Notes on the Deforestation of Manhattan
By Richard Howe
"Simply, clearing was America."
- Michael Williams
When the Dutch West India Company established what was soon to be called Nieuw Amsterdam in 1624-1625, the island of Manhattan was 80%–85% forested, with as many as several million trees covering some 10,000+ acres of its then total area of about 13,000 acres. What remains of this forest today is no more than a few thousand trees on a few hundred acres of forested parkland at the northern end of the island, and there are indications that much of the clearing of the island had in fact been accomplished no later than the early 18th century and possibly as early as the late 17th century. Is this possible? Could a town that had begun with just a handful of settlers in 1623–1624 and numbered only 7,500 souls a century later have cleared even a million trees from the island in 100 years or less?
Of these many uses of wood, fuel was by far the most important. Fully half, and probably much more, of all the wood ever actually used—as opposed to simply wasted: destroyed as a side-effect of forest clearing for other purposes—was burned as fuel, either directly for heating and cooking, or indirectly as charcoal to provide the high temperatures required for metal working and for brick, pottery, tile, and glass making. There was no economical alternative: wood was abundant and readily available while coal, though a superior fuel, was available only in the very limited amounts provided by surface outcroppings, and for all practical purposes oil and gas were to be a 19th century discovery. Like air and water, food and clothing, wood was the very stuff of life.
Wood is, as we have learned to say now that we are becoming aware of the larger ecological value of the world’s forests, dead trees. Its source is live trees, and these, in great dense stands, constitute the forests that once covered the greater part of the habitable earth. They were cut or otherwise cleared—usually by burning—not only for their many uses as wood but also because the forest is antithetical to the intense cultivation of domesticated grains, which requires open skies. The bucolic vista of sunlight dappled fields is a human creation, produced at the expense of forest cover. If much of Manhattan above the northern limit of the town in the 18th and 19th centuries was rural in character, it was because this great transformation, from forest to fields, had already been accomplished, mostly by the first few generations of European settlers. The supply of wood and wood products from the island north of the town was as much a by-product of this need for clearing as it was an effort to meet the town’s demands.
It is safe to say that nearly 100% of the energy requirements—heating, cooking, and basic manufactures—of 17th and early 18th century Nieuw Amsterdam and New York were met by fuelwood, the exceptions being a few wind, horse, and water mills, one of them a saw-mill up near today’s East 75th Street. Houses —- even the chimneys -— were built mostly of wood, as were ships and fences. Demand for wood and wood products was so great that within just a few years of its founding, Nieuw Amsterdam was importing wood from elsewhere in the region, and traffic in wood was becoming an industry and a branch of commerce in its own right.
Wood was so vital to the material life of the town that the Common Council had to take steps to regulate the growing commerce in it. Regarding a dispute over the right to cut wood the Council ruled in 1657 that anyone was permitted to cut trees on an unfenced property but if the property were fenced no one but the owner had that right. In 1677 the Council stipulated the cord as the legal measure of cut wood: 128 cubic feet or a stack of four foot pieces eight feet long and four feet high. The Council also appointed official corders to assure that the quantities put up for sale were honestly measured, though of course complaints about fraudulent measures continued even so. In 1684 the Council forbade the unloading of “Timber, Pipe Staves, wood or Other Lumber” at the Great Dock on the East River; and appointed market places for the selling of wood along the waterfront; more were added in 1688.
The Council’s regulatory interventions should not be taken to mean that the supply of wood from the island north of town was exhausted, only that its supply was no longer simply a private affair or a purely local concern. Lumber is said to have been rafted to the town from very early on in the Dutch adventure here. A cord of wood weighs as much two tons or more, and rafting wood in from New Jersey and Long Island would have been cheaper than carting it any distance on the island, with the result that the rate of clearing would get slower the further north it got. (The occasional evidence of 18th century drawings suggests that this was indeed the case, e.g., a view of Harlaem in 1765 shows a thoroughly wooded background to the village, though one must also make allowance for artistic license.) But this tells us little if anything about how long the process of deforestation went on before it was effectively complete, i.e., when there was nothing more to be gained from going any further with it.
There is -- if only just barely -- enough data to estimate the town’s annual aggregate demand for fuelwood for domestic use. Forest yield data lets us also estimate the acres of forest—whether on Manhattan or elsewhere -- required to meet this level of demand. Expressing this acreage as a percentage of the original Manhattan forest, the running total of the annual demands is then the cumulative potential impact on the forest of the town’s demand for fuelwood. The data are sparse and treacherous and we must not be seduced by the spurious precision of such calculations -- and in any event no single factor could ever explain it all. Nevertheless, the effort may give us a feel for the limits of the possible, and perhaps for the relative importance of other factors as well.
Aggregate demand for fuelwood for domestic use is in the first place a function of population, for which we have data for the years 1624, 1627, 1643, 1664, 1698, 1703, 1712, 1723, 1731, 1737, 1746, 1749, 1756, and 1771. I interpolate linearly to get the missing years; cumulative lived years is their running total. Williams cites per capita consumption figures ranging from a low of 0.8 cords per person per year to a high of 4.5. I use the mean of these figures: 3.7 cords per person per year. Annual aggregate demand is then just the population estimate for each year multiplied by the per capita mean. Williams’ figures for forest yield are equally wide-ranging; I follow his suggestion of 20 cords per acre as a “medium” yield. Sanderson estimates 10,331 acres of forest on the island of Manhattan around 1600; somewhat arbitrarily, I use 80% of that figure to define “effectively complete” deforestation, the remaining 20% being more than enough to leave the island north of today’s 155th Street largely untouched.
Estimated Consumption of Fuelwood in Nieuw Amsterdam / New York as Percentage of Original Manhattan Forest Acreage 1620-1720
The calculations show that a date of as early as 1672 for an 80% deforestation of the island is not inconsistent with the data and assumptions described above. Moreover, it shows that the use of wood for domestic fuel alone could account for this, which is not at all to suggest that other factors did not, in fact, also play important parts. Different assumptions yield different results: a few variations may suffice to show the range of effects:
• halving the assumption for per capita per year consumption of fuelwood for domestic use from 3.7 to 1.85 cords postpones the 80% deforestation year by about a dozen years, to 1685–1686;
• doubling the forest yield from 20 to 40 cords of wood per acre produces the same result; and, more importantly,
• taking both together postpones the 80% deforestation year by another two decades, to around 1706–1707.
Like the other figures in the calculation, these dates can only be suggestive of a range. What they tell us, really, is that a late 17th to early 18th century date for the effective deforestation of the island is not inconsistent with the little that we do know that can be brought to bear quantitatively on the question.
Demand factors other than fuelwood for domestic use would tend to speed up deforestation of the island, even as the economics of transportation would tend to slow it down. Williams estimates that a furnace producing 1,000 tons of pig iron annually could consume over 300 acres of forest. The temperatures required for brick and tile kilns and for glass-making are broadly comparable and at these rates even a few such enterprises would be significant for local deforestation, whether on Manhattan itself or elsewhere in the immediate area. Ten such enterprises would go through over 30,000 acres of forest in a decade: three times the extent of the original Manhattan forest.
Relative to the demand for fuelwood, demand for wood for buildings, ships, and fences was minor enough to safely ignore, at least for these early years. As late as 1744 there were only 1,141 buildings in the city. Braudel’s figure of five big trees to construct an in-town house in Europe suggests that no more than about 6,000 big trees were used for this purpose by 1744. On the plausible assumption of 100 such trees per acre of forest, this equates to no more than about 60 acres. Even doubling Braudel’s figure from five trees to ten would raise the total to only 120 acres of forest, a little more than 1% of the forest acreage at the start of settlement. The number of ships built in Nieuw Amsterdam / New York in these years was still too small to affect the deforestation rate appreciably, and much the same can surely be said about fencing.
There remains the question of labor productivity and the feasibility of accomplishing the deforestation of most of the island within the span of 50–80 years suggested by our calculations. Williams cites figures that range from an acre a month to an —- in his view unlikely -— high of an acre a day, but supports the view that “a healthy man with an ax” could clear an acre of forest in a month. The arithmetic alone implies 8,000 ax-man months or 667 ax-man years to clear 80% of 10,000 acres of forest, i.e., about 13 ax-man years per year to get the job done in 50 years or eight ax-man years per year to get it done in 80. These are modest numbers indeed and would be even if they proved to be too low by as much as a factor of four. So labor would not have been a gating factor, and in any event it seems likely that much of the actual work of clearing was done by slaves, first “imported” to Nieuw Amsterdam in 1626.
Manhattan was never completely deforested by the Europeans—though there are indications that this may have largely been accomplished once before by the island’s Native American inhabitants in the centuries prior to the demographic disaster that followed the 1492 ecological invasion, after which the forest gradually returned again—and some remnant of the forest of 400 years ago still stands in Inwood Hill Park at the northernmost extremity of the island. But by the end of the 19th century there were those who feared that a near total deforestation of the island was not far off and who then launched a movement to create a new “urban forest” in the form of street trees. This movement has continued, intermittently but effectively, on down to the present day, most recently in Mayor Bloomberg’s “Million Trees NYC” program, which aims to raise the street tree total in Manhattan from the 5,000–10,000 of a hundred years ago to something on the order 60,000 by year 2017. The program is already well ahead of schedule as of this writing (January 2012).
Deforestation was only the first of a number of major transformations, both physical and abstract, that have been wrought upon Manhattan in the course of New York’s 400-year history: others include the conveyance of the island into the conceptual space of European property law, the expansion of its dry land area by shoreline landfills and swamp drainings, the levelling—albeit often over-estimated—of its naturally hilly terrain, the subordination of two-thirds of the island to the speculative real estate logic of the grid plan of 1811, the replacement of its originally pervious surface—its soil—with an impervious surface of brick and stone, concrete and asphalt, and the physical connection of Manhattan to other islands of the New York archipelago and to the North American mainland via bridges and tunnels.
These transformations overlapped one another substantially in time and are causally related to one another in seemingly infinitely—and often frustratingly—complex ways. Nevertheless, the primary physical transformation—primary both as the first and as the foundation for all the rest—was deforestation: the clearing of Manhattan’s forest. It was on this basis, largely achieved in the first century of the fledgling city’s existence, that subsequent generations of New Yorkers accomplished the most profound of transformation of all: the creation of the greatest—the richest, the most powerful, the most civilized—city on earth.
Richard Howe is a frequent contributor to the Blotter, and is writing a history of New York as a built environment. He runs the photographic study New York in Plain Sight: The Manhattan Street Corners.
The late Michael Williams’ great Deforestation of the Earth: from Prehistory to Global Crisis (2002) and his equally great Americans and their Forests: A Historical Geography (1989) are an introduction to the subject that is in equal measure encyclopaedic and entertaining.
Eric Sanderson’s Mannahatta is an endlessly fascinating reconstruction of the ecology of the island as well as a rich source of data on all its aspects prior to the European settlement.
Ira Rosenwaike’s Population History of New York City (1972) collects and analyzes a remarkable range of statistics from the city’s earliest years on through to 1970.
The Union History Company’s long out of print History of Architecture and the Building Trades of Greater New York (1899) remains an astonishing source of data on just about every aspect of its subject, including the uses of wood and the commerce in it in New York, as well as statistics on the numbers of buildings for various years, starting in the 17th century.
Max Page’s chapter on the “Uses of the Ax” in The Creative Destruction of Manhattan 1900–1940 (1999) takes the story of Manhattan’s deforestation well into the 20th century.
Amy Johnson’s fascinating essay on “The Saw Kill and the Making of Dutch-Colonial Manhattan” can be found on the Gotham History Blotter at http://gothamcenter.org/blotter/?p=280.
I. N. Phelps Stokes’ Iconography of Manhattan Island (1915–1928) remains, as usual, indispensable for just about everything.