Thursday 13 December 2007

Healthy Holidays

December 12, 2007,

At this time of year it is the custom to bring plants that are typically outdoors inside.
Natural trees have many advantages over their petroleum based imitators, you can add one more to the list .
Spruce, pine and fir are generally non toxic. Their taste and texture will usually stop a curious toddler or pet from eating more than a nibble. While there is little chance you would eat a spruce tree or make a salad from your fir, there are a couple of plants you should watch out for. Holly and mistletoe are two holiday favorites that should be kept out of reach.
(Ilex opaca) with its glossy foliage and bright red leaves makes an excellent focal point on a wreath and adds a colorful accent to garlands. Unfortunately the berries are toxic to cats and dogs. Holly contains illicin, and triterpenoids, if your pet eats a small amount they may get sick, a large amount, and a trip to the vet will be in order. Keep in mind that a small pet needs only a small amount to become quite ill. The custom of kissing under the mistletoe, (Viscum album) dates back to the days of the Vikings and figured prominently in the death of the Norse God Baldur. This ancient plant has been bestowed with mystical properties. One not so magical property is its toxic potency . If pets eat mistletoe in any amount call your veterinarian immediately for advice on treatment.While I'm being a Grinch on holiday traditions, poinsettia sap can be a potent irritant to your pets mouth. Fortunately carefully washing the affected area is usually all that is needed to alleviate the discomfort.

Tuesday 4 December 2007

Winterize Your Landscape !

Photo C. Ashcroft

November 30, 2007,

Many people take the time to prepare their vehicles for winter. Few people take simple steps to help their trees through the icy blast!

The first step in being prepared for winter storms is to take a quick inventory of your trees. Evergreens and large deciduous trees have different requirements when frigid weather arrives.

Evergreens should have been well watered right up to freezing. Cedars, arborvitaes and junipers may benefit from an application of anti desiccant. Trees have difficulty replenishing moisture in needles and leaves when the ground is frozen. Anti desiccants form a waxy coating reducing the likelihood that foliage will be dried out when winter weather turns suddenly warm and windy.

Some winter guests may become pests. Deer, rabbits and mice can make your

landscape into a veritable salad bar of winter survival foods. Repellents can be effective in reducing foliage browsing by deer, but mechanical barriers work best for mice and rabbits. Whether a little, or a lot, hardware cloth can keep most rodents on the run and looking elsewhere for a meal. Limit the amount of leaves and debris a the base of shrubs and trees. Debris will act as cover and encourage rodent activity.

Do your own storm damage assessment by walking around the large mature trees close to your house. With the leaves gone you can see branches and damage that may have been hidden in the summer. Look for branches that are at odd angles, generally most living branches grow upwards. Broken branches may be hanging dangerously, over paths and driveways.

Inspect cables that have been installed previously with binoculars to make sure they are not overgrown or frayed. If they were installed more than 5 years ago you should have them professionally inspected to make sure they are not rusted and are up to modern standards.

Are there any unusual cracks? Is bark falling away from the tree? Both of these signs could be indications of larger problems inside.

Visual clues are not the only ones to look out for.

I have had clients call in the dead of winter because their trees are making strange noises. Winter climactic extremes can open up cracks that become groaning creaking monsters when winter winds blow. A quick inspection from an I.S.A. Certified Arborist may put your mind at ease. It will also reduce the chance of a unexpected failures.

Trees and shrubs are a substantial investment, accounting for up to fifteen percent of your property value. A few steps to winterize your landscape can guard your investment and protect your home. Be wise – winterize, your landscape!

Thursday 25 October 2007

Timely Pruning


When is the right time to prune my tree? This must be one of the top ten questions when it comes to the topic of tree care.
When considering the timeliness of pruning one must consider various factors. The correct timing is not always as the old adage says “when the saw is sharp”.
The first factor to consider is that every pruning cut on a living branch is an injury. Pruning wounds cause the tree to use energy to contain the decay that is inevitably caused by injuring the tree. Prune only the minimum amount needed to achieve your desired goal. Pruning excessively will result in permanent injury to the tree and increased frequency of corrective pruning in the future .
The second factor to consider is the species of the tree. Various trees have different growth patterns that affect the time of year that you can successfully prune the tree.
Trees like maple, willow and birch should not be pruned in late winter or early spiring. This will cause them to lose copious amounts of sap that will slightly weaken the trees and will make a sticky mess in your landscape. Trees that tend to lose sap can be pruned when they have fully leafed out or later in summer.
The third factor to consider is the presence of insect pests and diseases. Some trees may be made more susceptible to these problems when you injure them by pruning. For this reason species like elm and oak should only be pruned when dormant. Typically after the leaves fall and into mid winter. In many jurisdictions there are prohibitions on pruning elms and oaks during the growing season. Generally most flowering trees can be pruned right after they flower to allow new flower buds to set. Pruning these trees too late can result in poor flowering response the following year. The art of pruning apple trees is based on elements of style and timing. The art of apple tree pruning would take several volumes to cover adequately.
With many deciduous trees the later you wait to prune them in the winter the greater amount of adventitious shoots you will develop the following year. These succulent shoots are less likely to develop if the trees are pruned in fall or late summer when the trees are still in leaf. This propensity to sprout new growth is the force behind rejuvenation pruning. This pruning technique is mainly practiced on leggy declining shrubs and is not recommended for most trees. Rejuvenation involves cutting the shrub off to within a few inches of the ground and allowing it to grow back from the resultant stump. This is commonly used in willow cultivation to get large numbers of canes to propagate vegetatively. Again this process is not recommended for mature healthy trees.
Spruce trees and most pine trees can be pruned in the spring when they are putting out new growth. Generally most evergreen conifers follow this rule and should not be pruned from mid summer until fall weather cools things off. Finally, it is important that your tools be sharp and up to the job at hand. Cuts larger than ¾ of an inch should be performed with a sharp saw, bypass pruners are the preferred tool below ¾ of an inch. These few general rules will be of help, but for more specific answers to tree pruning questions contact and I.S.A. Certified Arborist.

Sunday 9 September 2007

One Mans Junk Another Mans Treasure

While traveling recently I was reflecting on people’s relationship with trees.

Quite often I will hear people describe this or that tree as a "junk tree".

It’s easy to attach labels to trees that for one reason or another have developed a bad reputation. Professional tree care people are often the worst culprits in this practice.

However one must proceed with caution, because as the title of this articles eludes "one mans junk is another mans treasure”.

In the Western Plains cottonwoods are revered as giants of the riparian forest. Riding along the banks of the Missouri river at the height of summer one can’t help but marvel at the majesty of these stately stands. Yet in the eastern parts of North America these very trees are ridiculed as being weedy, messy and totally undesirable. Similarly the box elder, also known as the Manitoba Maple is a very fast growing hardy tree that graces the yards and streets of many a prairie town. Again it is much maligned in the Midwest and New England.

It can be said that is that a weed is simply the wrong plant in the wrong place. This is true for trees as well. The Norway maple is fast growing and comes in varieties with beautiful burgundy foliage. This tree can become weedy and often escapes into the woods, successfully out competing native maples. There is some merit to calling invasive species less desirable or at the least not recommended for planting.

I have often considered many of the Asian elms to be in this category. In fact I once recommended the removal of one such tree to a client, due to its prolific seed production and numerous broken, decayed small branches over the patio in the court yard of the house.

“I would recommend taking this junk tree down, it will be nothing but trouble. “ I stated confidently to my client.

Listening closely to what he said provided an invaluable lesson. The potential client paused and then told me how he and his son had grown the tree from a small sapling in the woods to its present size. The tree had a very special sentimental value.

This illustrates how often, in Urban Forestry, you are dealing with the person’s feelings and emotions towards a tree and not just its botanical attributes. Junk or treasure, it is truly in the eye of the beholder. I’m sure many readers have similar stories. Please feel free to forward them to the address below. They may be featured in a future article. And I always like a good tree story.

No Sweat !

“Do trees sweat”? The answer is yes, in their own way.

Trees use the evaporation of moisture to cool themselves when moisture is easily available.

Moisture in the leaves comes up from the roots through the trees vascular system.

This process is both passive in the form osmosis and active with cells moving the water along like a vegetative bucket brigade. This all works well in a particular set of limited circumstances. For instance, when ground water is available and the tree is in relatively

dry air. Only then can the tree release tremendous amounts of water. Some estimates run as high as 350 gallons per day with optimum conditions. 95% of this water is lost to the atmosphere in the process called evapotranspiration. Trees don’t exist to emit water vapor into the air and cool the globe in the process. However this seemingly altruistic process does occur as a result.

Transpiration uses water to move minerals from the root zone to the leaves where they are combined in the process of photosynthesis to create sugars. When trees release moisture into the atmosphere it does indeed cool the leaf. This is important because the process of photosynthesis in most trees occurs in a relatively narrow temperature range. This range is between 15’c and 25’ c or 59 ‘f and 77’f. Within this small range of temperatures the whole process works in an optimum fashion. Too low a temperature and the process is not efficient. At high temperature it begins to slow down as carbon dioxide becomes a limiting factor. Evapotranspiration works to keep the leaf in this optimum range.

Leaves are also able to dissipate heat directly into the atmosphere using a process called convection. If the leaf is hotter than the surrounding atmosphere heat will waft away from the leaf on air currents. Typically a leaf in sun light is slightly hotter than the surrounding atmosphere. This temperature gradient in itself allows moisture to evaporate from the leaf even if the relative humidity in the surrounding air is high. Trees are not immune to loosing more water than they can replenish from the roots. This causes a water deficit. If the tree is able to replenish its supply of moisture before the start of the next day it is able to continue growing even though this situation does limit the overall growth of the tree. This condition is called a daily water deficit. If the tree is not able to re-supply its water needs it will become desiccated and die.

Tree leaves regulate the loss of water vapor through small openings in the leaves called stomata.

These specially modified groups of cells are found on the outer surface of the leaf, top and bottom. As moisture exits the leaf it creates a humid boundary layer around the leaf. Wind moves the moisture away and allows the leaf to continue transpiring. If the wind speed becomes too great the leaf will close the stomata to reduce moisture loss also reducing the cooling effect losing moisture creates. For a more detailed explanation of tree water relations contact an I.S.A. Certified Arborist.

Sunday 22 July 2007

Dutch Elm Disease

Its time to get out in your neighborhood and look for threats to our oldest and most stately residents!

While neighborhood watches are nothing new, the threat you’re looking for is Dutch elm disease. Dutch elm disease arrived in North America in the late 1940's from Europe where it had devastated European elms. It is a fungal vascular disease that infects elm trees water conducting systems and the tree literally dies fighting to prevent the spread of the disease within.

The disease is spread from tree to tree in two ways: as fungal spores on the bodies of elm bark beetles and secondly by tree-to-tree connections called root grafts. The disease typically appears in late June and early July as wilting leaves in the upper crown of native American elms. The leaves turn brown and remain hanging on the tree. The disease progresses downward through the trees water conducting vessels. Eventually it spreads to the roots where it may be spread to adjacent trees through grafts. A young vigorous tree may die quickly within 2 to 3 months. Older trees may last for a season or two but will eventually succumb to the disease. Once the tree has the disease there is little that can be done to save it. Injecting systemic fungicides can stop the spread of the disease if you start the injections when only 10% to 15% of the crown is affected. Unfortunately by the time the disease is discovered it has progressed beyond this stage.

Well the tree is dying it is extremely attractive to female bark beetles who lay their eggs in brood galleries under the bark. When these beetles emerge they will carry spores on their bodies that will spread Dutch elm disease to healthy elms. Healthy elms with pruning wounds are attractive to beetles laying eggs. To reduce this risk the Province of Manitoba has an elm pruning ban in place from April 31st to July 31st every year. Spraying elms with a registered insecticide at the base of the trunk in the fall can reduce the number of over wintering elm bark beetles and slow the spread of the disease.
Watch your elms this time of year for dead or browning leaves. If you see some thing suspicious and are in a town that is part of the Provincial Dutch Elm Disease program contact your town office. The Provincial Dutch Elm disease survey Crew can be contacted at 1-204-726-6444. Contact an I.S.A. Certified Arborist for the complete story on Dutch elm disease and recommended measures to prolong the life of your graceful elms.

Saturday 30 June 2007

Be Prepared, (to prevent storm damage)

The title of this article is the motto of a well known organization, and it should be your mantra when it comes to preparing for summer storms.

The first step in being prepared for summer storms is to take an inventory of you trees. Walk all the way around large trees that are within 100 feet of your home. Do they have any unusual cracks, bark tears or mushrooms growing out of the trunk? Damage to the bark and branches could indicate internal decay that could lead to sudden failure.

Some species of trees form weak unions where branches meet the trunk. If a branch is weakly, attached high winds could tear it from the tree and cause damage to your property and leave the tree damaged and unstable. Installing support cables early can reduce the chance of a catastrophic failure. If your tree has had support cables installed in the past you should visually inspect them. If they were installed more than 5 years ago you should have them professionally inspected to make sure they are not rusted and are up to modern standards.

Do the roots show any sign of disturbance? Cracks in the soil, heaving, lifting and tilting could be telltale signs of a tree that is starting to tip over. Soil erosion and drainage problems can leave many evergreens precariously rooted and subject to wind throw.

Trees along access roads, drives, garages and out buildings should be visually inspected before storm season and after major storms. Look out for hanging branches that may become lodged in the trees crown and not be readily apparent.

Electrical services telephone and cable wires should be cleared from branches and kept away from potential tree failure zones.

Treat all wires as if they were energized with lethal voltage. You never know what may have come in contact with the wires beyond your property. Always hire a professional who is qualified to work around electrical wires.

Mature trees close to buildings can act a a conduit for lightning strikes. The science of lightning protection can protect your home and save a prized tree. Large mature trees are a valuable asset to your landscape. The investment in a properly designed lightning protection system will pay off in the short run. Trees on large rocks or in open areas are particularly attractive to lightning.


An Interesting Video,

Most Certified Arborists will perform a storm risk inspection as a part of your annual property inspection. They will be able to address your concerns and point out items you may have missed. Be prepared consult your ISA Certified Arborist.

For more information on this subject or any plant health care related questions,

Saturday 23 June 2007

Green Ash

Trees of the Forest, Green Ash

June 25, 2007,

This tree has become one of the most popular trees for our streets and yards after onslaught of
Dutch elm disease. Green a
sh, also called red ash has one of the largest natural ranges in North America. It is found from Nova Scotia to Saskatchewan and as far south as the southern United States.

The leaves are pinately compound with five to seven toothed leaflets arranged oppositely along a central raceme. The leaflets are one to two inches long oval at the base and tapering to a point. The leaves are typically finely toothed above the middle of the leaf. The leaflets will fall off individually early in the fall and leave the slender hairy stalk on the tree through the winter. It has been said of green ash that it is last to leaf out and first to fall. Ash seeds are thin winged samaras that spiral down like propellers when they mature. Ash trees are dioecious, meaning there are both male and female plants. Female ash trees bear the seeds. Male ash plants will have flowers in the spring.

The Latin name of this tree, Fraxinus pennsylvanica refers to phraxix, Latin for to separate, and Pennsylvania the state where it was first identified in. I always assumed that its ability to split easily, as in firewood, was the source of the name, further research indicates it may refer to separating fields. Ashes were commonly planted in hedge rows to separate fields.

This tough hardy tree is still a favorite plant for shelterbelts. Ash trees have had a long history of human use. From baseball bats to furniture ash is a hard, strait grained wood.

When used as firewood green ash has high heat energy only slightly less energy than oak, fortunately it does not rot quickly if left uncovered.

This native tree is still highly recommended for planting and does grow quite quickly. Ash is susceptible to a defoliating fungus, anthracnose that attacks the leaf stems and leaves in the spring. If spring weather is cool and damp the trees may defoliate or have distorted foliage. Typically the tree will develop new leaves and it may not be a major problem. If the weather does not co-operate and the fungus persists over a number of years the tree may be weakened and develop unusual growth. Another problem pest with green ash is plant bug; this small insect punctures the tissue of the leaf and feeds leaving the leaf doted with small yellow dots. This may all change with the introduction of emerald ash borer.

Take the time to establish good branch structure if you are developing a tree for your yard. Keep in mind that in the wild, green ash is a river bottom tree and is tolerant of flooding. It prefers open sites but will grow in an existing canopy. It is moderately shade tolerant. Typically it will be found a bit higher in the riparian zone than Manitoba maple and below burr oak. Its neighbors may include willow, cottonwood, and where applicable American elm. For more information on native trees contact an ISA Certified Arborist.

Tuesday 19 June 2007

EAB, The Real Deal!

EAB, The Real Deal!

Over the years there have been many real and imagined pests and diseases that have destroyed or threatened to destroy our forests. With this in mind I was somewhat jaded when the Emerald Ash Borer was put to the top of the list as the latest threat to our trees. Not again must have rolled off the tongues of every tree lover in North America.

After following the progression of this pest from infesting a few counties in the Detroit Michigan area to its current extent of five states and the Province of Ontario, something less civil should roll off the tongue! This pest may very well turn out to be the real deal, decimating all species of ash trees in areas that it becomes established in.

Emerald Ash Borer, Agrilus planipennis Fairmaire, is an exotic pest that was introduced accidentally into North America in the late 1990’s. The original infestation was probably the result of green wood in the form of packing materials that originated from the beetles home range in Eastern Asia. Whether it came from Russia, Korea, China or Japan is of little importance now. Logs infested with the larvae of the beetle were probably used to shore up shipping containers and were off loaded in Detroit. From there the adults, who can fly several miles when mature, found a welcome place to lay there eggs in North American ash trees.

It took several years before any one found the initial colonization and by then this prolific insect had developed a large population. The adults themselves feed on the leaves of ash trees but cause little damage. In late June to early July, they lay there eggs on the bark of ash trees usually in cracks crevices and fissures. The eggs hatch, burrow into the inner bark, the cambium layer and begin to chew their way though the vascular cambium layer in up to foot long serpentine feeding galleries. The larvae pupate and over winter under the bark of the trees and emerge as adults the following May or June. The beetles emerge from a small D shaped hole around 1/8th of an inch in size.

The tree is unable to survive the injury to its vascular system, starts to wilt and die back and will last only one to three years once infested.

The initial area of North America has now expanded to over twenty thousand square miles and includes five states and the Province of Ontario. In the areas where the outbreak has been identified over 12 million trees have been removed in an effort to stop the spread of the Emerald Ash Borer. Official estimates in Ohio expect the prolific pest will cost 3 billion dollars in the next ten years.

Recently additional infested trees have been found further east in London, Ontario. Wood and wood products appear to be the primary means of transportation over long distances. Quarantines have been set up in infested areas.

Do not transport firewood from areas where the beetle is known to exist. As a measure of the severity of this threat, note that national agencies have begun an ash seed library to prevent ash tree extinction if quarantine measures are not successful.

Contact your local ISA certified arborist for up to date local information. Be on the look out for unusual die back in ash trees.

Sunday 20 May 2007

Fighting Defoliators One Worm at a Time

Fighting Defoliators One Worm at a Time

May 25, 2007

The new leaves are a welcome harbinger of spring. Green cankerworms eating the leaves are just as seasonal but not nearly as welcome. The process of controlling cankerworms starts in the spring and will result in decreased activity next year. You are not alone in your efforts. A number of parasitic insects feed on the eggs, larvae and pupas of these insects. Spiders, birds and small rodents also feast on the cankerworms at various times of the year. While all this eating is beneficial it does little to curb an epidemic population of worms. That is usually controlled by weather and soil conditions. Favorable weather conditions, like cold winters and late season frosts may control populations naturally. All of these factors combine to create a cyclical population boom and bust. Rather than waiting for the weather, or just talking about the weather, there are steps that you can take on your property to reduce the extent of the infestation next year. The first step is to arm your self with information on the life cycle of the two cankerworm species. The primary culprit that turns your elm, ash, or maple into a communal salad bar is the fall cankerworm, (Alsophila pometaria).

The life cycle of the fall cankerworm begins with the eggs over wintering in the upper branches of the host tree. The eggs hatch in late May as the new leaves unfold. Warm weather in spring will speed up the emergence of the leaves and the larvae. It takes approximately three weeks for them to mature and then the larvae spin a thread and drop to the ground like super heroes. When they reach the ground they spin a protective cocoon and change into pupae. Pupas are a stage in the development of insects where they change into moths. They emerge in September or October, as male and female moths. The males have wings and the females do not. At this point they have only to mate and lay eggs to start the process again. While the males are off being distracted by lights and flames, the females begin the long crawl to the top of the host tree to prepare to mate and lay eggs.

The spring cankerworm (Paleacrita vernata) has a similar life cycle with the larvae over wintering in the soil and pupating in spring. Both forms have wingless females. The female moth’s wingless crawl presents an opportunity to control both spring and fall forms of this insect. The application of sticky bands around the trunk of the tree will trap the females and prevent the deposition of eggs in the upper crown.

Start in mid summer, before the September long weekend, by lightly brushing off loose bark in a 6 inch band at 5 to six feet up the trunk of the tree. Do not girdle the tree by removing all the bark. You can then wrap glass wool, backed with stiff paper or foil in a four inch band around the tree. It can be secured with natural fiber like jute twine at the top and bottom of the strip. It is important to secure the band tightly to avoid the moths crawling under and not to tight as to injure the tree. Once you have the band in place paste sticky tangle foot, available from nurseries, evenly on the band. This will trap the females, so be sure to check it often to make sure there is no bridging over the trapped females. This would allow late arriving females to pass over the band. Reapply the tangle foot as necessary in the early spring to catch the spring cankerworm. Remove the bands in summer and reinstall in late summer. This will allow the tree to grow, and not damage the bark during the growing season. With single isolated trees this can significantly reduce the population of worms the following year. In a group, all trees will have to be banded.

When out breaks are severe, spraying with various products, as directed on the label, will give additional control. Btk, a bacterial insecticide works well when the insects are actively feeding.

Sunday 13 May 2007

Fruits of the Forest: High Bush Cranberry

May 13, 2007

You won’t likely find this cranberry next to your turkey this fall! That is unless you take the time to collect the berries yourself and make a delicious jelly with them.

The High Bush cranberry is some what underrated compared to other sweet berries of the woods.

High Bush cranberry, Viburnum trilobum, is a shrub with a large natural range. It is found in river valleys and open moist woods from the aspen parkland and the southern boreal forest. It is found in abundance along the Souris River, the Turtle River, and Assiniboine just to name a few areas. This shrub will attain a height of up to 12 feet in moist fertile soils, typically they are closer to 6 feet. This assumes that they haven’t been browsed by the local moose. The leaves are opposite, simple with three long pointed lobes typically 3 to four inches long. The Latin name, trilobum means “three lobed”.

The flowers are typical of most of the Viburnum family, flat topped white clusters of small flowers with larger sterile flowers, around the outer edge of the cluster. These sterile flowers may make the flower clusters more attractive to pollinators. You will see these flowers most often in June or early July.

The clusters of flowers once pollinated produce bunches of bright orange to red fruit.

These berry like drupes have a fleshy outer layer and a single large seed. The raw fruit is bitterly tannic and acidic. These are quite refreshing if you have a taste for them but should not be eaten in large quantities as they may cause cramps and vomiting. It is a favorite of bears and birds alike. Take care when gathering them in the wild not to startle the former. The Cree are reported to use the stems leaves and roots for a variety of medicinal propose. These range from pain relief to sore throat treatment. The bark is still boiled as a tea to relive menstrual cramps.

My personal favorite use for this fruit is in flavorful jellies. They have a unique odor, described by many as, sock like, but the taste is very good. I have included an untested recipe that seems to have the necessary amount of sugar. If anyone has good recipes feel free to email it to me.

This may be the plant to fill the gap in your diet as well as your wooded landscape.

For more information on native trees and shrubs contact an ISA Certified Arborist.

High Bush Cranberry Jelly

4 cups high bush cranberries

6 cups water

Additional water (as needed)

7 cups sugar

1/2 tsp. margarine or butter

1 pouch liquid pectin (Certo)

Bring the berries and water to a boil and simmer for 10 minutes. Crush the

berries or put through a food mill. Strain the juice in a cheesecloth-lined

sieve. Add any additional water if need to bring the juice up to 5 cups.

Bring the juice and sugar up to a boil. Add the margarine, then the liquid

pectin. Bring back to a boil, stirring constantly boil hard for 1 minute.

Remove from heat. Skim foam from surface and pour into sterile pint jars and

seal. Process in boiling water bath for 5 minutes.

Yield: 8 cups

Saturday 21 April 2007

Can you Build the Perfect Tree House?

April 22, 2007

Many a child has experienced the joy of gathering bits of cast off wood to create a lofty palace.

I remember many hours of hunting and gathering to make the perfect tree fort. In retrospect my lack of carpentry skills probably saved many a tree from an untimely death. Trees are long lived dynamic organisms that sway in the wind and grow over time expanding there girth and height. Houses are long standing static decaying structures that are built not to move and require constant input to keep them from falling apart. How can the two exist in a Tree- House?

Often times the answer is, not very well.

If the house is attached firmly to the trunk and wrapped around the branches completely two things will happen. First the house will start to break up like a ship on the rocks as the tree moves to and fro in the wind. Secondly the boards that are used to attach the tree to the house will slowly strangle the tree and eventually cause it to die off above the attachment point. Surprisingly one thing that won’t happen is the tree will not lift the house higher into the air as the tree grows. Trees don’t grow like Jacks bean stock. Trees grow incrementally adding layers of cells to the outside, like dipping a candle in wax or applying layers of paint. Trees gradually get thicker and larger. Only the growing tips of the branches will elongate and get taller or spread wider.

Now back to my lack of carpentry skills. Typically as a ten year olds we would gather

two by fours and old bent nails to attach a frame work in a few places to the tree. A piece of weathered plywood would be flopped on top of the makeshift floor joists. The whole thing was not very safe, not very sturdy, yet it was relatively harmless to the tree. A few strong winds and the whole thing would collapse or have to be reattached to the tree. These rarely survived the winter.

If you consider that half of the people that fall accidentally from 6 ft or higher do not survive the fall, it’s lucky my cohorts and I are alive. Some tree house makers may have grown up into crack liability lawyers.

Do all arborists wax poetic about there childhood tree adventures, or is it just me? The other day I was out to a property where a client had hired a professional carpenter to build a state of the art tree house in a multi stem willow. They had built it structurally to code.

Was there anything we could do to stop the tree from ripping the stoutly built structure apart? How long would the tree last with this house attached to it? The prognosis was not good; the tree had already started to swell over the 2 by 12’s that completely surrounded the stems of the tree and the roof was not in good condition either. With the tree house in place, the tree had 3 to 5 years before it started to die back and fall apart. The house was also supported by 4 by 4 poles that had either bent or lifted depending on how the house had shifted.

If you’re thinking of a tree house consider suspending it from large limbs with cables, like an extremely large bird feeder. You could also build a house on stilts next to a large tree. Position the house so it doesn’t rub on the tree and the tree doesn’t strike the house on stilts. If you’re determined to build your tree house, contact an arborist and a creative carpenter and you may come up with the perfect compromise.

Wednesday 21 March 2007

Suffering Sap Suckers?

March 22, 2007

As spring slowly warms up many migratory birds return to their summer territories.

Robins are always seen as a welcome harbinger of spring. One less welcome returnee is the Yellow Bellied Sapsucker. This small member of the woodpecker family can cause big damage to your prized trees. The bird itself is a little larger than a robin and has a bright red cap and white stripes on its head. The balance of its body is black and white with a yellowish tinge to the belly.

This industrious bird has been known to cause damage to a large variety of tree species.

It tends to prefer smooth barked deciduous trees like the linden, aspen and apple, but will frequently attack Scots pine, white pine and other conifers.

The damage caused is very characteristic, small pea sized holes in neat rows horizontally and vertically, sometimes girdling the trunk. These holes fill up with sap and the bird returns periodically to sip up his tasty handy work. Unfortunately the holes injure the tree directly by damaging the vascular system, preventing the flow of sap back down the tree. These holes also allow insects and diseases to enter into the tree and cause further injury.

Sapsuckers are federally protected migratory birds. You can not simply eliminate the problem by eliminating the birds. This would not only be illegal it would create a vacancy in the territory and a new bird will move in and set up shop. If the tree that is being damaged is not particularly valuable you may consider leaving it to the birds and protecting other more valuable trees. Remedies such as applying hardware cloth to the area being excavated or applying tangle foot to the bark to discourage feeding activity, have proven to be effective. Other people tie tinfoil pie pans, blow up owls, or plastic snakes to discourage the Sapsuckers.

If you are growing trees for specimens or timber you may wish to locate the hollow tree the birds are nesting. These birds normally nest in cavities of rotten aspens or other similar, easy to excavate trees. Mark the tree and eliminate it in the winter when the nest is unoccupied. The birds are quite attractive and do frequent suet feeders. If the damage is minor and you can encourage them to feed elsewhere, they can be quite entertaining to watch.

For more information on trees and tree pests contact an ISA Certified Arborist.

Sunday 18 February 2007

The Big Freeze

February 18, 2007

As you look out your window longing for spring take comfort in knowing that your trees are not really frozen. “That’s impossible with the temperature so far below freezing!” you may think. If your trees were frozen in the traditional sense, like your garden tomatoes, they would be dead.

Hardy perennials and trees have three strategies to prevent them from joining their green cousins every fall. An understanding of why your tomatoes are dead will help you realize why your trees are simply dormant.

In the fall when temperatures drop to the freezing point, ice crystals begin to form in the plants cells. While they are pretty to look at in a snow flake, forming inside a living plant cell

the results are devastating. The sharp water crystals puncture the plant cell causing its contents to leak out. The cell dies as a result. What you see is a wet limp leaf or stem that usually turns black. Commercial food production uses a fast or flash freezing to prevent ice crystal formation and keep your vegetables from getting mushy. Trees are by in large composed of water so how can they survive freezing weather?

Trees have several strategies to prevent ice crystal damage. Even the smallest amounts of

dissolved solids in the water in a tree will lower the point at which ice crystals form. This increases the plant’s ability to survive temperatures slightly below freezing. This is the same reason that salty ocean water freezes at a lower temperature than fresh water. In the case of plants, it is the dissolved sugar that prevents the plants from freezing at just below the freezing point of water.

As the temperature decreases the tree must be prepared by moving water out of the exposed plant cells and into areas that don’t freeze, like the roots. This causes the drying of the exposed upper stems and branches as well as concentrating the remaining sugars in the cells to prevent freezing. Much of the moisture remaining in the cells can be shifted to locations just outside the living cell in the intercellular spaces. Once outside the cell there is no danger that water crystallization will damage the cell.

The entire process reverses itself as the weather heats up in spring. Many plants are injured by rapid warming and freezing that can occur in areas that experience extreme changes in temperature. The ability to survive longer unusually warm spells, while not breaking dormancy, is an issue that affects winter hardiness. Plants that bloom or leaf out early in the spring, are more likely to be damaged by spells of unusually warm winter weather. For more information on winter hardiness contact an ISA Certified Arborist.

Sunday 14 January 2007

Bricks in Your Tree

January 14, 2007

The title (of) this month’s article pretty well sums it up. If you had called your tree surgeon as few as 20 years ago you may have ended up with this unlikely remedy. In the past it was standard practice to fill cavities in mature trees with solid materials to “support the tree”. Imagine if you will the surprise of a fellow arborist years later when he cuts into a seemingly solid tree to find it is full of concrete or bricks!

Cavities in trees form when wood dies and decays. Animals and insects will use the weaker rotten wood to form nesting sites or galleries for there colonies. The two most common causes of injury in trees are incorrect pruning and storm injury. Both actions can result in extensive areas of internal decay in otherwise healthy trees. These rotten areas once excavated by animals or insects can be quite large.

It is important to remember two principals when looking at these cavities: a hollow pipe is as strong as a solid rod and the tree has already formed barriers that will limit the spread of further decay. The first principal flies in the face of the thought, you must fill this cavity or the tree will be weak and fail. What really happens when you fill a living dynamic biological system, a tree, with a solid inert mass of concrete is quite predictable. The tree is further damaged by the constant abrasion of the concrete against the inside of the tree. The concrete is also chemically very different than the tree and will increase the moisture level in the cavity. It will also have a caustic injurious effect on the living wood of the tree. The second principle is that trees are living and act to limit the spread of decay in their tissues. Tree cavities are isolated from the living wood tissue in a tree by strong chemical barriers created by the tree when it was originally injured. If you have ever split firewood you will notice a dark staining around old dead branches in the wood. This is the chemical barrier the tree has erected to prevent the rot from spreading from the dead branch to the living tree tissue. These barriers are reinforced and redirected whenever the tree is re-injured. This injury process occurs every time a tree with a filled cavity moves in the wind. This process of creating resistant chemical barriers in wood is very energy expensive for the tree. Trees that do not have the energy to erect or maintain these barriers will be overcome by rot. When this happens the tree will die.

Occasionally trees will develop cavities that fill with water. It is not recommended to drill holes to drain this water as the tree has created barriers to prevent the water and rot from spreading. Drilling holes will further injure the tree and increase the size of the cavity.

So what is the preferred process for dealing with tree cavities? Access the structural strength of the tree. Is it able to stand with the sound tissue that remains? Access the proximity of the tree to potential targets should it fail. Examine the cavity and if necessary remove any loose debris that remains in the cavity with out injuring the living tissue. Monitor the cavity and see if the tree is putting on strong growth around the cavity evidenced by new healthy tissue.

If the tree is not posing an immediate danger to people or structures it may be safe to leave it where it is and continue monitoring it. When in doubt have a Certified Arborist evaluate the condition of the tree and give you an appropriate recommendation.