Save the Tangled Bank!

Although I submitted this article to Lehigh’s student newspaper a few months ago, The Brown and White, it never got published (in the paper or online) for unbeknownst reasons. It refers to the upcoming plans to renovate Williams Hall, and my concerns for the future fascinating and historical forest directly adjacent to the building.

The recently drafted Campus Master Plan lays out the administrative vision for future improvements to Lehigh’s Campus. (Check out the whole plan at  I had the opportunity a few weeks ago to attend a graduate student senate meeting focused on aspects of this plan, and was very troubled by the idea to re-landscape the area behind Williams Hall (the building behind Linderman Library that housed Earth and Environmental Sciences before STEPS was built) to allow more pedestrian access. Although plans have not been implemented yet, I worry that the ecological, historical, and educational significance of this location may not be given proper consideration—mainly because the area is not well known to Lehigh students and has apparently been mostly forgotten by the administrative body.

The forested area behind Williams Hall and Sayre Park Road is in fact a legacy left by Professor Francis Trembley (yes, the same guy that Trembley Park apartments were named after, although I doubt he would have appreciated this). Professor Trembley was a well-loved ecology professor who taught at the university for 42 years. He was remembered best in Robert Halma and Carl Oplinger’s book The Lehigh Valley: A Natural and Environmental History as “a teacher with a mission and an enthusiasm that became pivotal in shaping the ecological conscience of the Lehigh Valley.” The forested area behind Williams Hall, called the “Tangled Bank,” is one of the only non-manicured areas on Lehigh’s whole campus, and Professor Trembley fought hard to make it that way. In the 1960s, he advocated for the cessation of mowing in the area, allowing the plants to regrow naturally via the process of ecological succession. Since the late 1960s, the area has transitioned from domination by annual and perennial wildflowers to a small but diverse plot of forest that looks incredibly different from the park-like ornamental trees and grassy areas typical of the rest of the Asa Packer Campus.

But it’s not just about how this forest looks. Nor is it simply about the historical significance of the area. Professor Trembley’s vision was to provide students with an outdoor laboratory right outside of the classroom, and today the Tangled Bank is providing exactly this. Students in Professor Booth’s Ecology course (EES-152) are using the Tangled Bank to examine the processes underlying ecological succession.  Building on data collected by Trembley’s students in the 1960s, the area is providing valuable lessons about how forests grow back after being heavily modified—with implications for forest management and conservation. (See Professor Booth’s blog post for details on what the class is doing there:

The vision presented in the Campus Master Plan for this unique place is aesthetically pleasing.  Carefully manicured lawns and ornamental trees will create a nice walkway adjacent to or through the area, and the area will look similar to the rest of our beautiful campus. However, wouldn’t it be nice keep this area of wildness in the midst of our campus, and perhaps allow it to shape our vision of natural beauty?  And allow this area to continue to serve as an outdoor laboratory for generations of Lehigh students to come? This, much more so than the apartment complex that bears his name, would be an appropriate tribute to the inspirational spirit of Professor Trembley.

For more information on plans for the Tangled Bank, check out this article:


Experiential learning on the Tangled Bank: plant traits and ecological succession

What the EES 152 (Ecology) students are learning from the Tangled Bank so far. Hopefully we will be able to continue to learn from the plot behind Williams Hall if it is not re-purposed for more manicured walkway vistas.

Among The Stately Trees

An opportunity for experiential learning

In 1967 Lehigh University Professor Francis Trembley convinced the university to stop mowing a small area of the campus.  Professor Trembley named the area the “Tangled Bank,” and it became a place where students could observe nature right outside the classroom.  At one point in time there was even a “Tangled Bank” sign on the slope. One year after the mowing stopped, Professor Trembley had the foresight to encourage an undergraduate student to collect and identify all plant species growing on the Tangled Bank, and these collections were archived in the Lehigh Herbarium.  Read the full story of the Tangled Bank here (including some great recollections of Lehigh alumni in the comments).

In the fall of 2013, the Lehigh University ecology class (EES-152) completed a botanical survey of the “Tangled Bank” to document what species occupy the site today. The primary objective of this…

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Trembley’s “tangled bank” on the Lehigh campus

Another interesting bit of forest succession history on Lehigh’s campus!

Among The Stately Trees

“It is interesting to contemplate a tangled bank, clothed with many plants of many kinds, with birds singing on the bushes, with various insects flitting about, and with worms crawling through the damp earth, and to reflect that these elaborately constructed forms, so different from each other, and dependent upon each other in so complex a manner, have all been produced by laws acting around us. . .” – Charles Darwin

Where is the tangled bank?

Snippets of what little I could recall of the above quote from Charles Darwin bounced around my head as I read labels on some herbarium specimens.

My task was to reorganize this collection of carefully flattened and labeled dried plants, to make it more useful as a teaching resource.

According to the labels on these particular specimens, they were collected from the “Tangled Bank.” No other location information was given.  Where was this place?…

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Next stop…recruitment dates!

Just last week we finished the surveying of the Emmaus South Mountain Preserve, and now we’ve started coring trees for recruitment dates. By counting the rings on cores we extract from selected trees with an increment borer (shown below), we’ll be able to see  when each tree established in the forest. Put together, we can see the pattern of how the forest was populated with a given species.Increment borer

Next stop…Emmaus

Now that we’ve finished locating all of the trees in the Lehigh Experimental Forest, it’s time to start working on our next study site–a location about 20 minutes away, close to the Emmaus South Mountain Preserve.

Excited to finish the LUEF survey!

Excited to finish the LUEF survey!

Two undergraduate assistants stand at the edge of the just-completed LUEF survey area.

Two undergraduate assistants stand at the edge of the just-completed LUEF survey area.









The idea with this second forest site is to have a null model–that is, what would have happened if the forest wasn’t planted in such an unusual arrangement? We are looking at how/if the original planting arrangement affected the composition of the forest 100 years later. To get a good comparison, we need a forest that has almost the same factors playing into its development as we have in the LUEF.

Advisor Bob Booth counting tree rings on a fallen tree in Emmaus.

Advisor Bob Booth counting tree rings on a fallen tree in Emmaus.

First, this includes similar abiotic factors–slope, aspect and elevation. Then we need to think about forest history–both the forests need to be a secondary

regrowth of approximately the same age with relatively little

management (planting/harvesting of trees). We looked into these factors quite a while ago, and when they all lined up in Emmaus, we went out to check on the overstory composition and just see if there was an appropriate area to put the plot in the forest.

The corner of the study site in Emmaus

The corner of the study site in Emmaus

We found the site–and even found an area where there are similar edge effects to Lehigh–the LUEF is nestled between a road and a power line; in Emmaus the site is nestled between two power lines. Edge effects can sometimes allow a different set of seeds to enter the forest and establish competitively, so it helps to have that consistency between the two sites.

Progress update

Today is an exciting day in the forest! We just finished locating all of the trees in ArcGIS. That means we know where all the trees are, what their species is, and what its diameter is, and can create a map of these data that is georeferenced to known landmarks in the area. Here’s a rough sketch of what that map will look like in the future:

All Trees no Colors or sizes

Each red dot is the location of an individual tree, and has associated data with it–species, DBH, field notes, etc. That’s a lot of trees! Lucky for me (and thanks to some of the #SciFund funding!) I have two awesome undergraduate assistants to help me out.