Quick Fixes and the Sustainable Long Haul: Hemlock Woolly Adelgid, Hydrilla and Our Watershed

Quick Fixes and the Sustainable Long Haul

Hemlock Woolly Adelgid, Hydrilla and Our Watershed

Forthcoming in Network News 2/12, newsletter of the Cayuga Lake Watershed Network www.cayugalake.org. Thanks to Mark C. Whitmore and Judy Abrams for editorial assistance.

Hilary Lambert, Steward

In the winter 2011 issue of Network News, our lead article stressed the need to work toward a sustainable energy future for the Finger Lakes, in the face of a rapidly warming climate. The choices we make and paths that we follow in the near future will determine the long-term fate of the clean and plentiful water our region (and the  Great Lakes) is presently known for.

The Cayuga Lake Watershed Network Board of Directors’ actions and Network programs increasingly stress the interdependence of clean water and energy choices. The Network’s 2011 Strategic Plan  includes the goal of “supporting new and ongoing successful collaborative projects with short and long-term impacts on maintaining and improving the lake, its tributary creeks, and the watershed,” by “helping communities prepare for climate change impacts.” Further, in May of 2012, the Board voted to approve a “Position Statement on Hydraulic Fracturing,” stating that “We oppose the continuation of hydraulic fracturing and urge immediate emphasis on an energy policy that promotes conservation and renewable energy sources."

Early symptoms of climate change are extreme weather events and the movement of species into regions where they previously could not survive. The invasive species presently bedeviling Cayuga Inlet in Ithaca, Hydrilla verticillata, is from temperate latitudes similar to ours in Korea, and survives well in northern climates: it is not a true climate change opportunist. However, part of the Hydrilla Task Force’s initial response strategy was the hope that a cold winter would kill off plants established in shallow waters. Instead, the mild (or “missing”) winter of 2011-12 helped hydrilla survive and prosper. As with the Asian Clam infestation in Owasco Lake to the east, this apparently “new normal” weather benefits the spread of these aquatic invasive species.

For information about the excellent long-term eradication program developed by the Hydrilla Task Force of the Cayuga Lake Watershed, information about possible impacts of herbicide use, and “everything” hydrilla: http://www.StopHydrilla.org. To sign up as a Hydrilla Hunter, contact: ambismb@gmail.com.

Another aggressive invasive – this one attacking the hemlocks in our gorges – is the aphid-like Hemlock Woolly Adelgid (Adelges tsugae, aka HWA). A true climate change opportunist, HWA has been making its way north for decades with terrible destructive force, sucking the life out of majestic old hemlock stands in the southern mountains and valleys, and turning the hemlock stands in New Jersey’s wilder places and Pennsylvania’s uplands into brown skeletons (maps: http://na.fs.fed.us/fhp/hwa/maps/distribution.shtm).

Cornell’s Mark Whitmore is a forest ecologist and nationally-recognized expert on HWA, which first appeared in the Finger Lakes area of New York State in 2008. He has been mapping its spread and advising on limiting its immediate impacts, and is also concerned about the Emerald Ash Borer’s potential for ecosystem destruction/transformation, in this period of rapid climate change.

Why is HWA a problem? Most obviously, it destroys one of our most beautiful, evocative trees. In ecosystem terms, hemlocks are a keystone species for our cool creeks and their biodiversity. If hemlocks die, creeks will be exposed to the sun and warm up, and steep shale banks will erode and collapse, altering creek habitat and sending warmer, turbid waters to Cayuga Lake.

In 2009, HWA was found on hemlocks in Cornell University’s Cascadilla Gorge and around Beebe Lake. In response, a collaborative project, involving Cornell Plantations, Cornell’s Department of Natural Resources and Mark Whitmore, was organized to track and where possible mitigate HWA impacts. A trained group of citizen-stewards carry out regular monitoring for the spread of HWA in Six Mile Creek, Edwards Lake Cliffs, Fall Creek, Fisher Old Growth, Lick Brook, Steep Hollow, and Coy Glen. This local effort is part of a larger project, led by Whitmore, to meet the challenge of invasives by increasing stakeholder knowledge and involvement. That means you! Learn more and get involved via the Cornell Plantations invasive species web pages: http://www.cornellplantations.org/our-gardens/natural-areas/invasive

The non-winter of 2011-12 may be responsible for a sudden leap of HWA along Cayuga Lake’s western shoreline. In 2011, the infestation was mapped as individual infested trees and small stands, in the Glenwood Pines area along the southwestern Cayuga Lake shoreline. Not so any longer.

In early July 2012, Judy Abrams noticed something wrong with a big hemlock that holds down the banks of a steep shaley creek on her lakeshore property, several miles north of the Glenwood area. She learned that the tree was infested with HWA, and soon realized that all of her estimated 200 hemlocks are infested or will be soon. Judy called neighbors to the south, toward Glenwood – they have it too. A quick check revealed that it is present in hemlocks on all their properties.

Lakeside landowner Judy Abrams and affected hemlock tree.
Note the creek it shades, and steep shaley banks it stabilizes.

 As with hydrilla, the immediate, short-term management options for HWA include insecticides – infested hemlock trees can be protected individually with chemical insecticides. Cultural practices can also slow impacts; biological control agents are under study (Fact Sheet, Early Detection of the Hemlock Woolly Adelgid (Adelges tsugae) in Small Northeastern Hemlock (Tsuga canadensis) Woodlots, www.ForestConnect.info). 

Here we arrive at the question of the sustainable long haul mentioned in the title. Herbicides and pesticides applied over several years will have adverse impacts on Cayuga Inlet, and on our gorges and their creeks. The potential for homeowner misuse of currently registered soil drench pesticides and subsequent environmental contamination (proximity of streams) is great. Professional applications pose far fewer risks and can help save the local genotypes of hemlocks. However, maintaining the current habitats with pesticides is untenable for the long run. We’ve got to continue to develop biocontrol and tree resistance. Experts like Whitmore and the Hydrilla Task Force know this; monitoring of impacts from treatment programs is standard (although underfunded, in the case of hydrilla).

So, what about the sustainable long haul? In a situation of rapid climate change, when do we let the hemlocks go? Long-term, can we really prevent the takeover of our lakes by green mats of suffocating hydrilla, and impacts from other invasives steadily wending their way into warming places? Beyond the next few years, can we realistically expect to keep our cool creeks and clear waters?

A 2011 study reports that, by 2100, “global climate change will modify plant communities covering almost half of Earth's land surface and will drive the conversion of nearly 40 percent of land-based ecosystems from one major ecological community type -- such as forest, grassland or tundra -- toward another.” The study further states that the rapidity of change “will disrupt the ecological balance between interdependent and often endangered plant and animal species, reduce biodiversity and adversely affect Earth's water, energy, carbon and other element cycles” (NASA/Jet Propulsion Laboratory 2011, December 18. Climate change may bring big ecosystem shifts, NASA says. ScienceDaily; Jon C. Bergengren, Duane E. Waliser, Yuk L. Yung. Ecological sensitivity: a biospheric view of climate change. Climatic Change, 2011; 107 (3-4): 433 DOI:10.1007/s10584-011-0065-1).

This is not good news for the future of our favorite places, plants, animals, and water resources. We can ignore this freight train coming at us; we can say “It won’t happen until after I’m gone” – or we can begin to think and plan ahead in a meaningful way, that can lead to an increasingly different, eventually transformed – but healthy, sustainable – landscape and life for our descendants.

Locally, the Tompkins County Climate Protection Initiative (http://www.tccpi.org/) is already looking ahead. Their mission: “We are committed to helping Tompkins County achieve a dynamic economy, healthy environment, and resilient community through a focus on energy efficiency and renewable energy.” Their programs need everyone’s support to reduce greenhouse gas emissions locally, the results to serve as a template for other local communities.  As with banning fracking one town at a time (www.cedclaw.org ), perhaps we can slow this freight train down, one locale at a time. 

Let’s keep talking, thinking, and being creative. The quick fixes are good for what ails us right now; the sustainable long haul is necessary for what comes after us.

Here is what landowner Judy Abrams is doing right now, with an eye on the sustainable long haul: "I was horrified that all the hemlocks on my property were infected with HWA and relieved to learn from Mark Whitmore that even trees near death can recover if treated properly. Because the insecticide is an imicloprid product I weighed the consequences: untreated, badly infected trees last a year or two; less affected trees live up to 4 years. If my 200 hemlocks die, my beautiful gorge would be denuded, and the cliffside and driveway would erode. The insecticide is toxic to bees, but is painted on trunks and absorbed. This treatment plus slow release pellets later protects trees up to 7 years, and by then there may be natural control methods. On Mark's advice, I hired White Oak Nursery in Geneva. The cost of saving 200 hemlocks is less than the cost of removing two large dead trees."

To find out more about climate change, looming impacts, and what can be done, consult these sources:

http://environment.yale.edu/climate/about/ - Yale Project on Climate Change Communication;

http://climateaccess.org - The network for those engaging the public in the transformation to low-carbon, resilient communities;

http://climatecentral.org Climate central: why climate change matters.