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Tuliptrees and biomass models

Posted: Sun Feb 28, 2021 1:46 pm
by dbhguru
Hi Ents,

Tree Northampton, a program run by the city's tree warden, has a mission to assess the carbon value of trees slated for removal for development or other reasons. The folks who run the program have asked me to assist them determine the carbon content of the trees targeted for removal. I gave them a customized version of the FIA-COLE workbook that includes 189 species of trees. However, some important species are missing, tuliptree being one of them. However, there are many volume-biomass-carbon models available, many of which include tuliptree, aka yellow-poplar. I chose 8 to evaluate.

The two attachments show their application to the Monica Tuliptree in our backwoods. One of them shows a trunk form factor of 0.46275. That comes from the direct reticle measurement. Using that form factor, you can see that the Scott model comes closest to NTS. However, if I arbitrarily drop the form factor to 0.42, a figure used by some mensurationists to obtain a crude trunk volume estimate, we see that the Hahn model is best. As tree dimensions and form factor are changed, we see different models take over first place, except that Hahn-Hansen and iTree Design consistently under-shoot NTS.

The lesson here is to beware of estimates that you see for carbon content coming from otherwise reliable sources. There are many competing volume-biomass models for the species that interest us. And the estimates coming from those models are all over the board. Our NTS direct volume modeling has a potentially important role in picking winners and losers.

Bob

Re: Tuliptrees and biomass models

Posted: Mon Mar 01, 2021 8:03 am
by dbhguru
Ents,

Something happened to the attachments. I've reattached them, converted to jpg. The originals were png files.

I note that modeling trees for volume, biomass, and carbon has yet to attract the interest of many Ents. However, we in NTS are in an almost unique position to play a part in the carbon debates, especially at the local level where the decision to cut down a tree or not is increasingly framed around its carbon storage contribution. This is the province of urban forestry and there is this marvelous tool out there called iTree to estimate CO2 equivalent sequestration in a tree. The whole iTree system is eye-popping in its breadth, complexity, and presentation. Unfortunately, its CO2 sequestration prediction capability falls short to the point of being misleading. That is unfortunate, but with the skills we have in NTS, we can help provide town tree wardens with an advanced estimation capability. The difference may be whether or not a big beautiful tree is allowed to stand or not.

Bob

Re: Tuliptrees and biomass models

Posted: Mon Mar 01, 2021 11:15 am
by BeeEnvironment2020
Hi Bob,
I just realized that this photo error is apparently site-wide. No photos attached on any discussions are showing at all.
Here are some photos that I attached using the link option:

Click on image to see its original size
Above is a discussion I made on Stateline Woods Preserve a long time ago. As you can see, the photos are gone, and are replaced with the below message:

Click on image to see its original size
I hope this can be fixed. I also hope all photos were not deleted from the database.
Bee E.

Re: Tuliptrees and biomass models

Posted: Mon Mar 01, 2021 12:32 pm
by dbhguru
BeeE,

The links didn't work either.

Michael,

Do you know what is going on?

Bob

Re: Tuliptrees and biomass models

Posted: Fri Mar 05, 2021 9:46 am
by BeeEnvironment2020
Hi Bob,
It appears everything is working, and the images are restored. Happy that they were not deleted from the database.
Thanks for fixing this!
BeeE.

Re: Tuliptrees and biomass models

Posted: Sun Mar 07, 2021 3:15 pm
by dbhguru
Ents,

The search continues for reliable statistical volume-biomass models for tuliptree. So far, I've tested CSS, Hahn-Hansen, Hahn, iTree EQ#1, iTree EQ#2-a, iTree EQ#2-b, iTree EQ2-avg, Scott, and Jenkins versus an NTS model based on trunk form factor. I think I'm closing in on two good models after adjustment through regression equations. I could use reticle-modeled forest-grown tuliptrees to perfect the models. Anyone willing to contribute will have a reserved place in Tree Valhalla.

Bob

Re: Tuliptrees and biomass models

Posted: Tue Mar 09, 2021 4:22 pm
by Larry Tucei
Hi Bob-

I can help in the future but the trees are close to leafing out down here.
Noxubee NWR-Tombigee NF and Black Creek Wilderness- De Soto NF has the largest Tulips in Ms. that I've seen.

Larry

Re: Tuliptrees and biomass models

Posted: Sun Apr 11, 2021 9:05 am
by dbhguru
Ents,

It is my hope that a few intrepid Ents will sign on to a developing project to volume model tuliptrees using reticle and hypsometer and software designed to accept the data and compute trunk volumes of the modeled tuliptrees. The attachment shows the beginning of the project. We could make this a team effort and perhaps publish paper in cooperation with some forestry academics. I'm presently working with the director of the Forestry Program at the University of Vermont, and look to that partnership as a possibility. However, we would need to present Dr. Anthony D'Amato with a coherent study plan, which I would gladly do.

Although, much of the drive and sense of mission that our organization exhibited in years past has diminished (and greatly, I sadly, add), we still represent an almost unique corp of tree-measuring talent. However, since we are an all volunteer organization, it isn't easy to find academic repositories and uses for our data or come together to do projects that would have standing among academics. It has happened, but not often. The tuliptree modeling project could well be one. Any what would be its objective?

Liriodendron tulipifera is a very important timber tree in the U.S. It is also our tallest eastern hardwood, and one of the three or four most voluminous. Its main competition comes historically from the American chestnut, and today, the American sycamore, and Virginia live oak. Because of its very fast growth, it is also an important tree in terms of carbon sequestration. However, I'm not sure it is recognized in that capacity, and the attachment gives us insight into why not. Notice the iTree Design average carbon sequestered for the nine modeled tulips. It is 1,695 lbs. Not the amount of our modeling, i.e. 3823 lbs. That's a ratio of 2.25 to 1, which is quite a difference. iTree is the most frequently used model in urban forestry. The other statistical models come closer to direct measurement with the lowest being Hahn-Hansen, which was supposed to be an improvement over Hahn. Go figure.

Bob

Re: Tuliptrees and biomass models

Posted: Thu Apr 15, 2021 7:41 am
by bbeduhn
Bob,

I'll do some modeling. I need to find some raw data from a big one in Greensboro, NC. Aside from individual modeling, it seems like we should also be doing counts in coves or acres or some other measurement, to get data for how much carbon is stored for a given area. In second growth stands, the sizes tend to be consistent in the younger stands and even in some fairly mature second growth stands. A few trees can be modeled and then extrapolated for any given area.

We have detailed volume accounts of some large individuals already, like the Sag Branch Tulip and the Fork Ridge Tulip.

Brian