Why do leaves change color in the fall? Why is fall color better is some years than others?
Green leaves actually contain colorful pigments all season, but during the growing season those colors are masked by an abundance of green chlorophyll. Chlorophyll is used in photosynthesis, the process in which the tree uses sunlight to produce food. The shorter fall days signal to the trees that winter is coming and it will soon be time to shed its leaves. At this time the tree stops producing Chlorophyll and the colorful pigments that have been there all along are finally revealed.
The brilliance of fall color is affected mostly by the sunlight; however, temperature fluctuation and soil moisture also play a role. A series of warm sunny days, followed by cold, but not freezing night time temperatures will produce the best fall color. If the trees experience a fall with a lot of cloud cover and moderate temperatures, the color will be dull. In addition, a wet spring followed by a moderate to dry summer and fall will produce the best fall color. During late summer and early fall, if a tree is under a slight amount of stress due to dry soil conditions, it will have more brilliant color.
If you are interested in finding out more about the science behind tree color in the fall, visit the following link from the UNL extension office.
There are some steps you can take to prepare your tree to deal with the harsh winter conditions that we experience here in Nebraska.
Water: Watering through the fall months is always a good idea, but it is particularly important if we have experienced drought conditions during the summer months. The tree’s root system is still active and will take up water well into winter, so making sure water is available is vital to the health of the tree. It is also a good idea to water several times over the winter months, as long as the soil and air temperatures are above freezing. Visit our blog for more information about watering trees in the winter and checking soil temperatures in your area.
Fertilize: The tree’s root system is still very active during the winter and will be using and storing nutrients that it takes up from the soil. A fall deep root fertilizer application benefits the tree by making sure it has the necessary nutrients to get through the winter and to be ready to put on new growth in the spring.
Tree Wrap: Extreme temperatures or hungry bunnies and squirrels can cause permanent damage to the tree’s trunk during the winter months. Extreme fluctuations between day and night time temperatures can cause frost cracks on the trunk of the tree. If we have temperatures below freezing at night followed by a sunny, mild day, the bark can split when the sun heats up the south and/or west side of the tree. This can cause the bark to expand too quickly. The wound caused by frost cracks can make the tree susceptible to disease or insect infestation.
Bunnies and squirrels like to snack on tree bark during the winter when food is sparse. They particularly like younger trees and trees with softer bark like Crabapple trees.
Using tree wrap can protect the tree from harmful temperature fluctuations and animal damage.
Mulch: Mulch will act as a blanket for the tree’s root system. It will protect the root system from extreme cold temperatures. It will also help to keep moisture in the soil. Typically, 2-3” will do the trick. However, do not add mulch right up against the trunk as it is important to keep good airflow around the base of the tree to avoid rotting.
Our arborists are available year-round, so please continue to submit your questions to Ask the Arborist!
There are a few important issues to consider when choosing a tree to plant.
What will be the mature size of the tree?
are looking to plant a tree near the foundation of your house, choose a tree with an appropriate smaller mature size. You could also choose a tree with an upright, columnar growth habit, such as a columnar white pine.
All too often we see a tree that looked great close to the house when it was first planted but over the years grew too large for the site and had to have major limbs removed or even needed to be cut down. If you
Are there any obstructions above the tree?
While you are considering size, don’t forget to look up! If there are power lines above your planting site, you will need to either choose a different planting site, or choose a tree that will not interfere with the power lines when it reaches its mature height.
What is the condition of the planting site?
Site conditions include the amount of sunlight that the tree will be exposed to, the moisture level of the soil, and if the site is protected from or exposed to extreme Midwest elements. For example, a Japanese maple tree will do much better in a protected shady location as opposed to a site that is exposed to harsh winter winds and hot summer sun.
What purpose will the tree serve?
Are you looking for a large tree to provide your house with afternoon shade or are you looking for a small tree to add ornamental value to your landscape? Many trees will offer more than one benefit. A large evergreen tree, for example, can provide a windbreak that protects a house from strong winter winds while providing shelter and nesting sites to birds like chickadees, cardinals, and finches.
Many homeowners are looking for a fast growing shade tree so that they can enjoy the energy saving benefits as quickly as possible. It is important to keep in mind that fast growing trees tend to have softer wood than the slower growing trees and will not be as long lived as the hardwood trees. So, if you are looking for a tree that will provide shade for many years to come, you may be better off with a hard wood tree such as an oak as opposed to a soft wood tree like a birch.
Fall is a great time for planting trees! If you are interested in seeing how a tree will look when it has matured, the OPPD Arboretum has many examples of trees that do well in Nebraska. If you would like more information about selecting the right tree for your property, please contact us!
I've been told my trees have fall webworm. Does this mean I will lose my tree?
The damage done by the fall webworm looks much more devastating than it actually is. The webbing in the tree usually appears in late July or early August. The webbing starts at the ends of the branches and expands toward the trunk of the tree. Small black caterpillars are found devouring the foliage in and around the web. This activity leaves the tree looking very unsightly but not permanently damaged. In extreme cases, an entire tree may be defoliated. A healthy tree can withstand a fall webworm infestation for several consecutive years without suffering any major effects. A tree that has already been stressed or weakened by another pest may require action.
Generally speaking, fall webworms will favor fruit trees and ornamentals such as crabapple and pear trees. If the webbing is within reach, simply remove it with a stick, broom, etc. The areas of the tree that have been defoliated should leaf out with the rest of the tree next spring.
Tent caterpillar and Gypsy moth caterpillar are two types of pests that are very similar to fall webworm, but they are active beginning in the spring and will continue through the fall. Webbing usually begins in the forks of branches and expands toward the ends of the branches. These caterpillars can produce several generations during one season and should be removed when first noticed.
If the webbing is out of reach or the tree is heavily infested, chemical control may be required. As always, we invite you to contact one of our licensed arborists for any tree care concerns you may have.
My crabapple tree's leaves are turning black and dropping quickly. Is my tree dying?
Apple Scab leaf disease is most likely the cause of the leaf drop and will not kill the tree. The tree will most likely put on a second set of leaves this season. It is important to take steps to encourage good overall health of the tree to help it recover from the loss of leaves. Give the tree extra water during periods of extreme heat and less rainfall, avoid any injury to the tree or pruning for this season, and apply deep root fertilizer this fall. You may also want to consider preventive treatments for next spring.
Apple Scab is a leaf disease that thrives during cool, wet spring seasons. This last springbrought an extended period of cool, wet conditions which allowed the Apple Scab fungi to thrive. The spores are then spread during these ideal conditions and infect the leaf tissue. Once a leaf has been infected, there is not a treatment to cure the infection so the disease eventually causes the leaf to drop. If a tree is infected for several consecutive years, preventive treatments should be applied. Early leaf drop requires the tree to use extra energy to produce more leaves, which can become a problem if it happens continuously.
Click the link below, if you questions or concerns about your tree or our services. One of CM's certified arborists will schedule an appointment to discuss your tree care options.
The key to controlling many types of insect and disease issues is targeting the problem before it starts. For instance, we have talked about emerald ash borer. By the time trees show signs of infestation, significant damage has already been done and you are fighting an uphill battle to save the tree. However, there is strong evidence that indicates that disease is less severe in trees that have received preventive treatments.
We are currently applying our preventive insecticide treatment. This is a systemic injection that offers year long protection against most destructive pests. Injection occurs in the spring prior to the start of insect activity, protecting your trees from the following:
||*Flat head borers including Emerald Ash Borer (EAB)
|*Elm Leaf Beetles
||*Soft Scale Insects
||*Zimmerman Pine Moth
Coming up in late summer/early fall, our preventive fungicide treatment offers the same year long protection against Nebraska’s most common tree diseases such as:
||*Crabapple Leaf Disease
||*Diplodia Tip Blight
Click the link below, if you questions or concerns about your tree or our services. One of CM's certified arborists will schedule an appointment to discuss your tree care options.
If your tree’s leaves are starting to appear, you may think that the tree is in the clear as far as drought damage goes. However, during periods of severe drought, a tree may lose a significant portion of the root system because roots cannot live in soil that is dry for long periods of time. Also, the tree has used a good deal of energy and its reserves trying to keep itself cool in the hot temps and dealing with reduced water uptake. The tree will also have a difficult time fighting off insects and disease. So, how do trees recover from severe drought conditions?
WATER! Proper tree care requires that you monitor the soil moisture. Use a garden trowel or a screwdriver to check the soil moisture 2” below the surface. If it is dry, then it is time to water. Sometimes a lawn irrigation system will not water deep enough to reach the tree roots. You may need to pull out the hose to soak the soil. You want the soil to be moist but not soggy.
Maintain 1-3” of mulch around the base of the tree, but avoid mounding it against the trunk of the tree. Mulch protects the trunk from mower and string trimmer damage, maintains soil moisture and adds nutrients to the soil as it decomposes.
Monitor the tree for any signs of insect or disease problems. By catching the problem early and correcting it, you can help the tree fight off the problems it may not be able to handle on its own. Click the buttom below if you would like a licensed arborist to inspect your trees.
For a new tree, the only tree pruning that should be done the first year would be to remove any dead, damaged, or diseased branches. After the tree has been planted in the ground for one year, you can begin to prune the tree to improve structure and aesthetics. This may need to be done each year until the tree has a strong, balanced structure. Training young trees optimizes structural stability in the mature tree. By pruning a tree when it is young, you can avoid problems such as co-dominant stems, weak branch attachments, and crossing branches. This can greatly reduce the maintenance costs associated with correcting these structural defects in the future.
For a mature tree, how often you need to prune will depend on the history of the tree. If it has been well maintained through the years, the only pruning that may need to be done would be to remove any dead, damaged, or diseased limbs. If the tree was not properly trained when it was young, it may have problems such as splitting branch attachments, branches that are too low, or other structural defects. Typically, removing more than 25% of a tree’s leaf area during one growing season should be avoided. The tree may need to be pruned once every few years until it has good structure and aesthetics.
As always, we recommend consulting a licensed arborist before pruning.
The Emerald Ash Borer (EAB) is an invasive insect that has destroyed tens of millions of ash trees in North America and Canada since 2002 when it was first discovered in Michigan. The beetle is native to Asia and was brought to the US by infested wooden pallets. It attacks all ash trees, regardless of age or health. Trees become infested when adult beetles lay eggs on the bark. The eggs hatch into larvae that bore into the tree. They tunnel just below the bark and disrupt water and nutrient movement, eventually killing the tree.
Until recently, the closest the pest had been to the Omaha area was in extreme north east Iowa in Allamakee County. On July 20 of this year EAB was discovered in the Kansas City area and on Aug 29 it was discovered in Wyandotte County in Kansas. The borer is usually spread by moving infested firewood to campsites around the country.
The recommendation that the Nebraska Forest Service is using for when to begin preventative EAB treatments, which other states are using too, is not to begin treatments until you know EAB is within 15 miles of your location. We will continue to keep you up to date on the latest EAB news. There are several chemical treatment options that have proven to be effective in protecting ash trees from the devastation of EAB. While it is not impossible to save an ash tree once it has started to show signs and symptoms of an EAB infestation, the success rate of keeping an ash tree alive is much greater with preventative treatments. Symptoms can be difficult to recognize because many of them look very similar to the effects of drought stress on trees.
Some signs and symptoms of infested trees include:
Branch dieback from the top of tree
Delayed leaf out in the spring
Epicormic shoots/water sprouts
D shaped exit holes
S shaped tunneling under the bark
If the thought of losing your ash tree concerns you and confirmed sightings within 15 miles is too close for comfort, contact us and we will have a professional arborist take a closer look. We can answer any questions you may have regarding appropriate preventative treatment measures.
For more information on the devastating destruction of the Emerald Ash Borer on our ash trees, visit www.emeraldashborer.info
Not sure if you have an ash tree? Email a picture to firstname.lastname@example.org
Fall provides great planting conditions for trees and many nurseries offer discounts at this time of the year. If you finally made the decision to add a new tree to your landscape this fall here are a few tips on how to select a quality tree from the nursery and properly plant to ensure a long healthy life.
Selecting: When you go to your local nursery you will find that tree prices can run fairly steep compared to a big box store garden center, but don’t avoid going to a nursery because of that. Privately owned nurseries tend to have higher quality tree stock, offer longer warranties, and support local growers. No matter where you go, it is good to know a few hints on how to spot a good tree.
· It is important that the tree has a visible trunk flare (area where the trunk expands to the root ball). This is a sign of proper growth and strength.
· Inspect the tree for any damage to the bark, uneven branch distribution, and lack of new growth.
· Examine the foliage as signs of stress are easily visible by looking at the canopy of the tree! If the tree has been suffering it will be difficult to transplant and it could possibly die, wasting your money and time. Leaves should be full, large, and green depending on the type of tree and time of year.
· Some larger trees come in ball and bur lapped bags. Check to make sure the twine does not girdle the trunk and the root ball is moist. With smaller potted trees you can sometimes pull the tree out of the pot to examine the roots. Roots should be a healthy light color and fit snugly in its container.
Planting: To ensure that your newly selected tree lives a long healthy life it is important to plant it in the right place. Improper planting leads to a lifetime of disease or insect problems and often times death. Here are some simple planting tips that help improve the health of your tree.
· When digging a hole it is common practice to dig 2 to 3 times larger than the width of the root ball, but no deeper. The trunk flare should be a couple of inches above the ground level. Throughout time the tree will settle, but there is no need to amend the soil.
· Always be gentle when removing the pot and be sure to loosen up the root system. Place the tree in the middle of the hole and back fill with the previous dirt, lightly packing, not stomping, the soil.
· After ball and bur lapped bags are set in the hole, cut the twine and the top-most portion of the wired cage.
· Always water the tree immediately after planting. If the tree is large, you can water while filling the hole back up with soil. Infrequent deep soakings are recommended for the first year after a planting.
· Some trees may need staking. Be sure to monitor the stakes as they may require adjustments. Depending on the tree, stakes can be removed after 1-2 years.
· Mulching is a great idea because it helps maintain moisture, keeps weeds away, and maintains a cooler soil temperature. You only need 2-3 inch thickness. Avoid stacking mulch against tree bark to prevent restricting roots and causing disease.
Check out ReTree Nebraska’s 12 for 2012 for recommended species in our area