NASA Measure Tree height with Your Smartphone

[Lucas]

FYI

https://www.nasa.gov/feature/goddard/20 ... th-new-app

[dbhguru]

Lucas, et. al.,

I signed up using theGlobal Observer app as a citizen scientist and then went outside to try the app. It is a direct application of the Tangent Method, and they caution that you need to choose a straight tree. At least, they did give the caution.

I got 19' 7" for a 20' 2" young, straight white pine growing in our yard. I actually stepped off the distance to the tree to get the level distance from the point of measurement to trunk to see how well my normal pace works. I'll go to Childs Memorial Park or a similar place tomorrow, enter more trees, and report the results. The instructions suggest a distance from the trunk of between 25 and 75 feet. Of course that is inadequate for tall, broad-crowned trees by a lot. So, I plan to experiment to see how far I can stretch the app. But according to the instructions, you can get further away and enter the actual distance from point of measurement to the trunk.

More reporting to come.

Oh yes, thanks Lucas for alerting us to this app.

Bob

[JHarkness]

Bob,

So what is the scientific purpose of this tangent-based height data if it can only be applied to needle straight trees, and probably only ones of small size as well. If their goal is ground truthing, why not purchase laser rangefinders and send researchers into the field to collect this data, surely NASA could afford to purchase a couple dozen rangefinders for this purpose? Something about this just doesn't seem right to me.

Let me guess, we are going to start hearing about new height records across the globe because of tangent method error? Unfortunately, if that does happen, people will probably view the results as reliable because it is part of a NASA project.

Actually, I have a funny story to add to that. I was recently talking with an ecologist at Cary IES in Millbrook, NY, he recalls having some "highly skilled" climate scientists visit their forest for the purpose of recording tree height and diameter growth, well one of the scientists was quite excited to inform IES that he had found a 387' tall tree on their property. Several members of the IES staff were quite intrigued by how he had managed to come up with such a ridiculous number, so they asked him to show them the tree and measure it in their presence, it turned out he was taking the angle to the top from less than 10' from its trunk.

Joshua

[mdvaden]

Bob,

So what is the scientific purpose of this tangent-based height data if it can only be applied to needle straight trees, and probably only ones of small size as well. If their goal is ground truthing, why not purchase laser rangefinders and send researchers into the field to collect this data, surely NASA could afford to purchase a couple dozen rangefinders for this purpose? Something about this just doesn't seem right to me.

Let me guess, we are going to start hearing about new height records across the globe because of tangent method error? Unfortunately, if that does happen, people will probably view the results as reliable because it is part of a NASA project.

Joshua

The app isn't anything I'd use, but could it be an option for others to know whether a tree falls within a likely "zone" of height making it a worthwhile candidate to return and measure more accurately with other gear?

[dbhguru]

Mario,

What you suggest is exactly what I hope to propose to them, if I can find a communication channel to use.

Joshua,

OMG!!!

Bob

[Erik Danielsen]

A professor at SUNY Fredonia I'm working with on another project is apparently involved in this NASA programming- as I understand it from him the app is really more of an educational/public engagement tool to tie into the satellite modeling. He asked my advice on a hypsometer to use alongside the app for more accurate ground-truthing where it counts (turns out he has a Nikon Forestry Pro, which should be sufficient). We're supposed to get together sometime soon to update the "Big Trees of Fredonia" list on which I've volunteered to do the height measurements, so if I get any more insights into the program this app supports I'll be sure to bring them up here.

[Bart Bouricius]

Citizen "scientists". I guess they figure they can't get people interested in science if it is actually scientific. Science in a sound bite. It would be interesting to find whoever came up with this and ask them what they were thinking.

[Bart Bouricius]

Am I being too harsh? Did they say the tree had to be vertical or straight? I am glad you signed up Bob, maybe you can get to the bottom of the actual purpose of this. If it is only small and straight trees being addressed, is it wise to try to engage people in citizen science when they are not really providing valuable data, and when some foresters, insisting on the tangent method, can now say "go argue with NASA if you think my methodology is flawed".