Mark Norris

Signs have 2 sides, use both

Undergraduate research this week, #Arboreal project: Monitoring sticky tape installed at 3 positions (base, main stem in canopy, side branch) in 4 canopy-dominant tree species & finished installing chicken wire to inhibit vertebrates. Starting to see some captures in all trees and all positions!

While there, I paid homage to this lovely white oak

We evaluated deer browse via twig age (Waller 2025) including seedling/sapling height and noting fresh browse. The deer mgmt program began last year, culled 36 deer from the 200+ acre property.

This week in #Norrestry class (my Forest Eco & Mgmt course), we finished forest plot surveys at local Irvine Nature Center. We're collecting data to describe the forest composition and structure, focusing on deer browse, to understand early conditions as they implement a deer harvesting program.

A little outside time over the weekend including a sunrise over Caves Valley at Irvine Nature Center and a trail run at Liberty Reservoir. Both spots are just outside of the Baltimore Beltway and make it easy to forget that we live in a major metropolitan area.

Before

After

Our Environmental Club hosted a stream cleanup on campus this afternoon. I found a debris dam to work on, took an hour to fill two garbage bags including 115 single-use plastic bottles, a bunch more tiny alcohol bottles, and a lot of styrofoam. I left pretty surly.

Undergraduate research this week, #Arboreal project: Installed sticky tape at 3 positions (base, main stem in canopy, side branch) in 4 canopy-dominant tree species. Hopefully we'll get a sense of the crawling arthropod community & how it varies. Chicken wire installed to inhibit vertebrates.

The #Norrestry class (my Forest Eco & Mgmt course) has a new campus Witness Tree post exploring the tree-related microhabitats (TreMs) of the tree. Of course, we had to climb the tree to get the best views. www.instagram.com/stevensonwit...

More pictures of sample processing...

This week in Intro Biology: Ecology & Evolution Lab - we continued our biodiversity exploration of different habitats on campus. We've collected more organisms representing greater diversity that recent semesters. Students in both sections did a nice job examining organisms and patterns of diversity

She's on board! Her reply...
"Totally on board, but only if we can put them along the trails, you know, in their natural habitat."

Does Your Backyard Need a Stegosaurus?

I've sent a request to our department chair that we purchase a few of these dinosaurs, arguing that their presence on campus would foster great conversations on evolution, climate change, and so much more! The life-size T-rex is <$3k!
Free gift article from The NYT www.nytimes.com/2025/10/01/n...

stevensonwitnesstree on Instagram: "Towering high overhead rests our northern red oak's sprawling canopy, covering an average of 79.9% of the sky above. This was found…" Towering high overhead rests our northern red oak's sprawling canopy, covering an average of 79.9% of the sky above. This was found using a hemispherical lens (as seen in pictures.) These images were then processed through Gap Light Analyzer, a program to calculate canopy cover percentage. As you can imagine, this large canopy cover causes quite the lack of light available for any plants below, but just how little light is there? Using an AccuPAR LP-80, the light available in the understory was measured at an average PAR (photosynthetically active radiation) of 41.5 µmol/m²/s. For comparison, a nearby open field measured PAR of 1402 µmol/m²/s! This means that the plants below our witness tree have very little light to work with. Regardless of that, many young trees are powering through and manage to keep growing.This forest community surrounding our focus tree has a variety of both old and young trees, our tree likely being one of the oldest. As older trees die off, gaps in the canopy appear, allowing the younger and shorter cohorts to have more access to light. These cohorts not only must tolerate the shady understory, but manage to thrive in it. From just these few light related factors alone, we can begin to see how this community came to be what we see today. Hemispherical canopy images taken at the witness tree's canopy edge in each of the 4 cardinal directions.

The #Norrestry class (my Forest Eco & Mgmt course) has a new campus Witness Tree post
www.instagram.com/p/DPEJw0wjlc...

This week in undergraduate research, part 2. #Salamander project: Our most productive cover board transect was recently cleared of spicebush to restore tree regeneration and no salamanders were found last week. We did find 2 juveniles yesterday, and then established a new transect nearby.

This week in undergraduate research, part 1. #Arboreal project: got some climbing in to retrieve canopy trail cameras. We will soon use them to set up a long term canopy activity monitoring project in a couple of canopy-dominant red oaks on campus, along with other PUI collaborators.

This week in Intro Biology: Ecology & Evolution Lab - we started our multi-week biodiversity exploration of different habitats on campus. We're exploring the diversity of invertebrates (flying & litter-dwelling), soil microbes, and primary producers in each of a meadow, forest, and an ecotone.

Other critters encountered. Not pictured: mama mouse with a bunch of nursing babies.

Really disappointed to find that the most productive red-backed transect has been cleared of shrubs as part of the nature center's understory restoration efforts. It used to yield a bunch of salamanders, used to look like the first pic, now looks like the second pic with zero salamanders.

Fall salamander survey, continuing our red-backed salamander cover board project. Almost same pattern as in the past with none found on campus & only in one location at the nearby nature center. We'll continue to explore this pattern, examining the potential effect of shrub cover on predators.

Baltimore Water Watch Baltimore Water Watch maps water quality in Baltimore's streams, rivers, and Harbor. Water health is scored to answer the question, "How's the Water, Hon?"

Blue Water Baltimore's Baltimore Water Watch program samples our stream just upstream from where we sampled. The most recent sampling found high amounts of bacteria, conductivity, and total N.
baltimorewaterwatch.org

Results from one of the lab sections (same pattern to other section) indicating severe, moderate, or slight pollution impact depending on metric. I suspect that the variation in results is due to sampling bias as students generally seek crayfish or other obvious organisms (eg. waterstriders).

The third #Norrestry #WitnessTree post is up! One of our students describes the health status of our tree.
www.instagram.com/stevensonwit...

A few critters provided a distraction from the trees

Last two weeks in #Norrestry (my Forest Eco & Mgmt course) lab, learning to measure trees and forests including canopy cover, tree sizes (diameter, height, volume), forest volume, and calculating tree value.

He’s Spent 40 Years Studying Dead Trees—Here’s What He’s Found Forest ecologist Mark Harmon has been exhaustively examining dead logs for 40 years, and he’s found a complex world few people see

Forest ecologist Mark Harmon has been exhaustively examining dead logs for 40 years, and he’s found a complex world few people see

Did a Brooklyn Couple Kill a Neighbor’s Trees for a Better View in Maine?

Neighborly arboricide. Maine’s Board of Pesticides Control says two summer residents poisoned a neighbor’s trees so the couple could have a harbor view. They deny it (but agree to pay a nominal fine).
Free gift article from The NYT. www.nytimes.com/2025/09/11/u...

Monarchs hanging out on campus

It's Monday morning on campus and the interwebs is out.

Let's move everything to the cloud, they said. It will be GREAT!

Happy Monday!

5 old-growth forests in the Potomac River region to expand your hiking repertoire — Potomac Conservancy Our region’s old-growth forests improve water and air quality, provide vital wildlife habitat, and help fight the climate crisis. And, they also offer a diversity of recreational opportunities! What…

Old-growth forests improve air and water quality, provide vital habitat for wildlife and plenty more. Few of these grand forests remain but there are still several expanses remain in our region.

buff.ly/wi4m7MI