I hated everything about this. It took five months. I had to code the tool to make this and don’t even know basic HTML. There was calculus for plants.
Trees oscillate at a particular frequency that fluctuates throughout the year. That’s linked to unknown physiological processes and environmental cues. If we understand why by using accelerometers to measure their displacement, potentially you could hook a bunch of those up to a forest and passively monitor its health. Wildland firefighters could have Cybersen for trees.
This graph measures noise density, which fucks with data collection, on the Y axis and the frequency in hertz on the X. The blue line on top is the accelerometer the team had been using. The bottom red line is the only one I found after dozens of hours of searching non-standardised datasheets which came close to matching it on paper. Since trees oscillate in the sub-1Hz range which is well below what most cheap accelerometers measure, that dip from 0-1 is about a two order of magnitude improvement for the exact frequency range that the PI wanted to investigate.
I thought tree research would involve climbing trees and thinking about them real good. It isn’t. It’s all mathematics and coding and making motherboards. Science isn’t as fun as cartoons said it would be even when you go into the interdisciplinary ones because you know you can’t do mathematics or code.
What is Cybersen? Project Cybersyn?
Oops, yeah. My error.
It was such a neat project. Awful, that '73 coup.
It’s all mathematics and coding and making motherboards
i enjoy doing these things, but unfortunately i don’t know shit about trees
There’s a big need for it in the natural sciences. Interdisciplinary research like this has so many roles. Someone on oceanic research ships never took a class on whales but can code the trackers for them. I’ve learned too much about trees and was completely lost doing any of this, but it’s the tippytappy bullshit thing that makes the tree data legible for the arborists.
I feel your pain but this is amazingly interesting and you should be proud of yourself.
It’s nice to actually do formal science, but it reaffirmed I’m only good at applied science in the field. Holistically combining a bunch of different bodies of knowledge in a practical way is a lot more natural to me than a research lab is. It feels more scientifically validating to make a pollinator garden with a public education focus than it does to work on isolated problems with tools outside my comfort zone.
im sorry but this fucks i love it.
i legitimately wish i could do things like this with my make targeting systems for bombing brown kids degree
There’s definitely a role for that in this kind of research. Until I got this assistant gig, it was an arborist building the whole PCB and reprogramming the chips. Every tool used is one we’ve had to build ourselves because the commercial options are too expensive or not calibrated for our application. All the design constraints from power draw to the environmental conditions make it a fun thing to work on with a public patent. Every part of the accelerometer could probably be vastly improved if actual engineers were involved. If only as a neat side project it might be worth reaching out to your local university’s natural science departments to see if anyone wants help with their beepboop thing.
Science isn’t as fun as cartoons said it would be even when you go into the interdisciplinary ones because you know you can’t do mathematics or code.
lol same, I’m in geology and thought the grass looked greener for the forestry people. All comes back to graphs and stats in the end
What’s the time range on this graph? Or, you said the sub 1Hz range, so periods greater than 1 second, are we talking periods of minutes, hours, days?
This is one hour of data, with a sampling rate of 10 data points per second.
Cool cool, ty. So periods of ~10s of minutes. Fascinating!
neat!
This is really cool. Where can I read more about this? What does this graph say about tree health during the year?
It’s a pretty new field of forestry research. I’m a horticulturist so it’s way outside of my expertise and I don’t know much about it.
This graph was just comparing the two accelerometers on two similar 10m-tall trees. It only measured for a week and I used an arbitrary hour’s data to generate the graph, which just shows the sensitivity of the accelerometers as they undergo similar windloads with similar canopies. When they do install this new chip, they’ll get a cleaner reading of the really tiny vibrational shifts that correlate with something.
edit: Potentially though the factors involved could be the biomass of the leaves, the moisture levels in the stem/roots/soil, damage from a pathogen/weather event, temperature stress, and/or changes in the biochemistry. The PI thinks it’s some combination but that those have distinct enough changes to be isolated and flagged by some algorithm. Eventually that could become like a heatmap of drought, pest presence, microclimates, or seasonal changes as clusters of trees vibrate in the same way.
That is cool. To understand, is this a noise PSD in the position measurements of a tracker mounted on the tree?
I don’t understand the mathematics well enough to explain them, but PSD sounds correct. Those letters are in the code along with FFT, so I know it does those two things but can’t tell you anything more than a monkey with a typewriter could. It’s a 3-axis MEMs accelerometer and I’m drawing the Y-axis data from the Y-axis of those 3D movements in the tree. The accelerometers were screwed midway up the trunks of two straight trees.
Yeah, that is a PSD (power spectral distribution). To within a few constants it is the Fourier transform of the self correlation of the data. I was just wondering whether the variable is position, velocity, or acceleration.
In this context the FFT is most likely an acronym for Fast Fourier transform.
So are these lines measuring the oscillation frequencies a specific tree gives off? Or just, these are the oscillation frequencies of a bunch of different trees?
It’s physical movement, not EM radiation.
Each line is a single tree, with the two being different species but similarly shaped.
I don’t think the math quite lines up, but the red line is a bit reminiscent of the harmonic/overtone series.
