Measuring upper tree diameters with a Mirror Relascope

Lesson 6: An explanation on how to use a Mirror Relascope to measure tree diameters in different heights.
#unigöttingen
#forestinventory
#forestmensuration

[@chinggiskhan-pf3fu]

Thanks sir for your demonstration I'm a student of Department of Forestry and Range Management from Pakistan

[@BushyHairedStranger]

Excellent demonstration. Will be helpful for younger generations of Biometricians. I met & studied with Dr.John Bell & Dr. Kim Illes at OSU Both John & Kim were close friends with Walter Bitterlich, the inventor of the Spiegel Relaskippy.

[@dendeibrahimadekanmbi8022]

Thank you for the presentation. please, I am interested in purchasing Criterion 1000, that instrument in yellow color, how do I get it for research purpose?

[@emersoncleobarcellanojr5265]

Is it required to measure the horizontal distance or to have a fix distance when measuring upper diameter? Thanks

[@forestinventory]

There are two alternative approaches: 1) measuring distance and diameter to calculate the width that every Relaskope unit represents, or 2) using a fixed distance and use the known relation of 1:200 for every Relaskope unit. In a distance of 10m every narrow stripe represents 5cm (1:200 * 10m = 5 cm). My approach with measuring distance and width helps to use the full width of all scales, but is not a must. It can be an advantage to use a fixed distance of 10 or 15m, since you can then also measure the height of the position with the inbuilt scales at the same time.

[@roksolanapetrovska1023]

Could you please advise if instead of Bitterlich relascope I can use TruePulse 360 for measuring D7 (diameter at 7 m height). There is the Missing Line mode in TruePulse that allows measuring horizontal distances between two points. Bitterlich relascope is more expensive compared to TruePulse 360. I would appreciate your opinion!

[@forestinventory]

I would not recommend to use the missing distance mode for the measurement of upper diameters, because: 1) you would need a reflection from the edge of the stem, which is difficult, 2) I have no information about the precision of the inbuilt compass. The angle difference between left and right side of the stem is very small (depending on distance) and has a huge effect on the calculated distance. With a tachymeter or total Station I think it should work, but with the inbuilt electronic compass, I have my doubts. However, we never tried or compared this to other measurements. Interesting question!

[@roksolanapetrovska1023]

@@forestinventory Thank you again for the advice! I would opt for Bitterlich relascope then. Please continue with videos!

[@thinn643]

Is the volume 1.86 cubic meter?

[@forestinventory]

Yes, this is correct! First calculate the cross sectional areas as Pi/4*d^2 at lower and upper end and derive the average and then multiply with length!

[@dresoto2694]

what distance are you from the tree?

[@forestinventory]

In this example I used no fix distance. I find the distance where the dbh covers exactly all 8 relascope units. But you can also use a fixed distance. The width of each relascope unit is 1:200 of the distance then.

[@zahidahmad7905]

Plz make more content ....

[@intobirding6212]

I calculated 1,87 m^3

[@nekochan4137]

I can't see the numbers on these glasses clearly. Do you know the reason why?

[@lutzfehrmann5219]

If you are working in conditions with a lot of backlight, you can adjust the sunshade to see the scales better.

[@moshpic]

1,87m^3

[@zahidahmad7905]

Yes 👍

[@user-zk7co9gy5j]

Maybe i need to study english first... thank you so musch..!!

[@forestinventory]

Sorry, we have no subtitles in your language yet ;-)