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growth increments

jperry at UWC.EDU jperry at UWC.EDU
Mon Sep 23 11:02:28 EST 1996


Stump the anatomist time...

I have a block of oak wood (no bark) in front of me that has a very unusual
pattern within its growth increments. It was given to me with a question of
why this pattern exists. I'll do the best I can to describe it.

Looking at the cross section, *all* the growth increments (and I can count
16 of them in this block) between two multiseriate rays are displaced in a
radial direction (toward the pith). The displacement is such that the early
wood of the displaced increments fall in the late wood of growth increments
on either side. I'll try to create another way of explaining this:

"early" = early wood
"msr" = multseriate ray
"late" = late wood

Imagine you are following the circumfernce of the growth increments.

        ... msr early msr early msr late msr early msr early msr ...
        ... msr early msr early msr late msr early msr early msr ...
        ... msr early msr early msr late msr early msr early msr ...
        ... msr early msr early msr late msr early msr early msr ...
        ... msr early msr early msr late msr early msr early msr ...
        ... msr early msr early msr late msr early msr early msr ...
        etc...

Note that the late wood is in the displaced growth increment.

I can't imagine how the vascular cambium could be so perfectly displaced  to
cause this to happen in *one single* radial file of growth increments.

Does anyone know for certain (speculation is fine, but I'm hoping for a
definitive answer) how this occurs?

Jim Perry

        
James. W. Perry, Campus Dean
University of Wisconsin - Fox Valley
1478 Midway Road, P.O. Box 8002
Menasha, Wisconsin 54952-9002
Office: 414.832.2610
FAX: 414.832.2674
jperry at uwc.edu




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