Single-stem or Multi-stem?

[Don]

It occurs to me that this location is the perfect location for the ongoing discussion at NTS, aimed at informing AF's Measuring Guidelines Working Group of NTS input on the topic.
There's a wealth of posts/threads that may be cloned over, but for now, I'll post an image and initiate a discussion on fusion, single- versus multi-stemmed tree(s), fusion, and inosculation.
One tree? Two trees? Three trees?

               

                       

                       

On Big Tree Wayside Trail, along Newton B Drury Scenic Parkway, Prairie Creek Redwoods State Park

               

               

[Taken using Panorama Feature of Sony DSC-HG9V a 'travel zoom' style digital camera, at the 24mm wide angle setting (35mm equivalent), with some enhancement]

[Will Blozan]

Don,

I am not sure why you are even asking this question. Well, I guess I know you know your answer but that is in no way a single tree (pith ruling- not genetic).

Will

[dbhguru]

Will,

  Just a few observations. Don and I have a real challenge on our hands with respect to the single versus multi-stem debate in the AF MGWG. So, we keep exploring the subject from fresh outlooks. We're not wavering on our personal positions, but we don't want to get surprised by arguments that we haven't considered. Until recently, some aspects were clear in my mind. For example, your position on what is a multi-stemmed tree that began from a single seed versus separate trees that fused is bolstered by years of experience as an arborist. This has been enough for me. But I presume the same can be said about the experience of Mario Vaden. As I read each of your posts, it seems that you reach different conclusions on what can be consider a single tree for conifers that split into two or more trunks at near ground level. I am hoping other arborists, foresters, horticulturists, etc. who observe tree structures will voice their opinions. Can any of these white pines that I am calling doubles actually be from one seed? My current conclusion is probably not, but Mario Vaden's posts have made me less confident.

  My personal position is that the pith test is generally sufficient to identify doubles, triples, etc. in conifers most of the time. I can easily recognize a hardwood coppice, as can the rest of you, but for species like silver maple, I'm not always sure if I'm looking at two or more trees that began from separate seeds or a coppice that developed from a single root structure. In the case of the National Register, I would absolutely exclude the former from the competition, but would probably try to find a place for the latter. I prefer separate listings, but I'm not sure that I'll get my way.

Bob

[Will Blozan]

Bob and Don,

Seems to me a single trunk is to be measured, right? Thus it does not matter the origin of it- two seeds or coppice. Either way, they are separate trunks.

I am looking for examples I can cut to get my point across to Mario.

Will

[dbhguru]

Will,

  Point taken. I'm unsure of who out there believes that a distinction needs to be made between a truly separate trunk and a pair that are mashed together to form a continuous perimeter? Of course, I do. If we can agree that we measure only single trunks, we will be on the same page. The challenge then devolves to disentangling the fusion. We have ways of doing that where the separate trunks stand out at breast height. Again, I'm thinking of white pines. but where the seams are covered with bark, judgement comes into play. I hope we can develop good methods to deal with the less clear fusions. Big tree hunters have gotten away with murder (murdering the credibility of the champion tree programs) by measuring around the area of fusion.

Bob

[morgan]

What's the consensus on this one? Single stem or two?

This is a London Plane tree (hybrid of American sycamore and European plane tree) at Vassar College
.

[Will Blozan]

Morgan,

Nice tree! A pith trace and the seam indicate two fused stems to me.

Will

[edfrank]

Morgan,

Two fused trunks.

Ed

[tsharp]

Morgan:
Kind of obvious two stems.
TS

[Don]

Morgan-
The attached image is of a Texas State Champion Live Oak...do you see it as a single-stemmed tree, a multi-stemmed tree, or several trees that have over time fused together?
What 'rule' did you use to make your decision?
This is not an isolated instance, should you go through the national register, and look at those species that have associated digital images, I suspect you'd be surprised how many 'blur the line' between attempts to define them...
-Don

               

                       

                       

Where did they measure DBH ?