| What
can learn from our sites? |
Robert
Leverett |
| Aug
25, 2002 11:08 PDT |
Colby,
Will, Jess, et al:
My next site to complete for the Rucker
Index will be the Mount Holyoke
Range. Eventually, I'll get the Cobble Mountain Reservoir in
Mass, the
Claremont pine site in NH, the Tamworth Pines in NH, and a few
other sites
in New England that are small in acreage. New York holds
enormous potential
as does Pennsylvania. In terms of travel, I can get to eastern
New York fast
enough, but Pennsylvania presents logistical problems. Dale will
likely
cover western PA and maybe be can collaborate on the eastern
side of the
state.
Next year we should be able to get a
good fix on Hartwick Pines and
maybe I can bribe Paul Jost and Lee Frelich with wintergreen
creams from
Richardson's Candy Kitchen to assemble a list for the Porkies.
When Tom
Diggins gets settled into his Ohio abode, maybe we can get a
site or two
from him. I'm keeping my fingers crossed that Will Blozan will
head to Joyce
Kilmer and lay to rest where that great site belongs on the
charts. Of
course, it is no mean task to construct site indices.
I'm sure we would all agree that
computing these indices is is very
labor intensive. Does this place a practical limit on what we
can do? Does
it matter? Beyond personal satisfaction for the few, can we
contribute
knowledge valuable to others? Yes, we can - of several types.
But we have to
get efficient in the way we cover sites or its all just
academic.
It should be apparent to all that I want
to take the Rucker Index Mohawk
Trail State Forest to the limit accuracy and to do this I've had
to become
increasingly systematic as I creep towards the upper limits.
Without a
system, adding a few more decimal digits pushes me beyond the
point of
diminishing returns. However, we are still able to progress
satisfactorily
with the Mohawk model because we increasingly know where to look
for each
species in terms of growth potential. We are in the process of
separating
MTSF into key growing zones based on basic land form, aspect,
altitude, and
some site history. The aspect and altitude are easy to
determine. Site
history is scattered, but we have some. The land forms have been
by trial
and error, but we're really starting to get there and it is here
where we
are making our best progress. As of now, the land forms we've
classified in
MTSF that significantly affect tree growth (and tree form)
include:
1. Ridge top
environments where the land quickly slopes off on two
sides; i.e. a ridge crest.
2. Plateau
environments with shallow depressions and small hill
tops.
3.
Mountain/gorge sides:
a.
Concave with boulder field,
b.
Convex, including ridge backbones,
c.
Ledge environments with large benches,
d.
Ledge environments with small benches,
e.
Intermittant rock outcroppings,
f.
Sparse rock cover, lightly undulating surface form, wavy
across the ridge face,
4. Saddles
between peaks (can either be wind funnels or protected
areas).
5. Old river
terraces.
6. Newer river
terraces (closer to the parent rivers and usually a
lot larger).
7. Toe slopes:
a.
Dropping to river or stream,
b.
Dropping to terrace.
From the above land forms and using
topographical maps, we can calculate
the acreage that falls within each terrain class and classify
the forest
type(s) associated with each terrain class. For instance,
terrain classes 1,
5, and 6 are where most of the white pines grow in MTSF. They
grow in other
areas, but don't contribute significant habitat to impact the
Rucker Site
Index. The tall pines grow predominately on terrain class 6. The
more
acreage that falls in this class with trees in the 120+ year age
class, the
more that the species can maintain its effect on the Rucker Site
Index.
Extrapolating this kind of thinking was
what led to the table of
reapplied site indicies, updated below.
1 132.23
2 127.7
3 125.38
4 124.00
5 123.5
6 122.5
7 121.4
8 120.0
9 119.08
10 118.05
50 112.50
100 110.50
200 106.90
300 104.10
400 102.70
500 101.80
1000 99.60
2000 97.50
5000 95.80
Since each reapplication removes the
trees used for that application,
the process does not mirror long term stability of the index,
but rather the
depth of the tall tree populations. We wouldn't expect natural
events to
remove all the members of each iteration. So, practically
speaking over the
long term, what can we expect from the Rucker Site Index for
MTSF? I expect
it to vary between 126 and 132.5 (the adelgid and the beech bark
disease
will increasingly impact the index as they take out two species
that help
maintain teh average.). The MTSF range for the Rucker Site Index
represents
a maximum for the Berkshire-Taconic region as a whole. In terms
of the past,
my 'guesstimates' may have been slightly conservative. A
Pennsylvaina site
could have gone to 134. For New York, MA, etc. I'd still place
133 and the
upper practical limit, but admit to the possibility of a 134.
Now, what might a typical site index
range in the Massachusetts
Berkshires be today? Well, the Rucker Index will naturally be
all over the
place because of the variety of site conditions and frequency
and type of
land use history. A private site that has not undergone recent
cutting
(trees are 65+ years old) can be expected to have a Rucker Site
Index of
between 85 and 95 out of a potential of perhaps 120 for the good
locations
or about 75% of potential. I would guess that poorly managed
sites, in the
65+ year age range, will be down to around 60% to 70%. I may be
way off on
these numbers and I don't know where the analysis will lead, but
I would
hope that we could eventually establish some measures of good
forest
stewardship out of them - more realisticly, interest those with
the time,
qualifications, and resources to pick up on this type of
analysis.
One of the concerns I've had with the
models of forest management that I
see discussed on these lists is that they seem to bring the age
of the
forest down to around 60 years old. Even with the best of
intentions, I
worry about that becoming the norm, if it hasn't already. Sixty
years seems
to me to represent a gross underachievement, thinking like a
forest. Where I
go, I see forests that are between 70 and 130 years of age that
are
absolutely eye-popping. They are not old growth and my interest
in them isn't
related to my OG interests. What I think I'm seeing happening at
these sites
has practical applications. For instance, the Ash Flats forest
averages
around 200 square feet per acre of basal area (46 sq meters per
hectare) and
the Ash Flats canopy averages around 125 feet in height. In
places it
exceeds 130. Individual ash trees branch at 65 to 75 feet above
ground. They
are straight as arrows and would yield at least four 16-foot saw
logs. One
tree I know branches at 80 feet. That's 5 saw logs. Ash Flats
got to this
impressive state of development largely by being left alone for
a hundred
years. It can now give us a baseline to use as a measure of
natural
regeneration. That is a concept beyond the brains of most
loggers, but it
should strike resonant chords with plenty of foresters.
Going beyond Ash Flats, there are areas
of MTSF belonging to terrain
classes 3a, 3e, 5, and 7b that could also serve as baselines for
comparing
silvicultural success in areas of active timber management. By
not
appreciating the value of these recovering forests and what
they've produced
in periods of from 70 to 120 years, it seems to me that we are
missing the
opportunity to establish natural baselines that aren't already
skewed by
poor timber practices in the past. It is all fine and well to
have
confidence in one's self that one is doing the right thing in
implementing a
cutting plan to mitigate past damage. I realize that is a career
in and of
itself, but isn't there a legitimate place for this other body
of knowledge?
If others with silvicultural experience
were laying the heavy numbers on
to me, I'd be less inclined to believe that there was a
knowledge gap around
rates and limits of natural regeneration. However, what I see as
a reaction
to the fast growth places to which I take my friends with
silvicultural
experience usually surpasses moderate surprise. That alone says
a lot and
the knowledge to be gained at these sites isn't just a slightly
different
twist to an already well organized body of silvilultural data.
Before ENTS began scouring the old
growth, big tree, and tall tree
sites, except for the places that had big neon signs in front of
them, most
weren't on anybody's radar scopes. For instance, had I asked any
of the
UMASS silviculturists about ash growth potential throughout its
range, and
locally east and west of the Connecticut River, I would have
either been
directed to general tree growth tables (it already happened) or
would have
been met with blank stares (it too already happened). Now,
shouldn't a
profession concerned with growing trees understand species
minimums,
maximums, and averages at a local level where the knowledge can
do some
good? Well, there is a gap in the silvicultural knowledge base
that applies
to minimums, maximums, and averages for white ash, and other
species as
well, that have been growing in areas that aren't being
continuously
hammered. For instance, had silviculturists seen Ash Flats 30
years ago
would they have concluded that the trees there were about maxed
out - based
on their experience with the species elsewhere? If they did
reach that
conclusion, they would have been wrong. Very wrong. Isn't it
important for
them to know that so they can tweak their growth models? Or is
it better to
continue using outdated growth models and just argue the issue
from some
aloof position, taking the assinine turf stance, which is a
guaranteed route
to mediocrity.
No, folks, there is very useful,
practical knowledge locked up in the
growth history of the trees in MTSF, MSF, Ice Glen, and
elsewhere that has
been obscured by a presumption that the volumes of data that
already in
existence has answered all the revelant questions. Not by a long
shot.
"Thar's gold in tham thar hills" and it exists in the
form of tree growth
data.
Bob |
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