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.

Christmas Holiday Tree Nuts

December 1, 2006,

This time of year our thoughts turn to the holidays, trees and feasting. While no festive season is complete without the smell of a real home grown tree, tree nuts are also a part of many people’s holiday celebrations. I’m not talking about inviting your arborist over to enjoy holiday cheer, although that’s one way to ensure you will have a certified tree nut in your house!

Almonds, hazelnuts, walnuts and Brazil nuts are the tree nuts associated with this time of year. Although many people enjoy these delicious treats few stop to think of the origins of these delicious treats.

The ancient practice of eating nuts and other fatty foods is tied to the winter solstice festivals of ancient Europe. In the winter days are short and nights are long. Nuts, a food that causes the body to release endorphins, can create a feeling of well being and mirth. In addition nuts increase the amount of serotonin in the brain. In Low serotonin levels in people have been related to despondent, lethargic and irritable behavior. Eating nuts makes you feel happy!

The almonds in your store typically come from California. This fruit of the tree Prunus dulcis,

is known as “sweet almond”. This nut was carried as a ground mixture on the ancient caravan routes between Europe and Asia. Travelers spread this seed from its origins in Mesopotamia to Greece and the entire Mediterranean climate area of Europe. It is a distant relative of stone fruits like peaches and plums.

Hazelnuts typically come from growers in Oregon, although varieties are native to eastern North America right up to the sub arctic. All hazelnuts are from the genus Corylus and are also called filberts. Filberts are native to the higher elevations of the Mediterranean. They are delicious roasted or ground into a flavoring in lamb stews.

Walnuts have been in cultivation for over 8000 years. The Romans referred to walnuts as Jupiter’s royal acorns. The most popular ones we eat are European walnuts grown in California. All walnuts are in the family Jugulans. Locally you can find Jugulans niger, the black walnut. The fruit of this variety is more shell than meat.

The most intriguing nut story goes to the Brazil nut, the nut that a country was named after. Brazil nuts grow only in the intact rain forest of South America. The Brazil nut, Bertholletia excelsa is a major non timber forest product for the peoples of Brazil as well as Peru. These giants of the rain forest can reach 150 feet in height and can be over 800 years old. In the rain forest only one species of bee can pollinate the Brazil nut tree. This bee needs a specific orchid to complete its life cycle. These orchids only row in association with the Brazil nut tree in areas of intact rainforest. The Brazil nuts come in hard pods, harder than the shell of the nut. Only one rodent indigenous to the region can chew through this shell and disperse the seeds. The Brazil nut tree is at the top of this unique ecological web. If one species is missing from this triangle the Brazil nut is doomed.

So if you want to carry on a long holiday tradition, feel good while doing it, and save the rain forest, get a bag of mixed nuts this holiday season. You could invite a certified tree nut to join you, your Arborist.

Old Friends

While walking in a friend’s garden the other day I stepped on a stepping stone with the following inscription; “It takes a long time to grow an old friend”.

Trees are long lived organisms that can easily have life spans across human generations. While not all trees live hundreds of years some can live thousands. Large mature trees are adapted to extreme forest environments and threats. There are many strategies to help trees survive various natural catastrophes. For example fire resistant bark, roots that can regenerate after disasters and seeds that take years to germinate are genetic adaptations for survival. These survival strategies don’t always work for the trees in your front yard.

Changes in nature can be sudden or they can take years. Sudden changes include ice and wind storms that rip and tear branches from trees. Lightning, fires and floods also happen quickly. Long term changes that effect tree survival are soil erosion or deposition, encroachment by grass, and competition for light from other trees.

How does this relate to your front yard trees and their survival?

Simply, change requires adaptation and adaptation in trees is pre programmed. If the tree isn’t able to adapt to changes in it environment it declines and dies. If the tree does not have, within its genetic bag of tricks, the ability to survive fire, the tree will die. A burr oak tree, with thick fire resistant bark, would be able to survive a runaway grass fire without major consequences. A thin barked cherry tree would not survive.

If your tree isn’t able to survive changes in grade or soil compaction it will not survive construction of a new addition to your home.

Trees like American elm will survive changes in grade and soil compaction while white oaks will most likely decline as a result of root disturbance.

In the modern world we are able to affect great changes on our landscapes. Heavy equipment can literally move mountains. Why do we expect trees to survive after the mountain has been moved? Obviously we overestimate the ability of trees to survive construction damage. Trees are alive. Damaging roots has serious impacts on plant health. Tree roots are living plant organs that take moisture and nutrients from the soil environment. The top eight inches of soil contains 90% of all tree roots. Take a look at a storm toppled tree and you will see a broad shallow fan of roots.

So when we think of changing our landscape we should consider the impact that these changes will have on our “Old Friends” before we make the changes. If you’re not well versed in the capabilities of your trees contact your arborist well before construction begins. They will be able to help you minimize the impact of changes in your landscape and maximize the survival of all our green friends.

Dedicated to the Preservation of People

October 29, 2006

It is the small stuff that can kill you. And if it doesn’t kill you it can cost you lots.

Having operated a chain saw for 28 years I may be more at risk of injuring myself than

the novice user. There is in arboriculture a phenomenon that leads to headlines like

“experienced operator injured by chainsaw”. It’s called complacency. I had the opportunity to attend a professional chainsaw operator instructor certification course a few years back and was surprised that we would be spending 3 of the 5 days in a hands on field school. I was at the time operating a chainsaw on a daily basis and was confident in my ability to drop the tallest tree with little effort. What I didn’t know was that the smallest tree still requires more than a little thought to land it safely where it should go.

The basic geometry of tree falling has remained unchanged from the Stone Age.

In fact beavers, rodents not known for there cerebral abilities, use the same methods as we do. Cut or chew a notch in the side of the tree that has the greatest lean,

then go to the opposite side and make a back cut. Unfortunately Mr or Mrs Beaver sometimes never return to the lodge, they fall prey to the uncertainty of tree felling and get crushed. I’m not sure what goes through a beavers mind when he is felling a tree

but if you are not focused and concentrating on the basics you may not make it back to the lodge either.

The basic technique with a chainsaw involves making a horizontal cut no more than 1/3 of the way into the tree ninety degrees from the intended direction of fall. The tree generally will fall in the direction it is leaning. The next step is to cut a notch by making a cut on a forty five degree angle from above the first cut to meet in a perfect apex. This cut should not run over, under or behind the first cut. It is called a pie cut because it results in a perfect pie shaped piece. The last cut comes in from behind parallel to and slightly above the first; it should stop before it meets the pie by at least one inch. This small piece of remaining wood is called the hinge or holding wood. It will direct the tree and may save your life.

Any variation from this procedure and you will have problems. What problems?

Lack of control is the primary problem. With a large tree the problem becomes larger. If the hinge is cut incorrectly the tree may fall in an unintended direction. If the hinge is cut through, the tree will fall without control and in any direction. Take the time to review basic tree felling technique and don’t let your mind wander while chain sawing. Each cut involves risk and should be performed with care and caution. If you don’t it could cost you not only your lodge, but your life.

Good Leaf Bad Leaf

Now that the yearly crop of leaves has fallen it may be of interest what to do with them next. In this age of recycling it is all the rage to compost your leaves to recycle the nutrients. Well this is a great idea in principle depending on the trees on your property you may want to reconsider this approach. Back in the good old days people used to burn all there leaves and spread the ashes on there garden. While this practice isn’t the best from an air quality standpoint it does eliminate over wintering disease and insect problems on the leaves that may survive composting or just piling up in the woods. While it’s no longer recommend to burn your leaves, selected recycling and compost may be your best solution.

Trees that have old insect infested fruit, like apples, should have this disposed off site or buried to prevent the insect pests from over wintering in the fallen fruit. Similarly leaves from trees that frequently have outbreaks of fungi like lilacs, dog woods and ash trees should be gathered and thoroughly composted for more than one year away from the affected trees. Many trees have gall or other mites that disfigure the foliage with cocks combs or nipple like lumps. These should be moved off site or disposed of to prevent re-infection. Leaf shredders are an excellent way to speed up the process of composting, mixing leaves with other vegetable waste from the house and turning it frequently will promote proper composting.

Now that leaves have fallen and trees are dormant there are things you can do to help them get through severe winter weather. Even though the tops of your trees look dormant there is plenty of action in the root zone. Ensuring the plants have lots of available water at this time can improve survival when temperatures start to rise in the spring. Fall fertilization and watering your evergreens are two cultural practices that can make a big difference in winter survival and help your trees thrive next spring. Be careful when fall fertilizing follow label directions carefully and use low nitrogen slow released fertilizer. Watering and fertilizing can take place from now until the ground freezes. If you want more information on fall tree care contact an ISA Certified arborist, they are experts on tree care and plant health.

Free Digital Moisture Meter

Given that we all have twenty digits; I will point out which ones to use to see if your trees and shrubs are in need of water. Most people wear shoes or boots in the garden eliminating ten digits. As you may have guessed the most cost effective digital moisture meter is your index finger.

Stick it in the ground and if it feels moist and cool you don’t need more moisture. If the ground feels hard and dry, even dusty as you stick your finger in the soil it’s time to water!

It really is that simple and you will never have to buy batteries.

Trees and shrubs need ample, timely water to thrive. Plants need a certain minimum amount just to survive. Soil moisture normally constitutes 1/3 of the volume of soil; the remaining two thirds are occupied by the soil particles and air. Depending on the composition of the soil a varied amount of the water in the soil is available to the plants. Some water will be bound so tightly to the soil particles that it will be unavailable for plants. Water that isn’t bound to soil particles is said to be available soil water and this is what trees and shrubs can use.

Plants use water in a wide variety of plant processes including transporting nutrients and minerals throughout the plant. The greatest percentage of the water in most plants is used to cool the plant. Trees and shrubs cool them selves by allowing moisture to evaporate from leaf surfaces. This process is called evapotranspiration. Essentially evaporation and transpiration combined. Cells in the roots passively gather water through osmosis; they soak it up like paper towel, or a dry sponge. The water is then transported upward in the plants cells some times actively like a bucket brigade, or passively from cell to cell by osmosis. As it gets to the top of the plant it is exposed to the air and evaporates. This cools the plant much as you would be cooled if you were in a wet t-shirt on a windy day. Wind and heat affect the amount of transpiration that occurs at any given time. Trees and shrubs have small openings in the leaves called stomata that act as windows or valves controlling the amount of water vapor and other gasses that escape through the leaves. Trees and shrubs that are adapted to dry climates will have fewer and smaller stomata to reduce the amount of moisture loss. Thick waxy leaves also reduce water leakage between cells. Hairs and thorns on leaves slow wind speed over the leaf and reduce moisture loss. If the process is running smoothly the leaves will remain cool and firm inflated with water and turgid.

The pressure that keeps the leaf firm is called turgor pressure. When the leaf can no longer get enough water it loses turgor pressure. The first thing that happens when the pressure drops is the stomata close like windows keeping water vapor in. If moisture continues to be lost the leaf droops like a limp balloon. This may happen on hot days, usually the tree recovers from its moisture deficit in the evening and processes return to normal. If water is not available the tree will continue to struggle until it takes all the available water out of the soil. Then the passive process of osmosis reverses itself and the tree loses moisture to the soil. The tree responds by shedding roots and leaves. If this isn’t enough to restore the moisture balance the plant may reach permanent wilting point. This is the end for the tree and shrub. No amount of water will help it now it’s dead.

If your plants are looking a little wilted check the soil with your digital probe, is it dry and hot? Water your plants deeply rather than frequently; let your index finger be your guide!

When in doubt ask an ISA Certified Arborist, they will have the latest information on watering.

Mulch Problems

Given the benefits of properly mulching your trees you may be surprised to hear that mulching can cause problems. The problems can be divided into two categories: composition and application.

Typically mulch is composed hardwood chips, carefully shredded into uniform pieces. Mulch that is not properly shredded contains large chips and many twigs that make it difficult to spread and unsightly. This may this may be suitable for less formal areas of your landscape, or in your wood lot. Chips from fine textured trees like willows will have numerous fine twigs. Sharp blades in the chipper will usually solve the problem of stringy chips.

If the mulch is composed of pine, spruce or other soft woods, as it breaks down it will make the soil more acidic. This can be a problem if your trees and shrubs prefer a more basic soil. This can be of benefit if you have plants that thrive in acidic soils. Mulches made from rocks and gravel are ground covers and don’t provide the same benefits as wood chip mulch. Limestone crushed into mulch sized pieces will make the soil become very basic and damage your plants.

Some trees produce chemicals that eliminate the competition with natural chemical herbicides. Sugar maple, hackberry, cotton wood and black walnut are a few of the worst offenders. Allowing the mulch to sit in a pile for a season reduces the concentrations of these chemicals. You should avoid putting these materials directly into your vegetable garden. Tomatoes and some herbs are particularly sensitive to these natural herbicides. If your mulch is composed of sawdust or newspaper it will steal nitrogen from your trees as it decomposes. Composted mulch is best.

Beware the Mulch Volcano! Many people make the mistake of piling mulch too high against the base of the tree. Mulch that is applied too deeply can cause rot on the bases of trees. Mulch should not be in contact with the bark at the base of the tree. If this happens, the root flare area will rot or sprout adventitious roots both which injure the tree. Mulch should be 2 to 4 inches away from the bark of the tree to allow for air movement. The mulch should then be an even 3 to 4 inches out to the drip line. If you are putting plastic or weed barrier under your chips you will be excluding oxygen from the roots of the tree and suffocating the roots.

Commercially made mats of compressed mulch look very nice. These mats often maintain there shape and don’t decompose or allow the tree to grow. This can result in bark damage. Mulch that has been used to soak up road debris may have excess salt. If you have an area where salt splash or spray is a problem change your mulch after each winter to prevent the salt from leaching into the soil. Refresh your mulch as needed and don’t allow it to burry the plants. Mulching is easy and effective if you know the basics and understand the benefits it can provide. When in doubt ask an ISA Certified Arborist, they will have the latest information on mulching.