Tree Value Calcs for Students

jcrewe

Hi I am teaching high school environmental science and looking to do some basic calculations to get tree volume and then value. These students are 15 years old so basic is good at this level.

So far I have shown them how to get the height of a tree (isosceles triangles) and measure the circumference over bark with a measuring tape. When I tried to do some calculations I started coming up with numbers that made no sense (like volumes of 0.002m^3).

So once I get the circ over bark I change it to 'Diameter at Breast Height Over Bark' (DBHOB) with

DBHOB = circ / pi

Now following the calculations I am using Tree Basal Area (TBA) which is calculated by (DBHOB/200)^2 * pi

The site doesn't give any units to input at DBHOB so I am using meters though the example uses DBHOB as cm then somehow ends up with m^2 at the end...

Tree Measurement - fieldwork - L a n d L e a r n - Australia

Should I be using meters and using the equation (DBHOB /2)^2 * pi to get viable measurements instead?

The finally Volume = (TBA * Ht)/3 which if fine. I am subtracting 10% of the volume for a Form 2 tree and 20% of the volume for a form 3 tree (arbitrarily, but I want the $ to be lower for trees of poorer form).

Finally I want them to get a general measure by multiplying the volume by a dollar value to get a value for the tree. I want to get it basic by simply dividing it by hardwood and softwood for the time being. What values should I put in here? I know that there is a wide range by species and possible wood use but this is just basic estimations. The students know that the value varies but we are not going to do all those calculations.

I want get this as close to simulating real practice as I can with these values so any help would be appreciated. Any other facts/tips or ideas are also welcome as I develop this material.

Thanks

Jason

Garry Brockley

there is a button above that the industry uses called tree value

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Eric Frei

Why reinvent the wheel?

Tree surface area and tree volume calculator

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jcrewe

Thanks I have seen the online calculators available but I want the students to be able do the math. This links in well with their geometry education at the same time.

Small rant: Why don't those online calculators gave some insight into the methods and calculations? I don't like the magical black box approach where the answers just appear and no one has to do any thinking.....


Jason

Eric Frei

LOL, why don't most women drivers know how an engine works yet they're more than happy to turn a key and drive?

Why are people more than happy to eat KFC yet the 11 secret herbs and spices have never been disclosed including a court of law?

Why are environmental science teachers unable to validate the answers as corrrect without assistance from a tree guy?

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