Ancient trash heaps gave rise to Everglades tree islands

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edfrank
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Ancient trash heaps gave rise to Everglades tree islands

Post by edfrank » Mon Mar 21, 2011 2:05 pm

21st March 2011
Ancient trash heaps gave rise to Everglades tree islands
AGU Release No. 11–12
21 March 2011
For Immediate Release
http://www.agu.org/news/press/pr_archiv ... 1-12.shtml


Click on image to see its original size
Many of the tree islands that dot the marshy Everglades appear to be vestiges of ancient trash piles, according to new research (photo by Pablo Ruiz of Florida International Univ.)
SANTA FE, N.M.—Garbage mounds left by prehistoric humans might have driven the formation of many of the Florida Everglades' tree islands, distinctive havens of exceptional ecological richness in the sprawling marsh that are today threatened by human development.

Tree islands are patches of relatively high and dry ground that dot the marshes of the Everglades. Typically a meter (3.3 feet) or so high, many of them are elevated enough to allow trees to grow. They provide a nesting site for alligators and a refuge for birds, panthers, and other wildlife.

Scientists have thought for many years that the so-called fixed tree islands (a larger type of tree island frequently found in the Everglades' main channel, Shark River Slough) developed on protrusions from the rocky layer of a mineral called carbonate that sits beneath the marsh. Now, new research indicates that the real trigger for island development might have been middens, or trash piles left behind from human settlements that date to about 5,000 years ago. [Read the rest: http://www.agu.org/news/press/pr_archiv ... 1-12.shtml ]
Everglades “Tree Islands” Rooted in Ancient Trash Heaps
Revkin.net http://revkin.tumblr.com/post/400450951 ... rash-heaps

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"I love science and it pains me to think that so many are terrified of the subject or feel that choosing science means you cannot also choose compassion, or the arts, or be awe by nature. Science is not meant to cure us of mystery, but to reinvent and revigorate it." by Robert M. Sapolsky

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Marcboston
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Re: Ancient trash heaps gave rise to Everglades tree islands

Post by Marcboston » Mon Mar 21, 2011 3:23 pm

Wow that is so interesting, a good read.

Joe

Re: Ancient trash heaps gave rise to Everglades tree islands

Post by Joe » Mon Mar 21, 2011 5:48 pm

Marcboston wrote:Wow that is so interesting, a good read.
I think Ed. spend 24 hours per day looking for this stuff.
Joe

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edfrank
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Re: Ancient trash heaps gave rise to Everglades tree islands

Post by edfrank » Mon Mar 21, 2011 6:02 pm

Joe, Marc,

I don't spend 24 hrs a day looking for this stuff. I am on Facebook. I have "liked" a good number of tree related groups, conservation groups, and scientific groups that also have a presence there. I am "friends" of many people involved with tree research, climbing, etc. in addition to my personal friends and relatives. The posts I find and forward about these varied topics generally first appear in one these groups or from friends. If the subject looks interesting or is tree related I check it out. I often read some of the links provided in the referenced article and post the link to the Facebook "Native Tree Society" group. Share and share again. I post a few of these to the ENTS BBS if I think the topic is particularly relevant, interesting, or otherwise catches my eye. I will admit that when I am home the computer sitting beside my living room chair is usually on and running, but I am not searching on the web constantly.

Ed
"I love science and it pains me to think that so many are terrified of the subject or feel that choosing science means you cannot also choose compassion, or the arts, or be awe by nature. Science is not meant to cure us of mystery, but to reinvent and revigorate it." by Robert M. Sapolsky

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bbeduhn
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Re: Ancient trash heaps gave rise to Everglades tree islands

Post by bbeduhn » Tue Mar 22, 2011 10:17 am

These tree islands exist in many coastal areas. I've seen them harboring large live oaks in South Carolina and Georgia. They may have been remnants from early rice plantations in those states, however.
Brian

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Don
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Re: Ancient trash heaps gave rise to Everglades tree islands

Post by Don » Wed Mar 23, 2011 6:25 pm

Ed-
I was so familiar with the image you posted, I knew right away it's general location! But I didn't know of the tree islands currently ascribed origin.

My familiarity came from a firefighting training detail I was sent to, that at one point sent me to the everglades as a hotshot foreman, to fight a 125,000 acre wildfire in the everglades...we were to flank the fire that was burning north to the Big Cypress NP (with community of Native Americans)...issued fifteen flappers (kind of like a semi-truck mud flap attached to a hoe handle), a couple of drip torches with extra fuel...we proceeded, along with an Arizona hotshot crew, to run out a fireline, 'flapping'' the fire out on the unburnt side, so that our 'torch line' would burn into the wildfire, and take the uumphh out of it.

When we encountered the tree islands, we tried where we could to run the line such that we protected the 'tree islands' thinking that they were likely to be unique environments, and needing protection...locals laughed at us, saying that we should have encouraged a good burnout, as they'd been trying to get rid of them.
-Don
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edfrank
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Re: Ancient trash heaps gave rise to Everglades tree islands

Post by edfrank » Wed Mar 23, 2011 6:45 pm

Don,

They are unique environments worth preserving whatever their origin in the past. I would argue that just because someone lived nearby does not give them an omniscient l knowledge of what is worth preserving and what is not. You can't even be sure that the most vocal of the local residents represent the opinion of the majority of people in the area. I certainly don't believe that in every situation that local management of these unique resources is the best option for the environment or for the country as a whole. Special places like the Everglades and the Big Cypress Preserve, even if some of the land is privately owned, more properly should be considered to belong to the country and the American people as a whole, and not just to the people that coincidentally live nearby. I will stop now before I descend into a political tirade.

Ed
"I love science and it pains me to think that so many are terrified of the subject or feel that choosing science means you cannot also choose compassion, or the arts, or be awe by nature. Science is not meant to cure us of mystery, but to reinvent and revigorate it." by Robert M. Sapolsky

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Marcboston
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Re: Ancient trash heaps gave rise to Everglades tree islands

Post by Marcboston » Tue Mar 29, 2011 9:58 pm

edfrank wrote:Joe, Marc,

I don't spend 24 hrs a day looking for this stuff. I am on Facebook. I have "liked" a good number of tree related groups, conservation groups, and scientific groups that also have a presence there. I am "friends" of many people involved with tree research, climbing, etc. in addition to my personal friends and relatives. The posts I find and forward about these varied topics generally first appear in one these groups or from friends. If the subject looks interesting or is tree related I check it out. I often read some of the links provided in the referenced article and post the link to the Facebook "Native Tree Society" group. Share and share again. I post a few of these to the ENTS BBS if I think the topic is particularly relevant, interesting, or otherwise catches my eye. I will admit that when I am home the computer sitting beside my living room chair is usually on and running, but I am not searching on the web constantly.

Ed
Hey you could spend 24 hrs looking up that stuff or not. I am not picking on you. I think it is a very cool read. Makes you wonder how many or how large the Native American populations were on the east coast and if there were any large organized centers.

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Steve Galehouse
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Re: Ancient trash heaps gave rise to Everglades tree islands

Post by Steve Galehouse » Tue Mar 29, 2011 10:26 pm

Marc-

I agree--trash middens that extensive suggest a large population in the region.

Steve
every plant is native somewhere

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edfrank
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Re: Ancient trash heaps gave rise to Everglades tree islands

Post by edfrank » Wed Mar 30, 2011 12:13 am

Guys,

A large mound does not necessarily represent a large population. it could represent a long period of use by a small population. The question about the source of the shell mounds/middens is pretty complicated. Were they created by a sedentary culture that also practiced agriculture or were they a product of a hunter gatherer society? Maybe you can tell by other materials associated with the shells. What percentage of the populations diet is represented by the shellfish and fish bones in the midden? Did it make up 5%, 50%, 80% or what? Were the shell mounds created by seasonal occupation or year round occupation? If for example you had a population of 30 people and they produced 1 pound of shells per day per person, that is 30 pounds per day. over 365 days = 10950 lbs or about 5000 kg per year. A study from Japan found an average density for their site to be 1152 kg/cubic meter. This this hypothetical 30 person group would produce about 4.3 cubic meters per year of shell mound. One acre is about 4000 square. So in one thousand years, after compaction 30 people could create a mound 1 meter thick that covered 1 acre. If there were more people it would take less time. If the thirty were there longer they could make a bigger and thicker pile over the same span. It is not unreasonable that a site could have been occupied for several thousand years. Now the estimates of daily shell production would depend on what percentage of the diet was from shells, it could be higher or lower than the number in the example. If it were seasonal occupation then it would take longer to produce the pile.

Ed
"I love science and it pains me to think that so many are terrified of the subject or feel that choosing science means you cannot also choose compassion, or the arts, or be awe by nature. Science is not meant to cure us of mystery, but to reinvent and revigorate it." by Robert M. Sapolsky

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