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 cross-section. 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   Home