Western Maximum Tree Ages Edward Frank
July 08, 2009


The oldest official counts for ages of western trees are posted on the OLDLIST maintained by Rocky Mountain Tree Ring Research  Of the hundreds species listed in western  US (Audubon Field Guide), only a handful have "official" cross-dated ages.
For the most part dendrochronologists focus on collecting samples from long lived trees in order to create long histories of environmental, fire, archaeological events and sequences. For this reason there are only a few species that are heavily sampled. For other species there may be a few samples taken here or there as part of a larger study. The results of these often are not published or compiled in any systematic way as they are not the focus of the research. Until recently the International Tree Ring database http://www.ncdc.noaa.gov/paleo/treering.html  would not even accept dendro sequences less than 200 years old. Check on the current age listings on the OLDLIST  website: http://www.rmtrr.org/oldlist.htm   for the most detailed information.

In the face of this lack of published information the maximum ages that hundreds of species of trees and shrubs may reach is virtually unknown, and often misrepresented in various popular media and field guides. We can help remedy this situation.  I want to collect ages from as many of the other species as possible from ring counts on stumps and cores. So I am asking WNTS members count everything you find, write down your information on where, when, who, and how and send them to me.  At this stage the primary goal is to collect ring count ages from trees, shrubs and vines in western United, Canada, and Mexico.

To be included are:

  1.. Any ages from species not currently on the OLDLIST
  2..  Ages that exceed or approach the ages for the species on the OLDLIST
  3.. Ages that represent great age for the species.
There are some inherent inaccuracies with ring counts. There may be false rings or missing rings, but these limitations are understood within the context of the methodology. They are trivial compared to the degree of error in field guides. Better age range information will be valuable when considering the ecology and history of the small patches of old growth we are finding and documenting.

For foresters and field people there will be a tenancy to not count rings on some stumps because you "know" there are older examples out there that you have seen. However at this point, there is such a paucity of good numbers, I would encourage you to count what you find. If we get older counts later so much the better, but the goal now is to get something more reasonable. Along access roads there may be shrub-sized species, cut that are not normally harvested. Numbers for these species would be useful also.

A next step for the project, and one that can begin simultaneously, is the use of all collected data, both for "new" species and for old, to plot the ages known for various forests, and forest sections. This will allow a development of a beginning geographic data base of the age of various forests, and allow us to better understand and investigate the age structure of forest we are visiting and investigating.

I have created a table on the WNTS website:  http://www.nativetreesociety.org/dendro/wnts_max_ages.htm in order to compile this information.  To jump start this project and to add the first species to the list is a 70 year old by ring count Poison Oak vine by Mario Vaden. http://www.mdvaden.com/album_Poison-oak.shtml  

(Mario, where was this vine located?)
Edward Frank

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