Annual Insect and Disease Survey Shows SFNF Holding Steady

By SFNF

The results of the 2019 aerial survey of forest health are in, and the Santa Fe National Forest (SFNF) appears to be holding fairly steady against insect and disease mortality, thanks in large part to the amount of moisture the forest received last year.

Forest Health Protection (FHP), part of the Forest Service’s State and Private Forestryorganization, conducts annual aerial surveys of national forests to assess forest health, including tree mortality caused by bark beetles and defoliation by caterpillars that feed on needles and leaves. In 2019, FHP in the USDA Forest Service Southwestern Region surveyed more than 23 million acres of forested federal, state and private land in New Mexico and Arizona. The summary “story map” is published at https://go.usa.gov/xdxma.

While the SFNF saw an uptick in bark beetle mortality in ponderosa and pinyon (piñon) pine and Douglas-fir, mortality was down for spruce and fir species. The 10,130 acres of dead Douglas-fir are concentrated in pockets near wildfire scars, including the northern Jemez Mountains and the Sangre de Cristo range near the 2013 Jaroso and Pacheco Fires. Douglas-fir beetles are commonly found in scorched trees along the edge of fire scars because they are attracted to trees with fire injury.

Defoliators also took a toll on the SFNF in 2019. Forest visitors driving up NM State Highway 475 (Hyde Park Road) toward the Santa Fe ski basin probably noticed a lot of bare branches in the aspen stands along the way. The western tent caterpillar, a native defoliator that has been active in these popular aspen groves for the last few years, once again feasted on the trees. But the good news is that most of them will survive and refoliate to turn the mountain its usual autumnal gold. In addition to the Big Tesuque area, aspens in the northwestern Jemez Mountains were also attacked by the western tent caterpillar. Western tent caterpillars and aspen leaf beetles both fed on the aspens near Cow Creek on the Pecos side of the forest.

Another noticeable insect infestation in 2019 was along the I-25 corridor from Santa Fe to Las Vegas, where pinyon needle scale, a sap-sucking insect common to the southwest, attacked 9,000 acres. Pinyon needle scale seldom kills trees but can cause mortality when combined with bark beetles and drought.

And for some good news, the hungry Janet’s looper caterpillar, which made a rare appearance in 2017 and 2018 in the SFNF’s high-elevation fir and spruce, seems to be settling back into obscurity, impacting only 5,650 acres in 2019, compared to 10,670 acres in 2018.

“Overall, insect and disease activity on the SFNF is often driven by local forest conditions, and 2019 was what we might expect,” FHP NM zone lead Andrew Graves, PhD, said. “We’ll keep an eye on the winter snowpack and spring weather, which will set the stage for what we might see in summer 2020.”

For more information on the Santa Fe National Forest, visit our website at https://www.fs.usda.gov/santafe/ or join the conversation on Facebook and Twitter.