10/13/2026
Here’s a crowdsourcing data collection project in Rothrock Forest District to document the remaining hemlocks.
CALLING ALL FOREST EXPLORERS: Help Us Find the Lingering Hemlocks in Rothrock! 🌲
Pennsylvania’s state tree is in trouble. Eastern hemlock is being devastated by two invasive insects, the hemlock woolly adelgid and the elongate hemlock scale. Hemlocks anchor our cool, shaded streamside forests, protect water quality, and shelter wildlife from brook trout to songbirds. Losing them changes the whole forest.
But there’s hope, and you can help us find it.
What is the Lingering Hemlock Project?
In places where 80% or more of the hemlocks have died, researchers look for the rare trees still standing alive and healthy among the dead. These “lingering hemlocks” may carry natural genetic resistance to these pests. If we can find them, scientists can study them and work to protect and propagate that resistance, giving hemlocks a fighting chance to return to Pennsylvania’s forests.
Why it matters to the Bureau of Forestry
The DCNR Bureau of Forestry is charged with conserving and sustaining the long-term health, diversity, and productivity of Pennsylvania’s forests. Safeguarding hemlock for future generations is exactly that mission in action.
How the Lingering Hemlock Project Works
In areas where hemlock mortality hasn’t yet reached 80%, LHP will install Hemlock Health Monitoring Plots. Each plot covers about 20–40 living hemlocks. They mark and record the plot location, tag the trees, and document the site and any dead hemlocks. Then they revisit each year to track tree health, pest presence, and crown condition. Following hemlock decline over time helps researchers catch that 80% mark right as it happens, so we can find and save any resistant trees before they’re lost.
How YOU can help: use TreeSnap!
If you spot a hemlock that looks healthy among dying or dead hemlocks, report it:
1️⃣ Download the free TreeSnap app from your smartphone’s app store
2️⃣ Open the app
3️⃣ Under “Observe,” select “Hemlock”
4️⃣ Complete the prompts. Under “Collection purpose,” select “Lingering hemlock(s) data reporting”
5️⃣ Keep answering as new questions appear. Many are optional, but the more information you give, the better it is for the researcher reviewing your submission
6️⃣ Select “Save”
7️⃣ Choose “Upload Now” or “Upload Later.” Choose “Upload Later” if you’re outside cellular service. TreeSnap will remind you when an observation is ready to upload
🎥 Not sure what to look for? Watch the training video and find helpful field guides, photo tips, and more here:
👉 https://lingeringhemlockproject.org/lingeringhemlocksearch/lingering-hemlock-search-resources/
Every hiker, angler, hunter, birder, and curious walker in the woods is a potential citizen scientist. Your sharp eyes could help save a species! So next time you’re out on the trails, keep watch. Let’s find those lingering hemlocks in Rothrock! 🔍🌲
