We're seeing it a lot this year. Bur oaks, coveted for their resilience and strength, are looking sickly. Bur Oak Blight could be the culprit, but don't panic - we can help!

Bur Oak Blight is a fungal disease that affects bur oaks in the midwest. It's a fairly new disease, emerging in the 1990's. We speculate that the particularly rainy spring and summer is making our friend 'BOB' feel a little too at-home here in Omaha. More specifically, if the weather is cool and rainy while new leaf shoots are expanding, the leaves could already be infected with the fungus, then show symptoms later in August. 

Owning a tree service, we spend a lot of time looking at trees, even when we're not on the job. Yesterday, we spotted some very unfortunate pruning work that just happened to be in the parking lot of a major nursery here in Omaha. We cannot stress enough the importance of quality tree pruning. Seemingly small errors, like the ones pictured below, can lead to serious consequences down the road.

This information is taken from the USDA Forest Service's brochure "How to Prune Trees." It's a great resource!

Target the Cut
To find the proper place to cut a branch, look for the branch collar that grows from the stem tissue at the underside of the base of the branch (Fig. 6A). On the upper surface, there is usually a branch bark ridge that runs (more or less) parallel to the branch angle, along the stem of the tree. A proper pruning cut does not damage either the branch bark ridge or the branch collar. 

A proper cut begins just outside the branch bark ridge and angles down away from the stem of the tree, avoiding injury to the branch collar (Fig. 6B). Make the cut as close as possible to the stem in the branch axil, but outside the branch bark ridge, so that stem tissue is not injured and the wound can seal in the shortest time possible. If the cut is too far from the stem, leaving a branch stub, the branch tissue usually dies and woundwood forms from the stem tissue. Wound closure is delayed because the woundwood must seal over the stub that was left.

When pruning small branches with hand pruners, make sure the tools are sharp enough to cut the branches cleanly without tearing. Branches large enough to require saws should be supported with one hand while the cuts are made. If the branch is too large to support, make a three-step pruning cut (Fig. 6C) to prevent bark ripping (Fig. 7C). 

There are conflicting theories out there about whether mulch is harmful or helpful to trees. Mulch can help younger trees retain moisture and regulate soil temperature in the heat of the summer. It can also be used in areas where roots are exposed so you don't have to mow over and harm the roots. So if you like the way mulch looks in your landscape, use these tips to avoid harming your tree:

• Avoid the mulch "volcano" and keep it away from the trunk. Mulch piled against the trunk holds moisture and heat, which helps give diseases, such as canker, an easy point of access.
• Keep the mulch layer 2" deep or less.
• Watch this short video on proper mulching technique.

If you are tackling a DIY pruning job on your trees, avoid flush cuts. While your first instinct may be to remove as much evidence of that tree branch as you can, it is important to leave the branch collar intact to prevent decay from entering the tree. The diagram to the right shows where the branch collar is, and also a three-step cut guide for removing the branch while minimizing harm to the rest of the tree. Read more here. 

We recently took a trip to North Carolina to pick up a shiny new bucket truck. On our long road trip back to Omaha, we noticed that tree topping is a common practice elsewhere, and that, thankfully, the city of Omaha takes pretty good care of its trees.  We don't see a lot of tree topping in Omaha, but when we do - it makes us cringe
 
According to the International Society of Arboriculture (ISA), 

You may have noticed a lot of trees and shrubs didn't survive the dry winter last year (we especially lost a lot of pine trees and yews in Omaha). We call this Winter Disiccation Injury, which is a fancy way of saying the tree didn't have enough water throughout the winter. Be proactive this winter and protect your beloved and valuable landscape! 

If we're experiencing a dry spell and the temperature rises above 40 degrees, have your hose at the ready: It's time to provide water for your trees and shrubs.

Evergreens continue to use a fair amount of water in the winter, but all trees and shrubs would benefit from winter watering. Trees that are most susceptible to drought damage are:

• Evergreens: spruce, fir, arborvitae, yew, Oregon grape-holly, boxwood, and Manhattan euonymus
• Birches (European white and paper birches)
• Maples (Norway, silver, red, Rocky Mountain and hybrid maples)
• Lindens, alders, hornbeams, dogwoods, willows, and mountain ashes
• All young trees and shrubs

The easiest method of watering is to use a regular garden hose. You'll first want to identify where the drip line of your tree is. The drip line is located under the outer edge of the branches (see illustration).  The largest concentration of roots is usually halfway between the drip line and the trunk, but it can vary. Lay your garden hose down at this midway point and run the water for a minute or two until the water puddles, then move it to several other locations around the tree. For even more benefit, also water directly under the drip line and slightly beyond as the diagram shows.

It's really that easy! (Just don't forget to disconnect the hose when you're done!)

As always, mulching around your trees will help the soil retain moisture and slow water run-off. Here is a helpful video about mulching. 

Winter weather has arrived here in eastern Nebraska! The last of the leaves are hanging on and will soon be stripped away by the frigid northerly wind.

You may be feeling some relief as you're cleaning up your lawn and garden beds for the last time and putting your tools to rest. No more shrub pruning, no more weeding, no more cursing at the rabbits for munching on your prized veggies. 

But there is an important part of your landscape that shouldn't be ignored in the winter - your TREES! 

Dutch Elm Disease is one of the most destructive shade tree diseases in North America. It affects American elms and kills individual branches, then eventually the entire tree over the course of one to several years. It can also spread to nearby trees. At Arbor Aesthetics, we strongly recommend NOT trimming your elm tree between April and October when the trees are leafing. 

How is it contracted?

The DED fungus was first introduced to the U.S. on diseased elm logs from Europe prior to 1930. A tree can contract this fungus by way of:

What are the symptoms?

DED is a vascular disease, meaning it affects the way a tree is able to conduct water. Because water cannot travel down to the roots, leaves will wilt, yellow and drop.  The photo to the right shows the beginning symptoms of DED.

How is it treated and prevented? 

The key to conquering DED is early detection and prompt treatment. If you suspect any of your elm trees are suffering from DED, call Arbor Aesthetics and our certified arborists can discuss possible treatment options.

• Pruning. Careful pruning of infected branches can prevent the disease from spreading down the tree. One of our certified arborists will be able to tell whether or not pruning alone will be an adequate treatment or if injecting a fungicide is necessary.
• Injecting fungicide. Certain fungicides are effective in protecting elms from infection via the elm beetle. It is expensive, however, and must be repeated every one to three seasons and may also pose a risk to the health of the tree.