Sunday 21 December 2008

Yule Log Lore

This time of year abounds with tradition and folklore. Trees and tradition are always of interest to certified tree people!

The yule log is a tradition that traces its roots back to northern Europe including England and the Scandinavian countries. This time of year is also the approach of winter solstice, the shortest day of the year. With the shortest day comes the longest night. In Pre Christian times the Yule log was lit to celebrate the end of the long dark nights as days would be getting longer.

Pope Julius the 1st realigned the Christian calendar in the fourth century AD, to celebrate Christmas around the winter solstice. The tradition of the Yule log was adopted and continues in many countries to this day.

The basic tradition is as follows:

The family gatherers a log from their property, traditionally Oak or Ash. You could be given a yule log but never purchased. It is brought into the fireplace and decorated with evergreen boughs, cider, ale or other aromatic oils. The log was then set ablaze and allowed to burn throughout the night. Some traditions will have it burn for twelve days. The burning of the Yule log always indicated the start of the Christmas festivities. English tradition has it burning from Christmas Day through to Epiphany on the Sixth of January. Other traditions include a prohibition of labor during the burning of the yule log.

An unburnt piece of the log was kept until next year and used to start the following year's yule log to maintain continuity.

While the log was burning family and friends would gather round to sing carols and reflect on the year past. As in the Scottish New Year's Song “Auld Lang Syne”, personal faults, mistakes and poor choices of the year were thought to be consumed by the Yule log flames to be forgotten and forgiven.

Variations on the Yule log theme abound, tenant farmers would gather bundles of ash sticks tied together with ash binding or ribbons by unmarried maids. Once lit, the first bindings to break would indicate the first girl to be married the following spring.

In American Appalachian country the tradition of “ Back Stick” called for a very large log to be soaked in a stream to ensure a long burn time. This ensured that the party and celebration was long lived as the revelry was permitted to continue until the fire went out.

Urbanization has led to the adaptation of this tradition. I still have a candle holder that my nephew gave me that is a modern variation on the Yule log. Made from an oak limb, 12 inches in length 4 inches in diameter, split in half, this table top log adds rustic beauty to your celebration. Three holes are drilled in the round side of the log to place candles. The log is decorated with Holly leaves and evergreen boughs. The candles have various symbolism's and are lit on Christmas Eve. French traditions create an edible Yule log of wrapped sponge cake that allows celebration when you can't start a fire!

Cherish and enjoy your own holiday traditions and have happy safe New Year!

Wednesday 19 November 2008

Chainsaw Choices

Professional chainsaw users know just how dangerous these valuable tools can be. Unfortunately too many professionals have learned the hard way that any time you are close to a chainsaw you are at risk of injury. The typical chainsaw combines the brute strength of 3 horses with seventy five razor sharp knives. All this dangerous potential is literally in your hands when you pick up a chainsaw. Before you pick up a chainsaw you should make sure you have the right saw for the job.

First if your chainsaw is older it may lack any of the modern safety features like inertia chain breaks, hand guards and a host of other improvements. Drain the fuel and oil and donate it to your local museum. NEVER use older style chainsaws.

Home owner saws that you buy from the local mega mart may no meet the strict safety standards required by professional users. Why should you put yourself at risk?

A common and potentially deadly event when using a chainsaw is kickback, Kickback occurs when the upper portion of the tip of the chainsaw comes in contact with an object. The teeth on the tip of the bar stop abruptly and direct all of their energy back into the chainsaw. This results in it rapidly and uncontrollably spinning in an upward arc towards the user. Modern chainsaws have safety features like inertia chain breaks, to reduce the chance of injury from kickback.

Professional chainsaws come in two basic styles and a myriad of sizes. Saws are broken down into top handle and rear handle styles. As the name suggests top handle saws have the rear handle moved to the top of the saw to allow easier range of motion while climbing in the tree with the saw. If you are not climbing in the tree do not use this saw.
Even if you have come down from the tree, switch to a rear handle saw to cut up branches on the

Rear handle saws, with their trigger handle in a much safer position at the rear of the saw, direct kick back energy up and away from the user. When kick back occurs a top handle saw will rotate your wrist and hit you in the head or chest. The operative work is WHEN kick back occurs, not IF.

The largest chainsaw available may be good for your ego but it will not be good for your safety in the long run. A small to mid sized professional chainsaw will provide years of trouble free safer operation. If you really think about what you are cutting a small sharp chainsaw with a 15 to 17 inch bar will do 99% of your work. Typically these saws are in the 50 to 60cc size range. Most users should not use a top handle saw.

A chainsaw safety training class should be mandatory for chainsaw purchase. I doubt it ever will be mandatory for the home owner. Industry has been forced to provide training through legislation and increasing workers compensation costs. If you use a chainsaw you should make it your mission to get at least the basic safety training. Your life literally depends upon it.

Monday 3 November 2008

For What it's Worth

Trees have inherent value because of the useful goods and services they provide. A stack of 2x4's fours ready to turn into a new family room or that storage area you have been wanting can be taken to the till and paid for at your local lumber mart. Calculating the value of that lumber is easy! Calculating the value of a living tree is much trickier.

When you move to the services trees provide, shelter, shade, erosion control, wind, noise and pollution reduction these too can be calculated. Formulas have been developed over time to calculate these values per tree or for whole forests.

What happens when you wake up one morning and the construction crew working on the house next door is in the process of chipping up your favorite tree? Unfortunately these kinds of situations do occur and all to often they end up in litigation.

Fortunately there are arborists who specialize in this kind of tree valuation. These consulting arborists regularly deal with situations on landscapes that require accurate and verifiable appraisals of trees and groups of trees. Just as you would go to a specialist if you had a serious

medical condition, you would be well advised to go to a reputable consulting arborist if you ever find yourself in a potential legal situation involving trees.

The basic premise in calculating the value of a tree is that in most cases the landscape contributes 10% to 15% to the total value of your property. In special cases this may be slightly more or slightly less. It is not enough to take ten percent of value of your property and divide that by the number of trees and come up with a value for one tree. Doing this does not take into consideration a number of factors that effect tree value.

Consulting arborists use several formulas that allow for an accurate assessment of the value of a tree or trees. The arborist typically uses the value of the largest readily available replacement tree of the same species to start their evaluation. Next the diameter of this replacement tree and its value is used to extrapolate the value of the existing tree. Working from a chart of tree values, determined by groups of experts, a species percentage is assigned to each tree. Typically an oak will have a value of 100%. This is partly related to its value and longevity in the landscape and possibly the fact that even in colonial times oaks were highly valued. Oaks were considered the property of the king. A less desirable tree, like a box elder may only get a species rating of 50%. Trees are given species percentage values based on their attributes and loose percentage points if they have inherent problems that detract from their value in the landscape. Messy fruit, excessive branch drop, short lifespan, predisposition to rot or failure are all value detractors. Location on the landscape is then used as a weighting factor to further refine the value of the tree. The condition of the tree is then included in the calculation to take into account the physical shape and health of the tree. After a few more calculations a number is arrived at for the value of that tree. This value must than be proofed against the value of the home and the overall value of the landscape. This process continues until the consulting arborist is certain that he has a figure that will stand up in court if necessary.

If you have followed this article to this point it will be apparent that a certain degree of specialization is necessary to perform these valuations. Most arborists are able to refer you to a qualified consulting arborist if you ever have the misfortune to be in need of their services. In the end the value you put on your trees may be very personal and relate to moments in your life enjoyed under them.

Sunday 26 October 2008

How Trees React to Pruning

Trees are alive. This may come as a shock that I would have to make this statement but I think that many people forget this simple fact. Trees are made of living tissue, the wood we use to make our houses and furniture is quite simply, dead. You can carve wood, you can shape it and construct it into many useful things.

Trees on the other hand can be shaped, pruned but in some cases people carve them up like holiday hams.

The tree, being alive, reacts to these injuries in many different ways. Trees do not repair damaged tissue, they wall it off and grow around it. Like the unlucky crew members of a sinking ship caught behind the watertight doors, all the living tissues beyond the trees protective barrier are left to die. If the barrier is breached by disease or further injury the tree expends its dwindling energy to erect a new barrier. If the injury is severe the tree might not be able to recover and may just die.

Trees respond to pruning in a variety of ways. The first thing that happens is the tree has to wall off the injury location. It does this by... you guessed it erecting an impenetrable barrier to exclude the damaged tissue from the living undamaged tree. The tissues around the injury are stimulated to grow over the wound and replace missing branches with more living branches.

Pruning branches that died off for any number of reasons will generally not produce sprouts or water shoots. If while removing the dead branch you cut into the callus layer that has formed where the dead branch is still attached to the tree you will re injure the tree and likely initiate the development of new sprouts. On some trees simply nicking the bark will initiate a sprout to form. Savvy apple growers have used this to reshape crowns and initiate locations to graft onto.

Trees have evolved these responses over time as a way of making sure that when the tree is injured it will be able to form new branches and continue capturing sunlight, turning energy into sugar and ultimately new tree tissue.

So what can you do to prevent trees from developing waterspouts or suckers after pruning?

Avoid pruning to much from the crown. Twenty years ago 30% was the maximum amount you were recommended to prune your tree with out gravely injuring it. Today this has been reduced to twenty to twenty five percent. This amount is probably excessive. Prune the absolute minimum amount to archive your goals. Yes you must have a clearly defined goal before you start pruning.

If the goal is to frame a view, remove the minimum number of branches necessary to do this.

Too often homeowners will ask for additional pruning to be performed to get extra value. The logic is as follows, “ This pruning is costing me a bundle, I want a pound of flesh!”. Ultimately the tree responds by sending out growth in exactly the spot you didn't want it to. Thin the waterspouts out on the trunk rather than removing them completely. The remaining sprouts will suppress other sprouts from initiating. Use sprouts that are growing in the right direction to fill in thin or damaged areas of the crown.

When you are pruning to remove dead wood use caution to not cut into the callus layer that has formed around tree branches. Time your pruning to limit the amount of new sprout growth.

Most trees will sprout profusely if they are pruned late in the winter or early in the spring. The injury of pruning at this time mimics winter injury and is certain to result in lush bushy sprouts popping up through out the crown and where branches were removed. For more information on modern methods of pruning contact your certified arborist.

Saturday 4 October 2008

Pruning Article Reponse

We have a winner! A few months back I offered a professional pruning multi tool to one reader who sent in a tree pruning question or picture. See the original post here. The randomly selected winer from the many great questions and pictures we received is Mr. Dave P.

The question distilled to its essence is as follows; If you cut down a stand of aspen, Populus tremuloides, there is a technique of damaging the resulting suckers that will eventually prevent the suckers and kill the tree. Is this technique a valid way to prevent regeneration of the aspen or just a tall tale? Dave goes on to describe the method proposed.

Anyone who has removed aspen from their property or seen areas where aspen was harvested in the wild knows that they respond to sever pruning, cutting them down by sprouting hundreds of new shoots. These rapidly growing shoots will choke out the commercially more desirable species like spruce and pine. Typically these shoots are controlled by treating them with chemicals or by cutting them down. The technique Dave describes allows letting the shoot grow to several feet high and then cutting them partially through with a clearing ax , (pic above) at the base of the stem. You must only cut though enough to sever part of the stem and still leave enough to allow the tree to stand up right. Over time these damaged shoots will stop growing and eventually rot and break off at the injury. While they are slowly dying they will prevent the roots from sending up new sprouts and deplete the roots of energy resources.

While I spend most of my days trying to save trees the principles of botany that regulate pruning response could also be used to prevent a tree from re sprouting. Aspens are arguably the oldest living trees although their above ground parts don't last all that long. Aspen roots are know to live thousands of years. When aspens are injured by storms, harvesting, or by browsing the chemicals released by the buds and growing shoots to prevent sprouting and suckering are no longer present. The roots are then free to send up a tremendous flush of new sprouts. This continues until the new shoots are able to generate enough suppressing chemicals to prevent further initiation of shoots.

If you were to partially sever the phloem on the outside of the stem a small portion of the inhibiting chemical would still pass down to the roots and prevent further suckering. Also photosynthate would not travel down to the roots from where it is produced in the leaves. The roots would continue to provide water and nutrients from their stores transporting it upwards in the intact xylem. The roots would slowly starve to death. In the mean time the stems would begin to rot at the site of the injury and would eventually fall over and die as well. It is completely possible that this will work. The mechanisms of the plant regulators are more complicated than this but in this case this simple explanation will work.

I have seen trees with stems girdled by rodents leave out and look fine for a year or two and then just die once their stored energy was depleted. Dave, I hope you enjoy your multi tool. It may be small but you could use it to test this hypothesis! Good luck and thank you all for your questions.

Tuesday 9 September 2008

Be Strong, Watch for the Signs

This time of year we have an unparalleled opportunity to look into our trees future.

Like fortune tellers you can use your powers of observation to predict the future health of your trees and shrubs. Most trees and shrubs lose their leaves at this time of year. Even evergreens lose some leaves at certain times of the year. When and how much of their foliage is lost can give you a window on the future when it comes to the plants health.

Deciduous trees loose their leaves in a set order governed by day length, genetics and most importantly tree health. Ash trees typically lose their leaves sooner than oak trees or most maples. Within a group of trees of the same species individuals will loose their leaves at approximately the same time. Trees that loose their leaves sooner than their kin may be under stress. Insects, disease and drought can cause trees to loose their leaves prematurely. If you take the time to watch your trees at this time you may be able to identify individuals that are at risk and take action.

Birch trees that loose their leaves prematurely may have birch borers and there may still be time to treat them before next spring. Elm trees that loose their leaves prematurely may have late season infections of Dutch Elm Disease and can still be tested to see if they should be removed. Maples that are infected with verticilium wilt may have been struggling all summer and heat, combined with late season drought may have pushed your tree over the edge.

The process of losing leaves takes energy. Trees must form abscission layers at the base of the petiole, where each leaf stem meets the tree. If the tree is to weak or too diseased to form this layer it will not drop its leaves, they will simply wilt and hang on the tree. This symptom called flagging, is usually a sign that the tree has expired.

In nature there is a lot of variation between individuals of the same species and even more variation between different species. A good example of this is how some white oak species will retain a significant portion of their leaves right through winter. For white oaks this means very little. If your elm tree did the same it may have Dutch Elm Disease.

Occasionally you will have an early frost and trees will lose their leaves quite suddenly resulting in many still being left on the trees. Not to worry this is just an unusual occurrence and most trees are close to losing their leaves any way and will do so shortly even if the leaves have been frosted.

If summer continues and the first frost is a few weeks or even a month late, the trees will lose their leaves before the first frost. The wheels of change are moving as we approach winter. Take this brief opportunity to look into the future and see how healthy your trees will be next year. You may still be able to help your stressed tree get onto the road to recovery. If you are unsure of your trees health status contact your certified arborist.

Tuesday 5 August 2008

Tool Time

The old adage “ the right time to prune is when the saw is sharp” probably doesn't tell the whole story, but pruning with dull tools is always a disaster. The bests results come from professional-quality tools that are in good condition. Most professionals use hand bypass pruners and pole pruners day in and day out.

These can be expensive but after purchasing and being dissatisfied with several home use items I decided to purchase the pro tools and still have them after 10 years.

Pruning tools come in two basic types bypass and anvil style. Purchase only the bypass type. Anvil pruners bring a sharp blade down onto an anvil that results in a messy cut and injures your shrub. I recommend bypass pruners exclusively.

Bypass pruners work like scissors with two sharp blades opposite each other passing each other to making a clean cut. For cuts up to ½ inch in diameter a pair of sharp hand pruners work best. Bypass loppers are over sized hand pruners that will cut branches up to 2 inches in diameter.

Bypass pole pruners use the jaws of a lopper with a lever mechanism to get a mechanical advantage with out having the long handles of a lopper. This combined with the ability to insert pole sections giving you almost unlimited height makes for a very useful tool. A bypass pole pruner will work on overhead branches between ½ an inch and 1 inch. They also can be used for cutting low branches without bending over. For most homeowners 3 small 4 ft poles will be enough for shrub pruning. They are easier to fit in the trunk of your car as well. Interchangeable saw heads can be attached for tall branches.

Most pole saw heads also have a sturdy cast hook on the rear side opposite of the blade, this is used for breaking off small dead branches. You may have heard the phrase “ by hook or by crook”, this hook is the root of that statement. If you didn't have the king's permission to gather the twigs for your fire, you would fall into the later part of the quote. Another hint at the antiquity of this tool is the ring and spring arrangement that was used to secure a brush form the dark ages when all pruning cuts were to be painted over with tar. Still capable of multi tasking today the saw head can removed and used as a hand saw to cut branches larger than one inch that won't fit into your pole pruner. Professional pole saw blades are readily available and will fit wooden hand saw handles as well. Good tools will literally last you a life time so take the time to ask questions and get professional grade. If you have a pruning question or a great picture of your ancient pruning tools send them in! One question or picture will be selected at random over the next three months to receive the professional pruning multi-tool pictured at the top of this article! Send your questions and pictures from the link on the right tool bar.

Sunday 27 July 2008

Tipping the Scales

Photo: K Ashton, Lecanium scale

Your plants are having the life sucked out of them, literally!

Trees and shrubs are little more than sugar factories and there is no shortage of freeloaders that want a part of this sweet treasure.

In this case the culprit isn't some vegan vampire it may be a scale, a simple insect with a big appetite.

Scales are small insects that have evolved a protective waxy coating that protects them from the elements and predators. This waxy coating, or scale, is the source of the insects name and its secret weapon. The scale often resembles a twig, bud or the bark of its host, making it difficult to identify and confusing it's predators.

The insect spends most of its life immobile, sitting under its armor, quietly sipping sap with its mouth, firmly attached to it's host. As it grows it sheds its skin which becomes part of its protective coating. At a certain point in the year it lays eggs that develop into crawlers. These small exposed crawlers are so small that they escape predators can even blow on the wind to new host plants. Once they find a suitably delicious host they insert their mouth piece into the plumbing of the host and start their high carb diet. Some of the sap goes through the scale and drips onto the foliage or branches of the plant and leaves a stick black mess. There is still lots of energy in this mess and it is attacked by a sooty colored mold.

This black sticky film on the leaves of a plant, your patio furniture, or the paint on your car is often the first sign of a scale problem.

Scales come in two categories depending on the thickness of their waxy coating. Thickly covered scales, often looking like oyster shells under the microscope, are called armored scales. Less robustly covered scales are referred to as unarmored or soft scales. Typically the soft scales are covered in a waxy or fluffy protective coating that is thinner that their armored kin. Scales tend to be very host specific each one favoring a particular species or group of plants over all others.

Two common scales in the landscape are an armored scale on spruce and a soft scale on arborvitae. Pine needle scale, Chionaspis pinifoliae is an armored scale that prefers conifers to dine on. Spruce, pine, hemlock, yew and hemlock are all affected by this scale. This scale looks like tiny grains of white rice stuck to the trees needles.Predators will keep low levels of these in check but occasionally, in our landscapes they will reach numbers that require control. There are a number of products that can be used to control these but they all are best applied when the crawlers are active. This occurs in late June to mid July. It will take several years to get adequate control.

Arborvitae, cedars, are afflicted by a soft scale called Lecanium scale, Lecanium corni. This scale has evolved to look like a small shiny bud on the stem of the tree.

Lecanium scale's crawler stage is in mid July and applications timed to hit them while they are vulnerable are most successful. If your car is covered in sticky black sugar or if find something that looks unusual on your trees contact your Arborist. They will be able to tell if that lump on the branch is a scale and recommend a plan to thwart it's sweet tooth.

Sunday 22 June 2008

Like Lightning Striking Again....

Like the lines of Lou Christies smash hit, “again and again and again”, every summer I see the tragic consequences of this all to common occurrence.

The people who track these things indicate that you are more likely to be struck by lightning that win the lottery. I know trees don't by lottery tickets but plenty of them get hit by lightning.

Its is extremely rare for a mature tree to survive a lightning strike with out major damage.

In my experience large single trees on rocky out crops get hit with lightning all to often. This is the preferred habitat for oak trees and they have long been listed as the tree most likely to be struck by lightning. In fact oak is the favored tree of Zeus, the Greek god of thunder, for just that reason.

Lightning takes the path of least resistance to the ground, this may be on the wet bark on the outside of the tree, or it may penetrate into the moist cambium layer and heart wood. The tremendous energy super heats the moisture in the tree causing it to explode. This can be quite dramatic, throwing splinters and debris for great distances. The force of the explosion can even break windows and in one case blew the wall paneling off the interior walls of the house.

More often than not the lightning flashes across from the tree into the houses electrical system causing extensive damage to appliances and electronics.

The solution to this problem is a simple as Ben Franklin's kite and key experiment.

Lightning protection in trees typically consists of a thick copper conductor running from the top of the tree to a ground rod driven deep into the ground. It sounds simple and it is.

The top of the conducting wire is attached to an air tip, a conductive rod that terminates the copper lead. The lead is held to the tree with bronze stand offs that are driven into the bark. If the tree is extremely wide or has more than one main trunk several leads may branch off from the central conductor. All metallic objects in the tree must be bonded to the central lighting conductor. This includes bolts and cables used to support the structure of the tree. Specialty hardware is used to connect the system together ensuring a good electrical contact.

Lightning protection, when properly designed and installed, can reduce the risk of lighting flashing across into your home.

Does this improved grounding of the tree make it more susceptible to lightning strikes?

Probably not, but it does make it more likely to survive a direct hit. The materials are expensive and the skills needed to install the system are beyond the average home owner. Have your certified arborist inspect large trees close to your house to see if they are candidates for lightning protection. The results will pay out more reliably than the lottery.

Saturday 21 June 2008

Bored to Death!

There are few trees that can rival white birch for its four season beauty in the landscape.

There are also few trees that can be so heartbreakingly disappointing when they suddenly fail. Growing up my parents had a large European white birch that gracefully dominated the front yard of our house. Every spring we would dutifully treat it to prevent bark borers.

One by one the birches in our neighborhood were removed after the slow process of dying back from the top down. Last year we took the birch down, not because of borers, it had gown so large that it no longer fit the landscape and was mechanically unstable.

The nemesis of most white birch trees is the bronze birch borer, Agrilus anxius, this North American beetle has caused extensive die offs of native birches in the past.

Most white barked birch trees are susceptible. European variety's are so prone to attack that they are not recommended for planting. In the wild birch trees prefer moist north facing slopes that allow them to have full sun on the crown of the tree and shade to keep the roots cool. This is a far cry from conditions most birches face in urban and suburban landscapes. Most birches in peoples yards are under stress. Stress makes birch trees attractive to bark beetle infestation.

The beetles lay their eggs on the rough patches of bark normally near the attachment point of branches. Eggs hatch and the larva tunnel into the cambium layer excavating zig zag tunnels around the tree cutting off the flow of sap as they destroy the trees vascular system.

Healthy trees may be able to wall the larva off by forming a callus layer around the insect and preventing it from excavating the tree tissue. More often the tree is stressed and slow to respond to the invasion and loses the battle. The callus tissue forms a lumpy mound over the larval tunnel that can be seen on the outside of the bark. The process from egg to adult can take a year or more and is dictated by the weather. Cold conditions slow the process down.

The result is active adult emergence and egg laying throughout the summer months starting in early June.

If you see the tops of your birch trees dying back you may have birch borers. Close examination of the dead branches will probably reveal raised tunnels under the bark can dark “D” shaped exit holes on the bark. Pruning out infested branches to below areas with any visible activity will be helpful. There are treatments available that can be applied to the bark or systemically to the root zone to limit the impact of the borers. Heavily infested trees should be removed from the area to prevent infestation of adjacent trees. Maintaining vigor and reducing stress factors present will be of great benefit. Properly mulching the area below the tree will help reduce root temperature and increase the vitality of existing plantings. Acting before you have any signs of borers will be of greater benefit than trying to catch up once they are present. The long term key to preventing birch decline is to chose resistant species and maintain the vigor of those that are susceptible. Contact your certified arborist for recommendations on birch trees to plant as well as maintenance regimes for your existing birches.

Saturday 17 May 2008

Lethal Weapons!

In the early seventies a man was going through a car wash in Houston Texas. He was watching spinning car wash brushes when an idea hit him, like a diamond right between the eyes. Why not use rapidly spinning plastic brushes to cut grass!

George Ballas is credited for inventing the string trimmer in 1971. Who knew that a tin can, some fishing line and an electric motor could produce such a useful and potentially deadly tool. From that point in time forward no tree has been safe from its ravages!

Trees are living organisms. There bark is designed to keep moisture in and keep insects and diseases out. Bark is no match for a string trimmer designed to cut tough fibrous grass. Trees and shrubs are susceptible to string trimmer injury year round but the most devastating damage occurs in late spring. Once trees leaf out the trunk start to grow in diameter. The vascular cambium, a slippery layer of plant cells just under the bark begins to divide and produce new living cells. Some cells differentiate in to phloem tissue immediately below the bark. Other cells differentiate into xylem closer to the hard woody tissue in the center of the tree. Xylem transports water and nutrients upwards in the tree and phloem brings carbohydrates back down the tree for storage and fuel to power plant processes. While this growing and differentiating is taking place the bark is “slippery” meaning it can release from the tree exposing the living wood of the tree. This is in stark contrast to later in the year when these cells have hardened and removing the bark is almost impossible.

You can test this on a twig or small branch, just dig your fingernail under the bark and see how easily the bark releases from the living wood underneath.

Impact from a trimmer string at the slippery stage can remove whole sections of bark.

The damaged area dies and the top part of the tree becomes disconnected from the bottom. If the damage completely circles or girdles the tree the tree will die. If the damage is less extensive the tree will struggle and eventually die.

While I don't advocate returning to the dark ages and cutting each blade with hand snips, I do have a few tips that can eliminate the damage caused by string trimmers.

Remove grass and unwanted plants from the area directly around the tree. Correctly munching under trees can eliminate the need for string trimming close in. There are commercial guards available that will protect the base of the tree. I don't recommend using them unless they are the only solution as they may restrict the growth of the trees by binding the root flare. Porous 6 inch plastic drainage tile, cut into a 6 inch tube and sliced on one side will allow the tree to breath. If you have to use these guards make sure they are loose and remove them frequently to check for damage. I have had great success with this on boulevard trees where the city was maintaining the lawn.

If you have an idea to protect your trees from string trimmer damage check with your certified arborist, they are experts in tree preservation.

Wednesday 30 April 2008

It's Raining Landscapers!

The title of this article brings humor to a subject that is truly not funny, and may even prove fatal.

Arborists are tree care professionals with years of practical experience and extensive education that makes them experts in their fields. Having credentials alone is not enough to allow you to practice legally in most jurisdictions. State and Provincial licences prevent the lay person from pruning or treating tree diseases in most locals.

Furthermore working with trees can be extremely dangerous. Workers compensation plans are aware of the risk involved and charge higher premiums to tree care companies as a result. As a comparison landscapers typically pay 6% to 10% of every dollar in wages to their compensation plans. Tree care professionals are required to pay 30% of every dollar in wages to be properly covered for workers compensation. Liability and damage insurance are also much higher for legitimate tree care companies. Knowing these risks professionals make sure they have in house safety programs for tree climbers and tree care workers.

The International Society of Arboriculture offers training for all levels of tree care workers from the person on the ground to the most experienced climber. Professional tree care companies use these programs to insure worker safety and maintain there ability to get affordable insurance.

When you consider that statistical research has proven that in an accidental fall situation 50% of all people falling from 6 feet will die, training and proper insurance are a necessity.

Aside from the noted safety issues Arborists are tree care professionals that have the most up to date information on tree care. This ensures that you are getting todays best practices and treatments for your home's valuable assets, your landscape trees.

I work with professional landscapers everyday. Many of them have great knowledge of plants and shrubs. The best ones know their limits and know when to call in tree care professionals to complement their work on the landscape. The experienced professionals know that when your working off the ground you need to be licensed and insured. Some have learned this the hard way after damaging property or injuring themselves or their workers.

You may think you are saving a few cents hiring uninsured unqualified companies or workers. When they injure themselves on your property and seek legal redress, you won't be hiring a lawyer from the temp agency.

I have included a collage of a news item and hand bill advertisements that one commonly sees. This guy was lucky. I didn't include a different news item of a landscaper that was taking down a large tree with unskilled help. The worker was pulling the tree over with a rope he had wrapped around his arm. The tree fell the wrong way violently pulling the worker into an adjacent tree, his baseball cap offered no protection as his head was slammed against the tree. He was pronounced dead on arrival at the local hospital. A high price was paid by this worker for his lack of experience.

For your tree care contact a tree care professional, an ISA certified arborist.

Sunday 27 April 2008

Winter Injury

photo MSU

For the avid plants person spring is the most thrilling and heartbreaking time of the year.

It is at this time that we get to see which of our old friends has made it through winters harsh blast.

While some trees and shrubs may look as though they are headed to the great hereafter, caution is always the rule at this time of year. More than one plant, having been given last rites, has literally come back from the roots on the compost heap! Take caution before writing a survivor off.

To understand how plants succumb to the ravages of winter we must have a basic understanding of plant physiology. Leaves are incredibly useful plant organs are notoriously fragile when it comes to freezing. Hardy trees and shrubs generally lose these most tender parts in preparation for winter. Those that don't lose their leaves have thick waxy cuticles, or skins, that prevent dessication. Dying out over winter has led to the demise of many a plant. You don't need a microscope to see how thick and durable a spruce or pine needle is, just hold it in you fingers and break it.

If you failed to water your evergreens last year they may be looking a little burnt out at this time.

Check to see if the buds are swelling and pinch the bark to see if its supple and alive. If you scrape back the bark with your finger nail you may see green, it may not be the end for this tree, wait a few weeks and see what happens.

Arborvitaes, junipers and other scale leafed evergreens may look scorched at this time of year, again wait a few weeks before you throw these babies out with the bath water. In most cases simple preparation in the fall could have prevented some if not all of these types of injuries.

Watering well until freeze up is a good strategy. Antidesicants, waxy sprays applied in the fall, are good for established plants that can have problems as well as fall planted evergreens that have yet to establish.

Late summer fertilization of evergreens is not recommended as it may delay the onset of dormancy and leave trees and shrubs susceptible to winter injury. Wait until trees are in the process of becoming dormant before fall fertilizing.

As for the trees and shrubs that are suffering from the effects of last winter? They should be watered well and monitored for signs of improvement. A small amount of fertilizer or better still an organic soil enhancer like pulverized liquid sea kelp can help with root growth and speed recovery.

Don't over water trees that have been winter injured but don't let them dry out completely either.

Use your finger to see if the soil in the root zone is dry. Be patient you may save an old friend from the compost heap.

Saturday 26 April 2008

For Strong Winds

While it's true that “things will change, come what may”, it is a good idea to think about what you can do to prevent wind damage in the first place.

Knowing the resistance to wind damage of the trees your planting is a great place to start.

The following list of trees arranged from the least wind damage resistant trees to the most resistant.











This list should be used as a guideline and if you decide to plant trees that are more prone to wind damage you can take steps to reduce the chance of damage.

When planting spruce plant in groups, single trees are more likely to wind throw. Spruce and pine trees need to be periodically thinned and dead wooded to open up their crowns and allow for air movement.

Trees like cherry and silver maple have hard brittle wood. Care should be taken to grow trees with good form free from co-dominate stems. These trees can be trained to have stronger structure and thinned to reduce crown density.

All trees benefit from having well drained sites. This should be arranged before planting.

Changes in drainage on your property or adjacent properties can have negative effects on your trees root systems.

Changes to grade or any injury to the roots of a tree will increase the chances of failure during strong winds. Construction on existing properties must take into consideration the effects on the root systems of mature trees. It take surprisingly little traffic to injure the roots of large trees.

Mature trees should be inspected for dangerous rot and large dead branches on a seasonal basis. Large dead branches should be removed promptly to prevent unexpected failure. Keeping the trees crown clean allows you to spot new dead branches and monitor the tree for signs of decline. Take the time to look at your trees before the wind sets you landscape back years! If your not sure what to look for contact your certified arborist.

Monday 24 March 2008

Who Has Seen The Wind?

The title of this article pays homage to W.O. Mitchell's tale of life on the prairies during the dust bowl years. I don't think that there could be a more fitting title for a frank discussion of the visible effects of strong winds. We really don't see the wind, what we do see daily is its dramatic effects on the trees in our landscapes.

Trees are long lived stationary organisms that deal with wind on a day to day basis.

The events that lead to dramatic and some times tragic failures of trees, branches or entire forests often depend on changes to the the trees normal environment.

Take for instance wind, both its direction and strength. For any given location winds will come from a prevailing direction. Trees grow roots and crowns in patterns that compensate for this type of wind. A wind coming from any direction other than the prevailing direction, will cause more damage. Winds also blow at predictable strengths for most locations. Unusually strong winds from any direction will cause extensive damage to trees.

People have been watching the effects of wind long before hi-tech devices to measure wind speeds were available. Knowing common indicators of wind speed can give you some insight into tree damage and failure. One system of measuring wind speed related to its action on sailing ships was developed by Sir Francis Beaufort, a British admiral. The scale was updated over the years to include wind indicators for those of us on land. Beaufort's scale indicates that little tree damage occurs below 22 mph ( 35 km/h). At 27 mph, ( 44 km/h) umbrella use becomes impossible and large branches begin to sway. As wind increases up to 42 mph ( 68 km/h ) twigs begin to break off of the larger branches. Damage continues to increase and when you reach 60 mph ( 96 km/h) whole trees begin to topple over. Beyond this point damage increases dramatically.

What Beaufort's scale fails to take into account are the site conditions of the trees. Trees that are in full leaf will fail at much lower wind speeds. My own personal observations indicate that at 42 mph ( 68 km/h) trees in full leaf in saturated soils will topple readily. Soils that are drenched with rain or melt water do not hold roots with the same strength as when they are dry. Trees that have lost their leaves and are in frozen soil can survive much stronger winds. Drought stressed trees lose fine roots that anchor the support roots of the tree. The result can be increased potential for wind throw.

The answer to the question “ Why did this tree fail?” can be complicated. The correct answer may include the following: Root loss due to drought. Unstable soil conditions due to rain or thawing. Wind blowing from an unusual direction. Wind blowing at unusually high speeds. Rot or decay in the root system. Decay in the trunk of the tree. Recent or past construction in the area. One has to take all the factors into consideration to determine when a tree will fail. The answer to the failure question may be quite simple. Once trees or limbs are dead they begin a slow countdown to the moment when they break off and succumb to gravity. This is often chaotic and unfortunately can be tragic. A properly trained arborist can identify potential hazards an hopefully avert unfortunate failures of trees and branches. When was the last time your trees had your trees inspected?

Sunday 10 February 2008

Three Cuts to Success

The difference between a professional branch removal and a poor pruning job is often a result of poor technique. Before we discuss how to make a professional pruning cut we should discuss when its appropriate to make your own cuts and when you should call in a professional.

I don't perform surgery on my dog, I will do first aid to dress a small wound or remove a sliver. I don't have the necessary veterinary expertise. You should keep this in mind when you work on your trees. Prune your tree with a specific goal in mind. A small branch removal can be performed by most home owners with the right knowledge. If you have to leave the ground, or are unsure of the results of your pruning call a certifed arborist. Any amount of pruning on a tree causes injury. With this in mind I will out line a technique to remove most small branches up to 2 inches in diameter.

When removing small branches back to another branch make sure the remaining branch is at least 1/3 the size of the large branch that was removed. This will ensure the remaining branch is of adequate size to take over the role of terminal bud. If you left a ¼ inch twig at the end of a 1 inch branch that you removed the 1 inch branch would sprout at the cut and the twig may just die off.

The three cut method is the standard for removing larger branches.

Make your first shallow cut on the bottom of the branch 3 inches from the swelling where the branch attaches .
This swelling, the branch bark collar and it separates the branch tissue from the main trunk tissue. Never cut into the branch collar


Make your second cut on the top of the branch a few hand widths away from your first cut . This second cut will follow right through the branch. You will note haw as you approach the bottom of the branch the wood tears away and rips the bark back to the first cut on the bottom of the branch. The first cut is to stop the bark from ripping all the way down the trunk of the tree. Hasty pruning will result in these ugly tears.

The third cut starts below and just outside the branch bark collar and cuts strait through to the top of the branch. Once the weight of the branch is removed the bark will not tear. You will have a nice clean cut and no left over stub.

Again if you are thinning a tree out make sure the branch you leave behind is at least 1/3 of the size of the branch removed to allow it to take over with our excess sprouting. A good rule of thumb is to never prune more than ¼ of the live branches at anytime to allow the shrub to recover from the injury. You can always come back next year and do a bit more.

Sunday 13 January 2008

Send Them Packing!


Mega deals at the mega mart lead to increases in invasive forest pests. Improvements in transportation mean that a forest pest that laid eggs in packing crates on one continent can have its offspring delivered to the other side of the world just a few short weeks later. Add one more to the list of infamy that includes the Asian long horn beetle and the emerald ash borer.

The Sirex wood wasp is the latest unwelcome guest that has hitchhiked its ways to our shores in the cargo hold of high speed container ships.

Sirex noctilo F. is a native of Europe, Asia and Africa where it is considered to be a minor pest of stressed Scots pine. When it was accidentally introduced to pine plantations in South America it was no longer a bit player in the world of forestry.

In South American pine plantations mortality of up to 80% was recorded. Most of these plantations are planted with native north American trees such as Ponderosa, jack and lodgepole pine. White pine are less affected but are subject to attack.

In North America we have at least a dozen native wood wasps. Wood wasps are typically 1 to 2 inches in length, wasp like insects and generally are black and brown in color. The Sirex wasp has characteristics that distinguish it from the native species.

Sixex adults are generally blue to blue black with the males displaying an orange mid torso. The females have large reddish yellow feet which will be black on the rear legs of the males. The antennae on both the males and females are black.

If you thing you have spotted one please contact an expert for positive identification.

Native wood wasps attack dead and dying trees but Sirex wasps attack living trees.

The actual feeding of the larvae cause some of the damage, but a symbiotic fungus, Amylostereum areolatum that the female injects into the tree as she is laying eggs does the bulk of the damage.

The wasp completes its life cycle in one year. Adults emerge in mid to late summer and the females make an initial flight to a stressed tree. The females have been reported to travel up to 90 miles making quarantine efforts ineffective. Given that many trees are drought stressed at this time of year hosts will not be difficult to find. The female drills her ovapositors, a specialized egg laying appendage, into the bark of the tree and deposits up to 250 eggs and the symbiotic fungus under the bark of the tree. Fertilized eggs develop into female wasps, unfertilized develop into males. The larvae tunnel into the interior of the tree for up to a year. Pupae form close to the the surface before the adults emerge the following summer.

With the large number of two three and five needle pine in North American forests this pest is

expected to have a substantial impact.

Another hitchhiking newcomer, the emerald ash borer has just been located in Toronto, Canada as it continues to spread.

Saturday 12 January 2008

White Pine Weevil

From the Professor Tree Question Line

My name is Silvia, I have planted Scot pines from PRFA for many years,
but the oldest ones 7 years old loose the top part of the tree.
The tree cracks at a certain height and the upper stem part falls.
In addition all the needles are yellow and the bark is not hard,
but like a film reddish that cracks peels.
The area also exudes sap, there is also a whitish substance.
The problem looks likeit starts from the trunk, and moves
outside toward the end of the branches.
The soil is very sandy and also very dry, and these past
two years have been very windy.
The trees were all in good shape at the beginning of the spring,
Are the Scot pines trees could suffer from some disease.
Is there anything I can do? I appreciate any help and
advise you could give me.
Thank you so much.
Silvia C.
I am very worried because it takes a lot for a tree to grow
here and now that these trees are big, they lose the top
part of trunk and branches.

Based on your description and the photos the problem is white pine weevil Pissodes strobi .

This native insect attacks Scots pine, white pine as well as white and Norway spruce. The damage is caused when the adults lay their eggs in the upper shoots of the effected tree. The larvae feed on the area under the bark known as the cambium. This feeding disrupts the flow of sap from the shoot and results in its death. The tree seldom dies from this damage and usually ends up with a misshaped top as a result. The damaged tops resemble a shepherd's crook this is a quick visual cue that the insect is present. Young trees are usually the target of this weevil. Removing the damaged crooks, by cutting them out a little below the damage, is an effective method of controlling these pests. The ideal time to do this is early to mid July around the time wild raspberries ripen. There are also chemical controls that are effective when combined with sanitation pruning.