: wet or dry; sand, clay or loam; shallow or deep; compacted

• Regular irrigation or au natural

• Will lawn/plants be grown underneath

Species traits to research:

• Height and width at maturity

• Evergreen or deciduous (bare in winter)

• Pest and disease resistance

• Drought tolerance or tolerance of irrigation

• Root characteristics: shallow or invasive

• Drops fruit, seeds or cones

PHOTO COURTESY MIKE JUNEAU


Our beautiful native Mountain Hemlock, aslow-growing, narrow tree

NARROW TREECULTIVATORSFOR TIGHT SPACES• Mountain Hemlock

(Tsuga mertensiana) 20 by 8 feet —slow growing native conifer withgood pest resistance

• Adirondack Ornamental Crabapple(Malus “Adirondack”) 18 by 10 feet— spring flowers and nice fall colorcomplemented by disease resistance

• APOLLO® Sugar Maple(Acer saccharum “Barrett Cole”)25 by 12 feet — excellent autumncolor

• Columnar Sweet Gum(Liquidamber styraciflua“Worplesdon”) 35 by 15 feet —improved, slow growing form

• Crimson Spire Oak(Quercus x “Crimschmidt”)45 by 15 feet —THE oak for smallgardens, leaves bright orange-red infall

• Weeping Alaska Cedar(Chamaecyparis nootkatensis “Green Arrow”) 35 by 5 feet

Other nice trees for our climatecan be found at Great Plant Picks atwww.greatplantpicks.org.

RESOURCESMike Juneau, ISA Board CertifiedMaster ArboristJuneau Trees and Landscape, [email protected]

Find an ISA certified arborist tree carecompany or consultant in our area byvisiting the Pacific Northwest ChapterInternational Society of Arboriculture atwww.pnwisa.org or contacting ISA’sinternational website below.

For information on tree pruning andother tree care techniques:ISA international, www.treesaregood.comhttp://hort.ufl.edu/woody/pruning

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