Thinning on the Angeles National Forest> > "Ian St. John" <> wrote in message

Bob Weinberger bobsstuff at
Tue Feb 24 02:54:19 EST 2004

"Ian St. John" <istjohn at> wrote in message
news:T1x_b.5089$253.524315 at
> It isn't that close. Obviously the land is grouped into denser and less
> dense stands but that doesn't obviate the metric. Overall, the SDI is
> low, and this calculation was for 'mixed size average', which is still
> ( according to the documentation ). It may not be as precise as a region
> region assessment but it still give a 'rough estimate' of the stocking
> levels overall.

The above is a prime example of your lack of familiarity with conditions in
the PP region leading to faulty reasoning and conclusions.  Of what use is a
"rough estimate of the stocking level overall"  for determining whether
trees are likely to be under stress on specific sites, in an area where
stocking is extremely clumpy and variable - the normal condition in many PP

> The 'SDI' maximum on which the 'fully occupied' is based is 35 of maximum
> stand density and that has been documented as 800 for Ponderosa Pine. As
> have not given a basis for the SDI being any different in this neck of the
> woods, your claims of superior knowledge ( aka argument by authority ) are
> dismissed for the fool bait they are.
> >   Depending on the specific site
> > productivity- which varies greatly from site to site, often in very
> > gegraphic distances - a fully occupied PP stand my have as many as  600+
> > 3-5" TPA or as few as 30 10-15" TPA.  On many of the lower PP sites
> > crown coverage is all the site can support.
> SDI is a metric that is independent of the dbh. That is why it is used.
> really ought to take forestry 101 if you don't even know that much! The
> smaller the tree the smaller the basal area and therefore the larger the
> number of trees for the same SDI. That is why your piece above is stupid.
> is just an expansion of the SDI for different average dbh levels, but does
> not say that the SDI would be any different.
Congratulations, you have apparently learned a new term. Now if you only
learned how to calculate SDI, and how to apply it properly you might start
to understand what  I am talking about.  SDI is a measure to be used to
determine  the level of inter - tree competition for a specific species ON A
SPECIFIC SITE PRODUCTIVITY CLASS. It is NOT a measure to be used to
determine the stockability of a specific site.  A maximum SDI ( or a Max. BA
fo that matter) only has relevance for a specific site productivity class.
If a maximum SDI for a species across its entire range is stated, it is only
a measure of the maximum that species can reach on the best sites it can

Secondly, despite the fact that I may have confused you by using stands with
2 different quadratic mean diameters, if you knew how to calculate SDI,  you
would have quickly determined that the SDI of the first stand ( 600TPA with
an assumed  QMD of ~ 4") has an SDI over 4 times that of the second stand
(30 TPA with an assumed QMD of ~ 12").  In any case comparing the SDI's of
the two stands is irrelevant, since the examples were given to illustrate
that they can both represent  fully occupied conditions for the sites they
are on.  The above is not "argument by authority" since you can verify it by
retaking Forestry 101 or at least doing a little more thorough reading of
Dr. Reineke's treatment of the concept.

Re: your repeated claim that  I am using an "argument by authority" tactic -
It became apparent to me long ago you will not believe my first hand
observations and experience. That is why at almost every opportunity I have
urged you  to come see conditions and relationships in the PP region for
yourself rather than continue to make statements that do little other than
show your lack of understanding of the area you are addressing.  It is
perhaps telling that you have failed to acknowledge these pleas in any way.

> Still looking for that 1000 trees per acre you claim. I can't find
> for ponderosa pine in the Kaibab region. Could you interpret your dreams
> again and tell me where to find it?

Here's a little clue - rather than seeking out data that gives region-wide,
National Forest wide, or even watershed - wide average data for stocking
levels and site productivity class, get the stand level data.  If you are
particularly interested in a specific National Forest you can write them and
ask for the specific data.  Most NF's in the PP region will be able to send
you a long list of PP stands with stocking exceeding 1000 TPA.
Also as I stated in an earlier post, if you are still interested in photos
of PP stands with >1000TPA, remind me in about a month, when conditions
should be such that I can get out and about in the woods, and I will take
such pictures and email them to you if you give me a valid address.

> At any rate, you beat me. I admit it. No matter how much I pointed out
> total lack of substantiation or references, you manages to be totally fact
> free for the entire thread. Not a thing that wasn't 'trust me' or
> extracted from your anus. I suspect, but cannot prove, that this is not a
> coincidence....

Again with the ad hominums from the one who decries such tactics?

I have never asked you to trust me.  You can verify everything I have said
if you simply take the time to seek out the level of data that is pertinent
( provided you learn the appropriate application of the data you are
reading) or better yet vist and spend some time in the region under

Since you dispute or ignore anything that comes from me, it is fruitless for
me to try to raise your level of understanding to a point that you might
begin to understand what those of us who are close to the issue are trying
to convey to you. And no that's not arguing from authority, its simply a
statement that you need to do a little deeper homework yourself instead of
assuming that you already know it all,  or can gain instant understanding by
visiting a few URL's.

Bob Weinberger
La, Grande, OR

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