Tree care and maintenance

by Sally Bouorm | December 1, 2010 10:56 am

[1]

By Jeff McMann

Trees play an important part in a landscape environment, often providing the backbone around which backyards are built. They improve the quality of the air we breathe, absorbing, trapping and filtering harmful pollutants. They provide shade around the pool in the summer and shelter in winter. Well-placed trees can reduce noise from neighbours and vehicles, lessen glare and provide shade and shelter from harmful ultraviolet (UV) rays. In addition, trees also provide benefits to landscapers, adding an extra dimension and grandeur to a backyard design.

Despite these benefits, trees are often neglected in a few ways. There are many prevalent misconceptions about trees, even amongst industry professionals, and several persistent myths that can actually perpetuate more harm than good. Pool and landscape professionals must understand how a tree grows, what it needs and how it should be properly maintained. Below are a few of the more common myths associated with trees and their care.

Myth 1: Topping is good for trees

Topping is the drastic removal or cutting back of most of a tree’s large branches. It is often confused with pollarding. Pollarding is a pruning system in which the major limbs of the tree are dramatically cut back. Each following year, the long slender shoots that grow below the cuts are then removed, and a new set of shoots quickly take their place. The tree develops a stubby and knobby appearance, resulting in a dense mass of foliage and branches.

[2]

The pollarding process, which has been practiced for many centuries in Europe to maintain trees at a certain height, should begin when a tree is very young. It is a high-maintenance practice; depending on the tree species, annual or biennial pruning is required.

Trees are often topped so they can fit a given area or be maintained in a smaller shape. However, unlike pollarding, topping can be harmful to trees. A proper pruning cut should be made just beyond the branch collar at the branch’s point of attachment. The tree is biologically equipped to close such a wound, provided it is healthy enough and the wound is not too large. Topping, however, creates cuts above the branch collar (the swollen area of trunk tissue that forms around the base of a branch), creating stubs with numerous wounds that may not close. In actuality, it is one of the worst things you can do to a tree. Some incorrect assumptions many professionals make about topping include:

• Topping does not injure the tree;
• Topping ‘invigorates’ a tree; and
• Topped trees add value and beauty to a property.

Topping, in fact, severely injures a tree. Consider the process—by removing most of the leaves and branches, large wounds are left exposed. This leaves the tree susceptible to insect attacks and decay. Very few trees can defend themselves against the multiple severe wounds caused by topping; as a result, exposed tissues begin to decay. Decay organisms are given a free path to move down through the branches. The tree becomes stressed and, consequently, more vulnerable to insect and disease infestations.

In addition, since every tree needs foliage to produce food, a topped tree will try to compensate for the excessive removal of its branches and leaves by exhausting its stored resources to produce new branches. As a result of this quick growth, new branches are weakly attached and more susceptible to breakage and storm damage. A topped tree can become hazardous and cause property damage (e.g. a loose branch falling on to a person or parked car), making it a liability, rather than an asset. Furthermore, the tree can actually grow to be taller than it was before topping was performed.

Ultimately, a topped tree requires more attention in the future than a properly pruned tree (more on that below). It may survive the process, but its lifespan will be significantly reduced. The end result lacks all natural beauty and form, and may actually have a negative impact on a design.

Myth 2: Pruning is a minor tree maintenance task

Simply put, pruning is the practice of cutting or removing branches or parts of trees, to improve their shape or growth. It is, in fact, the most important tree maintenance procedure one can perform. Trees are pruned to remove dead, damaged or diseased branches and crowded or rubbing limbs; eliminate hazards; and increase light and air penetration, improving the tree’s health and appearance.

Though it may not seem like glamorous work, pruning has a significant impact on tree health. Pruning should not be done indiscriminately, but rather with a purpose in mind—specifically, to produce a strong, healthy, attractive tree. By understanding how, when and why to prune—and sticking to a few simple principles—this goal can be easily achieved. Consider the following tips when tackling tree pruning:

• When cutting off a branch, always leave the branch collar intact. If you prune away the collar, you remove not only branch wood, but also trunk wood, opening the plant to more extensive decay.
• Pruning branches flush to the tree’s trunk is another common mistake. Flush cutting is harmful in several ways, primarily because it removes the branch collar and produces an open wound. Keep in mind, however, that cutting too far from the branch collar will leave a stub.
• Do not rush the pruning process. Work slowly and think carefully about cuts and their impact on the tree. Sometimes, a second opinion can be valuable.
• While dead branches can be removed at any time, most trees and shrubs can only be pruned at certain times of year. This is usually when the plants are dormant, typically in late fall or winter. The best pruning time will also vary according to tree type.
• When dealing with deciduous trees, pruning after the leaves have fallen off will give you a better idea of how it will affect the tree’s shape. Some fruiting and flowering trees should be pruned at other times of the year, depending on whether they flower on the current or previous year’s growth.
• Use proper tools, like a good pair of secateurs or pruning shears, or saws with curved blades.

Trees need pruning for a variety of reasons, including the following:

Safety

This often involves removing branches that could fall and cause personal injury or property damage, or trimming branches that interfere with sightlines along streets or driveways.

Tree health

This entails the removal of diseased or insect-infested wood, thinning the crown to increase airflow and removing crossing and rubbing branches. Pruning can best be used to encourage trees to develop a strong structure and reduce the likelihood of damage during severe weather. Removing broken or damaged limbs also encourages wound closure.

A general rule when pruning any tree is to remember the ‘three Ds’: dead, diseased and dying. These types of wood should be removed first, followed by crossing or rubbing branches. It is never advisable to remove more than one third of a tree’s branches.

Esthetics

Pruning for esthetics involves enhancing the tree’s natural form and character or stimulating flower production. For trees that flower in the spring, a general rule of thumb is to prune shortly after they are finished blooming. For those that flower in the summer, prune in late winter or early spring.

Myth 3: All trees have tap roots

A tap root is an enlarged and usually tapered root that grows vertically downward. It forms the centre root structure from which other smaller roots spread out laterally. The dandelion, for instance, provides an excellent example of a tap root. However, very few (if any) trees in an urban setting have tap roots. This is because when the water table is close to the soil surface or the soil is compacted or clay-heavy, tap roots do not develop.

Basic tree biology tells us all roots need oxygen to survive. This is why roots are typically located in the top 1 m (3 ft) of soil; they get air from the fine roots absorbing the oxygen located in air pockets within the soil. If a tree had tap roots, how would it get this much-needed oxygen?

Myth 4: Tree roots do not expand beyond the drip line

A tree’s root system holds the key to its survival. At construction sites, protecting tree roots is the most important step to keep existing trees healthy. Unfortunately, most people do not understand tree biology, and may have mistaken ideas about tree growth.

[3]

As a tree grows in height, it requires more oxygen. As a result, the finer roots extend well beyond the drip lines of the branches (i.e. the area directly under the outer edges of the tree branches). Frequently, roots extend from the trunk as far as the tree is tall. In fact, the root system on trees and shrubs planted in a given landscape can grow up to three times the distance of the tree’s branch spread within a few years of planting.

Since most of the root system is in the top metre of soil, finer roots are concentrated in the top several centimetres of soil. Therefore, any soil disturbances, major or minor, can injure or remove a large portion of the absorbing roots. Excavation, topsoil removal and trenching activities that cut roots will prevent trees from absorbing critical supplies of water and nutrients.

This is of particular importance when dealing with existing trees on a project site. During construction, keeping equipment and trucks away from the tree trunk is not enough to prevent damage, as they will compact the soil, squishing out air spaces in the root zones. Damaging roots on one side of a tree may cause branch dieback on that side only or in random areas throughout the crown. Even then, damage may not be immediately evident. Trees store energy in their branches and trunks, which they use to survive after roots are damaged. It may take two or three years to notice any decline, and up to five or 10 years before root damage leads to tree death.

Since many of the fine roots are located close to the soil surface, one must also take great caution when changing soil grades. Even adjustments as small as 150 mm (6 in.) can cause extensive root system damage. Soil should never be added to or removed from the area within the drip line of an existing tree that is to be saved.

When adding new trees into the landscape, remember to choose the right tree for the location. One should consider avoiding the planting of large fruited trees over, or adjacent to patios, pools, decks and spas. Trees that produce fruits and berries can also potentially stain the patio and furniture, although certain cultivars with small or persistent fruit will not drop and cause a mess.

Any new tree plantings should be made at a distance from any pool or spa installation. The exact closeness of the tree depends on the variety and growth habits. Also remember that the hole dug for planting should be at least two to three times the width of the root ball; this will set the tree a minimum distance from the pool or spa under ideal conditions.

Myth 5: All trees are basically the same

[4]

Another misconception is that any tree will do for a particular site, or that all trees need the same care. While trees can contribute greatly to the overall look of residential or commercial space (perhaps more than any other part of the landscape) one must still select the right variety and make sure it is planted in the proper location. Like pools, trees are a long-term investment. As such, designers must take time to carefully plan a tree’s place within the landscape before any planting takes place. Here are some quick tree selection tips:

Plan for the future

Before picking a tree, investigate the size it will be when it is fully grown. Ensure the height and width of the mature tree will not overpower or become lost amidst other landscape elements (e.g. pools, spas, gazebos, etc.).

Pick your spots

Avoid planting trees with fruit litter near pools, decks and paving; also steer clear of planting trees too close to the house. In these cases, consider using smaller trees or shrubs. Analyze the sunlight and shade the site receives and choose varieties based on their tolerance to those conditions.

Location, location, location

Find out if the selected tree variety is well suited to the landscape’s geographic location. Although many trees are quite robust and capable of surviving in many places, not all of them will flourish under all conditions. Consult with colleagues or other professionals about what has worked in nearby projects. Also look for trees that are indigenous to the area, to help ensure healthy and strong growth.

To avoid future problems, learning as much as possible about the tree species’ characteristics before planting is very important. Ask about the tree you are interested in or research its needs and its eventual size or shape. With so many new choices and cultivars available, it is always possible to find a variety that will fit the client and landscape’s requirements, both now and as the tree matures.

 

Jeff McMann is a certified International Society of Arboriculture (ISA) arborist based in the Greater Toronto Area, with nearly 30 years of industry experience in landscape construction and maintenance. He is also a graduate of the Niagara Parks Commission School of Horticulture. McMann can be reached at jtree@hotmail.ca[5].

Source URL: https://www.poolspamarketing.com/trade/tree-care-and-maintenance/

---