But First, a Movie!

Before we start on our adventure, let’s watch one, a movie made by the BBC about El Dorado,  the Lost City of Gold in the Amazon.

Sit back and watch the show in full-screen by clicking the small box on the extreme right side at the bottom of the player.


Terra Preta Today


Significant current research on Terra Preta is conducted at Cornell University by a team headed by Dr. Johannes Lehmann.




It Wasn’t All Preta…

In 2009, at a workshop on biochar at the Pony Farm in Temple, NH,  Hugh McLaughlin gave some history and ideas about the actual formation of the Black Earth.  First, most of it was not black.  There was Terra Mulata, brown earth.

Hugh refers to the book, 1491 – New Revelations of the Americas Before Columbus, by Charles C. Mann. It is worth the read!

Dr. Hugh McLaughlin

Hugh McLaughlin, PhD, PE has a professional consulting practice in Chemical Engineering. He is an expert on the properties and production of chars, created by pyrolyzing biomass, and the subsequent conversion to activated carbons.


Charcoal in American History

The Tri-State area where New York, Massachusetts, and Connecticut border each other was the home of military ironworks for the Revolution, the Civil War, etc. The forests were stripped of trees for charcoal needed to produce iron. Quite a few iron furnaces have been reconstructed, but of the charcoal kilns these are the only ones I know of, reconstructed and left in nature in the hopes that they will be respected.  In fact, I have mixed feelings about putting them up on the Internet and, as you might have noticed, I have been cagey about where they are located.

Charcoal Kilns, Dutchess County, New York
This how they are sited, only a few feet separating them.  I have no idea how many there were in this particular spot.

For scale
Showing the scale and also the retaining wall behind the kilns.  They were built into an incline so that fresh wood could be loaded into the top from wagons.

From the rear, showing where the wood was loaded on the hill.

Front Detail
Here is the detail for the lower entrance. I wonder if the more even, rectangular rock is phyllite, found in this area and used since colonial days for fireplace hearths because it was thought to hold up very well to fire. It would make sense and phyllite does resemble this rock, but I am not a geologist!

Inside, showing the loading area and, above it, a circular vent. I assume that the vent was closed off once the fires got working.

Other vent holes can be seen part way up.

About one meter from the ground are some regularly-spaced rectangular holes that might have supported some iron beams to hold the biomass above the fires.

Around the kilns are these chunks of glass from the ash.

Charcoal Pits in the Northeast

Scattered through the woods in the Northeast are remains of other methods where charcoal was more commonly made during the colonial era.