Visiting a new residential development with lots of mature trees, an arborist made acquaintance with one of the property owners. The resident expressed his admiration for a tree service whose distinctive work appeared at several of the properties nearby. As a result of their crew’s skill and artistry, passersby could now view from the street the splendor of each home through the “sculpted” trunks and scaffold limbs that were stripped bare of their irksome foliage. To accentuate the trees’ sculpture-like appearance, each branch cut was masterfully executed to be flush against the trunk or limb. Foliage aloft had been left dense to provide shade and that classic “look” that was so desirable.

Lion's-Tailing

The arborist offered that such practice was actually not to industry standards and harmful to trees. “But this was a family business, and they’d been doing it this way for three generations,” said the property owner. “Then they’ve been doing it wrong for three generations,” replied the arborist.

The above description of what is acceptable – even desirable – tree pruning is tragically common. Like mulch volcanoes, you see it everywhere. Stripping trees this way is called lion’s-tailing and results in poor branch taper, poor wind load distribution, and higher risk of branch failure. It also deprives the tree of foliage it needs to make its food, so the tree will quickly produce “water sprouts.” Some people see these as proof that such pruning doesn’t hurt a tree because the foliage grows right back. (Sounds logical.) But these shoots signal the tree’s urgent reaction to excessive wounding; they create energy drain, and they form weak attachments to the tree because they form from latent buds.

Water sprouts on same tree, 8 months later. Note the water sprouts as a reaction to over-pruning.

Flush cuts are also terrible practice. They cut into the branch collar and injure stem tissue. This increases the likelihood of decay. A proper cut is outside the branch collar, but not so far that a stub remains.

A qualified arborist is familiar with the American National Standards Institute (ANSI) standards for tree pruning (and safety). These cover types of pruning based on specific goals, such as crown cleaning, thinning, reduction, and vista pruning. The standards recommend how much foliage one should remove in a session, from where on the tree to remove it, and other correct practices. Any pruning cut is a wound, and mature trees do not respond as well to wounding as younger trees. A good arborist knows why and how to execute these wounds to protect the tree’s biological processes and structural integrity.

A tree is not yard art; it’s a complex, living organism. That means a beautiful tree is a healthy tree, and one that’s retained its dignity by respectful treatment based on informed practice.

In the next article, we’ll return to the ground. We’ve discussed watering newly planted trees, but many homeowners have irrigation systems to sustain their landscapes that include mature trees. Certain pathogenic fungi just love these situations. Stay tuned.

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Coming soon: Trees and Irrigation, the next article in the series→
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Pictured left to right: Brian Frierson, Nelson, Dave Powell, Vince, Ovidio, Mark, Rene, Shawn, Sammy, Leonard, Ken, Skyler, Matt Storey, Alex, Francisco

Adult winter moths congregate at the front door of this property in Dartmouth, Massachusetts. The moths are harmless but their offspring feed aggressively on most deciduous trees. Contact a Bartlett Arborist Representative to find out about simple treatments that can help to minimize damage to your trees.

This tree can still benefit from removing, in stages, the stem on the left. This will allow the right stem to take over as the central leader.

In a way, a young tree is like a crystal ball to an arborist. He or she can look at it and tell its fortune:

Those two equal-sized stems that branch from the trunk will grow larger someday, and their bark will meet between them. This will cause weakness and greater risk of failure.

Attached to a main leader, that long, skinny limb branches into four similar-sized limbs. They will grow larger someday, compete for dominance, and cause imbalance and interference in the crown.

There’s more: the girdling root, the buried root collar, soil conditions, foliage abnormalities, and other signs and conditions. These tell an arborist whether this tree is more likely to thrive, have beauty, and be more structurally sound or whether it will struggle, look poorly, pose hazards, and even die young.

We will cover correct pruning of mature trees in another article, but scheduled, structural pruning of young trees, along with other maintenance measures, can

• reduce the tree’s structural weaknesses,
• form a more beautiful tree,
• increase the tree’s ability to withstand stress and resist disease; and
• spare its owners more costly corrective measures later.

Some of the measures for proper planting can be employed correctively for a young tree. These include excavating the root collar, addressing stem girdling, ensuring adequate hydration, and applying mulch over the root zone. An arborist can also conduct soil analysis and inspect for insects and diseases. A proper formulation of fertilizer that includes beneficial fungi can promote rapid growth and improve root system health and function. The arborist also has the opportunity to address pest and disease problems before they do extensive damage.

A key aspect of young-tree maintenance is selective pruning. Property owners will never have a better opportunity to influence the structural integrity of a tree than when it’s young. Ideally, a tree has a central leader from which other branching develops and is spaced appropriately, but young trees rarely grow this way without help. A trained arborist can correct structural defects that are common in young trees, but not all at once. As with any pruning, removing too much foliage in one session can harm the tree.

Isn’t it more natural and kind to let a young tree grow as it will without interference from humans? No, not when it’s going to be near a home, shading children, in a location where people gather, or in a similar urban setting. Directing the structural soundness of a young tree reduces its risk of failure in maturity. And seeing to its other health concerns increases the likelihood that the tree will better withstand stresses and be more resistant to pests and diseases.

On a regular basis, we treat mature trees for many of these same issues, but nurturing a tree from its youth is more likely to produce a healthy, beautiful, and safer adult tree. It’s a proactive approach that’s worth the investment.

Having covered pruning of young trees, we’ll look at pruning mature trees in the next article. It’s one of the most misunderstood and poorly performed practices we see in our industry.

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Coming soon: Pruning Explained, the next article in the series→
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Hemlock borer photo courtesy of Steven Katovich, USDA Forest Service, Bugwood.org

Hemlock borer requires a stressed or weakened host. The two major causes of stress for hemlock are defoliation and drought. Susceptibility to drought results from the fact that this conifer is very shallow-rooted and typically does best on moist-to-wet sites. The species is so sensitive to changes in soil moisture conditions that merely opening up a stand of hemlock too much or removing associated hardwoods in mixed stands and leaving the hemlock is often enough to set the stage for hemlock borer.

Read more about plant health care recommendations for hemlock and schedule an appointment with a Bartlett arborist if you’ve noticed the pest or the symptoms on hemlocks on your property, or to make your trees less susceptible to the hemlock borer.

Ash dieback photo courtesy Andrej Kunca, National Forest Centre - Slovakia, Bugwood.org

Chalara fraxinea is being treated as a quarantine pest under UK national emergency measures; it is important to report any suspected cases.

The disease caused by the Chalara fraxinea fungus results in leaf loss and crown dieback in ash trees, which can lead to tree death in affected trees. Ash trees suffering with symptoms from Chalara fraxinea are increasingly being found across Europe and now have been confirmed at sites in the UK.

Chalara fraxinea Symptoms
Chalara fraxinea can be visible on leaves, shoots and branches of affected trees. In severe cases, the entire crown can show leaf loss and dieback, epicormic shoots can also form on the branches and trunk.

The Foliage
Leaves can suffer from wilting and a black-brownish discolouration can occur at the leaf base and midrib. Dieback of shoots and twigs is also very characteristic.

Branches and Stems
Small lesions or spots appear on the bark of the stems and branches and enlarge to form cankers. This can cause wilting and dieback of shoots and branches in the upper crown.

The Tree
Trees with withered tops and shoots are very typical. Heavily affected trees will have extensive shoot, twig and branch dieback and often have extensive epicormic shoots. Chalara fraxinea has also been isolated from the roots of symptomatic trees, as well as from leaves, shoots and branch/stem lesions.

How the disease spreads
How Chalara fraxinea spreads is uncertain, but local spread may be caused via rain splash or insects. Over longer distances the risk of disease spread is most likely to be via the movement of diseased ash plants. Movement of logs or unsawn wood from infected trees may also be a pathway for the disease.

Bartlett Tree Experts in the News
Bartlett staff are often interviewed on topics concerning plant health. Below are links to interviews and reports about Chalara dieback of ash in which Bartlett’s experts were involved.

ITV: Deadly ash tree disease spreads across the UK

BBC Radio 4: Ash dieback ‘beyond containment’

The Telegraph: Ash dieback now beyond containment

If you have ash trees on your property, contact Bartlett to have an arborist come to your property and inspect your trees. In the UK, call 0845-600-9000 or make an appointment online.

This staking method can be improved. Visit TreesAreGood.org for consumer-friendly tree planting information.

The first rule of staking is not to if it’s not necessary. Trees need movement to develop girth, taper, and healthy roots. A tree staked improperly or too long might grow in height, but it will suffer in other ways. Obtain more on proper tree staking at TreesAreGood.org.

Moisture deprivation is a common reason for young-tree death. A generous watering delivered quickly won’t have time to saturate the root ball. Rather, it will rush to the base of the planting hole and mostly sink in to the soil beneath it. A slow watering with a soaker hose (or similar method) will ensure that moisture delivery is effective. Avoid the urge to overwater. Depending on the season and rainfall amounts, watering a newly planted tree about once a week should be adequate, but check the soil often. Hot Texas summers might necessitate more frequent watering.

We all wish there were such a thing as a “no-maintenance” tree or shrub, but most of us know better. A newly planted tree requires careful monitoring (and informed care) during an establishment period that can last a few years.

Except for pruning any broken branches, a newly planted tree should not be pruned. After a season or so, it’s important to begin a schedule of corrective pruning as part of a young-tree maintenance program. We’ll explain in the next article why this proactive process can save you headaches, heartaches, and money.

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Coming soon: Young Trees and Shaping the Future, the next article in the series→
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Saturday, September 29 — 10:00 to 11:30 a.m.
Free, RSVP requested

• Meet by the flagpole and sundial gardens
• Come early for light refreshments
• In case of rain, the program will be rescheduled
• Pease RSVP to Rye Town Park at (914) 967-0965
• Co-sponsored by the Friends of Rye Town Park

Licensed arborist Frazer Pehmoeller of the Bartlett Tree Experts Company will lead people through the park, talking about the kinds of trees that are found in the Westchester area. He will describe what things an arborist looks for in a tree to know if it is healthy; and, he will explain what steps can be taken to ensure that each homeowner has trees that minimize the inherent risks of failure which all trees pose.

Topics to be covered include preparing trees for storms, drought, diseases (such as the emerald ash borer beetle), and protecting trees from construction damage and basic soil compaction. As the program progresses, participants will have plenty of opportunities for questions and discussion. Members of FRTP will also discuss their goal of planting additional trees on the park and how people can help in this project.

Mr. Pehmoeller has worked in the arboriculture and horticulture industry for over 30 years. He has been working on projects in Rye since 2000. He received a BS from the University of Connecticut in Horticulture and Natural Resource Management.

Rye Town Park and the Friends believe that the Park can be a wonderful learning laboratory for how to maintain a healthy lawn area for support of wildlife and human enjoyment.