Q: My Leyland cypresses are dying from the bottom up, and it's spreading from tree to tree. is this blight or some kind of insect?
A: It the tree is really a Leyland cypress, the likely culprit is Seiridium canker. This could eventually kill the tree. Depending on the geographic location, Leyland cypress also can be infested with cedar bark beetles, but these beetles are often mistakenly thought to be the problem when Seiridium canker is the real culprit. It would create visible cankers on the bark and cause sap to ooze on the trunk. Unfortunately, no effective treatment is known. It's best to have a licensed arborist take a look at the tree to confirm the problem and offer additional solutions.
Applying the Screw
Q: I am an avid gardener and have many fir trees in my yard. I want to place a bolt through the trees to hold some hanging flower baskets, bird feeders and a hammock. Will drilling completely through a tree kill it? Can I drill part way through without killing it? Is there a certain kind of metal bolt that I should use or not use?
A: We recommend you use spring-loaded screws designed specifically for attaching baskets and feeders to living trees. These are available through a search on the Internet or through some hardware or outdoor stores. They come in various lengths. Screw them into the tree and then expand them outward (using the spring-loaded function) as the tree grows.
Q: In November, I received an 18-inch Fraser fir that I keep under a fluorescent plant light. It was dropping yellow needles until I started spraying it with distilled water every two days. Now, it's growing like crazy. Will this cause problems later?
A: The tree dropped needles in response to a change of light and humidity conditions from its previous location. Healthy plants respond by attempting a flush of new growth. Spraying with distilled water was probably coincidental, but Fraser fir does poorly in hot, dry climates, so continue misting unless you see a decline and keep it away from drafty heat registers.
Q: I have two hickory trees that I need to cut down or top. They are more than 50 feet tall, and I prefer to remove approximately 20 feet. Please advise.
A: Reducing the height of your trees is fine. Topping itself is a particular way of achieving that, but isn't necessarily the preferred practice. Crown reduction by cutting back to lateral branches in the canopy interior is usually preferred. Remember that to keep the tree healthy, only one quarter to one third of the canopy should be removed during a single pruning operation. This means taking 20 feet off a 50-foot tree should be done in increments over several years to avoid losing the tree entirely.
Q: I live in New Orleans and have 20-plus citrus trees. I usually fertilize twice a year in March and June. I use citrus fertilizer stakes as prescribed, but my crop seems to be receding, especially my navel oranges. Friends have suggested that I use about 25 pounds of lime per tree twice a year to increase production. What's the best fertilizer program to increase production of my trees?
A: Lime should be added only when the soil is acidic. You can conduct a soil test to determine the pH level and nutrient requirements for the area around your citrus trees. Check with your local USDA Cooperative Extension System Office (www.csrees.usda.gov/Extension/) for information on where you can send a soil sample for testing in your region. Another thing to note is that the freeze from last season may have also adversely affected your trees.
Q: I have a silver maple that is about 20 feet in circumference at its base. The tree has a rotten section from the ground up to about three feet and has a little cave of rot inside the hole. What can I do to help the tree?
A: Unfortunately, internal decay cannot be arrested. Improve plant health and the tree's natural defenses by fertilizing, watering to prevent drought stress and pruning dead wood. The hole can be covered with hardware cloth and then sprayed with insulation foam. Let this dry and then cut back the excess. This may provide a surface for callus tissue to grow over.
Q: I have huge, beautiful oak along the edge of my back property line. An arborist lust came to my door to inform me that my neighbor is cutting the tree. I'm devastated. Can anything be done?
A: It's tough when tree branches or roots expand over property lines and homeowners wonder what they can do about neighbors wanting to trim their trees. Unfortunately, in many states, removing roots or branches to the property line is allowed. You have to check with your state's laws on the topic. But if the pruning would cause the tree to decline, the neighbor might have overstepped what's allowed. It's always best to have a conversation with your neighbor so you can come to an arrangement that is fair to both of you.
Q: I have a 10-year-old tree with roots that were covered in two feet of stone by a landscaper. A trench was also dug a foot away from the trunk. The tree is now dying. Are the landscaping additions to blame?
A: That is the most likely culprit. First, covering a tree's root system will cut off its oxygen. Then, trenching into an area of tree roots will remove a portion of those tree roots. Trenching within a foot of the trunk probably severed 45 to 50 percent of your tree's roots, which means 45 to 50 percent of the tree canopy will die back as a result.
Q: I am new to pruning and caring for trees. I have a couple of trees that have branches growing from under the ground around the tree. Last year, I tried cutting them on one of the trees, but they grew back stronger. Is this normal? What should I be doing to ensure the proper care of these trees?
A: Your description sounds like basal sprouts coming of a graft union. This is normal, but not desirable. The sprouts originate from the root stock and should be removed near the ground line. If left to develop, the resulting top would look different than (and likely inferior to) the desired tree.
Tree Doctor questions are answered by The Davey Tree Expert Company. Got questions? Visit www.americanforests.org/treedoctor.