Early disease development in bur oak leaves

Bur oak blight (BOB) is a native fungal leaf disease that affects certain native varieties of bur oaks, and to a lesser extent swamp white oaks. Not all bur oak trees are susceptible, due to genetic differences in bur oak species. Though not directly life threatening, BOB can weaken oak trees over time and make them susceptible to more serious problems such as Two-Lined Chestnut Borer and Armillaria Root Rot.

Extended periods of damp, wet weather in early May create conditions that cause the BOB fungus to infect newly forming oak leaves. Symptoms begin as browning and dropping leaves in July and August in the lower third of the canopy and progressing to the upper canopy as the disease progresses over the years. A telltale symptom of BOB are leaves remaining on the tree throughout the winter rather than dropping off like normal shade trees. Fungal spores are produced on the dead leaves as well as on affected branches and twigs, allowing for continual disease spread throughout the year.

Infected leaves remain attached to tree all winter to infect new leaves the following spring.

Management of BOB is centered on keeping the tree as healthy as possible. Watering and fertilizing are key maintenance procedures that are critical for long term survival. Other treatments worth considering include insect control to prevent and control two-lined chestnut borers. For moderately affected and high value trees, fungicide trunk injections can reduce leaf browning and loss. Plant growth regulator application to reduce growth may allow trees to conserve more energy needed to leaf out each spring.

Here’s what we can do

Shadywood Tree Experts can help maintain your Bur oak trees with the use of fungicide trunk injections, annual fertilization and if needed, insecticide and growth regulator applications. When you sign up for plant health care from Shadywood, we administer the recommended protocols for disease prevention control to keep your trees healthy. With each visit, our arborists assess trees for overall health.

Additional things you can do to maintain the health of your tree

Water trees regularly using a lawn sprinkler for at least an hour (soaking) once every one  to two weeks to minimize moisture stress. Mulch root systems when possible, using natural wood chips to protect the trunk, condition and improve the soil, and to conserve soil moisture. If you see anything that doesn’t look right, have your trees inspected by one of Shadywood Tree Experts International Society of Arboriculture Certified Arborists.

Exit hole of adult Bronze Birch Borer Beetle

Bronze birch borer (BBB) is a common native wood-boring insect that feeds on tissues under the bark of birch trees. BBB is an opportunistic borer that only attacks weakened and stressed birch trees. Severe infestations can kill birch trees. Paper, European white, ornamental purple and cut leaf varieties of birch are very susceptible, while river and yellow birch are more resistant to BBB. Typical symptoms of BBB include branch/tip dieback in the upper canopy and the telltale 1/8” “D” shaped exit holes on the bark of dead and dying branches.

Minimizing tree stress through frequent watering (one to two hours every one to two weeks using a lawn sprinkler) and annual fertilization can greatly reduce the occurrence of BBB.  Preventative treatment options for BBB include soil and trunk injected systemic insect controls. Shadywood Tree Experts offers both treatment options. As preventative treatments, both treatment options have proven effective in preventing and treating BBB. In addition, therapeutic treatments are successful if the infestation is caught early and when damage is minimal.

Here’s what we can do

Shadywood Tree Experts can help maintain your birch trees with the use of systemic insecticide applications and annual fertilization. When you sign up for plant health care from Shadywood, we administer the recommended protocols for disease prevention control to keep your trees healthy. With each visit, our arborists assess trees for overall health.

Additional things you can do to maintain the health of your tree

Water birch trees regularly using a lawn sprinkler for at least an hour once every one to two weeks to minimize moisture stress. Mulch root systems when possible, using natural wood chips to protect the trunk, condition and improve the soil, and to conserve soil moisture.  If you see anything that doesn’t look right, have your trees inspected by one of Shadywood Tree Experts International Society of Arboriculture Certified Arborists.

Apple scab (Venturia inaequalis), is one of the most common and serious fungal diseases of flowering crabapples in Minnesota. Symptoms appear as olive-colored spots on leaves and are  first seen in late May and early June. As the disease progresses into June and July, leaves yellow and begin to fall, causing crabapples to become thin. Consecutive days of cool, wet weather in April and May when leaves are immature lead to new infections.

Crabapples infected with apple scab are weakened and stressed due to the leaf loss and can be prone to more serious problems. Spraying crabapples preventatively as new leaves emerge and fertilizing on an annual basis are the best method of controlling and minimizing the impact of apple scab.

Here’s what we can do

Shadywood Tree Experts can help maintain your trees with the use of systemic and/or contact fungicide spray applications and annual fertilization. When you sign up for plant health care from Shadywood, we administer the recommended protocols for disease prevention control to keep your trees healthy. With each visit, our arborists assess trees for overall health.

Additional things you can do to maintain the health of your crabapple tree

Water trees regularly using a hose or small sprinkler for at least an hour once every one to two weeks if we do not receive adequate rain. Avoid spraying leaves directly when watering as wet leaves can promote fungal diseases. Mulch root systems when possible, using natural wood chips to protect the trunk, condition and improve the soil, and to conserve soil moisture. Rake up and dispose of fallen diseased leaves. If you see anything that doesn’t look right, have your trees inspected by one of Shadywood Tree Experts International Society of Arboriculture Certified Arborists.

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Apple scab has caused this crabapple tree to appear thin and unhealthy.

Apple scab infected leaf

Constantly spraying leaves with irrigation can cause apple scab to become worse. We have been treating the crabapple trees at this property and asked the home owner if they can have their sprinklers adjusted to avoid spraying leaves.

EAB exit hole

Across the country the Emerald Ash Borer has killed millions of Ash trees. Here in the twin cities we haven't been hit hard yet, but it will happen. Slowly the population of Emerald Ash Borers grows until it explodes exponentially.

EAB larva

The resulting effect is the death of all the ash trees in an infested area, unless the trees have been treated. The destruction left by these beetles is considered a natural disaster. I can only imagine how depressing it will be to see the aftermath, when entire neighborhoods boulevard ash trees are removed. Or worse seeing an entire neighborhood full of dead and declining ash trees.

Removal of these trees will come at a huge cost to cities and homeowners, but there may be other costs as well. Recently an article "When Trees Die, People Die" by Lindsay Abrams has pointed out a rise in heart disease amongst people living in areas where ash trees were wiped out by emerald ash borers. She makes an interesting case that trees have a profound effect on our well being, both physical and emotional. Whether or not there is a correlation between the death of millions of trees and an increase of disease in people is debatable. I do recommend reading the article, it is well put together and thought provoking. http://www.theatlantic.com/health/archive/2013/01/when-trees-die-people-die/267322/ 

If you do have an Ash tree or trees on your property it's not too late to start treating them. Shadywood Tree Experts has treatment options available to protect from Emerald Ash Borers. 

Sign of bad tree work

When you find yourself in need of tree work, or plant health care, here are some words of caution. Many tree services drive into the Twin Cities from out-state to find work by going door-to-door, follow storms, etc. Often times, they show up with a pickup truck, a chainsaw and little else. They usually have no ISA Certified Arborist affiliated with their company, may have little tree knowledge, typically are not covered by Workers’ Comp or General Liability and often do not charge/or pay MN sales tax.

Sign of bad tree work

They talk a good game and encourage you to do the work right on the spot, “while they are in your neighborhood.” Unfortunately, the homeowner is the one who can suffer the result of agreeing to have tree work performed by such a company.  There are some horror stories that involve being charged too much, being given bad advice on what should be done, paying in advance of the work being completed and being left with a partially removed tree, or logs stacked on the boulevard with no way to contact the workers, etc.

Then, Shadywood gets called to “fix” the situation. Being an aware consumer can save you money and ensure that the proper work is being done for you.  For example, there are many issues that a local company will be conscious of that an out-of-towner may not, such as not transporting any ash lumber outside the county to try and limit the spread of the Emerald Ash Borer, or not leaving firewood for you, if the tree is infested with Dutch Elm Disease. 

Any number of scenarios have been described to us and the homeowner is the one who suffers and ends up spending more money in the long-run. With this in mind, when you need a tree professional, take these precautions:

• Don’t make a decision impulsively, when someone knocks on your door and suggests tree work you haven’t solicited
• Ask for proof of insurance (General Liability, Workers’ Comp)
• Ask for referrals, if needed to ease your mind
• Check their reputation with the Better Business Bureau and/or Angie’s List
• Is there an ISA Certified Arborist doing the bid and the work?

Shadywood Tree Experts has eight (8) ISA Certified Arborists on staff.  We have the expertise to give you a knowledgeable bid with recommendations and also the presence of an ISA Certified Arborist on the crew as well.  We can help you avoid all of these pitfalls. 

Healed cut

For decades it was a common belief that applying pruning sealer to tree wounds was the perfect remedy for preventing decay and insect infestation in trees. Although applying a wound dressing may be helpful in some situations, it’s important to remember that it can have a negative impact as well.

So before you head into the yard with a chainsaw in one hand and a can of spray paint in the other, keep the following information in mind.

Decay from a bad cut

• Trees are governed by a complex biological system regulated by natural resources. By adding pruning sealer you’re more likely to seal in moisture, which will slow the healing process and prevent sunlight from drying the wound.
• Dark areas with trapped moisture are the perfect atmosphere for the development of fungi, which can lead to decay in trees.
• Pruning sealers are asphalt and petroleum based products which are toxic to plants. If pruning sealer is applied to a tree wound, the vascular system may be working just as hard to prevent the translocation of toxic chemicals throughout the canopy as it will to heal the wound.

One of the most important areas of a tree which helps prevent decay and insect damage is the area called the branch protection zone. It can be found just outside the branch bark ridge and branch collar.

By making your final cut just outside this area at a 45 degree angle away from the tree, the branch protection zone will remain in tact and be able to perform its primary function of wound enclosure. To help facilitate this process, make sure the tool you’re using has a sharp blade or chain.

Although it is known that wound dressings do not prevent decay or increase the likelihood of wound enclosure, there are situations where the application of a pruning sealer is necessary.

If pruning a tree during high risk disease season, for example oak wilt (Ceratocystis fagacearum). A light coating of pruning sealer can mask the scent emitted from tree wounds, that can attract insects carrying the oak wilt pathogen.  We do not trim oaks in the high risk season unless it’s absolutely necessary to trim a broken limb. A wise person once said “the best defense is a good offense.” 

In this case a great offense would be a combination of applying the proper cutting technique, using a sharp tool and pruning during the right time of year. If you’re going to use a wound dressings, make sure it’s not a petroleum based product. Following these rules will increase the likelihood of full wound compartmentalization, while at the same time allowing the tree to naturally recover on its own.

Good luck and safe cutting! Keith Curtis ISA Certification #MN4130-A

Hiring a certified arborist to care for your trees will undoubtedly ensure receiving a higher quality, more professional service than hiring a non certified individual.

Certified arborists are held to a higher standard based on professional ethics and personal integrity. Some of the many hats arborists wear include educators of the public, company managers, tree climbers, foresters, landscapers and sales consultants.

The International Society of Arboriculture is the organization that certifies arborists in the tree care industry. To be eligible for ISA certification one must have three years of full time experience in the field of arboriculture or a two year degree in an arboriculture and two years of practical experience in a related field. Shadywood Tree Experts has 8 certified arborists of staff. 

This is a question we get asked from homeowners all the time. There are many factors which can affect the health of pine trees.

These factors are environmental stresses, insects and diseases, age of the tree, herbicides and salt damage. Any one or combination of these factors can have an adverse effect on the health of your tree.

Before I get started I want to clear up one common misconception: all evergreen trees are not pine trees. In a way it's true, but to be more specific the pine family covers a large group of evergreen trees including Spruce, Pine, Fir, Hemlock, and Tamarack.

The two most commonly found in the urban landscape are spruce and pine trees. An easy way to distinguish the two are the length of their needles: spruce trees have shorter needles ½ - 1 inch long while pine trees have longer needles 2 to 4 inches long.

Environmental Stresses: Pine trees planted in the urban landscape undergo significantly more stress than their forest counterparts. Soil compaction, poor soil types, heavy clay soil with poor water drainage and/or drought are a few of the problems urban trees face. The best thing when deciding on a tree to plant is to choose one well suited for the location you are planting in. Some need full sun and others shade, some do well in wet locations and others dry.

Insects and diseases: Pine trees that have become stressed from environmental factors also become susceptible to insects and diseases. Left untreated the symptoms vary from branches dying on the lower portions of the trees, to needles falling off the branches, deformation of the tree, or the tree eventually dying.

Age of the tree: At some point all trees reach the end of their lifespan. This can be noted as a slow decline over many years. The tree starts looking rough, there’s not as much new growth as there once was, branches might die leaving open and bare spots in the canopy. 

Herbicide and salt damage

Herbicide and salt damage: There are many types of herbicides used to control weeds in turf. When pine trees are exposed to these chemicals there can be severe consequences. Symptoms can vary from a distortion and twisting of needles, as seen in the photo below, to yellowing of needles and death of the tree. Pine trees planted near roads may be exposed to salt during the winter months. The salt damages needles it comes in contact with, as well as the soil surrounding the tree. We recommend watering to wash the salt away or dilute it.

Summary: There are many factors which can affect the health of pine trees. A combination of one or more factors can have severe consequences to your trees health. As always consult with one of Shadywood Tree Experts’ ISA Certified Arborists to determine the best care and maintenance plan for your trees.

Additional reading http://files.dnr.state.mn.us/assistance/backyard/treecare/forest_health/whitesprucediagnosis.pdf

By David Anderson, ISA Certified Arborist #MN4444A

3-point cut diagram

The best method for pruning limbs is called the 3 Point Cut. Practicing this approach will keep you safe and your tree healthy. It will ensure wound compartmentalization and prevent the branch from peeling the bark away from the trunk as it releases. To better communicate this idea, extend one arm straight in front of you. Imagine this is the limb you are going to cut.

1. Keeping in mind the length of your arm (branch), make an undercut approximately 10% out from where your arm connects to you shoulder. Only cut about 20% into the branch, so a not to pinch the saw.

Clean cut

2. The 2nd cut will be above this cut, approximately 12-13% out from where your arm meets your shoulder, leaving a little gap in between the first and second cut. The top cut will cause the branch to sag, eventually severing the branch cleanly.

3. The final cut takes place on the top side of where your shoulder meets your arm. At a 45 degree angle and with a sharp saw, cut downwards and away from the tree trunk. If your arm is still hanging in front of you, your top cut would start at about 1% away from the shoulder and finish on the bottom about 2-3% away from your armpit. Provided you still have both arms, make sure to practice this technique a few times on smaller limbs (2-3” diameter) before working your way up to large limbs over structures.

A bad cut

Or even better, call the professionals at Shadywood Tree Experts for a free estimate. Examples of good and bad cuts:

The impact of drought can have severe and long lasting effects on trees.

This problem can lead to secondary disease and insect problems years after the initial drought, which can then lead to the decline or death of your trees.

The best way to avoid these problems is with regular watering of your trees. This will minimize drought stress.

A general rule of thumb is to water a tree one time per week for 1-2 hours with a lawn sprinkler during summer if we do not receive 1” of rain that week. Another rule is to water 5 minutes per 1 inch of trunk diameter. For example, a tree with a 5 inch diameter trunk can be watered for 25 minutes.

Mulching the area underneath the leaf canopy of trees also helps conserve water by retaining soil moisture.

Over watering also causes problems, here are a few tips to avoid over watering.

• For trees planted in heavy clay soil watering once per week during drought should suffice.
• Trees planted in light sandy soils can be watered twice per week.

One sure way to know if your tree needs water is to dig down a few inches, if the soil is dry you can water but if it feels moist you can check again in another couple of days.

Many of our customers water their lawns with irrigation systems and while that may help trees somewhat, the amount of watering is too short to be of great benefit.

Because a lawn can easily be replaced but a 50 year old tree cannot we encourage homeowners to give priority to water trees.

Magnolia tree lacking water

Maple tree showing signs of stress from lack of water

Tree lacking water

200 year old oak tree

Trees are an important part of the urban landscape, adding value and beauty to our homes. The addition of an annual tree fertilizing program is a great way to maintain the health and vigor of your trees. Tree fertilizer provides the 3 macronutrients required for growth and metabolic functions. Additionally healthy trees are more resilient to stress, diseases and pests.

In the natural setting trees live in perfect harmony with their environment.  Leaves and twigs breakdown on the forest floor, recycling the nutrients needed for growth.  In the urban landscape trees face a number of challenges.

Pin oak in a driveway island, there is limited root space and radiant heat from the asphalt

• The organic layer of black topsoil has been stripped away from the ground when new homes are built.

• There is no recycling of leaf litter, leaves and grass clippings are bagged and removed.

• The soil is subject to compaction from irrigation, foot traffic, and construction.

• High ph commonly seen in clay soils can cause micronutrients to be unavailable.

• Restricted root zones, trees planted near roads and buildings.

• Competition from turf grass and other shrubs.

• Heat and drought stress are more severe in the urban microclimate.

Benefits of fertilization

A healthy elm tree shows the benefits of fertilizing

• Supplements 3 macronutrients, Nitrogen, Phosphorus, and Potassium, essential for growth and metabolic activities.

• Non water soluble Nitrogen provides a slow feeding. Water soluble nitrogen commonly used in lawn fertilizer has a quick release and is prone to storm water runoff.

• More fine roots are found in soil where Nitrogen is present. Enabling trees to better uptake water and nutrients.

• Soil injection with a root feeder probe puts fertilizer below turf grass roots where trees benefit the most. Additionally there is some aeration from injection, lessening soil compaction.

• Can speed the recovery and wound closure of pruned trees.

• Young trees can grow and establish faster with annual fertilization.

The best time to fertilize your trees is in spring or fall.  Spring is a large growth period for trees.  During fall trees will absorb some of the nutrients before going dormant and will have the rest in place for spring growth.

Tree fertilization is an excellent component in maintaining the health of urban trees, providing nutrients for growth and minimizing stresses.  Cultural practices such as regular watering and pruning are also recommended.

River birch before and after leaf chlorosis treatment

Here is a before and after picture of a River birch we treated for chlorosis.  In this case we fertilized with a micronutrient trunk injection.  Then we established a maintenance program of soil applied fertilizer with the addition of chelated micronutrients Iron, Manganese and Sulfur.

Occasionally, here in Minnesota “Old Man Winter” throws us a heavy snow or ice storm, which can cause damage to trees and shrubs. In some cases a large limb falls off, which could cause property damage or even prompt the removal of the tree.

As a homeowner the best thing you can do is have an arborist evaluate your property, and prune trees which may have structural weaknesses before a storm can take them out.

Many woody shrubs are also prone to branch breakage. In many cases woody shrubs have the ability to generate new growth from the ground up, which in turn rejuvenates the shrub and replaces the older growth in time.

In cases where evergreen shrubs branches become bent down or broken it’s a little more difficult. They do not generate new growth, so removing a branch will permanently leave an empty space. I also see a lot of homeowners tying them back up to hold their shape, but they never look the same and replacing might be the best option

What is leaf chlorosis?

Leaf chlorosis is a yellowing of leaves caused by a lack of chlorophyll. 

What causes leaf chlorosis?

When soil conditions are too alkaline, micronutrients like Iron solidify and become unavailable.  When trees become deficient in Iron they cannot make chlorophyll and develop leaf chlorosis.  Since trees need chlorophyll for photosynthesis, trees with severe chlorosis weaken and die.

Trees commonly seen with chlorosis are:

• Oak

• Birch

• Maple

Treatment for leaf chlorosis

In moderate to severe cases we use trunk injection with micronutrients to treat the deficiency. 

The treatment lasts 1-3 years and needs to be followed up after symptoms return. Annual fertilization with a slow release tree fertilizer is also recommended to promote health and reduce stress.

River Birch we treated last summer responded very well to treatment in a short period of time. Pics on left are before pics and ones on right are after treatment a few months later.

By: David Anderson, Plant Health Care, Shadywood Tree Experts ISA Arborist

Leaf chlorosis (lack of chlorophyll)

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Tree suffering from leaf chlorosis

Chlorosis treatment before and after

Soon it will be spring and time to begin our spring fertilization program.  You may be wondering if tree fertilization is right for your trees.  The answer to that question can be complicated, but I am here to simplify things. 

Trees in the urban landscape face a number of unique challenges that can limit their growth and potential; they also face an increased mortality rate before reaching maturity. 

What challenges do urban trees face and how can fertilization benefit?

• Nutrients

In the forest there is a natural process of decomposition that constantly recycles nutrients.  In the urban environment, debris is cleaned up and there is little if any nutrient recycling.  We use a slow (microbial) release fertilizer which mimics the natural process of decomposition.  Research shows an increase in the rate of growth of fertilized versus non-fertilized trees. This is especially true for small to medium sized trees in the vigorous phase of growth.  Large mature trees are in a slower phase of growth but also benefit from the additional nutrients.

• Competition

Young trees are working hard to grow and become established.  They are also in direct competition with turf grass roots for space and nutrients.  Research indicates that height and trunk caliper growth is slower than trees grown in bare soil or wood mulch.  Leaf canopy is also noticeably thinner on trees grown in turf grass.  We use a soil probe to inject the fertilizer into the ground, placing it beneath turf grass roots where trees will get the most benefit.  The addition of tree fertilizer promotes the development of fine absorbing roots.

• Compaction

Soil compaction is unavoidable in the urban environment.  Foot traffic, lawn mowers and even irrigation systems all contribute to compaction.  The main problem with compaction is it reduces micro pore space in the soil which holds oxygen.  Trees fine absorbing roots require oxygen and are negatively impacted by compaction.  Our soil injected fertilization program can reduce some compaction, but there’s no best way to dramatically reduce it.  If possible mulching the entire area beneath a tree with wood mulch can reduce further compaction and improve soil structure in time.

These are just a few of the challenges urban trees face. The main point is everyone would like to have a large shade tree at their home.  Trees provide many benefits to the environment and increase our quality of life. Fertilization is one of the many practices which help trees overcome the challenges found in the urban environment.

David Anderson; Plant Health Care, Shadywood Tree Experts ISA Arborist

Often times during winter the bark on young trees can be damaged by deer rubbing their antlers on them, or by rabbits feeding on the bark tissue.  The injury to your trees could take years to heal or in cases where the trunk has been completely girdled, cause the tree to die within a few years.

Deer and rabbits cannot resist thin bark, especially those found on young maple, linden and crabapple trees. Other times of year deer and rabbits might also graze on your landscape plants and shrubs.  It’s recommended to choose plants they dislike, although they will eat anything if they are hungry enough. 

Spray-on products that smell or taste bad can deter them to a degree, but if you live in an area with large deer or rabbit populations, some foraging is common.

The best defense is to put a corrugated plastic tree guard on the tree.  Ideally keep it on from November through early spring.  They are commonly found at hardware stores and garden centers.  I recommend using them for the first several winters until the trees develop thicker bark. 

By David Anderson, Shadywood Tree Experts ISA Certified Arborist  

Additional reading: 

http://www.extension.umn.edu/garden/yard-garden/wildlife/rabbits-and-trees-and-shrubs/  

Deer girdle

Use a trunk guard to protect young trees

Deer girdle