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How many bf/year am i growing in my yard?

Started by Gilman, June 07, 2007, 11:13:35 AM

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Gilman

Does someone know where I could look up growth rates of different trees? 

I'm just curious to see how much the older trees are growing and how the newly planted trees are growing. I know there is a huge amount of variables but I figure there is something out there.

Thanks in advance,

David
WM LT70, WM 40 Super, WM  '89 40HD
Cat throwing champion 1996, 1997, 1999. (retired)

Dodgy Loner

The rate of tree growth depends much more heavily on the site than it does on the species.  If you'd like to know how fast your trees are growing, there are a couple ways to figure this out.  The first (and most time-consuming) method is to measure the DBH (diameter at breast height, 4.5') of your trees.  This can be done by measuring the circumference with a flexible tape and dividing by pi.  Next, measure the height of the trees.  This is more complicated, and is best done with a hypsometer.  There are many types of hypsometers; I use a clinometer.  For mature trees, you can just guesstimate the height, and assume that it is not changing (because it probably isn't).  Using the diameter, the height, and a species-specific volume equation (which many members of this forum could direct you to), you can determine the total volume of your trees.  Wait 1 year, and repeat.  Find the difference between the two volumes.  This will provide a rough estimate of annual growth, but it will be inaccurate if the previous year was unusually wet or dry.  The more years you can average, the better the estimate will be.

The second method is to determine the amount of diameter growth over the last few years by taking a sample of the growth rings at breast height.  This is best done with an increment borer, which removes a small, straw-like section of wood from the tree, and will not damage the tree.  Next, measure the DBH, and subtract the width of the previous year's ring x 2 to get the previous year's DBH.  You can go several years back like this.  Unfortunately, you will not be able to measure the previous years' heights, but for mature trees, this won't matter much.  Find the volume of the tree this year, and in the past, say, 5 or 10 years.  Find the average growth per year.

Pretty complicated, huh?
"There is hardly anything in the world that some man cannot make a little worse and sell a little cheaper, and the people who consider price only are this man's lawful prey." -John Ruskin

Any idiot can write a woodworking blog. Here's mine.

Gilman

WM LT70, WM 40 Super, WM  '89 40HD
Cat throwing champion 1996, 1997, 1999. (retired)

Ron Wenrich

I've always liked Karl's work.  He puts stuff out in a matter of fact way.

Never under estimate the power of stupid people in large groups.

Dodgy Loner

That is an excellent paper, and one that I wish most forest owners would read.  But realistically, the average rate of growth for a given species in your region is almost certainly NOT the same as the growth of that species on your property.  I have two "cookies" that I cut from two loblolly pines on my property.  One of them is 19" in diameter has 14 rings.  The other is 3.5" in diameter and has 46 rings.

If you already know the age of your trees, then you can easily figure out how quickly your trees are growing if you can provide the DBH and height.  We just need to know what species you're dealing with.  Is it Doug-fir?
"There is hardly anything in the world that some man cannot make a little worse and sell a little cheaper, and the people who consider price only are this man's lawful prey." -John Ruskin

Any idiot can write a woodworking blog. Here's mine.

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