What is killing my trees?

We’re weeks into the growing season, and our trees are happy to show off their fresh appearance: a full, blooming canopy, sprouting flowers and—wait, are those curling leaves? Damage to tree leaves and stems is often the first sign of a bigger tree problem, possibly an insect infestation.

If you’ve seen something odd on your tree, find out what the problem is. Use our checklist below to pinpoint what insect could be damaging your trees and how to stop it.

SIGNS & SYMPTOMS OF APHIDS

>> LEAF CURLING, TWIG DIEBACK, STUNTED GROWTH, A SUGARY SUBSTANCE CALLED “HONEYDEW,”BLACK, SOOTY MOLD 

  • What insect is damaging my tree: Aphids, the resident “plant lice”
  • What do aphids do: They feed on plant juices with their straw-like mouths, prevent proper nutrient and sunlight intake and cause premature leaf drop.
  • How to control aphids on trees: Stop aphids with horticultural soap/ oil treatments.
  • When to control aphids: Talk to your arborist as soon as you spot symptoms.

SIGNS & SYMPTOMS OF CANKERWORMS

>> CHEWED, RAGGED-LOOKING LEAVES

  • What insect is damaging my tree: Cankerworms, the hungry, hungry caterpillar, although native to North America.
  • What do cankerworms do: They eat away at leaves, stripping the tree of nutrients.
  • Most common tree victims of cankerworms: Elm, oak, apple, maple, linden, beech, cherry, hickory, and ash.
  • How to control cankerworms: Apply a horticultural oil in dormant seasons to remove cankerworms. Then prevent the fall with an insecticidal tree band.
  • When to treat cankerworms: Control this pest in spring and focus on cankerworm prevention in fall.

SIGNS & SYMPTOMS OF JAPANESE BEETLES

>> CHUNKS OF LEAVES CHEWED DOWN TO THE VEINS, BROWNING LEAVES AROUND THE TOP OF THE TREE CANOPY AND LEAVES FALLING IN SUMMER

  • What insect is damaging my tree: The flying, feeding Japanese Beetle which is NOT native to North America.
  • What do Japanese beetles do: They feed on tree leaves in warm, sunny weather. This tree pest often eats the entire leaf, leaving behind only the skeleton.
  • Most common tree victims of Japanese beetles: An incredible generalist that feeds on more than 300 plant species.
  • How to control Japanese beetles: Their are many methods available including hand-picking them into soapy water, using beetle traps, applying horticultural oil, and controlling their grubs with beneficial nematodes or milky spore
  • When to treat for Japanese beetles: Act during peak growing season, from mid-June through August.

SIGNS AND SYMPTOMS OF EASTERN TENT CATERPILLARS

>> LARGE, SILKY WEBS AND TREE LEAF LOSS, ESPECIALLY ON BLACK CHERRY TREES

  • What insect is damaging my tree: The Eastern Tent Caterpillar. Although native to the Eastern U.S., Tent caterpillars can be considered a nuisance but aren’t really a disaster. You could do nothing, they’d eat all the leaves, the leaves would grow back pretty fast, the tree would be fine, and life would go on.
  • What do Eastern tent caterpillars do: They chew on foliage, leave behind webs and create an unsightly appearance. On black cherry trees, this pest is a serious threat due to defoliation, but the damage is usually aesthetic and not fatal to mature trees, though repeated or severe defoliation can weaken young or small trees. 
  • Most common tree victims of Eastern tent caterpillars: Black cherry, ash, birch, sweetgum, willow, maple, and oak
  • How to control Eastern tent caterpillars: Clip the tents and either move away from any cherry trees or dispose of.
  • When to get rid of tent caterpillars: Remove when the silky webs are active. Your arborist can also apply a treatment to control the larvae.

SIGNS & SYMPTOMS OF BAGWORMS

>> CHEWED LEAVES OR NEEDLES, MILD TO SEVERE LEAF LOSS, AND BRANCH DEATH WITH NO REGROWTH ON EVERGREENS

  • What insect is damaging my tree: Bagworms, the camouflaged critters.
  • What do bagworms do: Bagworms consume tree leaves/needles, often unnoticeably, until severe damage occurs.
  • Most common tree victims of bagworms: Juniper, arborvitae, cedar, spruce, honeylocust, linden, willow, maple, oak, birch, elm, and poplar.
  • How to treat bagworms in trees: Begin by handpicking and destroying all bags. If that’s not practical, your local arborist can apply an specific treatment.
  • When to control bagworms: Remove bags as soon as you spot an infestation.

SIGNS & SYMPTOMS OF SCALE INSECTS

>> UNDERSIZED, YELLOW-MOTTLED LEAVES AND CANOPY THINNING DUE TO LEAF DROP AND BRANCH DIEBACK

  • What insect is damaging my tree: Scale Insects – two groups of scale insects: armored scale and soft scale
  • What do scale insects do: Scales are sap-sucking insects common on backyard trees and ornamental shrubs. They anchor themselves into the vascular tissue of leaves with their threadlike mouthparts.
  • Most common tree victims of scale insects: All woody plants 
  • How to treat scale insects in trees: Treatments should be applied when the nymphs are emerging from their eggs and during the second instar stage. Several different approaches are available, depending on the situation.
  • When to control scale: Dormant oil will kill most armored and soft-scale insects that are in the susceptible stage. They tend to be more effective against soft scales.

Natural Landscaping

What is natural landscaping?

Natural landscaping refers to landscaping with the goals of improving the local environment, reducing soil erosion, beautification, creating biodiversity and wildlife habitats, as well as restoring and/or correcting existing environmental problems on the site. Landowners benefit from natural landscaping, as there is often less maintenance required over the long term. There is less time spent mowing, watering, fertilizing and treating this type of landscape.

The most common goals for planting native species are:

• Erosion control

• Enhancement and beautification of the landscape

• Increasing biodiversity and wildlife habitat enhancement

• Correct environmental problem

• Ecological restoration

Naturalistic landscaping focuses on natural occurring landscape and not a formal alone. Naturalistic landscaping mirrors patterns found in nature, like meadows, woodlands, wetlands, etc. For example, a lawn can be converted to or planted as a meadow or grassland, using native flowers and grasses. A wet site can be converted to a wetland plant community by selecting specific plants to grow in the conditions existing on the site.  Plants sharing similar requirements found on the specific site are called communities.  They support different habitat types like wetlands, meadows and woodlands.

How to choose the best plants for your site?

Check sun exposure, soil moisture and soil type where you intend to plant. To select plants that grow and thrive in those conditions, follow the cultural guide information for each species.

Look through a local guide, mark plants appropriate to your site, the habitat, as well as wildlife species you wish to attract to your site. Choose a variety of plants for the site. This extends blooms from spring to fall and creates biodiversity. In addition, the variety of plants will create food, cover and shelter for a variety of insect-life, birds and other wildlife.

Eastern North America has a large variety of native plant species. These native forbes (flowers) and grasses each have adapted to specific habitat categories such as woodland, upland or wetland sites.

The dominating factors in selecting native plants are:

• Amount of sunlight

• Soil type and porosity

• Soil moisture level

• Height of plant

• Bloom color and time

• Plant spacing

Always select a combination of plant species that will create the desired landscape effect. The species you select should be compatible with the site conditions and should meet the goals of the owner. The owner should consider the mature height, bloom color, and bloom time of the selected plant species, as well as the site condition, such amount of sunlight the site receives, soil moisture content and soil types like sandy, loamy or clayey.  All these factors need to be taken into consideration before selecting what natives to plant.

What Is Killing My Trees

We’re weeks into the growing season, and our trees are happy to show off their fresh appearance: a full, blooming canopy, sprouting flowers and—wait, are those curling leaves?

Damage to tree leaves and stems is often the first sign of a bigger tree problem, possibly an insect infestation.

If you’ve seen something odd on your tree, find out what the problem is. Use our checklist below to pinpoint what insect could be damaging your trees and how to stop it.

SIGNS & SYMPTOMS OF APHIDS

LEAF CURLING, TWIG DIEBACK, A SUGARY SUBSTANCE CALLED “HONEYDEW,”BLACK, SOOTY MOLD, STUNTED GROWTH

• What insect is damaging my tree: Aphids, the resident “plant lice”

• What do aphids do: They feed on plant juices with their straw-like mouths, prevent proper nutrient and sunlight intake and cause premature leaf drop.

• How to control aphids on trees: Stop aphids with horticultural soap treatments or insecticides.

• When to control aphids: Talk to your arborist as soon as you spot symptoms.

SIGNS & SYMPTOMS OF CANKERWORMS

CHEWED, RAGGED-LOOKING LEAVES

• What insect is damaging my tree: Cankerworms, the hungry, hungry caterpillar

• What do cankerworms do: They eat away at leaves, stripping the tree of nutrients.

• Most common tree victims of cankerworms: Elm, oak, apple, maple, linden, beech, cherry, hickory, and ash.

• How to control cankerworms: Apply a pesticide in spring to remove cankerworms. Then prevent the fall with an insecticidal tree band.

• When to treat cankerworms: Control this pest in spring and focus on cankerworm prevention in fall.

SIGNS & SYMPTOMS OF JAPANESE BEETLES

CHUNKS OF LEAVES CHEWED DOWN TO THE VEINS, BROWNING LEAVES AROUND THE TOP OF THE TREE CANOPY AND LEAVES FALLING IN SUMMER

• What insect is damaging my tree: The flying, feeding Japanese beetle

• What do Japanese beetles do: They feed on tree leaves in warm, sunny weather. This tree pest often eats the entire leaf, leaving behind only the skeleton.

• Most common tree victims of Japanese beetles: An incredible generalist that feeds on more than 300 plant species.

• How to control Japanese beetles: Apply one or two pesticide treatments a few weeks apart.

• When to treat for Japanese beetles: Act during peak growing season, from mid-June through August.

SIGNS AND SYMPTOMS OF EASTERN TENT CATERPILLARS

LARGE, SILKY WEBS AND TREE LEAF LOSS, ESPECIALLY ON BLACK CHERRY TREES

• What insect is damaging my tree: The extremely troublesome Eastern tent caterpillar

• What do Eastern tent caterpillars do: They chew on foliage, leave behind webs and create an unsightly appearance. On black cherry trees, this pest is a serious threat.

• Most common tree victims of Eastern tent caterpillars: Black cherry, ash, birch, sweetgum, willow, maple, and oak

• How to control Eastern tent caterpillars: Clip and destroy the tents.

• When to get rid of tent caterpillars: Remove when the silky webs are active. Your arborist can also apply a treatment to control the larvae.

SIGNS & SYMPTOMS OF WHITEFLIES

YELLOW SPOTS ON TREE LEAVES, PREMATURE LEAF DROP, A CLEAR, SUGARY SUBSTANCE ON OR UNDER YOUR TREES, BLACK FUNGUS, AND LOTS OF ANTS

• What insect is damaging my tree: The un-welcomed whitefly

• What it does: Whiteflies suck plant sap from new, tender tree leaves.

• How to control whiteflies: You can get rid of whiteflies by using horticultural oil treatment.

• When to apply whitefly treatment: Depending on the species, whiteflies pose no immediate threat and may be controlled by other predatory insects.

SIGNS & SYMPTOMS OF BAGWORMS

CHEWED LEAVES OR NEEDLES, MILD TO SEVERE LEAF LOSS, AND BRANCH DEATH WITH NO REGROWTH ON EVERGREENS

• What insect is damaging my tree: Bagworms, the camouflaged critters

• What do bagworms do: Bagworms consume tree leaves, often unnoticeably, until severe damage occurs.

• Most common tree victims of bagworms: Juniper, arborvitae, cedar, spruce, honeylocust, linden, willow, maple, oak, birch, elm, and poplar.

• How to treat bagworms in trees: Begin by handpicking and destroying all bags. If that’s not practical, your local arborist can apply an insecticide treatment.

• When to control bagworms: Remove bags as soon as you spot an infestation.

SIGNS & SYMPTOMS OF SCALE INSECTS

UNDERSIZED, YELLOW-MOTTLED LEAVES AND CANOPY THINNING DUE TO LEAF DROP AND BRANCH DIEBACK

• What insect is damaging my tree: Scale insects – two groups of scale insects: armored scale and soft scale

• What do scale insects do: Scales are sap-sucking insects common on backyard trees and ornamental shrubs. They anchor themselves into the vascular tissue of leaves with their threadlike mouthparts.

• Most common tree victims of scale insects: All woody plants 

• How to treat scale insects in trees: Pesticides should be applied when the nymphs are emerging from their eggs and during the second instar stage. Several different approaches are available, depending on the situation.

• When to control scale: Dormant oil will kill most armored and soft-scale insects that are in the susceptible stage. They tend to be more effective against soft scales.

Seasonal Tree Care Routines

Seasonal tree care is extremely important. Depending on the season, your trees will require different treatments and care. Proactive care protects plants from seasonal dangers. These dangers may come things such as extreme weather, insects, or diseases. Below is a quick guide to help you navigate your seasonal tree care.

Spring Tree Care (March – May)

Fertilize to stimulate root growth. Fertilizing trees is one of the best ways to keep them healthy. Applying fertilizer in the spring will introduce nutrients and improve plant growth.

Spray to prevent fungal diseases. The cool moist weather of spring creates a perfect breeding ground for fungal infection and diseases like Anthracnose, Root Rot, & Leaf Spot. Invest in preventive sprays to keep your trees from being infected.

Invest in a year-long plant health care plan. Spring is when all the tree diseases and pests begin to emerge. Prevent these pests & keep your property healthy from Spring- Fall by investing in a year-long plant health care plan.

Mulch (2-3 inches deep, not touching the base of the tree). Mulching provides a series of benefits. Mulch retains soil moisture, promotes organic matter development, and prevents soil compaction.

Water to keep plants hydrated. In spring, trees and shrubs are pushing out new growth. To be successful they need to stay properly hydrated. Watering will also flush out their system if they’ve been exposed to ice melts/rock salt. Adjust procedures appropriately to prevent excessive water from overwatering.

Protect you & your family from mosquitoes. Mosquitoes and ticks bring deadly diseases, like Zika, West Nile, and Lyme, into your property. Protect your family with an Organic Mosquito & Tick Control Program.

Watch for tree & shrub pests. The warm weather of spring activates lots of insects and diseases that can damage your trees & shrubs. Keep an eye out for damage so you can catch these pests early.

Summer Tree Care ( June – August )

Summer Tree Care (June-August)

Inject the trunks of elm & ash trees. Early summer is the time to protect your Elms from Dutch Elm Disease & your Ash from Emerald Ash Borer. Preventive trunk injections are the best way to fight these ailments.

Aerate to prevent & fix soil compaction. The dry summer months tend to lead to soil compaction. Using high-velocity air tools, an Arborist will fracture the soil and create pore space. This de-compacts soil structure and allows nutrients to reach the roots.

Prune dead, dying, & diseased branches. Dead, dying, and diseased branches are a danger to people and property. These are often the limbs that break and fall during summer storms. Make sure to prune these before they fall.

Re-apply mulch if needed. Heavy rains and foot traffic can sometimes wash away mulch. Check to make sure your mulch is 2-3 inches thick. If not, you will need to re-apply some mulch.

Water to keep plants hydrated. In summer, trees and shrubs are faced with high temperatures. Keep them hydrated by watering once a week. To water, put your hose on a dribble, place it in the Critical Root Zone, and leave it for 2-3 hours. Repeat 2 times.

Protect your property from mosquitoes. Mosquitoes and ticks bring deadly diseases like Zika, West Nile, and Lyme, into your property. Protect your family with an Organic Mosquito & Tick Control Program.

Watch for tree & shrub pests. The warm summer weather helps tree bugs reach high population levels quickly. Act fast if you notice a problem, or your trees will have extensive damage.

Fall Tree Care ( September – November )

Fertilize to prepare your tree’s roots. Fertilizing is one of the best ways to keep your trees healthy. Applying in the fall helps protect the tree from winter damage.

Rake to remove fallen tree leaves. Disease causing fungi love to hide and overwinter in a tree’s fallen leaves. Raking these leaves & removing them will limit your tree’s chances of contracting a disease.

Plant new trees during fall. Fall is the best time to plant new trees. With cooler temperatures, there is less chance of the new tree dying from sun scorch or drought.

Mulch 2-3 inches deep around trees. Mulching insulates a tree’s root system, helping protect it from the approaching cold of late fall and winter. It also helps the soil retain moisture and organic matter.

Water to keep plants hydrated. Although the summer heat has passed your tree can still suffer drought stress. Make sure your trees are hydrated. Adjust procedures appropriately to prevent excessive water from overwatering.

Prep for winter by treating, pruning, and cabling. To keep your tree’s needles from turning brown apply Anti-Desiccants. To prep for winter storms, prune deadwood and cable your trees for support (if needed).

Inspect trees annually. Late fall, when leaves are off the tree, is a great time for inspection. Inspections can spot structural issues that could be dangerous.

Winter Tree Care ( December – February )

Horticultural Oil. A horticultural oil application to coat the stems and foliage of your plants. This helps prevent wind/winter burn and smothers soft bodied insects and their eggs so they do not survive/hatch in spring.

Spray anti-desiccants on evergreens. Anti-Desiccants prevent windburn (brown needles) by reducing the amount of moisture lost through the leaves pores.

Prune while the tree is dormant. Winter is the best time to trim trees. Tree trimming while trees are dormant allows them to heal better and not be exposed to insects/diseases. It also stimulates flower growth.

Wrap your young & newly planted trees. Wrapping your trees can protect them from sun scald. Sun scald is a common ailment for young or thin-barked trees in winter. It causes the tree bark to dry and crack.

Prevent deer damage. Deer damage exceeds $2 Billion annually. Deer also cause accidents, attack, & bring ticks to your property. Protect your trees & shrubs from deer browsing, feeding, & male rutting with a deer protection program.

Avoid rock salt or ice melts. Sodium Chloride dehydrates tree’s roots & needles. Remove what salt you can see & water your tree to flush out the soil & its system. Or opt for Magnesium chloride melts instead.

Remove heavy snow from branches. With heavy snow, gently brush the snow off the branches in upward strokes. For upper branches, GENTLY use a broom in an upward sweeping motion. Don’t shake branches or brush downwards or they may snap.

Inspect trees annually. Winter, when leaves are off the tree, is a great time for inspection. Inspections can spot structural issues that could be dangerous.

Different Pruning Cuts

Because pruning cuts are wounds, it is important to make cuts in a manner that increases the likelihood that the wounds will seal and maintain the health of the plant.

There are four basic pruning cuts:

  • Heading cut
  • Thinning cut
  • Re-leadering cut
  • Jump cut

HEADING CUT

Use heading cuts:
  • On small branches – To reduce the number of buds the plant needs to feed and grow, creating the possibility of more vigorous flowers and fruit from the buds that remain.
  • On large branches – To restructure a plant (a multi-year process).
  • On all branches – To remove dead, diseased, or damaged wood.
What is a heading cut?


Heading removes only a portion of a branch — either only the branch tip and the next few buds or a branch down past one or more lateral branches.

Make the cut about one-quarter of an inch above a bud or branch. If cutting to a bud, notice its direction. The new branch will grow in that direction.

Use heading cuts sparingly. They may seal poorly and become a disease portal. Depending upon the plant, they may cause the growth of a profusion of new branches called a “witches broom”.

THINNING CUT

Use thinning cuts for four purposes:
  • To remove dense growth and allow more air and light to flow into the center of a plant and across to its shady side.
  • To stimulate growth from the branches below each cut.
  • To reveal the structure of a plant.
  • To finely tune the shape of a plant.
What is a thinning cut?


A thinning cut removes an entire branch at its point of origin on the trunk of a tree or on another branch. Be careful. Do not remove the branch collar, which is the enlarged portion of the branch where it meets the trunk or another branch.

This collar contains specialized cells that grow over and seal the wound. Cut immediately outside that boundary, leaving no stub that extends beyond that boundary. Stubs are physical barriers to the growth of the specialized cells in the branch collar that extend over and seal the cut.

When branch collars are not obvious on some plants, the branch collar is not apparent. Use the illustration below to locate the angle of the correct cut.

  • Imagine a line that parallels the branch that will remain after the cut.
  • Next, notice the angle between that imaginary line and the line of the branch bark ridge (marked as “A”).
  • Finally, repeat that same angle on the other side of the imaginary line (marked as “B”) and cut along that plane.


RE-LEADERING CUT

Purpose of releadering cuts:
  • To reduce the height, width, or density of a plant
  • To redirect the growth of a plant. This allows reduction without topping or mechanical shearing.
What is a re-leadering cut?

Removes a portion of a branch at the point where two or more branches split – typically a “Y” junction of two branches. At this junction, one branch is always longer and thicker (the dominant branch or “leader”) and the other is always thinner and shorter (the subordinate branch).

This cut removes the dominant branch at this point, and the side branch becomes the new leader. Reduces crowding by eliminating a portion of a longer or taller branch (one that is expanding a plant’s height and width) in favor of a shorter branch. Does not remove the dominant branch at its point of origin. Given its dominance, its point of origin is further down the plant, perhaps all the way at the base. As a result, the dominant branch has no branch collar at the point of the cut.

Thinning vs. Re-leadering

The two images below illustrate the difference between a re-leadering cut and a thinning cut. The left image illustrates a thinning cut. The lateral branch on the right is removed at its origin, just outside the branch collar. On the right, the vertical (dominant) branch is removed, allowing a the lateral branch to become the new leader.

Notice the location of the cut. It occurs just above the branch that will become the new leader, without cutting into the branch bark ridge.

When making a re-leadering cut, it is important to follow three rules:

Rule 1: The branch that remains after the cut (the subordinate branch) should be at least one-third the size of the portion of the parent branch to which it is attached and which remains. In the illustration above, the lateral branch that remains should be at least one-third the size of the branch piece shown as severed. 

Rule 2: the angle of the cut should be midway between the angle of the dominant branch and the angle of the subordinate branch. 

Rule 3: A stub is often inevitable but try to leave a very short stub of no more than one-eighth to one-quarter of an inch where the leader is removed from the plant.


When you have co-dominant leaders

A re-leadering cut also can be used to shorten or eliminate one of two co-dominant leaders. Co-dominant leaders are two trunks of roughly equal diameter that meet at a shallow angle.

  • The shallow angle creates a weak branch union and the likely site of a future break.
  • In older trees, the branches may be too large to risk removing either, because a large cut may leave both a misshapen tree and a large wound that may not properly seal.
  • It is important to subordinate one of the trunks by shortening it.
  • In younger trees, it is advisable to remove or shorten one of the two co-dominant leaders as early in the tree’s life as possible. This early removal greatly reduces the diameter of the cut and the tree’s consequent effort to seal it.
Removing a co-dominant leader in phases

In the illustration below, notice the co-dominant leaders and how the succession of cuts – over two or three years – first shortens and then removes one of the competing leaders.

JUMP CUT

A jump cut removes heavy branches in three steps to avoid tearing the bark and damaging the plant. Use a jump cut to sever and lighten a branch just beyond an intended final cut. This weight reduction avoids having the severed portion snap at the point of the cut and harm the plant.

How to make a jump cut (see diagram below)

• Make the first cut (A) from below the branch, 4 to 12 inches away from the final cut, and one-quarter to one-third of the way through the branch.
• Make the second cut (B) 1 to 2 inches further out the branch and all the way through. The portion beyond B will fall, and any tear in the bark will stop at A.
• Make the third cut (C) just outside the branch collar and all the way through.

Trees Are Vital

As the biggest plants on the planet, they give us oxygen, store carbon, stabilise the soil and give life to the world’s wildlife. They also provide us with the materials for tools and shelter.

Not only are trees essential for life, but as the longest living species on earth, they give us a link between the past, present and future. It’s critical that woodlands, rainforests and trees in urban settings, such as parks, are preserved and sustainably managed across the world.

Trees benefit health

The canopies of trees act as a physical filter, trapping dust and absorbing pollutants from the air. Each individual tree removes up to 1.7 kilos every year. They also provide shade from solar radiation and reduce noise. Over 20 species of British trees and shrubs are known to have medicinal properties. The oil from birch bark, for example, has antiseptic properties. Research shows that within minutes of being surrounded by trees and green space, your blood pressure drops, your heart rate slows and your stress levels come down.

Trees benefit the environment

Trees absorb carbon dioxide as they grow and the carbon that they store in their wood helps slow the rate of global warming. They reduce wind speeds and cool the air as they lose moisture and reflect heat upwards from their leaves. It’s estimated that trees can reduce the temperature in a city by up to 7°C. Trees also help prevent flooding and soil erosion, absorbing thousands of litres of stormwater.

Trees boost wildlife

Trees host complex microhabitats. When young, they offer habitation and food to amazing communities of birds, insects, lichen and fungi. When ancient, their trunks also provide the hollow cover needed by species such as bats, woodboring beetles, tawny owls and woodpeckers.

One mature oak can be home to as many as 500 different species. Richmond Park is full of such trees, which is one of the reasons it has been designated a National Nature Reserve and Site of Special Scientific Interest.

Trees strengthen communities

Trees strengthen the distinctive character of a place and encourage local pride. Urban woodland can be used as an educational resource and to bring groups together for activities like walking and bird-watching. Trees are also invaluable for children to play in and discover their sense of adventure.

Trees grow the economy

People are attracted to live, work and invest in green surroundings. Research shows that average house prices are 5-18% higher when properties are close to mature trees. Companies benefit from a healthier, happier workforce if there are parks and trees nearby.

Trees protect the future

Soon, for the first time in history, the number of people with homes in cities will outstrip those living in the countryside. Parks and trees will become an even more vital component of urban life. We must respect them and protect them for the future.

Why Topping Hurts Trees

Learn why topping is not an acceptable pruning technique and discover recommended alternatives.

Topping is perhaps the most harmful tree pruning practice known. Yet, despite more than 25 years of literature and seminars explaining its harmful effects, topping remains a common practice.

What Is Topping?

Topping is the indiscriminate cutting of tree branches to stubs or to lateral branches that are not large enough to assume the terminal role. Other names include “heading,” “tipping,” “hat-racking,” and “rounding over.” Topping is often used to reduce the size of a tree. Homeowners may feel a large tree poses a risk to their property; however, topping is not a viable method of height reduction, and may increase risk in the long term.

Topping Stresses Trees

Leaves are the food factories of a tree; however, topping can remove 50-100% of a tree’s leaf-bearing crown. Removing the leaves can potentially starve a tree and trigger various survival mechanisms. Dormant buds are activated, forcing rapid growth of multiple shoots below each cut. The tree needs to grow a new crop of leaves as soon as possible. If a tree does not have the stored energy reserves to do so, it will be seriously weakened and may die. A stressed tree with large, open pruning wounds is more vulnerable to insect and disease infestations. The tree may lack sufficient energy to chemically defend the wounds against invasion, and some insects are actually attracted to the chemical signals trees release.

Topping Can Lead to Sunburn

Branches within a tree’s crown produce thousands of leaves to absorb sunlight. When the leaves are removed, the remaining branches and trunk are suddenly exposed to high levels of light and heat. The result may be sunburn of the tissues beneath the bark, which can lead to cankers, bark splitting, and death of some branches.

Topping Leads to Decay

Correct pruning cuts are made just beyond the branch collar. The tree is biologically equipped to close such a wound if the tree is healthy enough and the wound is not too large. Cuts made indiscriminately between lateral branches create stubs or wounds that the tree may not be able to close. The exposed wood tissues begin to decay. Normally, a tree will “wall off,” or compartmentalize, the decaying tissues, but few trees can defend the multiple severe wounds caused by topping. The decay organisms are given a free path to move through branches.

Topping Can Lead to Unacceptable Risk

The survival mechanism that causes a tree to produce multiple shoots below each topping cut comes at great expense to the tree. These shoots develop from buds near the surface of the old branches. Unlike normal branches that develop in a socket of overlapping wood tissues, these new shoots are anchored only in the outermost layers of the parent branches and are weakly attached. The new shoots grow quickly, as much as 20 feet (6 m) in one year in some species. Unfortunately, the shoots are weakly attached and prone to breaking, especially during windy or icy conditions. While the original goal was to reduce risk by reducing height, risk of limb failure has now increased

Topping Makes Trees Ugly

Topping destroys the natural form of a tree. Trees form a variety of shapes and growth habits, all with the same goal of presenting their leaves to the sun. Topping removes the ends of the branches, often leaving ugly stubs. Without leaves (for up to six months of the year in temperate climates), a topped tree appears disfigured and mutilated. A tree that has been topped can never fully regain its natural form.

Topping Is Expensive

The cost of topping a tree is not limited to only the job cost. Some hidden costs include:

• Increased maintenance costs. If the tree survives, it will likely require corrective pruning within a few years (e.g., crown reduction or storm damage repair). If the tree dies, it will have to be removed.

• Reduced property value. Healthy, well-maintained trees can add 10–20% to the value of a property. Disfigured, topped trees are considered an impending expense.

• Increased liability potential. Topped trees may pose an unacceptable level of risk. Because topping is considered an unacceptable pruning practice, any damage caused by branch failure of a topped tree may lead to a finding of negligence in a court of law

Alternatives to Topping

Sometimes a tree must be reduced in height or spread, such as for providing utility line clearance. There are recommended techniques for doing so. Small branches should be removed back to their point of origin. If a larger limb must be shortened, it should be pruned back to a lateral branch that is large enough (at least one-third the diameter of the limb being removed) to assume the terminal role. This method of branch reduction helps to preserve the natural form of the tree. Sometimes the best solution is to remove the tree and replace it with a species that is more appropriate.