There are 2 issues associated with a minimum standard. One is what we
measure and one is how we report it.

If we all measure the same then there is no problem understanding what each
of reports. However, we measure for different objectives, with different
budgets, and with different organizational histories. Thus, it is important
that how we measured is properly identified. This is usually well documented
in the methodology of a publication. However, the results are reported
separately from the methodology and in comparisons between different
studies/inventories the specifics in the methods may be overlooked. As such
as a standard practice, I suggest that we always include the minimum
diameter limit in the unit e.g., 200 cubic metres (>7.5 cm dia.) when we
report area based total dead wood volume. And if our measurements enable, we
should report at other minimum diameters to enable comparison for others.


Cheers

Jeff

Jeff Stone
Timber Supply Analyst
Kamloops Forest Region, Ministry of Forests
515 Columbia Street
Kamloops, British Columbia V2C 2T7 Canada

Telephone: 250-828-4171  Fax: 250-828-4154 
Email: jeff.stone@...

-----Original Message-----
From: Simon Grove [mailto:simon.grove@...]
Sent: Monday, May 27, 2002 8:52 PM
To: dead_wood@yahoogroups.com
Subject: [dead_wood] What do we mean by CWD?


Dear deadwoodologists

I'm sometimes asked by colleagues what exactly I mean by coarse woody
debris, especially by people looking to pick holes in estimates of CWD
volumes. I have to explain that what I mean by CWD may not correspond with
what others mean, and hence our figures are not always entirely comparable.
With all the upsurge of interest in dead wood (e.g. for carbon accounting
and for biodiversity), isn't it about time we standardised on our
definitions? I appreciate that we all put the data to different uses, but
are our uses so different that we can't standardise?

Maybe this is old news, and standards may have been developed and adopted.
But if so, what are they, and where are they laid down? Two key
discrepancies come to mind: whether or not CWD includes standing dead wood;
and what is the minimum diameter below which CWD becomes fine woody debris?
Some people use 7.5 cm, others 10 cm, others 15 cm; others use inches which
almost (but don't quite) correspond to these cm definitions. Likewise ha or
acres. Personally, I have tended to exclude standing dead wood and have
specified a minimum diameter of 7.5 cm. However, the lower the minimum
diameter, the more work involved in working out volumes per unit area, and
the law of diminishing returns applies since smaller diameter material
generally contributes little to overall volumes.

If readers feel that we still lack standards and that it would be worth
developing some, I'd be pleased to see some discussion through this list.
If support was strong enough, we could perhaps consider setting up a
web-page that allows people to vote on alternatives, and could invite
members of related lists (e.g. forestry, carbon accounting, bryology,
entomology, mycology) to vote too.

Any comments?

Simon Grove


`'*:-.,_,.-:*'``'*:-.,_,.-:*'``'*:-.,_,.-:*'``'*:-.,

Dr Simon J Grove, Biology and Conservation Branch,
Division of Forest Research and Development
Forestry Tasmania, GPO Box 207, Hobart, Tasmania 7001, Australia.
Tel. 61 3 6233 8141. Fax 61 3 6233 8292.
Email: simon.grove@....
Web address: http://forestrytas.com.au/



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