Page 14 - Tree Line - North Carolina Forestry Association - First Quarter 2023

Invasive Forest Pests &
the Search for Surviving Trees
By Allison Melrose, Hemlock Restoration Initiative/AmeriCorps Project Conserve and Kelly Oten, NC State University
Invasive species are one of the most impactful
forces affecting forests today. These forest pests
are an increasing environmental issue, with no
end in sight. The spotted lanternfly and elm zigzag sawfly were first discovered in North Carolina this year.
Of the many invasive pests we battle, two stand out for their impacts on our forests: the emerald ash borer and hemlock woolly adelgid. Both of these invasives are causing widespread mortality of their host trees: ash and hemlock.
Emerald ash borer was detected in North Carolina nearly
a decade ago. Since then, it has spread quickly, leaving behind countless dead ash trees. Young larvae feed beneath bark, girdling the tree. Unless treated with insecticides, nearly all ash trees that encounter the beetle die in a few years.
Hemlocks face a similar battle with the hemlock woolly adelgid. First imported to the East Coast from Japan in the 1950s, this insect feeds at needle bases, inducing a tree response restricting water and nutrient transport within the tree. Mature hemlocks die within eight to 10 years, leaving stands of “gray ghosts.”
Top: Jon Kressuk, a PhD student at NC State University,
looks for surviving ash trees in a stand decimated by the emerald ash borer. More than 200 surviving ash trees (above) are being monitored at this site.
12 ncforestry.org / FIRST QUARTER 2023
KELLY OTEN SHEA PHILLIPS