Saturday, 7 February 2009

Shrub Pruning 3 Technique



In the first part of this article we discussed the correct timing of pruning on most trees, shrubs and dwarf conifers. The second part of this article was dedicated to choosing the correct tools for pruning small trees and shrubs In this article we will discuss the techniques used in correctly pruning small trees and shrubs.

Terminology for pruning

Before we continue we should have a basic understanding of a few of the terms used to describe the basic anatomy of shrubs. Buds are dormant plant parts. Inside each bud is a complete bud or flower. Buds are described based on their position on the twig. Terminal buds are located at the end of a twig and lateral buds are located below the terminal bud on the sides of the twig. Buds can be arranged opposite each other on the twig or in a zig zag pattern alternating sides along the twig. The location where each bud or group of buds is located is called a node. The piece of twig between the buds is called the internode.

Techniques for pruning

As a general rule pruning cuts should take place just past the node, at a distance equal to the width of the twig. Cutting to close to the node will damage the bud and cause die back. Never cut in the middle of the internode. Cutting in the middle of the internode will result in an unsightly stub that will die back and may be an entry point for disease or insects. Two broad terms for pruning are heading back and thinning out.

Heading back is best described as when you indiscriminately reduce the size of a shrub to conform to a preset size or shape. For instance you may want to prune your carragana hedge into a 4ft by 3ft box. You would accomplish this by using a power shear to cut back the twigs in a uniform fashion. The carragana would quickly sprout a bushy broom on each tip and cover up the unsightly cuts that would result. The problem with heading back shrubs and hedges with this method is that eventually you end up with an umbrella of dense foliage at the tips of each leggy stem and little else below. Formal hedging often requires that you vary your technique by occasionally thinning out the dense canopy by cutting a series of windows in it to allow light and air to penetrate the inside of the plants.


Thinning is a more sustainable method of pruning that involves selectively removing branches back to the appropriate unions with other branches. As you can imagine this isn't done with a power shear. When thinning a hedge you need to determine your over all goal, say thin by 25% or open the hedge up every foot or so. You would then go through the hedge and cut out dead diseased and crossing branches back below the canopy by a foot or so every few feet. You would also remove healty branches back to the appropriate unions in selected locations. You could do this after you sheared it and still keep your formal look with a few small gaps. The hedge will respond by putting out new growth inside and below the existing canopy layer. Over time this method would allow you to reduce the overall size of the hedge without having it end up looking thin or over pruned.

Thinning is the method of choice when you want to maintain a shrub at a certain size and have a more natural form. When pruning shrubs in this style take a tip from your carpenter. Cut once - measure twice. You may notice that a tape measure was not included in my list of tools. You need to step back take a look at the shrub and measure with your eyes. Cut a bit and then step back and view your progress. Before removing larger branches give them a shake and see how they relate to the rest of the plant. Then remove that large branch in stages checking the form of the plant as you go. Once you have made your choice reach into the center of the shrub and cut the branch just slightly above the node of an outward facing bud. This will allow new growth to move away from the center of the shrub and avoid crowding. If you have a hole to fill in the shrub prune back to above a bud that faces the hole. Make a few cuts and then step back and have a look. Eventually you will reach a point that looks good to you then stop. If the shrub is viewed from multiple angles be sure to look at it from all sides. You can make the cuts at an angle if you wish, a clean cut at any angle is best.

Rejuvenation pruning is an extreme form of heading back that can be valuable when dealing with shrubs in mature landscapes. Over time some shrubs will become two leggy and unmanageable. You see this often in older gardens. One radical method of saving old plants is to rejuvenate them. Lilacs are the classic example of this. Lilacs need to have the older branches removed to allow the new growth to flourish. You can do this by removing the older stems back to 6 inch stubs. You leave any new shoots to take over. Typically you would remove 1/3 of the older shoots per year. In three years you will have all new shoots and a much invigorated plant. You will lose some flowers in the first few years and be rewarded with a bounty in the years to come.

A note of caution

Some plants are susceptible to diseases spread by pruning tools. Members of the rose family like cotonea aster and mountain ash should be pruned with sterile techniques to prevent the spread of fire blight. Black knot of cherry is another disease easily spread by unsterilized tools. The solution to this problem is dousing your tools with alcohol between cuts. Cut sterilize, cut sterilize and sterilize between plants.


Sunday, 1 February 2009

Pruning Shrubs Part II - Tool Kit


In the first part of this article we discussed the correct timing of pruning on most trees, shrubs and dwarf conifers. To recap that article, generally the best times to prune trees and shrubs are when they are dormant or just after flowering. The best time to prune dwarf pines like mugos, is while they are still candling. In this article we will discuss the

selecting and using the correct tools for pruning.

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. Bypass pruners work like scissors with two sharp blades opposite each other passing each other to making a clean cut. Anvil pruners bring the sharp blade down onto a flat surface, damaging the bark causing die back at the point of pruning.

For cuts up to ½ inch a pair of sharp hand pruners works best. Bypass loppers are over sized hand pruners that will cut branches up to 2 inches in diameter.

Loppers are sized to fit in between hand pruners and pole pruners and often stay on the shelf while the latter two tools do all the work.


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 foot 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 or 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 lifetime so take the time to ask questions and get professional grade tools. Contact your certified Arborist for more information on shrub pruning and watch for the third part of this article dealing with pruning techniques.


Sunday, 11 January 2009

Shrub Pruing Basics, Part 1, When to Prune


Landscapes make our houses into homes. Trees and shrubs not only contribute pleasant feelings to our surroundings they add up to 15% to the value of your property.

It often takes several years for newly planted shrubs to establish and then before you know it they are on their way to becoming leggy overgrown monsters.

Most shrubs will appreciate even the smallest amount of pruning and reward you with rejuvenated foliage and more abundant buds.

Time to prune

The first key to correctly pruning your shrub is to know what you are growing. Proper identification is essential to correctly prune your shrub. Many shrubs flower on last year's growth and if you are pruning yearly you may never get flowers. The classic example of this is the lilac. Shrubs like these should only be pruned immediately after they bloom to ensure a good set of flower buds for next year.

In contrast to the old wood flowerers some shrubs only bloom on this years new growth. These shrubs should be pruned before the growing season begins.

As with so much of nature there are shrubs that don't fall into either of these categories and flower from both last years growth and this years growth. These typically flower later in the growing season and can be pruned while dormant or right after blooming.


Pruning Chart


Location of Flowers

Best Time to Prune

Typical Plants

Last Years Growth

Right After Flowering

Lilac Forsythia Saskatoon

New Growth

Before Growing Season

Clematis Spirea Hydrangea

New and Old

Right After Flowering or While Dormant

Potentilla Rose

Mock Orange


There are some shrubs that we grow primarily for foliage, like red osier dogwood, elderberry, willows, and barberry. This group should generally be pruned in the winter season before growth begins. Moose prune their dogwoods in the winter and so should you.

Most conifers like spruce, juniper and cedars can be pruned at anytime with the exception of pines. Pines are best pruned in early summer when the new growth is emerging. These long shoots known as candles can be cut or pinched off at the half way point and the shrub will set new buds for future growth. If you prune pines after the shoot has fully elongated and you will be left with a half shoot. Without buds on the end it will loose its needles and leave you with a dead stick.

Contact your certified Arborist for more information on shrub pruning and watch for the second part of this article dealing with tools and techniques.

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
ground.

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.