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How long does it take a fallen tree to fully decompose?
Posted: Jul 05 2009 6:38 pm
by joebartels
Through the power of HAZ and looking at old photographs it seems trees take much longer to decompose than I would have guessed. I'm sure it's directly related to sunlight, rain and such.
My Humphreys photos dating 11 years back
http://hikearizona.com/phoZOOM.php?ZIP=7033
appear to have barely weathered to this year when Bob crawled through
http://hikearizona.com/phoZOOM.php?ZIP=98713
Hank's photo
http://hikearizona.com/phoZOOM.php?ZIP=100365
got me wondering if this tree has been here for thirty plus years

Re: How long does it take a fallen tree to fully decompose?
Posted: Jul 05 2009 6:48 pm
by nonot
I think alot depends on the amount of dampness and the quantity of bugs and insects (ants, grubs, and termites). In the rainforest I bet entire trees disappear in a few years, but old stumps in Arizona could likely be untouched for hundreds of years. It depends on what type of wood it is as well. Cypress and Oak will be around alot longer than pine and apple trees.
Re: How long does it take a fallen tree to fully decompose?
Posted: Jul 05 2009 6:56 pm
by PaleoRob
Wood used as beams in ancient ruins can be dated back over a thousand years. No reason why a large log couldn't take an extremely long time to break down as well.
Re: How long does it take a fallen tree to fully decompose?
Posted: Jul 05 2009 6:58 pm
by joebartels
In response to nonot:
Good point, I bet there's fewer bugs in the 10k range too.
In response to PageRob:
I was in doubt before but I'm turning into a believer now.
Re: How long does it take a fallen tree to fully decompose?
Posted: Jul 05 2009 7:08 pm
by SuperstitionGuy
Cedar stumps along the California, Oregon and Mormon trail in Wyoming are still in good shape after approximately 150 years. That's why the early cowboys preferred cedar posts for fencing. The barbed wire would rust away before the posts gave out!
And of course any fallen tree branch in my neighbors yard will be their till hell freezes over or until his wife buys a chain saw and cuts it up for a crafts project! :bigth:
Re: How long does it take a fallen tree to fully decompose?
Posted: Jul 05 2009 7:43 pm
by Sredfield
The Custer Expedition of 1874 (or there abouts) took numerous pictuires of the Black Hills in South Dakota. Sometime in the early 1970's the glass plates from the photos were discovered in the Capitol Building. A researcher took them and attempted to re-take the photo 100 years later. Some locations of course could not be found, but many were. In several, the same log was visible. In a brilliant demonstration of what to keep and what to dispose of, I no longer own the book of before and after photos. This book also demonstrated the over-forestation of the area.
Re: How long does it take a fallen tree to fully decompose?
Posted: Jul 05 2009 7:46 pm
by big_load
Yosemite NP's Tenaya Lake has stumps carbon-dated to around 1300.
Re: How long does it take a fallen tree to fully decompose?
Posted: Jul 05 2009 8:52 pm
by Crocodile Ryan
the lignin in wood is highly resistant to degradation, very few things degrade it and most are specialized fungi, not someting you see in the dry forests of AZ,
a good burn and that thing will be gone....... not wishing that on humphreys though
wood that is high in lignin will also burn hotter and longer than wood low in lignin
Re: How long does it take a fallen tree to fully decompose?
Posted: Jul 06 2009 5:00 am
by azbackpackr
Yeah, I think aspen will decompose pretty fast compared to fir, up here in the Whites.
Re: How long does it take a fallen tree to fully decompose?
Posted: Jul 06 2009 6:10 am
by big_load
azbackpackr wrote:Yeah, I think aspen will decompose pretty fast compared to fir, up here in the Whites.
Aspen with the bark on will be gone in a hurry. It can last a very long time with the bark off, though, such as in a beaver dam.
Re: How long does it take a fallen tree to fully decompose?
Posted: Jul 06 2009 7:46 am
by azbackpackr
Oh, interesting!
There are some pretty huge stumps up around here, from back when they were doing the logging. Some areas must have looked totally different back before that.
Re: How long does it take a fallen tree to fully decompose?
Posted: Jul 06 2009 6:29 pm
by Dave1
Part of the "Point Huitzil" route at GC has the hiker climbing down a tree trunk located in a crack in the Coconino sandstone. This tree is said to be from about 1150 AD and was used by Anasazi Indians.