Friday, February 17, 2023

A New Environmental Resource Inventory for Princeton Takes Shape

There's a nice writeup on Princeton's Open Space Manager, Cindy Taylor, in TapInto Princeton. She'll be leading a presentation on Wednesday, Feb. 22, about the new edition of the Environmental Resource Inventory (ERI) that she's been working to prepare for Princeton. Among the many others contributing to the update are councilwoman Eve Niedergang and members of the Princeton Environmental Commission (PEC). The PEC will host the presentation, which should get going soon after 7pm. The public is encouraged to tune in and participate.

If you are wondering what an Environmental Resource Inventory is, you can take a look at the current ERI, which I played a considerable role in creating. Starting in 2007, as a member of the PEC, I worked closely with a consultant, Chris Linn, on that previous update of the ERI, the first update since 1978. 

It seemed appropriate that a resource inventory would include plant inventories--long lists of which plants are found where in town. And so the next year, in my role as resource manager for the Friends of Princeton Open Space, I led many walks in various preserves to inventory the plant life. With help from a Princeton University summer intern, Sarah Chambliss, we compiled 22 plant inventories. 

I added many photos, and a section on invasive species, including mention of the emerald ash borer. Though the ash borer had yet to reach NJ in 2010, it has by now already killed most ash trees in our area, just 13 years later. 

To document some environmental history, I'll mention the following. The PEC, chaired by Wendy Kaczerski at the time, paid for the 2010 ERI using borough and township funds and a matching grant from The Association of NJ Environmental Commissions (ANJEC). The study was carried out by the Delaware Valley Regional Planning Commission (DVRPC), with input from the PEC and borough/township staff. 

Chris Linn of the DVRPC did most of the work to compile and write up the ERI. That document has served the town since it was published in January, 2010. Some of the acknowledgements are below. Looking at the names now--among them Rosemary Blair, Grace Sinden, Casey Lambert, Vicki Bergman, Greg O'Neil, Charles Rojer, Wanda Gunning, Gail Ullman, Ted Thomas--brings back good memories and is a reminder of how deep are the roots of environmental advocacy in Princeton. 

Liquid Winters and Time-Bending Blooms

Long time local botanist Betty Horn sent me an email some days back--February 10, to be exact--reporting that she had just found a hepatica blooming in Herrontown Woods. Hepaticas in early February? This was news. 

Without asking, I knew nearly exactly where she had found it. If you're a field botanist, you maintain a mental map of where you've found certain special plants growing, and in Princeton, my mental map has exactly one location for hepaticas, along the ridge in Herrontown Woods. Sure enough, she had found it there, given a head start by the warmth of a nearby boulder and the snowless winter. 

Hearing the news, another botanist friend, Fairfax Hutter, checked out some hepaticas she knows of in Hopewell. No flowers, nor any buds, she reported. Betty looked back at her records and told me that "the usual time for hepaticas to bloom is early to mid March, and sometimes as late as the first week in April." 

Another early flower is snowdrops--a nonnative spring bulb that decorates the grounds around Veblen House. The first bloom I noticed this year, for the record, was on Feb. 6.

Before moving to Princeton in 2003, I lived in Durham, NC for 8 years. Winters there were much like the one we've had here in New Jersey this year. The default was no snow, and if a snowstorm did come, it became a spontaneous holiday, with schools shut down for several days. It could be said that New Jersey is the new North Carolina, with Georgia in hot pursuit, so to speak. 

The shift towards a liquid winter has made for dramatic changes in our "fillable-spillable" minipond in the backyard. It's a 35 gallon tub that captures runoff from the roof, originally conceived as a pond that could be easily emptied when our pet ducks had made it muddy. 

Like an artist who has lost inspiration, it hasn't produced very interesting ice patterns the past few winters, nothing like that stretch from 2018-19, when intermittent freezes and thaws caused it to behave like a canvas for the profound artistry of nature. Each freeze would bring new and endlessly varied patterns in the ice. 

Saturday, February 11, 2023

How Fallen Leaves Can Reduce Flooding

A kindred spirit in Durham, NC, naturalist Riverdave Owen, took the time last fall to count the fallen leaves freshly fallen on one square yard of his land near the Eno River. 

Posting this photo on facebook, he said the count totaled 1600 leaves. "After extrapolating that count, I estimate this year's autumn leaf drop for this entire half acre property to be approximately THREE MILLION LEAVES! Instead of raking, blowing and hauling them away, they are left as food for a myriad of tiny intermediaries who then return the foliage's organic nutrients back to the trees from whence they came .."

As Riverdave points out, the habitat created by leaves certainly is important. Just think of the spectacular increase in surface area they provide when they fall on the ground. Each leaf has surface area on front and back, and as they accumulate they create myriad tiny spaces inbetween. 

An additional benefit of leaves that tends to go unmentioned and unexplored is the impact of leaves on stormwater runoff. If I had the patience to collect data, I would take that square yard of leaves, weigh it when the leaves are dry, then soak the leaves and weigh them when wet. The difference in weight would be the amount of rainwater sequestered by the leaves themselves during a storm. Multiply that by all the square yards covered by leaves in a community, and you'd find out how much water is absorbed by leaves rather than contributing to downstream flooding. 

But leaves do more than absorb rainwater. They also help make the ground beneath them more absorbent. Exposed soil can harden and dry out, making it behave more like impervious concrete when the rains come. If instead the ground is covered by leaves, the leaves' slow decomposition softens the soil with organic matter and promotes soil life whose activity in turn opens up and maintains channels for water to seep into.