Infestation of dwarf mistletoe in Jemez Mountains underestimated

The Santa Fe National Forest reported Friday that its Southwest Jemez Mountains Collaborative Landscape Restoration project underestimated the incidence and severity of the dwarf mistletoe infection in some areas. Courtesy photo

Unlike its kissing cousin, there’s nothing romantic about dwarf mistletoe.

It’s a menace that grows on trees, slowly killing them by robbing them of food and water. It raises fire danger in the woods and wildlands and causes major losses in the timber industry.

The parasite is a major problem in native conifer forests throughout the world. Most of the dozens of species are native to western North America, and at this time of year, they do their dirty work. The ripening pods explode, spreading their sticky seeds at speeds of up to 60 mph, 35 feet or more in all directions.

Foresters say dwarf mistletoe is bad for a healthy forest.

Rob Heyduck, a senior research specialist with New Mexico State University, said that since the 1990s, public and private land managers have set goals to reduce the density of dwarf mistletoe. Although it might not be seen on every tree in every stand, he said, “It’s nearly everywhere,” causing a “kind of slow death.”

Thinning stands will cut down the infestation by creating more space between trees, but in many cases, it is impossible to rid the forest of dwarf mistletoe without clear cutting.

The Santa Fe National Forest reported Friday that its Southwest Jemez Mountains Collaborative Landscape Restoration project underestimated the incidence and severity of the infection in some areas.

According to a news release, trees along Forest Road 10 are heavily infected. There are about 530 acres of heavy mistletoe infection including smaller patches along Forest Road 270 around Sierra los Pinos and the East Fork Trail.

While the small, parasitic flowering plant has been evolving for millions of years and is a natural part of the ecosystem, the infestation is unnaturally high because of fire suppression and overcrowded forests, the release said. The Santa Fe National Forest’s goal is to return the mistletoe to its natural levels.

In Utah, New Mexico, Arizona and Colorado, the trees susceptible to dwarf mistletoe infestations include ponderosa and lodgepole pines, as well as piñon, bristlecone, limber, blue and Engelmann spruces, white and subalpine firs and Douglas fir.

The dwarf mistletoe affects the growth of trees, reducing their size and diameter, causing large knots and spongy, weakened wood, swelling at infected sites, and over time, the death of the tree. Foresters report that trees in the Rocky Mountains are dying off sooner due to drought.

One sign that a tree is infected is the heavy branching of limbs called witches brooms. The stubby brown or yellow stems that resemble juniper branches can provide ladder fuel, leading to hotter and deadlier crown fires.

Tree mortality can also increase the risk of a high-intensity wildfire.

A 2001 report of the condition of Colorado’s state forest estimated the loss of growth per year caused by dwarf mistletoe was 400 billion cubic feet per year.

The recommended treatment is to remove infected trees and plant healthy young ones in their place.

Contact Anne Constable at 505-986-3022 or aconstable@sfnewmexican.com.