Lake Tahoe’s sugar pine trees are dying — here’s what you can do to help

LAKE TAHOE — As you look at the beauty of Tahoe from the top of any peak, there are pine trees as far as the eye can see. These pines, in varying shades of green — tall and strong, with their distinct outline — add to some of the best panoramic views in the world.

Nestled among them is the sugar pine, the tallest and largest of all pines, soaring up to 200 feet in some places and up to 9 feet in diameter.

But take a closer look, and you might discover a disturbing trend. Many of Tahoe’s sugar pines are stressed and dying. If you are a local or frequent visitor to the area, you may have noticed an increase in dead or dying pine trees in Carnelian Bay, Crystal Bay and many other areas around Tahoe.

The question is: “What is stressing our sugar pines and what can we do about it?”

Unfortunately, the answers are as complex as nature. White pine blister rust is a non-native invasive fungal pathogen that is decimating all white pine trees. The white pine family includes all five-needle pines and sugar pine is one of them.

Are the trees stressed from drought, blister rust, bark beetles or a root fungus? Likely, it is a combination of more than one stressor. The consensus among arborists and foresters is that the biggest problem is ultimately the drought.

Drought-stressed trees are more susceptible to bark beetles. Also blister rust infected trees are more susceptible to beetle infections. Pine beetles are just a secondary pest. The blister rust and drought have weakened and stressed the sugar pines so much that the beetles move in and finish the tree off.

In addition, if a tree has a major root fungus or blister rust infection, vascular tissue stops working properly and the tree can die from lack of water. The treatment depends on what came first. We recommend trees are treated at the first sign of stress or blister rust. If you wait until the tree is losing needles and full of beetles, it’s too late and there is nothing to do but remove it.

So, how do you save your sugar pine? Just as in your own health, the first step is prevention. Water your sugar pines and fertilize them. Contact an arborist at the first sign of stress — a flag (branch covered in orange needles), beetle holes, pitch on the bark, and/or general discoloring. The arborist will evaluate your tree and set up a plan for treatment and monitoring.

What kinds of treatments are available? To answer this question, we consulted Tyler Boutelle from Alpine Arborist Tree Care. He said: “Treatments can include: pruning dead limbs, treating for bark beetle, deep root fertilization and a deep watering schedule. In the spring, we can spray pines and firs with synthetic pyrethroids, a preventative for bark beetle. This will protect the trees for the season and actually kill any beetles that try to bore into the tree. It is a preventative treatment and won’t kill beetles already in the tree.

“There are also trunk injections, one product is Tree-Age made by Arborjet. The cost can be high but will kill beetles already in the tree as well as any that bore into it. Terminex out of Reno can do it and has done injections with good results, but it runs about $20 per inch diameter. Standard treatment for blister rust is to prune out any infected limbs and then be sprayed for bark beetle and deep root fertilized once per season.

“The deep root feeding is essential but again if the tree has bad rust or other fungus it may not be able to utilize the water and fertilizer. This has to be done at the very first sign of stress or blister rust infections. More often than not, people call arborists a year after noticing that the tree seemed stressed and by the time we get there its losing needles, full of beetles and there is nothing to do but remove it.”

If you can’t save your sugar pines, at least you can plant seedlings to replace them. Sugar pine seedlings are available for purchase from the Sugar Pine Foundation, a local nonprofit working to save Tahoe’s sugar pines and other white pines from the threat of the non-native, incurable fungus called white pine blister rust.

SPF finds sugar pines that are resistant to the blister rust fungus, collects their cones, and organizes educational planting events where local schoolchildren and community volunteers can help propagate the their progeny.

Maria Mircheva is Executive Director of the Sugar Pine Foundation. Visit sugarpinefoundation.org to learn more.