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Editor’s Note: Swamp Story

This Editor's Note refers to a story about Sharon's Atlantic White Cedar Swamp which ran in SFOC's Spring 2006 newsletter. The story precipitated a number of Letters to the Editor to which the editor is responding in this note.

June 8, 2006

The picture in the print SFOC Newsletter to which Katherine Byrne objects was mistakenly taken of this area due to ease of access. The scene is easily visible from the roadside. The Newsletter apologizes for the confusion it may have caused. The picture has been removed from this website but is still viewable by downloading the PDF file of the SFOC Newsletter. Despite this photo error, the editor of the SFOC Newsletter stands solidly behind the article.

The area that Katherine Byrne’s and Alice Cheyer’s letters refer to—where the picture was taken—consists of approximately 14 separate acres by the northeastern corner of Sharon’s Atlantic white cedar swamp. This is a section where there has been excessive and prolonged flooding (years long) in this area due to its being isolated by railroad and street embankments on all sides, beginning over 100 years ago with one railroad embankment and later another embracing railroad spur to service Lake Massapoag’s ice industry. At different times these 14 acres were drained and at times flooded due to artificial, uncontrolled or intentional events. Hence, water level history within this area is not representative of the Cedar swamp.

Some might read the article, and incorrectly conclude, as Katherine Byrne seems to, that swamp restoration would mean permanent high levels of standing water. Actually the ideal goal is to divert water into the swamp but with due control over water levels in order to mimic the natural periods of higher and lower water most conducive to cedar growth and regeneration. Water level control would also involve—as the article points out—a careful monitoring of human-use water pumped from the swamp-fed aquifer. Tim Simmons of Massachusetts Natural Heritage & Endangered Species Program writes:

“Some [towns in Massachusetts] are pumping thousands of gallons per year with no detectable change [in swamp water tables] while a wetland on Long Island was completely dried up and replaced by upland vegetation as a result of excessive pumping.”

Restoration of Sharon’s cedar swamp would not involve flooding it. It would mean raising the water table to near the ground level, the swamp floor (This is the ground in the hollows and not over the mounds.) For short periods, higher water might be allowed in order to mimic nature wherein temporary higher water levels inhibit and prevent propagation of detrimental species which compete with Atlantic white cedars. A study[1] by the Massachusetts Water Resource Commission regarding a cedar swamp in Foxborough states:

“A threshold water table elevation of 154.00 feet NGVD[2] is required for the peat layer. This level is intended to keep water within one foot of the wetland hollow surface, as indicated by Atlantic White Cedar Swamp experts as being within the range necessary to maintain the ecosystem. This level will be monitored in both the shallow and deep peat layers at three locations, one at the edge of the Atlantic white cedar swamp nearest to each of the Witch Pond wells, and one at the nearest edge of the wetland restoration area. Monitoring the deep peat layer is intended to allow observation of potential drying from the base of the peat layer as a result of hydraulic influence from the underlying aquifer. The peat may be subject to desiccation and compaction if continual dewatering occurs.”


“…individuals with expertise in Atlantic white cedar in Massachusetts were consulted to ascertain the hydrologic conditions necessary to maintain the Atlantic white cedar swamp ecosystem values and functions. To maintain its habitat and to prevent invasion and dominance by other plant species, Atlantic white cedar swamps require periodic inundation and a near-surface water table.”

Alice Cheyer criticizes the article as lacking background and being an “opinion.” However, co-author Clifford Towner has long and considerable experience managing Lake Massapoag. He is highly knowledgeable about the Lake-associated hydrology. He is a current member of Sharon’s Water Management Advisory Committee as well as the Lake Management Study Committee. Further, as a very long-time Sharon resident and outdoorsman he has observed the cedar swamp over a long period (40 years) of time. The editor believes Mr. Towner qualifies as an “expert.”

The editor has also contacted the Sharon Water Department. They maintain that drainage ditches are a main culprit as far as the ecologically damaging low water table in the swamp. But ditches, combined with drawdown from well pumping (Sharon’s average is over 1 million gallons per day.) and increased transpiration from invading upland deciduous trees and shrubs (which can cancel out 17 to 22 inches worth of rainfall per year) all conspire to keep swamp water table levels too low for too long—especially in the drier months—for cedar health and success.

The editor questions a second-hand citation in the letter of Katherine Byrne. In the study she cites:

FM-East agrees with the opinions expressed by Bruce Sorrie relative to the proposal to restore the red maple Atlantic white cedar swamp and cites Motzkin (1991): Increased water levels caused by human interference with normal drainage patterns appears to be the single factor most frequently responsible for recent site degradation.

Glenn Motzkin’s 1991 publication, Atlantic White Cedar Wetlands of Massachusetts does not mention Sharon and does not refer to any Sharon site. Motzkin is referring to a list of sites throughout Massachusetts and his meaning is that, on average, a majority (but by no means all) of cedar swamps have suffered from flooding.

Alice Cheyer cites a WRPB study done in the year 2000 but she does not mention that it also stated “Portions of this 250 [3] [sic] acre swamp are dying due to ditching and drawdown of groundwater levels.”

As SFOC Newsletter editor, I verified the facts of Mr. Towner’s article prior to publishing. Following publication, and in view of the objections of Ms. Byrne and Ms. Cheyer, I undertook to explore the swamp myself. The new pictures on this website were taken during that walk. There were few living cedars and those were of small size. I saw no seedlings or saplings. I saw many, many dead cedars leaning and fallen. I also noted the rampant invasive upland vegetation which normally thrives in soil too dry for Atlantic white cedar. A picture on this website’s home page shows a small dead cedar growing alongside a towering live white pine. Most significantly, the day of my walk was the day following a record rainfall event. Amazingly, I found the swamp floor dry. (While a detriment to cedars it was a boon to me as I was not wearing boots and could proceed dry-shod!)

As to Ms. Cheyer’s criticism omission of sources, they were not included in the print version of the Newsletter due to space limitations. They are now available with the online version of the story. I have compiled an even more extensive list of sources and quotations regarding Atlantic white cedar swamps. (Available on request, since there are many website links in this list.)

Ms. Cheyer also has attempted to portray the cedar swamp as a source of mosquito-borne disease by stating “cedar swamps are habitat for the mosquitoes that spread the Eastern equine encephalitis virus through bird populations.” This is extremely alarmist and misleading. The cedar swamp certainly has no monopoly on the mosquitoes that transmit these diseases. There are many other breeding places—other wetlands, waters, backyard birdbaths and even old tires. If wetlands and bird carriers were a threat should we fill all wetlands and destroy all birds? In reality the disease threat is miniscule and, as with shark attacks, greatly exaggerated. Last year there were two cases of EEE in Massachusetts and no cases of West Nile Virus.[4]

Ms. Cheyer also notes: “Six years ago there was intense disagreement over whether a new well could be sited on Chase Drive near the cedar swamp without affecting it by pumping; that debate is ongoing. I do not think SFOC should involve itself uncritically on any side of that debate.”

The editor contends that the proposed well site debate does not affect the facts of the article—that overall average swamp water tables are too low to sustain the cedar swamp. The article does not take sides on any issues, just as stating that the moon is full on some nights would not involve “taking sides” on a debate concerning street lighting.

The editor stands by the article. If it has aroused controversy, it has also aroused interest and so much the better.



[2] NVGD means, essentially, sea level.

[3] 250 acres is the area where this preliminary study focused. Sharon’s entire cedar swamp comprises about 600 acres.


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