Hemlock forests and brook trout

Climate change discussed at the Upper Delaware Council

Posted 8/10/21

NARROWSBURG, NY — A presentation at the August 5 meeting of the Upper Delaware Council (UDC) brought the topic of climate change to the center of discussion.

Rich Evans, an ecologist who …

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Hemlock forests and brook trout

Climate change discussed at the Upper Delaware Council


NARROWSBURG, NY — A presentation at the August 5 meeting of the Upper Delaware Council (UDC) brought the topic of climate change to the center of discussion.

Rich Evans, an ecologist who formerly worked with the National Park Service (NPS) at the Delaware Water Gap (DWG) National Recreation Area, gave a presentation titled “Climate change and our hemlock forests and brook trout.”

Evans began the presentation by citing a Trump administration study which stated that “the evidence of human-caused climate change is overwhelming.” From that foundation, he moved to describing his own studies on the effects of climate change on the DWG.

A number of studies conducted in the Upper Delaware River Region showed that the climate had become significantly warmer and wetter over the past century, he said, with temperatures increasing by an average of two degrees, with average precipitation increasing by around 5.5 inches and with severe weather events such as floods becoming more common. These elements of the climate had measurable impacts on the ecology of the DWG.

Eastern Hemlock forests suffered indirectly from warmer temperatures, as one of their greatest threats—infestations of the hemlock woolly adelgid, an invasive insect which feeds on hemlock trees—thrived in areas with warmer winters. Evans cited mortality rates of up to 60 percent for hemlock forests which he had monitored in the DWG area over a 20-year period.

Brook trout suffered too from warmer temperatures; they needed cold waters to thrive, and while 83 percent of stream habitat in the DWG was thermally suitable for their growth at present, Evans said, the effects of climate change could reduce that number to as low as 48 percent.

Public comment

Multiple members of the UDC in attendance expressed skepticism as Evans presented his findings.

When Evans displayed pictures of hemlock trees devastated along a stream-bank, several attendees expressed in asides that it looked more like storm damage than the effects of climate change.

During the public comment period, those asides turned into direct questions.

Aaron Robinson, the UDC’s Shohola representative, asked about the two degree temperature increase: was that a local measurement? Or a national one?

It was a local figure, said Evans, derived using data from national weather stations.

A member of the audience challenged the same figure on its time scale. Two degrees was well within the expected range of variance for temperatures over that period of time, he said, right?

“No,” said Evans. “It’s not.”

Taking the most recent 30-year period and comparing it to a 30-year period from the early 1900s would show a significant increase in temperatures, well outside of the expected range of variance.

A 30-year period sounded marginal when attempting to establish statistical deviation, said Robinson. “I’m not doubting what you’re saying,” but 30 years was not enough of a sample size to reliably establish deviation.

Climatologists use 30 years as a standard sample size when trying to measure the environment, said Evans; there was nothing unusual about that number.

We’re trying to make plans on the human scale, he added. We can’t afford to wait another 100 years and see what happens.

In other business

The UDC also discussed plans to secure state funding for the Upper Delaware River region.

Camille O’Brian, NY State Senator Mike Martucci’s Director of Legislative Affairs, spoke to efforts to get funding for the region as a line item in the 2022 NY State budget.

The battle over the line item would not be fought until January, she said. But if any town body or municipality wanted to have funding requests included in the executive budget (A set of recommendations from the governor’s office which forms the starting point of legislative budget negotiations), now was the time to write letters addressed to the governor’s office asking for support.

On the Pennsylvania side, UDC Executive Director Laurie Ramie mentioned that herself, UDC Chairperson Jeffrey Dexter and UDC Resources and Land Use Specialist Shannon Cilento brought a poster explaining the council’s mission and funding requests to a recent legislative breakfast.

While few legislators attended in person, Ramie said, their poster caught the eye of Tom Caffrey, the Northeast Regional Director in the office of Governor Tom Wolf, and she was hopeful that they could make progress in securing funding through that connection.

Edit: A pervious version of this article incorrectly stated that UDC President Larry Richardson attended the Pennsylvania legislative breakfast.  This should state that UDC Chairperson Jeffrey Dexter attended; the article has been updated as of Thursday, August 14 at 4 p.m. to reflect this correction.

Upper Delaware Council, Delaware Water Gap National Recreation Area, brook trout, hemlock, climate change


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