In my original thread in this forum (http://forums.gardenweb.com/forums/load/verm/msg0322443013790.html?29) I made the following comment in an effort to illustrate that 'things' are not "the same all over":

QUOTE

On a seasonal basis in Alaska, primary production can be high, but on an annual basis, it is VERY low. (There are often 50 annuli per inch on birch and spruce trees.) Therefore, soil production is low. While there are those in Alaska that "compost" - in the typical use of the term - there is a great deal of labor associated with marginal product volume and quality.

END QUOTE

Since there seems to be no paucity of skepticism here at this forum, (that's not complaint, just observation), AND since I happened to stumble across verification/corroboration of the above "50 annuli per inch", I thought I'd offer something better than "a thousand words".

I was in my shop "making little ones outta big ones" when I noticed the growth rings on a piece of black spruce (Picea mariana) I had taken from the firewood pile to make a mallet from. I sliced off a piece of it suitable to fit under my dissecting microscope and produced the following picture:

And closer so you can read the scales:

If you "do the math", (20 annuli per 6.324mm) you get 80 annuli per inch. Something a bit more than even 50 per inch. If you think about it a bit, it should impress you with how slow some things grow in "The Great White North". While there were certainly periods of growth for this tree in which it grew at a lot faster rate, there was at least one 20-year period in which it added less than 5/8ths of an inch, (15mm), to its girth. And this tree grew in the fairly mild climate of the maritime "south central" Alaska.

Paul