Thank you for your clear video teaching how to get form factor of a tree. let me ask one question that is it possible for natural forest trees found in Africa?
Sir 49.3 is the diameter or circumference. The way it is measured shows that its circumference. If you calculated the diameter by circumference please tell about that also. DBH = GBH/3.14 THANKS
We are here using a diameter tape, which is very common in forestry. It does exactly what you mentioned, the scale is divided by pi. This means you can directly read the diameter. Check out video on dbh measurement.
Unfortunately I don't have the original copy from 1929. In Kramer & Akca I found this citation: Denzin 1929. Schätzung der Masse stehender Waldbäume. FA, 382-384.
Denzin's formula is for the whole tree including crown and branches down to a diameter of 7 cm. In fact, if you recalculate the form factor you will see that Denzin implicitly assumes a factor of 0.5 for a tree of 25m standard height (assuming you calculate volume = basal area * tree height * form factor). Form factors for commercial volume are higher, like 0.8.
@@forestinventory Thank you, so timber height. Should I be using the timber height (up to 7cm top diameter) when using Denzin's method for broadleaves, such as oak. Or, is total height, base to tip, used for all trees? I've used this for several species and the form factors vary from 0.48 to 0.65, using the 25m standard height for 'volume correlation percent'. Is the Norway spruce in this video not a commercial volume? My understanding is spruce form factors are about 0.6? This single tree volume method can be used for all trees, open grown or in a plantation? Should you ever change the 25m standard height? E.g =(DBH^2/1000)+(DBH^2/1000)*(height-)*3%
Denzin is using the total tree height from base to tip to adjust the height depending form factor. The result is always total volume (up to 7cm), which is called "Derbholz" in German. Later he also suggested some species specific corrections, but they differ only slightly from the overall 3% per meter height difference to 25m. But his formula is just a fast and simple approximation since form factors might vary with site conditions. I think for trees growing in open areas the h/d relation might be very different. Form factors for total height and volume for spruce in Germany vary from 0.38 to 0.57 depending on tree age and site quality.
Edwine is here using a diameter tape with pi scale from which you can directly read the diameter. Watch our video on tree diameter measurement to learn how...
If you are not familiar with a diameter tape which has a pi scale, see our video on diameter measurement. It's right that Edwine measures a circumference, but on the tape he can directly read the diameter (assuming a circular shape).
With due respect sir, I think the diameter you measured was actually 49.3 inches and not in cm. When you convert it to cm, it becomes 125.2cm or 1.25m. The height is 28.8m. Now applying quarter girth formula here, (1.25×1.25×28.8)/16, the calculated volume becomes 2.81 cu.m . This formula is 78% correct which gives buyers advantage during sawing of round timber. I am forest officer from India and here we follow this. Now, if we calculate cylinder volume, it becomes approximately 3.6 cu.m. Now, the form factor is (2.81÷3.6) = 0.78.
Thank you very much for detailed formula.
Sir, can you please suggest me which one is the best laser range finder?
Thank you Professor
Thank you for your clear video teaching how to get form factor of a tree. let me ask one question that is it possible for natural forest trees found in Africa?
Grüße geht raus an alle Waldwissenschaftler aus Freiburg!
Sir 49.3 is the diameter or circumference. The way it is measured shows that its circumference. If you calculated the diameter by circumference please tell about that also. DBH = GBH/3.14
THANKS
We are here using a diameter tape, which is very common in forestry. It does exactly what you mentioned, the scale is divided by pi. This means you can directly read the diameter. Check out video on dbh measurement.
Thank you for the detailed information! How do I correctly cite Denzins formula?
Unfortunately I don't have the original copy from 1929. In Kramer & Akca I found this citation: Denzin 1929. Schätzung der Masse stehender Waldbäume. FA, 382-384.
@@forestinventory Thank you!
@@forestinventory This source includes the correction for norm height, right?
Is this calculating the volume of the entire tree (branches? Crown?) or up until the timber height? Thanks
Denzin's formula is for the whole tree including crown and branches down to a diameter of 7 cm. In fact, if you recalculate the form factor you will see that Denzin implicitly assumes a factor of 0.5 for a tree of 25m standard height (assuming you calculate volume = basal area * tree height * form factor). Form factors for commercial volume are higher, like 0.8.
@@forestinventory Thank you, so timber height. Should I be using the timber height (up to 7cm top diameter) when using Denzin's method for broadleaves, such as oak. Or, is total height, base to tip, used for all trees?
I've used this for several species and the form factors vary from 0.48 to 0.65, using the 25m standard height for 'volume correlation percent'.
Is the Norway spruce in this video not a commercial volume? My understanding is spruce form factors are about 0.6?
This single tree volume method can be used for all trees, open grown or in a plantation?
Should you ever change the 25m standard height? E.g =(DBH^2/1000)+(DBH^2/1000)*(height-)*3%
Denzin is using the total tree height from base to tip to adjust the height depending form factor. The result is always total volume (up to 7cm), which is called "Derbholz" in German. Later he also suggested some species specific corrections, but they differ only slightly from the overall 3% per meter height difference to 25m. But his formula is just a fast and simple approximation since form factors might vary with site conditions. I think for trees growing in open areas the h/d relation might be very different. Form factors for total height and volume for spruce in Germany vary from 0.38 to 0.57 depending on tree age and site quality.
How do you directly take the diameter reading?
Edwine is here using a diameter tape with pi scale from which you can directly read the diameter. Watch our video on tree diameter measurement to learn how...
@@forestinventorythank you very much.
Do you understand the difference between diameter and circumference?
If you are not familiar with a diameter tape which has a pi scale, see our video on diameter measurement. It's right that Edwine measures a circumference, but on the tape he can directly read the diameter (assuming a circular shape).
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The measured diameter is 49.3 and you are calculating with 49.9
Yes, this was a mistake during video production. It is also mentioned in the subtitles
I need Eucalyptus tree volume formula with form factor for calculating tree volume
With due respect sir, I think the diameter you measured was actually 49.3 inches and not in cm. When you convert it to cm, it becomes 125.2cm or 1.25m. The height is 28.8m. Now applying quarter girth formula here, (1.25×1.25×28.8)/16, the calculated volume becomes 2.81 cu.m . This formula is 78% correct which gives buyers advantage during sawing of round timber. I am forest officer from India and here we follow this.
Now, if we calculate cylinder volume, it becomes approximately 3.6 cu.m.
Now, the form factor is (2.81÷3.6) = 0.78.
Hi Arup, dbh was measured in cm here! Converting 43,9cm to inch would be 19,4inch.
Sorry, 49,3 cm...