All that sand was left by a glacial lake. The Pine Bush ecosystem sitting on that sand, however, may have been created by Native Americans practicing fire management techniques. At least, that’s what some people believe.
One of those people is Dr. Harvey Alexander, professor at the College of St. Rose, who spoke at the Dec. 10 SPB dinner at the Unitarian Church in Albany. Doing some fast talking, he laid out the story of the formation of the Pine Bush for the 30-40 people who stayed to listen.
According to Dr. Alexander, about 14,000 years ago the Mohawk River, fed by melting glaciers, was a raging, frothing waterway as wide and deep as the Mississippi, and carrying huge amounts of sediment. This young river emptied into a vast lake that extended from present-day Lake Champlain south 200 miles to Poughkeepsie, and was some 50-60 miles at its widest. As the glaciers retreated, the volume of water in the Mohawk decreased and the lake became smaller.
While the earlier, wilder river carried heavy sediment and rocks into the lake, this later, quieter Mohawk carried a fine, silt-like sand into the last remnant of the lake, which was located over the present day Pine Bush. The sand of the Pine Bush is made of ground up granite brought here by water from the west. These sand particles range from .25 to .67 millimeters in width, and are composed mostly of feldspar and quartz. The grains have sharp edges, which indicates that the sand was covered by vegetation immediately after the lake disappeared. If the sand had blown about in the wind for a while, such as dunes along the sea coast do, then the grains would have smooth, rounded edges.
Rain water passes through this sandy soil very quickly, leaving the surface dry and nutrient poor. Plants must adapt to these desert-like conditions, which is one major reason why the ecosystem is different from surrounding areas. Water filtered clean by the sand collects on top of the impervious clay underneath the sand and forms an aquifer, which is an important source of drinking water for the region.
Periodic fires are the key to continuation of the ecosystem. If there are no fires to burn off organic material, humus will form on top of the sand. This topsoil will hold rainwater and nutrients, and plants typical of any New York forest will take root. Soon the pitch pine, scrub oak and blue lupine will die out in the shade of larger broad-leaf trees.
If fires are too frequent, however, the plants and animals will have trouble surviving. Pitch pines, for example, while able to endure the lack of water and nutrients in the Pine Bush, would grow much better in forest humus if they could compete with broadleaf trees. These twisted but oddly attractive pines have adapted to low-level fires, even so that fire encourages the pinecones to open so that the seeds can sprout. If fires are too frequent or too hot, these trees will perish. A big spurt of growth always happens after a fire, this because fire releases nutrients locked up in existing organic material. If fires happen too often, these nutrients are simply destroyed before new plant life can use them.
The Cause of Fires
by Daniel W. Van Riper, Jan./Feb. 92
Dr. Alexander adheres to the astounding theory that the periodic fires in the Pine Bush were set throughout its existence by humans. Native Americans, and after 1600 white settlers have been burning off the vegetation about every ten years for the past 10,000 years. This was done to enhance hunting and gathering conditions. If this is true, then the flora and fauna of the Pine Bush have adapted to human conditions. The Pine Bush is unnatural, and would never have occurred without human intervention.
The esteemed Mr. John Wolcott lent credence to this theory by pointing out that a number of experts have advanced this idea in recent years.
This writer expressed strong objections. While acknowledging the high sophistication of native culture in this region at the time of European settlement, I expressed doubt that fire management could have been sustained by shifting native societies over as much as 10,000 years. Dr. Alexander countered this by pointing out that there is strong evidence that native peoples in Africa and Australia have been fire managing vaster regions for a much longer time. (Dr. Alexander was kind enough to pass along an article from Australian Natural History which tells how Australian Aborigines have practiced "firestick farming," that is, burning off much of the Australian grasslands every year for the past 40,000 years! The author of the article, Tim Flannery of the Australian Museum, feels that a wave of extinctions of medium sized mammals on the Outback from the early 1800’s to present has been caused by interruption of these yearly burnings.)
While I conceded that fire management may have occurred at various times in the life of the Pine Bush, especially in the last thousand years, there is no reason to think that periodic fires could not occur naturally. Dr. Alexander felt that lightening, the most likely source of natural fire, does not strike frequently enough to cause regular burn-offs of vegetation. I pointed out that lightening certainly must have struck often enough in the 40 square miles of Pine Bush- which was its size until recently. About every ten years or so in this region, a year or two of drought occurs after a period of wetness. Vegetation would build up during the wet period, and the following drought would be a time of extreme dryness in the Pine Bush because of the nature of the soil. One lightening strike could send up the whole region. Couldn’t this become a stable natural system?
This is much room for debate here, and members of SPB are invited to send their comments to this newsletter.
Letters to the Pine Bush
Dear Pine Bushers:
As regards whether or not the Albany Pine Bush owes it’s existence to fires caused by lightning strikes or by Native Americans, let me add some facts gathered by John McPhee about the ecology and history of the New Jersey Pine Barrens:
McPhee finds it true that in the last 150 years the greatest numbers of fires have been started by people (sometimes on purpose, sometimes by accident). He also finds it true that certain areas of the Barrens hardly ever receive lightning hits. However, some areas of the Barrens seem extremely prone to lightning strikes. Some areas of the Barrens almost seem to attract lightning hits. These areas are, as one might expect, higher than the surrounding terrain and face the usual path of oncoming storms. Were it not for fire fighting efforts by man, it is possible that fires caused by lightning strikes in lightning-prone areas could indeed sweep across the Barrens fairly often, even burning off the brush in lightning-safe sections.
Today’s Albany Pine Bush might suffer lightening strikes too rarely to sustain itself, but once it was connected with a much wider Pine Bush terrain, a portion of that terrain might have been lightning prone.
It would be interesting to outline the greatest extent of the ancient Pine Bush, then superimpose over it a map of lightning strikes in upstate New York over, say, the last 50 years. That might provide a clue as to whether the Pine Bush is more man-made or nature-made.
(McPhee’s book, published in the 1960’s, I think, is called The Barrens-if I remember rightly.)
A reader from Albany
Recent News-Controlled Burnings in Pine Bush a Success
The following is from the Times Union, Nov. 13, 1991 by Peter Wehrwein
A program of controlled burning in the ecologically precarious Pine Bush went off without a hitch this fall, and managers of the preserve are aiming to do more. "We hope they will get bigger," said Stephanie Gebauer, director of the Albany Pine Bush Research and Management.
A total of 44 acres of the 1700 acre preserve was burned this spring and over the last couple of weeks, said Gebauer. The goal is to eventually burn about 200 acres each year.
Albany Deputy Fire Chief Warren Abriel confirmed the burns were kept under control and caused no property damage.
The Pine Bush-a patchwork area of scrubby pine (sic) and sandy soil on the western edge of the city that spills into adjacent towns- is home to Karner Blue butterfly, an endangered species. Gebauer said one reason for burning is to create more open space, which allows the wild blue lupine to grow. The lupine plant is the sole source of nourishment for the Karner Blue.
The burning this fall started Oct. 28, accounting for 30 of the total 44 acres burned. Fire-setting crews comprising a dozen or so volunteers used torches fueled by diesel gasoline mixture to ignite the fires, Gebauer said. Most of what was burned, she said, was ground cover- grass, pine needles and low growing plants.
Gebauer said burning aids the germination of some plants because it weakens their hard outer covering. [Pitch pine cones open during fires- ed.] Fire tends to "top kill" plant life, scorching the above-ground growth but leaving the roots intact.