On 13 March 1996, Jarmo Saariko wrote:
++++++++++
Original question:
"Can anyone please tell me anything about the origins of the TERM
'old-growth'? I guess it originated in the Pacific NorthWest of North
America and has become widely adopted in Australia and elsewhere."
++++++++++
My original posting in response:
Old growth stands have three key elements:
1) Age: most trees in the stand are approaching their pathological age.
A long time has passed since a large-scale disturbance.
2) Coarse woody debris: present in large quantities and in large size
classes.
3) Vertical diversity: Tall trees, medium height trees, little trees, the
latter two size classes filling the gaps where old trees have fallen down
due to wind, disease, etc.
++++++++++
To which Jarmo responded:
>Unfortunately I cannot answer the original question on the origin of the
>term either, but I would like to raise another aspect of the definition.
>
>This definition problem came up in a recent discussion here at Metla:
>Often we would need to define are we discussing the age of the forest or
>the virginity/naturality of it?
I agree. Toss in the "ancient forest" term, and you have real confusion (or
obfuscation) of the issue. I firmly believe that we can manage a forest so
that it has many -- if not nearly all -- of the structures and functions of
the "virgin" forest. Most of us (who own and/or manage forest land) choose
--rationally -- not to, because public policy (e.g., taxation) provides no
incentive to do so, on both private *and* public land.
>Point (1) above combines both age and scale. Are these always
>interconnected? Can we have small-scale forests which could be
>called "old-growth"?
I would not go below the stand level. The stand must be of a size large
enough to buffer the interior from impacts of more intensively managed (or
non-forest) lands adjacent to it. You can have "postage stamp" areas of old
growth, but they are the living dead unless there is some way that the
species, structures and functions can be maintained in the face of eventual
disturbance.
>Also, we may have managed forests, which are old ("at pathological age")
>or very young natural/virgin forests (e.g. after fires), which usually
>would not be called "old-growth" according to any of the points 1-3.
No disagreement here. The issue is scale, level, and frequency of
disturbance. "Old growth" forests, at least as I've attempted to define
them, could have a mix of age classes (note that I did not define the size
of patches in point 3), but the relative proportion would clearly tend
toward the older classes. Coarse woody debris can be present in large
quantities and size classes on managed forests, especially if we are trying
to manage for older forests (but it looks "messy" to the uninformed, and
"wasteful" to the utilitarian).
>The term "old-forest" is in wide use in Finland.
I like that term.
Best regards,
Donald Mansius
cndmans@state.me.us
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