Old Growth Density  

TOPIC: old growth density

== 1 of 9 ==
Date: Mon, Oct 13 2008 6:13 am
From: "William Morse"

Hello all,

I have a friend working on a project for school regarding stand
densities/ trees per acre. Does anyone have any information regarding
tree spacing or density in unmanaged/old growth forests, particularly
broadleaf and mixed forests of the northeast? Is there an old growth
characteristic that includes spacing or density?

Best regards,
Travis Morse

== 2 of 9 ==
Date: Mon, Oct 13 2008 6:36 am
From: "Joseph Zorzin"

Good question- I can't answer it definitively but I suggest 50-75 trees per acre is a good general purpose rule of thumb- the figure would vary greatly depending on species, location, etc. Conifers generally will have more trees per acre in old growth and more volume and they can, generally, withstand higher density. This sort of info exists in forestry textbooks.

Forest researchers have plotted the growth of density, size, growth rates, etc. for all sorts of forest types. Your friend needs to find a good library. In addition to the textbooks, the Journal of Forestry has countless such research papers.

I'm sure others here who specialize in studying old growth have better info and can direct you to specific research papers.


== 3 of 9 ==
Date: Mon, Oct 13 2008 8:15 am
From: dbhguru@comcast.net


Densities vary greatly in old-growth forests, responding to the wide variety of disturbance regimes. One of the best sources of information on the subject is:

"Information About Old Growth for Selected Forest Type in the Eastern United States" by the USDA Forest Service. Principal research scientists include Lucy E. Tyrrell, Gregory J. Nowacki, and Thomas R. Crow.

From my own research, I can easily verify a wide range of densities with the conifer stands most densely packed as Joe Zorzin points out. As a general rule 50 to 125 trees per acre in the range of 4 inches in diameter and greater covers the majority of old growth stands.
The person to really weigh in on the density question is Lee Frelich. Don Bragg and Don Bertolette will also have excellent insights.


== 4 of 9 ==
Date: Mon, Oct 13 2008 11:02 am

This text is found online at:

== 5 of 9 ==
Date: Mon, Oct 13 2008 2:17 pm
From: "Joseph Zorzin"

I just downloaded that file- it's 473 pages and took about an hour. I haven't read it yet- but I'm sure there must be a vast amount of info there worthy of discussion in this forum. Has anyone read it through? Is it well written by the standards of the ENTS community? Did anyone in this forum contribute to that report?


== 8 of 9 ==
Date: Mon, Oct 13 2008 2:32 pm
From: Lee Frelich


The density in old growth stands (i.e. multi-aged stands) is variable. Even
within one acre, there would be patches that are very dense and patches
with few trees. The density in younger stands is more uniform because most
of the trees are about the same size.

The most interesting factor that changes is the shape of the diameter
distribution, which goes from unimodal (close to normal) with a small mean
dbh and small variance in young forests to unimodal with large mean and
wide variance in older forests of the stem exclusion stage of development
(say 100-120 years old), to unimodal with a second peak on the left in
forests in the transition to uneven aged (120-150 years old), which have
clumps of small trees entering gaps and the remnants of the unimodal
even-aged peak, to almost negative exponential in old-multi-aged stands, so
that there are a lot more small trees than large trees.

Density goes down as even-aged stands age and the remaining tree crowns get
larger and larger, it reaches a minimum in old even-aged stands and then
goes up in old multi-aged stands, but not quite as high as a young
even-aged stand, as gaps vacated by the death of large trees are filled
with clumps of saplings.


== 9 of 9 ==
Date: Mon, Oct 13 2008 2:57 pm
From: dbhguru@comcast.net


Many contributed to the document. I was one of them.


TOPIC: Old Growth Forest Document

== 1 of 1 ==
Date: Mon, Oct 13 2008 7:55 pm
From: "Edward Frank"


Paul Jost posted this link:


Title: Information about old growth for selected forest type groups in the eastern United States.

Author: Tyrrell, Lucy E.; Nowacki, Gregory J.; Buckley, David S.; Nauertz, Elizabeth A.; Niese, Jeffrey N.; Rollinger, Jeanette L.; Crow , Thomas S.; Zasada, John C.

Year: 1998

Publication: General Technical Report NC-197. St. Paul, MN: U.S. Dept. of Agriculture, Forest Service, North Central Forest Experiment Station

Abstract: Compiles information about old-growth attributes for nine forest type groups that occur in the eastern United States. A range of values for each old-growth attribute for each forest type is summarized regionally from published and unpublished sources.

This is a large file that is 244 MB in size. If you have a fast modem I would encourage you to download the full document. It should take less than an hour on a cable modem. The file is an Adobe Acrobat pdf file. Essentially there is an image of every page put sequentially into the pdf document. You can't cut and paste text from the file to another application. The total file is 433 pages in length. Of this total over 300 pages are tables of one sort or another, and another 40 are bibliographies and other appendices. Much of the useful information in the document is compiled into these tables and appendices. However, if you just want the text of the document, and the key diagrams, I have posted two files totaling 12 MB file temporarily to the ENTS Google list site: http://groups.google.com/group/entstrees?hl=en The first OG_forest_types1.doc contains the introductory material. The second OG_forest_types2.doc includes the breakdown of the information by forest types. They total 88 pages, a much more printer friendly total to read through. The data in the tables can be perused in the complete pdf file listed above. My file also is a cut and paste of images of the pages included in the pdf file and not in a text format. it shall be up for only a limited time as I do not want to hog the file sharing section of the Google site.

Ed Frank