It only takes a quick run into the mountains to see the devastation. Mountain pine beetles are killing thousands of acres of forest in Colorado, leaving huge swaths of dead trees.
What about here in Douglas County? Should we be worried about our pine trees? Are we facing an epidemic here? What should we do to protect our trees?
Well, the good news is that we're not in an epidemic. Not yet anyway.
The bad news is there are a lot of beetles around this year, so while I don't advocate widespread panic attacks just yet, I would recommend learning a bit about them so you know what to look for.
I'll try to keep this simple. They are just bugs, after all.
What are they?
We have two main beetles attacking our Ponderosa Pines; the mountain pine beetle (MPB) and the Ips beetle. Both are small, around 1/4" to 3/8", and bore just under the bark to lay their eggs in the cambium layer. They're closely related, like cousins that look about the same but have wildly different lifestyles.
The MPB is the more deliberate of the two. They have a yearly life cycle and prefer older, bigger trees to support their larvae. They go house hunting once a year; the larvae will stay the winter and fly the following season.
The Ips beetle, on the other hand, is a lot more active. They don't much care about the size of their victim, often targeting young recently transplanted trees or the thinner, weaker trees in the forest. They reproduce like crazy, sometimes 3 times a season. These guys live fast and party where they can.
Why are there so many around?
There are a few reasons why both beetles have been enjoying good times the last few years; some natural, some man-made.
The winters have been relatively mild. Though the woman in line at the airport the other day might disagree on that ("This winter was horrible! I just want it to end!"), the fact remains it takes a few consecutive days of really cold sub-zero temperatures to kill off the over-wintering larvae, and we just haven't had it. I'll let you stay with your own opinion on whether or not warm winters are a man-made phenomenon.
Although last year was better, our forests are still feeling the effects of a few years of drought. Trees in dry south facing slopes have been especially affected. It doesn't help the cause that this winter has been dry around here, too.
Last, but certainly not least, all the building that has been going on in forested areas has impacted and stressed out a lot of trees.
A stressed out tree is like a lunch with those same cousins; they might have different lifestyles, but they all like the same food. And boy are they hungry.
How do I know if my trees are being attacked or at risk?
The sad fact of the matter is by the time you notice your beloved pine turning brown its too late. There are a few things to look at when evaluating your trees before your trees reach that point, though.
Pitch balls oozing from the tree are a dead giveaway (pardon the pun). Look for them on the trunks of your pine trees, from the base all the way up. These are formed when the pine sends out sap, or pitch, in response to the beetle's boring.
Look for small piles of sawdust around the base of the trees or in the crotches of the branches. This is another sign of the beetle chewing their way in.
When I am evaluating a pine tree's risk of being attacked, I first look for signs of little or no new growth. A weaker pine will look much less full than a healthy one and often have a lighter color to the needles.
I will look for signs of disturbance around the base of the tree, in the root zone. Most tree problems can be directly related to problems with their roots.
Some other things to look for; has there been excavation recently? Is the tree being over or under watered? Have herbicides been used in the area? One of the worst things you can do is use things like Weed-n-Feed on the lawn around your trees. If you have any sort of trees near or in your lawn, avoid this type of fertilizer.
What can I do?
Tree companies make a lot of money pushing products like tree fertilizers and preventative spraying. One thing to keep in mind when the company rep is trying to sell you a bunch of chemical applications is that they have a lot of money invested in equipment and they want to stay busy.
I am not a big fan of chemical tree fertilizers for our native pines. There's a reason why they grow here, after all, and they have done just fine on their own for a very long time. Too much fertilizer leads to a lot of nice green growth, which unfortunately can lead to lots of broken branches in those heavy wet spring snows we get. I have seen well fertilized trees with lots of new growth fall prey to Ips beetles, so don't make the mistake of believing that fertilizing will protect your trees.
There is a pesticide available that, when applied correctly, is a good means of preventing beetles from attacking your pines. It works by killing the beetle when it ingests the chemical while chewing the bark. The effect is kind of like putting Everclear in your partying cousins' punch.
Some companies will try to sell you on spraying every tree on your property. Remember, they are in the business of keeping those expensive spray rigs busy. Remember also, that the pesticide will affect more than just those nasty beetles. Sixty percent of even the best spray application is lost to drifting, and that drift has to go somewhere. Those chemicals are poison to a lot of beneficial insects, also.
Look for a company that will evaluate your trees, and spray only those which they deem to be at risk.
So, in conclusion, yes we have pine beetles flying around Douglas County. This will likely be a good year for them and a bad year for weak pine trees. The key as a property owner is to be proactive, understanding what you are dealing with, and taking what steps are necessary.
If you are interested in learning more about pine beetles, here is a great site from the CSU website
http://www.ext.colostate.edu/pubs/insect/05528.html