The Kiss of Death : Forest Service Says Dwarf Mistletoe Is Strangling Pines Near Crystal Lake

At a time when mistletoe sprigs tied with red ribbon appear in grocery stores and Christmas shops, the U.S. Forest Service is trying to control the plant in the forest, where the popular Yuletide symbol is a tree-killing parasite.

True mistletoe, with its broad, furry leaves, is of less concern than a more virulent cousin known as dwarf mistletoe that is strangling big trees in the Crystal Lake recreation area above Azusa in the Angeles National Forest.

Angeles forest officials are in the fourth year of a five-year attack on mistletoe near the Crystal Lake campground and picnic area. Ponderosa, Jeffrey pines and white firs there have been “severely impacted by mistletoe,” said Karen Fortus, resource officer for the Mt. Baldy District of the forest.

About 800 trees have been marked for treatment, and each spring, crews have cut infested limbs and branches, which are chipped into compost and spread on the forest floor. But several trees as tall as 150 feet have been so severely infested that they have had to be cut down, Fortus said.

Both true mistletoe, which mainly attacks hardwoods such as oak, and the dwarf variety that most often infests pines and other conifers, are naturally occurring parasites can ravage trees weakened by drought or disease.

Both types are parasitic, but dwarf mistletoe is more harmful because it depends entirely on the host tree for nourishment, causing branches to swell and break as it slowly saps the tree of life.

Dwarf mistletoe spreads quickly as the female of the species produces berries. As the berries swell with water in the spring, the pressure causes them to burst, spitting out sticky seeds that can travel 30 or 40 feet.

Mistletoe is pervasive, and control efforts often are focused on popular recreation areas in tall timber, both to preserve the big trees for the enjoyment of visitors and because trees killed or weakened by mistletoe become a safety hazard.

Steve Bear, resource officer for the Tujunga district of the Angeles forest, said foresters have had to do “selective surgery” from time to time. Two years ago, about 50 trees were removed from a heavily infested area at Mt. Gleason.

Mistletoe is also common in the Saugus district of the Angeles forest north of the Santa Clarita Valley, but it does not now pose a serious problem, district ranger Mike Wickman said.

Rick Burgess, a board member of the Channel Islands branch of the California Native Plant Society, said he supports the Forest Service’s efforts.

“As long as they are very selective and they don’t remove too many trees, that might be an effective way of controlling the mistletoe,” he said.

Foresters in Los Padres National Forest are planning their attack on dwarf mistletoe that threatens a 200-acre stand of trees at Pine Mountain north of Ojai.

“If we let it go any longer, all the trees up there will die and it will be Bald Mountain instead of Pine Mountain,” said Terry Austin, resources forester at Los Padres.

Control measures will probably include pruning affected branches and, in some cases, removing infected trees. No chemical treatment is planned.

The felled trees would be replaced with native species that are not susceptible to mistletoe.

Austin is in the process of marking all of the trees, ranking them by degree of infection and the type of treatment they will need. She said people, possibly misguided campers fearing all marked trees would be cut down, have been removing the tags and making her job more difficult.

“I have tagged 580 trees so far and 75 of them (tags) were taken down,” she said.