Radial
Growth Rate 
Edward
Frank 
Mar
05, 2007 18:37 PST 
ENTS,
I will elaborate of the discussion of the how to determine
radial growth per year. As an aside, in math class there were
always two phrases that bothered me. When the instructors would
get to a critical point in the problem they would come up with:
"it is intuitively obvious that" Perhaps it was
obvious to people with advanced degrees in mathematics but it
wasn't to the many of the people, myself included taking the
introductory courses. The second phrase was "I have changed
notation here in order to simplify the problem" I had just
figured out the old notation, now they were changing to
something completely different. It in no way did this simplify
the problem for me. I think oft times they were trying to
demonstrate they were smarter than everyone else. That is
proposition I highly doubt. So when I try to explain how to do
something, I include even the most basic steps. It is not to
denigrate anyone's intelligence, but to avoid the
"intuitively obvious" trap.
First if you have a circumference in feet and inches, it must be
converted to a uniform type of unit. You can do this by either
changing all of the figures from feet and inches to just inches.
The other way is to convert the inches to decimal feet.
Fractions of an inch must be converted to decimals: 1/4" =
0.25", 1/2" = 0.5", 3/4' = 0.75" and so
forth whichever option you choose to use.
To convert to decimal feet divide the number of inches by twelve
and add it to the number of feet. There is no need to do any
decimals beyond two places, because the measurements just aren't
that accurate. In Larry's example the original cbh
(circumference breast height) was 14' 7". That is 175
inches or 14.58 feet. The ending
circumference is 23 feet or 276 inches.
For this purpose I will work with inches of circumference. The
formula for the circumference (or cbh) and radius relationship
is:
cbh =
2(pi)radius with pi = 3.1415, therefore:
radius = cbh/ 2(pi); or radius = cbh / 6.283
So if you want to calculate the change in radius, change = 276 /
6.283  175 / 6.283 , change = 43.93  27.85 =
16.08 inches
This can be done in a simpler way by combining the calculations
to get: (end cbh  start cbh) / 6.283; in this
case the numbers work out to be (276  175) / 6.283 = 101 /
6.283 = 16.08 inches.
To determine the rate of growth divide the change in radius by
the number of years.
In this example: growth rate = 16.08 inches / 73 years = 0.22
inches per year. It is likely the number of the years is closer
to 72 than 73, so that the growth rate is closer to 0.223
It is reasonable to use three decimal places in this final
calculation.
Edward Frank
 Original message

From: tuce@msn.com
> The Friendship Oak,is located at
University of Southern Ms., in Long
> Beach. The tree was measured and
registered with the Live Oak Society in
> 1934, CBH14'7". In 2007 it
measured CBH23' a 9'7" difference. We have
> the Ruskin Oak growth rates and we
have the Friendship Oak growth rates
> for this 73 year period! The Ruskin
Oak grows on a small hillside, while
> the Friendship Oak grows near the
beach. It had about 15' of water under
> it during Hurricane Katrina in 2006
and about the same from Hurricane
> Camille in 1969. I'm sure it has
been under several more times in its
> 300400 year life! My point is one
tree has not been flooded with
> saltwater, while the other
has. 
