“Cabling” proposed before Fair
By John Colson
Sopris Sun Staff Writer
The Town of Carbondale is trying to save the large, double-stemmed cottonwood immediately to the west of (and somewhat behind) the Sopris Park Gazebo, after tests showed that the aging tree is suffering from internal rot and fungus.
As a result, town workers are expected to erect barricades to keep people from parking on the ground above the tree’s root system, and to string supporting cables between the two trunks, so that they provide mutual support and prevent a potentially “catastrophic” rending of the junction of the two trunks, according to town staff and a report filed recently at town hall.
Known as a split-stem “plains cottonwood” (scientific name, Populus deltoids var occidentalis, the tree is estimated to be 70-80 years old, according to the town’s arborist, David Coon.
The tree towers 95 feet above the southwestern corner of the park, and its branches spread in a roughly 85-foot diameter, providing deep shade to the Gazebo and the surrounding area.
During the annual Carbondale Mountain Fair, the tree also shades the heavily used backstage area that typically springs up under a canopy behind the gazebo, and nearby booths staffed by mountain fair volunteers handling such things as T-shirt sales, volunteer registration and sign-up, and other fair affairs.
The testing of the tree’s integrity was conducted in June by Aspen Tree Service, at the request of the town’s Tree Board and Coon, and at a cost of $750, Coon said.
In a highly technical report, the tree was rated as presenting a “moderate” risk of either losing large limbs or, more potentially damaging to its surroundings, falling over.
As part of the testing procedures, on June 13 the tree received a “safety pruning” (the arboreal equivalent of a hair trim), and its overall health was pronounced to be “fair” according to standards developed by the International Society of Arboriculture, stated the report by specialists Andrew Pleninger and Jason Jones.
But the tree’s structure was judged to be “poor,” owing in part to the fact that cottonwoods characteristically are considered “weak wooded” trees that are “prone to failures in normal weather events and more susceptible to decay” than other species.
In fact, according to the report, on June 20-21, “during the completion of this report, a healthy 8-inch diameter branch with no notable decay failed over the parking area, apparently due to what is known as ‘sudden limb drop.’” This typically occurs “during high temperatures and is thought to be caused by increased or disrupted water flow through a branch,” the report stated.
The evaluation of the tree included a visual inspection of the “root crown” and trunk from the ground, and an inspection of the upper branches and the crown of the tree using an aerial lift.
The inspections, according to the report, showed that the tree exhibits open wounds on its southern side, fungal decay in the trunk and “cavity openings” in some places, which “weaken the structure of wood and structural unions.”
The report stated that “the union of the two stems” that divide near the ground is considered a structural defect, but that the union appears to be in good shape.
Drilling into the trunk with specialized equipment, the Aspen Tree Service technicians found decay in the split stems, mostly in the southern stem, which was termed “moderate” in some spots and “high” in others.
But overall, the specialists seemed to conclude the tree does not present any great immediate danger and is of some worth to the community.
“The tree is a significant specimen adding aesthetic value and environmental benefits to the site and the community,” the report stated in its findings. “It is generally healthy for a tree of its age, however it is entering overmaturity (sic). Measures should be taken to preserve its health by prohibiting parking on the root zone and aeration of compacted soils” around those roots.
The ISA risk rating, the report finds, is “moderate,” and might be improved to a “low” risk level by pruning of some of its branches, as long as the pruning is not so severe as to result in a negative impact on the tree’s health.
Coon told The Sopris Sun that the tree will be continuously monitored, though an annual, formal assessment probably is “not necessary.”
He said the tree likely will be pruned some more, and the cables installed, before the start of Mountain Fair on July 29, although work on the tree is dependent on Tree Board recommendations.
As for the remaining life of the tree, Coon concluded, “It’s really hard to say. I don’t think we’re ready to make those kinds of predictions.”
With ongoing TLC, according to Coon, the tree could have “a lot more years” of standing at the corner of South 7th Street and Euclid Avenue.
Published in The Sopris Sun on July 14, 2016.