Radial
Growth Calculations 
Edward
Frank 
Aug
12, 2007 05:40 PDT 
ENTS,
I am posting a series of article explaining the very basics of
some of the calculations used in our study of trees. This is the
next installment.
Annual Radial Growth is the amount of growth a tree has per year
as measured by the increase in the radius of the tree. This is
essentially the same as the width of the annual growth ring for
the tree. In this formula the average annual radial growth is
calculated for the life of the tree given the circumference of
the tree and a known age for the tree..
(circumference in feet / 3.14) = diameter
diameter / 2 = radius in feet
radius in feet x 12 = radius in inches
These numbers can be combined into a single calculation:
circumference in feet x 1.91 = radius in inches
radius in inches / years = average growth rate per year =
average ring width per year
[(circumference in feet / 3.14 )( 12 / 2 )] / years = average
growth rate per year = average ring width per year
(circumference in feet x 1.91) / years = average growth rate per
year = average ring width per year
Edward Frank

RE:
Radial Growth Calculations 
DON
BERTOLETTE 
Aug
13, 2007 20:04 PDT 
Ed
Of course this brings up the dbh versus circumference
debate...your annual radial growth of course, is average annual
radial growth, since different parts of the tree will add on
different amounts of cellulose...
DonB

Re:
Radial Growth Calculations 
Edward
Frank 
Aug
14, 2007 03:47 PDT 
Don,
I had meant to elaborate on that point, but sent off the email
before I jotted anything down. This is a fair approximation for
the tree. The circular "diameter" for a tree is
generally somewhere between the long axis and shorter axis of a
generally elliptical shape crosssection. The longer axis would
have a higher annual growth rate , while the shorter axis would
be slightly slower annual rate. For irregularly shaped tree
well something needs to be used as an approximation.
Ed

