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Re: [ITRDBFOR] Field methods for aging Western red cedar stumps


Chronological Thread 
  • From: Torbjörn Axelson <dendro AT taxelson.se>
  • To: itrdbfor AT itrdbfor.org
  • Subject: Re: [ITRDBFOR] Field methods for aging Western red cedar stumps
  • Date: Fri, 4 Jan 2019 15:30:52 +0100

Hi Julie,
Although I don't know anything about western-red cedar, I may do some reflections:

* Maybe sanding stumps works in your area, in my Scandinavian ears it sounds peculiar. Sanding needs dry wood, and it would not work on any stump around here. Cutting a clear surface with a very sharp knife/razor etc would be the option. But it is different climate and different species, so I don't know. (Adding some water n the surface may make the cutting easier anyway)

* As it is fresh stumps of living trees your concern is to find the age of the oldest ring, so preparing a good measurable surface of e.g the innermost 70-100 rings is probably enough. if you have a good local master. If not it is necessary to build one, and collecting cores from the outer part (as deep your corer reach - 40 cm or more?) of the stumps is strongly recommended, I think. You can than extend it with measurements from the photographed inner/older (wider?) rings .

*Photographs gives some distortion, but seems not to be a big deal if you just want to perform crossdating. Figure out a strategy for how to take a series of overlapping photos from the same distance, and don't forget including a ruler - both to safely identify the same ring in the overlapping part of 2 pictures and for calibrating!  

*Maybe coring (with a special, one-sided handle) starting from near the pitch and core sloping but as near the stumps surface as possible, should be tried. In this way you will likely get good cores from the oldest parts of your stumps - and if you also sample the normal way through the bark, you can combine them through crossdating oan you will have have samples useful also for other studies in a later stage. Than you can also use a microscope ti try to find extremely narrow rings etc which you can't on a photo.

I haven't actually used the photo method on stumps very often. Around here (Sweden) stumps rarely exceeds convenient size for coring them with a 40 cm increment borer but stumps cut some years ago sometimes have an intact surface under which insects have eaten the wood so it is not possible to core anymore. Than i have sometimes found this method useful. It has also happen that I have quickly have wanted to know the age of newly cut trees and than cut the surface and measured the inner part on photos taken with cellphone (I have dendro programs  - CooRecoorder and CDendro - in my laptop i usually bring with me, but have not always increment borer in my case...)   

An old post on a maybe a bit similar method issue is on http://www.cybis.se/forum/viewtopic.php?f=10&t=28&p=63&hilit=photo#p63 Unfortunately I do not find anything about the distortion-problem for the moment.

Hope someone else has more adequate experiences to share!

good luck

/Torbjörn Axelson


Den 2019-01-04 kl. 02:07, skrev Julie Nielsen:
Hi all, I was hoping to get a few expert opinions about field methodologies for aging western-red cedar trees (using stumps), as I am planning for the Spring 2019 field season. We will be attempting to age large (greater than 100cm diameter at breast height) western red cedar trees using dendrochronological methods with stumps, which will have had minimal exposure to the elements (we will access stumps 2-6 weeks post harvesting). We would like to obtain an age estimate of the stump in the field (so we are not having to bring back "stump cookies" to the lab for ring analyses). We have been advised that a small portable electric belt sander could be used to smooth out two “transects” across the stump surface area (any recommendations re: belt sanders to buy?…we are in Vancouver, Canada). We would then take photographs of ring sections along the transects in order to analyze and count the rings using a computer program (WinDENDRO) in the lab. 
Instead of sanding, it may be possible to cut out a splice of the stump surface, using a knife since cedar is a fairly soft wood, and observe the rings in the cross-section of fresh cut wood (then either take photographs of the cross-section or do a direct count of rings in situ).   We assume that counting rings in the field, even with a magnifying glass, would lead to much greater inaccuracy in aging than if the rings were analyzed from photographs in a computer program. We feel it would be much more difficult to correctly identify early and late wood rings and/or false rings in the field. We have thought two transects across the longest diameters of the stump to suffice, although would like to know if there is a standard number associated with this method.   Any comments or advice regarding the methods I have described would be much appreciated. Any other recommended methods would be welcome as well. We are unable to rough-cut a cookie off the stump with a chainsaw, due to logistics with transport etc. If anyone has done similar work with tree stumps & aging I would love to hear from you (please send along any published papers or reports you may have as well). We acknowledge that our tree age estimates are just that, estimates, as we will be dealing with a fair amount of heartwood rot in these trees, and therefore will have missing or indecipherable rings from the pith outward.    Thank you in advance,
Julie

Julie Nielsen, MSc., RPBio. REM PhD Candidate Conservation and Policy Research Group Forest Ecology and Management Lab School of Resource and Environmental Management Simon Fraser University


I respectfully acknowledge that I work and live on the unceded territories of the Coast Salish peoples of the xʷməθkwəy̓əm (Musqueam), Skwxwú7mesh (Squamish), and Səl̓ílwətaɬ (Tsleil-Waututh) Nations.





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