How are tree height's *officially* measured?

[Plasmech]

I know about the simple ground trig technique for estimating the height of a tree. But what is an official record is wanted, say some Smack Muppet says they have the tallest white oak tree in the world and he wants to prove it? Is this done optically from the ground or does someone have to actually get to the top somehow and laser the ground or GPS it?

 

[outofmytree]

I went looking for a link to a video of a climber measuring the height of a redwood but alas I cannot find it. I thought it would be fun because to my great surprise, with all the gadgets you can use today, it was done with a piece of string!

Maybe someone else will find it. Used a cool crossbow adaptor to set his throwline...... I think I need one of those....

 

[Boa07]

Well there certainly are still some climbers that use the old fashioned method of a tape from the very tip right down to the ground...

http://isaac.org.au/info/bigtrees.htm

 

[Boa07]

I think this is the video you were looking for http://www.youtube.com/watch?v=sIoZ0J7x1Cg&feature=related

 

[Tree Pig]

http://www.lasertech.com/TruPulse-Rangefinders.aspx

 

[NCTREE]

Experience and a good eye has always worked for me, it's only a close estimate though. Try a biltmore stick, it is fast and easy. Clinometers are pretty accurate too.

 

[moss]

Check out the Eastern Native Tree Society (ENTS) measuring guidelines page, they advocate using a laser rangefinder, clinometer and the "sine top/sine bottom" method to make very accurate measurement from the ground in parks or on difficult terrain in deep forest conditions.

The ENTS frequently compare manual tape drop measurements to ground based sine top/sine bottom measurements. For instance in February 2009 in Congaree National Park the ENTS tape dropped and ground measured the new national champion Loblolly Pine at 167.8' with an approx. 1" error between the tape drop and the laser/clinometer method.

The stick trick or using just a clinometer are usually good enough for rough estimates but can be very inaccurate, especially for dealing with lean and the crowns on deciduous trees where a rangefinder is very helpful in finding the actual higest point in the tree. For most purposes it doesn't matter but if you want a very accurate measurement take a closer look at the ENTS methods.
-moss

 

[outofmytree]

I think this is the video you were looking for http://www.youtube.com/watch?v=sIoZ0J7x1Cg&feature=related

Thats the one. Thanks Sean!