How do you all perform your "tree surveys"? Do you use GNSS & an offset and live with the fact you may be +/- a few feet? Do you traverse and use a combination or horizontal angle/distance offsets? What parameters do you record (Diameter, drip line, species, height, elevation @ base, ect)? How would you define a "tree survey"?
It's been a number of years since I've done this kind of work, but we would traverse through the wooded area and use hz/dist offsets to tie them in, we'd estimate the diameter, pace the drip line radius, we typically didn't need height, & note down species in the description with the rest of the data. Ex. Tpine50 5 (this would plot as a pine tree with a 50cm diameter and a 5m drip line radius. It wasn't a fast method, but it worked and was much more accurate than trying to us GNSS. I'd start using the term tree survey when the majority of time spent of the survey was tying in trees. Of course, we'd need to find and tie property corners and usually other site survey features but if it meant a week of picking up and tying in 600 tree's, it was a tree survey to us vs just a normal site survey.
In Kentucky, many corners are trees. I use a Javad GNSS unit with base and shoot the trees with an offset and I'm pretty close to the center of the tree. No less so than taking a robotic shot to a prism at the side of a tree and then rotating to the center for angle. My GNSS shots are within 5' of the tree. Boundary surveys don't involve 600 trees at a time generally. I was tasked once with locating every tree greater than 8" within 50' of a creekbank (in deep woods) that I had to topo for 10,000 feet. I just gave dbh diameter and species and on that job, used a Trimble S6 with distance and angle offset. When I worked in California, dripline was always part of the data. Kentucky is so tree rich that tree preservation hasn't been codified quite as much as the states where dogs have to run fast just to get to the next tree to pee.
Depends on the kind of survey. If it's a handful of trees sprinkled around a design topo then I'll probably do an offset to the center like I do telephone poles and record a diameter and drip line. If it's a forest thing where accuracy standards are more loose then it's either spraying them with direct readings or putting the rod next to the tree and taking a shot, diameter but no drip line. I've never tried to label any tree more specifically than evergreen or deciduous.
What's a tree? (supporting the knowledge that Kansas was largely a treeless plain at the time of the PLSS surveys)
Offset routine in data collector: shoot a distance to the side of the tree/pole and then turn angle to center of tree. Gets recorded combiing the two seperate pieces of data. Then shoot three shots on the dripline for each tree to define the canopy. Usually this was on trees to be protected under a forest easement.
As you alluded to in your question, "Tree Survey," can mean different things for different people. My first step is to figure out why the tree survey is needed. If it's just for land disturbance calculations per some defined point system relating to tree diameter, I use a forester's tape and lean a GNSS receiver next to it because that's all that's needed. If it's for a landscape architect, I will speak directly with them to delineate portions of the total tree survey area where they know the trees will be removed so I don't spend too much time on location there. When speaking with architects, I find it helpful to throw on my pinky ring and beret so they'll take me seriously😉.
With large area tree surveys, I'll get a grunt to use a forester's tape and flag every tree and write the diameter on the flagging. While we're running the boundary and topo with a TS, we'll locate as many as possible via reflectorless shots and creative offsets, then pull off the flagging as we go and hope the crew chief knows some basic dendrology. Lately, it seems like foresters need to be involved if folks are expecting Latin or division beyond: oak, maple, pine etc..
I'm in the middle of a tree survey. All big oaks 24-36" with a few at 48". Drip lines out to 50ft radius and hanging down to 2-4 foot above the ground. I put the robot in whatever open spots there were with a 3 ft HI and I used a 2 ft prism pole. I got 90 to each tree using a right angle prism, set the pole, used offset distance shots, measured to the tree, noted the diameter and type and tied white flagging. Took me 4 hours to measure 30 oaks plus some big rocks. The next batch to do is a grove of maybe 50 citrus trees with very limited visibility from any direction. Not really a hard job but for some reason it just irritates the shit out of me.
Westchester Country, NY requires a tree survey for many projects. Some want trees 8" and up, at least one municipality wants trees 2" and up. Some just want diameter and species, some want the tree tagged, and a chart with all the data. Once in a while drip lines are requested.
Initially I used a dot of paint, but that leaves a mess. About 30 years ago I got one of these from Forestry Suppliers:
https://www.forestry-suppliers.com/p/57050/12311/forestry-suppliers-chalk-tree-marker
It is a good way to keep track of the trees you've located if not tagging them. Unless there is very hard rain, the marks last a few weeks, but the client does not get stuck with obnoxious paint marks.
If tagging the trees, buy numbered aluminum tags, and use aluminum nails to help the tree companies who will be cutting the tree someday. I found it best to go through the site, nail the tags up with about 6 inches of flagging, record the tag number, tree diameter and species, then come back locating the tag number in the notes and removing the flagging to keep track.
I do not do much of this these days, being up in Dutchess County, where the environmental consultants have not taken over yet...
Try it.
Ken
When doing a tree survey in the woods your main purpose is to inventory the trees and not to precisely locate them. A horizontal distance offset shot is is sufficient for the purpose. OUAT, and owing to a forestry job I had before I began surveying in earnest, I learned how to reliably identify all the native species of tree in the Pacific Northwest. That skill was hard won, and I've never met another non-forestry surveyor who shared it. I ask my crews to note "conifer" or "deciduous" and leave it at that. More detailed identifications are left to the arborist.
For street or other trees in developed areas I shoot 3 (or more) reflectorless shots on the tree trunk at roughly breast height and calculate a 3 point circle. That gives me a fairly precise position and diameter. Such trees are generally non-native and any guess I could take at species is definitely a job for a pro. Conifer or Deciduous.
Around here, at least, every site development job needs a report by an arborist. I once had one tell me that all he expected from the survey was to be able to tell one tree from another, as plotted. He found our attempts at species identification amusing and did not accept our noted sizes in his reporting.
Thank you all for the replies so far, there's some great knowledge being shared here.
Has anyone attempted to use laser scanning for data acquisition for the purpose of tree surveying? I'm toying around with a workflow at the moment, there's been some hiccups in testing but I think I've found a solution to most of the issues.
Has anyone attempted to use laser scanning for data acquisition for the purpose of tree surveying?
No, but I wouldn't be surprised if it's 10 times faster to just run around with a rod and tape than it is to move a scanner around a buncha times.
Possibly, our Riegl VZ600i can perform a scan in under one minute & at a scan spacing of 30' per scan we could cover an acre in under an hour. Not exactly lightning fast but an acre of data capture per hour isn't too bad. Of coarse you would need to factor in registration time and data extraction time. I can extract a tree in 10-30 seconds depending on what parameters I need.
But if I can use a SLAM scanner, I can capture about about 10 acres per hour and the tides may begin to turn. Another benefit of SLAM is the processing input time can be as low as a few clicks of the mouse.
So if that 10 acres contained 500 trees I could be looking at maybe 4 hours +/- which includes data capture, registration & feature extraction. This could also provide results much more accurately & has the added benefit of having the point cloud to use to extract other information as needed. The issue people often bring up when using scanning for tree extraction is species identification, but if you're using a structured point cloud and imagery is captured, it's incredibly easy to jump into the panorama images to ID the species during digitization.
Could a field crew pickup 500 trees in 10 acres in 4 hours while marking them & measuring trunk and drip line diameters? I'm not so sure, any thoughts?
We locate trees that may indicate a boundary, and for architect site plans. Three direct laser reflection observations will collect the information needed to determine the diameter, and central location of each tree. Unless I am sure of the species, the trees get a deciduous or coniferous label. Then the drip line, measured with a tape or the prism pole is use to scale the tree symbol on the map.
Historic boundaries and conservation efforts.
@bc-surveyor I forgot about those slam scanners. If you can walk the whole site waving that scan stick thing around then yeah I bet that's pretty fast.
Several years ago, I was tasked with providing a design survey on around 50 acres of clear cut on the Oregon coast. The engineering client wanted the location and diameter of the trees along the perimeter of the cut. I just set up my MS50 and scanned a swath along the perimeter while I mapped the clearcut with RTK. The MS50 was slow and it took multiple setups, but it didn't matter since I was busy trudging through the slash. Once in Cyclone it was a breeze to give them location and diameter of hundreds of future stumps.
I never understood why the need for tree survey. The site was donated to the school district by a major timber company that owned all of the surrounding land and then some. Any tree that was a problem would have become 2x4s in a heartbeat.
Could a field crew pickup 500 trees in 10 acres in 4 hours while marking them & measuring trunk and drip line diameters? I'm not so sure, any thoughts?
I'm not sure about including marking, but depending on the position maybe. If the trees are spread out enough that you only need 2-3 setups to get everything and you've got a decent crew, it could be done.
Here is NSW, Australia, all topo surveys (the equivalent of ALTA) must show trees with spread, height and trunk thickness. One of my most hated jobs was doing tree surveys on a golf course. Parts of it were being sold for residential development and prior to any approval being granted, all the trees had to be located. From memory it took about a week for a two man crew, 4 or 5 areas, about twenty lots each. It's just so damn boring measuring tree after tree after tree.
What got my goat was that a few years later I was in the same area with a different company, putting in transmission underground feeders. All the trees were gone. What was the point of locating every tree, just to chop them down?
Could a field crew pickup 500 trees in 10 acres in 4 hours while marking them & measuring trunk and drip line diameters? I'm not so sure, any thoughts?
I'm not sure about including marking, but depending on the position maybe. If the trees are spread out enough that you only need 2-3 setups to get everything and you've got a decent crew, it could be done.
Here is NSW, Australia, all topo surveys (the equivalent of ALTA) must show trees with spread, height and trunk thickness. One of my most hated jobs was doing tree surveys on a golf course. Parts of it were being sold for residential development and prior to any approval being granted, all the trees had to be located. From memory it took about a week for a two man crew, 4 or 5 areas, about twenty lots each. It's just so damn boring measuring tree after tree after tree.
What got my goat was that a few years later I was in the same area with a different company, putting in transmission underground feeders. All the trees were gone. What was the point of locating every tree, just to chop them down?
I feel your pain about coming back to a site to see every tree taken down after spending so much time locating them. Brings back terrible memories haha
You bring up an interesting point about need tree heights, do you just eye it out and make an estimate of RL in a branch near the top?
You bring up an interesting point about need tree heights, do you just eye it out and make an estimate of RL in a branch near the top?
99% of the time I eyeball it. I really don't think anyone cares that much, some clients have questions the location of a tree, especially when it's close to the boundary but never the height.
The only time I would locate a tree more thoroughly would be in a boundary dispute, where the tree was causing some level of encroachment. I haven't had anything like that yet and chances are I never will.
Trees can be a pain in the rear end because most local councils will go through hell and high water to preserve them even if it leads to problematic designs and other issues down the line. Some councils don't allow any kind of tree cutting, so if you've got a big tree on your property, you're pretty much stuck with it and should you ever want to build, it'll have to be designed around the tree.
The idiotic thing is that there is no shortage of trees, they are everywhere. On the road reserve, parks, private and public land. Only trees you are allowed to cut down easily are invasive species.
The only time I would locate a tree more thoroughly would be in a boundary dispute, where the tree was causing some level of encroachment. I haven't had anything like that yet and chances are I never will.
A tree fell in a residential area near me and killed a child. Last I heard, 5 different surveyors had been involved in locating the tree in relation to the property line to see who was liable. Glad I was not one of them.
Distance and offset when using a GNSS or total station. Site plans and tree inventory plans in many places in SW Ontario require coniferous/deciduous classification, diameter at chest height (ie. DBH), and dripline diameter. We typically code:
TRD 400 15
TRC 200 8
The cogo points are scaled in C3D based off that info.
We are attempting to test this software out to see how well it compares to "on the ground" surveys:
https://forsys.sefs.uw.edu/fusion/fusionlatest.html
We feel it has large potential for data extraction from combined aerial and terrestrial means.
QGIS and TBC also have modules to extract the info from what I remember reading. GreenValley's says it can extract the info, but it is $$$. Global Mapper can extract some of the tree info, but I do not believe it can do DBH.
Mapry's solutions are good for inventory purposes in our tests, but not so hot for location data (but this is to be expected). We are investigating Bluetooth RTN RTK for our iPhones to see how well the app does with that. Admittedly, Android is much easier to set up in this regard.
Papers on the free Mapry products:
https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/2041-210X.13900
https://academic.oup.com/forestscience/article/70/4/304/7664433
https://www.tandfonline.com/doi/full/10.1080/01431161.2024.2409996
https://apps.apple.com/ca/app/forestscanner/id1599055402
If using the app, please run audits to see if it meets your precision budget. Currently, for us, it does for simple single trunk trees, but its horizontal positioning is not there yet IMO. It also struggles with non-single trunk trees and coniferous ones in our experience.
I am a curmudgeon who would still likely do an audit check if it was a boundary tree (ie. swing ties, total station offset, etc.). People are rather concerned about them now, especially in the cities:
https://www.protectyourboundaries.ca/blog/post/boundary-trees-in-ontario
https://www.defranlaw.com/public/downloads/reports/newsletter-jun-2021.pdf
https://boundarytrees.com/the-2013-ruling-on-boundary-trees/