Multitrunk Trees  Edward Frank
  Dec. 16, 2007

TOPIC: Multitrunk Trees

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Date: Sun, Dec 16 2007 8:28 pm
From: "Edward Frank"


I have posted a new page to the website that will be the index of a section of the website devoted to Multitrunk trees and other odd forms. It is posted at: It is essentially what I posted about a few weeks ago. I intend to devote a separate page for discussion and elaboration of each of the categories I have proposed. This is a work in progress and is subject to change as our ideas evolve.

Looking over our past discussions I wanted to post with some revised comments based on a post I made two years ago, that did not have any takers at the time. It was a summary of comments made by a group of people concerning the topic.

Multi-trunked Trees (part 3)

At this juncture we have had some good discussions on multi-trunked trees, but a number of questions remain unanswered. Some perhaps people on this list can answer now, others probably must wait until we gather more information and have time to figure them out. I would like to summarize some of what was determined and restate the questions remaining.

Bob Leverett has expressed an interest in expanding our measurements of multi-trunked trees. These are outlined initially in a post dated Jan 04, 2005. Will Blozan on the other hand (Jan 04, 2005) expressed the opinion: "The seed sprouts a single stem, and that is an individual. What the tree does from there is to be considered by ENTS, but the accomplishments of a single stem are what I am interested in."

As I see it the answer is all of the above. If some people are interested in doing more detailed measurements of multi-trunked trees, and they are going to measure them using ENTS high standards, there is not reason not to support the effort and publish the results on the website. The standard measurements of height, cbh, and crown spread should be taken for the largest stem of the group so that data from the multi-trunked tree can be directly compared to those single stemmed trees, and additional information and measurements can be taken of the other stems and incorporate into a separate data set focusing on multi-trunked specimens.

2) How do these multi-trunked trees form?

Lee Frelich (Jan 05, 2004) wrote:
"One of the main ways to identify the boundary of old growth stands in the northern hardwoods is the presence of multi-stemmed trees, which signal the end of the old growth. The one exception to this is basswood, which sometimes sprouts a ring of smaller trees around the mother tree in the absence of disturbance. In a 1953 blowdown in the Porcupine Mountains in sugar maple, red maple, red oak, basswood, yellow birch forest (with very few white pine, white spruce and hemlock), the areas that were salvaged have many multiple stemmed trees that are crooked, whereas the areas not salvaged have straight trees with much bigger trunks. All the species in this forest except the conifers will stump sprout, especially younger trees up to 80 years old. Older trees die if the top is lost. In other forest types, such as floodplain forest of cottonwood and silver maple, stump sprouting is more common and occurs after natural disturbances such as wind and fire. Oak forests, especially northern pin oak, northern red oak and white oak stump sprout prolifically after fire or logging, and multiple-stemmed trees are the most common, especially in forests that have frequent fires. Aspen forests root sprout, rather than stump sprout, and multiple stemmed trees are therefore not common."

3) Are double trunked trees fundamentally different from multi-trunked trees? Is there some biological difference that allows double trunked trees to grow in areas where single trunks are the norm - as opposed to multitrunked that tend to form in areas that have been timbered?

I pose this question again. Scott Wade wrote (Jan 13, 2005): "One thing to add is that there is a balance that the tree wants to maintain as a system. If a limb is lost from another tree falling onto it, the tree reacts by trying to replace the lost canopy as quickly as it can to re-balance the canopy to root zone ratio. I believe that is why suckers that grow from around a wound grow so fast. The tree has to make x amount of sugar to support y amount of mass. When a tree is cut to the ground, the suckers that form grow at an amazing rate. It only takes one nibble of a terminal bud from a deer to get a two stem tree. Also, a tree that is alternately branched will have more of a tendency to maintain a single leader, where a tree that is oppositely branch will tend to form two. This is not a rule though, as anything can, and will, happen in nature." This is something that could be investigated statistically.

Lee Frelich commented (Jan 15, 2005): "Not much is known about why some trees sprout and others don't, across species or within species, or within one tree, since the probability of sprouting changes over a trees lifetime. We can speculate that unique events in the evolution of each species has led to the type of sprouts, and that unique disturbance history in each stand leads to a pattern of single stemmed or multiple-stemmed trees. Most of the stuff in the literature is observational (i.e. trees sprout more when young than old, intense fire makes aspen more likely to sprout on some sites and less likely on others). There isn't much known that is mechanistic, so we can't make any sense of it or make any predictions.

[These explanations are part of an answer, but though I am not satified completely with the explanations proffered so far.]

4) Do you get multiple trunked specimens of trees that don't stump sprout? How do these form?

5) What should be considered a trunk in a multi-trunked tree?

Ed Coyle wrote (Jan 05, 2005): We could have a category for coppices. It could not be compared with anything else. A multi trunked silver maple could not be compared to a single stemmed one. What would be the point? You could get some mind blowing numbers if you included the included bark bunch though. Some have suggested adding the stems greater than 3" dbh to quantify the plant. Good idea for the coppice category.

I suggested an alternative definition of what is a trunk (Jan 05, 2005): This is something to consider, at least it is a start. If you are looking at a tree with a wide variety of stems from finger sized to a couple feet in diameter, it might not be practical or useful to measure every wisp of stem. I personally am interested in some of the smaller tree species, dwarfed forests, and shrubs like rhododendron so a 3" diameter measurement would not be a useful criteria at this lower end of the measurement spectrum. Perhaps something more like stems at least 3 inches in diameter, or at least 20% the diameter of the largest stem in the grouping.

[Looking back on this, I am still not sure what to do. In the new page I suggested leaving it up to the discretion of the investigator to determine what is or is not a significant stem.]

8) What measurements should be taken for multi-trunked trees?

Bob Leverett Proposed (Jan 04, 2005) The system of reporting only the largest trunk measurement where were are multiple trunks seems to me to miss the whole point of comparisons. If the point of split is changed by a few inches, what was a 20-foot circumference tree shouldn't shrink to a 9 or 10-foot circumference. By gum it ain't right! One the other hand, what should be done? Well, if we're trying to reduce a tree to a single composite measurement, the multi-stemmed trees will always present us with headaches. For my purposes, which aren't better than those of any of the rest of you, just my thinking, I would want to see
the following numbers.

1. Total height
2. Longest limb extension
3. Average crown spread
4. Height at branching point
5. Circumference at base
6. Circumference at narrowest point between base and branching point.
7. Circumference of each trunk above branching point when that can be determined.

This series of measurements would certainly not be taken for all trees in our collective database - just the biggest ones. I think I would like to begin applying the above or something close to it for the biggest trees in Massachusetts.

I proposed (Edward Frank, Jan 21, 2005) :

a) species - common name and scientific name
b) The number of significant trunks....[edited] ...A significant trunk would be any trunk greater than 3" in diameter at breast height, or 1/4 the diameter of the largest trunk in the coppice.
c) The girth (cbh) and height of the tallest trunk. If a girth for a branch of trunk fused at the base is taken at some height other than breast height that height needs to be noted.
d) location
e) measurement of the composite canopy spread of all of the trunks in a multitrunked tree. (Edward Frank, Jan 21, 2005)

Better Information ( all of the above plus):
a) The canopy spread of the tallest trunk.
b) The height and girth of both trunks of a double, and/or the height and girth of each of major trunks of a multiple.
c) The girth of each of the significant trunks of a multiple.
d) The composite canopy spread of the entire coppice.
e) Basic description of the tree form and growing location.

Optimal information (all of the above plus):
a) The height, girth, and canopy spread of each major trunk.
b) More detailed tree description and detailed description of the location as outlined by Don Bragg. His comments are listed below.
c) GPS location

Don Bragg wrote (01-18-2005):
"I have a few thoughts in regards to your question as to what ecologists may like to have measured from champion trees. Given conventional uses, circumference/diameter at breast height (C/DBH) or its accepted equivalent (e.g., adjustments made for buttressing or burls), height, and crown spread are the most useful, as most allometric relationships can be estimated from these numbers. Certainly geographic location (as precise as possible, including driving directions, if permitted). I think it would also be
valuable to include information on the physical structure of the tree e.g., one or many trunks) and location (cove, ridgeline, etc.). Ideally, other information on local stand density (basal area, or trees per acre), site quality (site index, or other information on soil type). I would also suggest taking at least three photographs of the tree from different perspectives, with a standard scale or reference item placed alongside the trunk. One photo would be the standard shot of the bottom of the bole, another would be shooting up the bole towards the crown, and another (if possible given stand conditions) would be from a distance showing the full
height and breadth of the tree."

10) Scott Wade suggested a formula for comparing mutitrunk diameters with those of single trunked trees (Jan 0, 2005). I was pondering some formulas for MS (multi-stemmed) trees. tell me what you think. - Average circumference of all stems > 3" dia at the break. plus the cbh of the trunk at it's narrowest point below 4.5', divided by two. for it's cbh points.


Example (not a real tree): leaders of 50, 69, 88, 57 have an average of 66" circ. say the main trunk measures 150 circ at 2.5 ft. so the points awarded would be 108?

I am not sure that this is workable given our lack of numbers to test the idea fairly. In a broader manner, I am not sure the idea of comparing multitrunk trees with single trunk trees through a mathematical formula is useful.

I will close for now and ask that you view the webpage and consider the issues presented and the groupings I have proposed.

Ed Frank

TOPIC: Pine doubles vs forked trees

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Date: Sun, Dec 16 2007 8:42 pm
From: "Edward Frank"


There is a small couple acre patch of pine trees along the road on my way to work. The owners of the property have removed all of the brush and trees aside from the white pine. In the summer the area is mowed as if it were a lawn. This area was logged multiple times in the past, and the trees are likely in the range of 70 to 80 years old and not very large. At first glance it looks like there are many double-trunk pines, ghowever when you look more closely, you see that really these are not doubles, but trees that fork close to the ground. I know pines don't stump sprout, so I have been wondering a couple of things. How did these low forked trees grow that way? Was the top (terminal bud) nipped off by wildlife or human process.resulting in two side branches each curving upward to form separate trunks?

What I also am wondering is if a fair amount of the pine and hemlock trees we have been calling doubles, might really be low forking trees instead, where the forks have fused together?


TOPIC: Pine doubles vs forked trees

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Date: Mon, Dec 17 2007 5:25 am
From: James Parton


Will and I found a huge White Pine at the Kellogg Center that branches
out very close to the ground but starts as a single trunked tree. The
tree was nearly 5 feet in diameter! I uploaded a picture of it that
Will took, to the file page where all can see it. I had walked by at a
distance many times from this tree and had not gave it more than a
passing glance. Will noticed it immediatly.

James Parton.