Trunk diameter variation in Sabal palmetto

[DavidMac]

We have a little over 450 Sabal palmetto growing in the main campus of Florida State University in Tallahassee,FL zone 8b that show considerable variation. One of the things that has interested me is the difference in trunk diameter in specimens- I realize that there are a number of factors that can contribute to such variation-but I supect that genetics plays a strong role. Do you know of anyone who has documented some of these differences and/or has propagated "skinny" or "stocky" Sabal palmettos? Here is a photo showing some of this variation-one is growing at the Sandels Building, the other is behind the Strozier Library.

Edited March 29, 2013 by DavidMac

[ErikSJI]

I just started germinating some Sabal Riverside seeds and had noticed how much larger the seeds were compared to the regular Sabal

[DavidMac]

Seed size is indeed another variation as well as the length of the flower/seed panicles-some extend well beyond the fronds yet others are shorter and are hidden. Sabal 'Riverside' is a hybrid that we would love to have on our campus. Hint,hint

[ErikSJI]

I will send you some up when they germinate.

[sonoranfans]

I think trunk diameter variation is partly a result of water supply. Ive seen it have a huge impact in Roystonea, skinny to fatty. Water supply can be effected in a big way by soil. Sandy soil or sloped ground makes it harder to ensure a good water supply...

[sarasota alex]

I think trunk diameter variation is partly a result of water supply. Ive seen it have a huge impact in Roystonea, skinny to fatty. Water supply can be effected in a big way by soil. Sandy soil or sloped ground makes it harder to ensure a good water supply...

I also think this to be one of the major contributor in many species and it kind of goes both ways in different species. One of the most vivid examples are the queen palms. In the Sarasota area we have many growing "wild" and also many in yards and places that are not regularly irrigated during the dry season. Those are usually about half as thick if not more then the well watered ones. I've also noticed this with Archontophoenix and Chambeyronias. On the other hand what I'm seeing with the bottle palms is the more they are starved for water - the fatter they get. Maybe it's the need to preserve. Kinda like humans, if you starve yourself, next time you eat body will store more fat.

[_Keith]

Not to mention that Sabals, like some other palms species are quite promiscuous. Pure genetics can be hard to find nowadays.

[DavidMac]

Nearly all of the newer Sabal palmettos we have on campus were dug from the wild (many in our area come from the Gulf Hammock area near Chiefland,FL) from very similar ecosystems, similar soil, moisture,etc... However a few have come from near Port St.Joe and a very few have been dug in south Florida-I have no idea where the older trees on campus were acquired from. In cases where they were stressed from drier conditions resulting in thinner trunks where they were originally growing you will see are marked increase in trunk size on the trunks that corresponds with the time they were transplanted and received better care . I am aware of this variation but that doesn't explain the healthy thin trunked specimens such as the one growing at the Sandels Building. I was told that there is a population of tall thin trunked Sabals growing along the Indian River and I do know of some very stocky trunked ones growing near Port St.Joe- all true Sabal palmettos but obviously showing some natural variation.

[sonoranfans]

Also it could be that thin trunks result when many palms are competing for sunlight. We all know about elongation to reach the light. The thickest sabal palmettos Ive seen get a good sun exposure and good water supply.

[sonoranfans]

I think trunk diameter variation is partly a result of water supply. Ive seen it have a huge impact in Roystonea, skinny to fatty. Water supply can be effected in a big way by soil. Sandy soil or sloped ground makes it harder to ensure a good water supply...

I also think this to be one of the major contributor in many species and it kind of goes both ways in different species. One of the most vivid examples are the queen palms. In the Sarasota area we have many growing "wild" and also many in yards and places that are not regularly irrigated during the dry season. Those are usually about half as thick if not more then the well watered ones. I've also noticed this with Archontophoenix and Chambeyronias. On the other hand what I'm seeing with the bottle palms is the more they are starved for water - the fatter they get. Maybe it's the need to preserve. Kinda like humans, if you starve yourself, next time you eat body will store more fat.

Ive seen the same with queens, alex. And my alexandre are kind of fat, well watered. The bottle observation is very interesting as well....

[Just Another Dave]

I'm working on my forestry PhD at UF studying Sabal palmetto. So far, I've come up with more questions than I can answer in four years!

The only paper on establishment phase time estimated that cabbage palms in the Yankeetown coastal forest area can take between 30 and 60 years before putting on aboveground trunk. I'm guessing that those numbers are different in other parts of the state and in other kinds of ecosystems.

No one really knows what triggers height growth but during that time in the establishment phase, the diameter increases to some nebulous maximum for that tree. As Tomlinson puts it, palms don't change diameter so they are 'over-built' when young and reach the limit of mechanical strength as height increases. Some tall palms pass the calculated buckling limit and change the mechanical properties of their stem. The way he puts it, its almost as if the palm 'knows' how tall it will grown in that environment and builds diameter to suit!

Genetic or environmental? Good question! How far can a robin fly before 'depositing' that seed in the landscape? My guess is that trunk diameter is related to some soil characteristics and the light environment where it sprouts. When we move palms from that place, the diameter increases and, as you say, is a sort of date-stamp of that transplanting event.

I don't know how many cabbage palms we have on UF campus but it is a lot! I've measured quite a few and we have the sort of diameter range that you observe up there. Attached are photos of a 'man down' after some wicked thunderstorms this weekend. Note that the stem break is a foot or so BELOW the diameter change.

One can often tell if a Sabal palm was planted on purpose or if it is there due to 'laziness': A colleague noted that many cabbage palm seedlings are treated like grass in the landscape (weed whacked) until they begin producing expanded leaves. Then, rather than getting a shovel to dig up the weedling in the flower bed or hedge, the young palm is left to grow. Those palms found in 'awkward' locations are likely larger in diameter than those that were transplanted because they began their life with good sun, water, and a periodic shot of fertilizer! See the other attached photo ...

[NorthFlpalmguy]

I have a good friend who he and his dad dig native sabals as their business. Funny you should mention UF's sabals, or cabbages as we refer to them, my buddy's dad dug and installed 50-60 of those on University Ave and in other places on campus. They are all from around Steinhatchee and they also bought some more later on for their study on "hurricane cut" sabals. It was a comparison of survival rates in hurricane cut vs other landscape methods at that time. Hurricane cut was a newer method back then and some diggers were not trimming out the heads back then. Nowadays, you will not find a digger that doesn't hurricane cut them unless you specify not to.

They tend to find fat trunks in hammocks but also in some dry, sandhill situations... some of the fattest trunk cabbages I have ever seen have been in the upland areas that drain well. What I find most interesting about cabbages is that in quickly drained sandhills, the boots of the cabbages will be tightly formed... so variation due to area-specific conditions seem possible. To back this up, the layers of boots in wet areas tend to be easy to trim off, if not easily fall off without a booting shovel to cut them off.

In general, a trunk of a native transferred cabbage will not grow as fast as it would in the wild, even with fertilizer and water properly. I suspect the larger root system on the once well-established tree is why though. Even regenerated head cabbages seem stunted, even though the head has been regenerated in the nursery or temporary field.

Also you tend to find variation in trunk diameter where they have been booted by man with a shovel and naturally booted in the wild. I have no idea why.... Over trimming possibly?

[Alicehunter2000]

Dave did you mean 3-6 years? Interesting discussion.

[floridascape]

No definately 30-60. I have been observing sablas since I was very young so I can reference almost 20 years worth of growth on some trees. And one of my trees has put on 6 ft or so of wood in that time but still holds its boots the tree now is 17ft from ground to crown. I have been most interested in the variation of infloresence length. Some are incredibly long 8+ft in some and vert short less than 2' in others.

[Just Another Dave]

Dave did you mean 3-6 years? Interesting discussion.

No, 30-60 ... Here is the reference:

McPherson, Kelly, Williams, Kimberlyn. 1995. Establishment growth of cabbage palm, Sabal palmetto (Arecaceae). American Journal of Botany, Vol 83, Issue 12, pp 1566-1570.

Abstract: Cabbage palms (Sabal palmetto) go through an establishment phase during which the stem grows downward for a period of time before growing upward. We estimated the duration of this phase for cabbage palms growing in coastal forest in Florida using a matrix model approach. All data were collected over a 2-yr period (1993-1995) in coastal forest at Waccasassa Bay, Florida. The minimum time projected by the model for a plant to develop an aboveground trunk was 14 yr. We estimate that the fastest growing 1, 10 and 50% of plants would develop an aboveground trunk in 33, 42, and 59 yr, respectively. The projected duration of the trunkless phase is surprisingly long but not unlike other palms with similar types of establishment growth. Our estimates are much longer than anecdotal estimates for cabbage palms grown under nursery conditions but are similar to anecdotal estimates for plants grown in field conditions. Management practices that remove cabbage palms with aboveground stems usually leave a population Of palms without aboveground stems that serves as temporary reserve for relatively rapid recovery of the palm stand. This may foster the perception by many that cabbage palms are fast growing.

Your mileage may vary ...

Edited July 30, 2014 by Just Another Dave

[NorthFlpalmguy]

I do not believe that one bit LOL

The reason I say that is sabal pop up in planted pines quite a bit here. Now these lands are wind-row bedded, so massive skidders pull plows and rolling pins that the sabals would not survive underground. Pine cycle rotations are 15-20 years (seedlings or liners to harvest) and most pine stands have sabals from 6-14 ft of clear trunk. That's where my buddy digs 60% or more of theirs is behind the pine loggers. No way those trees are that old.

I also have grown sabals from seed and when fertilized and watered correctly they will have trunk in less than 8 years. The sabal hits a growth spurt about year 5-6 and will growth 10x above ground than before... very similar to a lobolly pine. That happens in native conditions as well or their would not be a sabal left along the coastline as many as they sell and ship for landscaping.

Edited July 31, 2014 by bbrantley

[floridascape]

...that is under "nursery conditions" not a good representation of what sabals have to contend with in nature. Trees that are bird planted in the field will grow below ground for almost 5-8yrs. another thing to consider Iis the actual length of the terminal bud during that adolescent faze they seem to be more elongated than when they mature and start to form the tight crown they have as mature trees.

[NorthFlpalmguy]

Not in planted pines, those are all native palms. I know for a fact that is not correct as 18 years ago we planted 300+ acres of pines on a piece of our land, bedded and then once again sprayed to keep competing vegetation out to jump start the pines and I now pull 6-10 ft clear trunk sabals from in the pine stand frequently.

[Alicehunter2000]

Yes 30-60 years does seem extreme regardless of the study. Very odd. Kind of goes against what I purchased from Fishbranch last year.....a 5 ft. CT Sabal causiarum...field grown...doubt they have been growing it for 30-60 years. In fact I think I asked them and they said they were around 20 years old....that's with 5 ft. of trunk. Extrapolating this info.... I would imagine (not sure) that a S. causiarum would start trunking around 10 years.

But a study is a study.......not disputing that.

[NorthFlpalmguy]

Straight from UF EDIS site:

"The slow-growing seedlings can take 15–30 years to develop a visible trunk under natural conditions, but in nurseries this can occur much faster (McPherson and Williams 1996). Initial trunk elongation can be quite rapid under favorable conditions (up to 6 inches per year), but this quickly slows to less than an inch per year as the palm matures (McPherson and Williams 1996)."

Can being the key word in that sentence....but most around here develop twice as fast as their only competition for nutrients and light are the pine stands.

[Matthew92]

Couldn't resist taking pictures of this robustly-trunked Sabal palmetto at a nursery here in Niceville, FL. I think it is obvious this one has been grown in ground at this location since first sprouting. On transplanted, mature Sabal palmetto's, there is usually a "kink" in the trunk marking the time when it was planted in ground (as pointed out in a picture earlier in this thread). Most of the time, the trunk width above the "kink" is much thicker than below (I think this looks unsightly).

Transplanted Sabals

 

Edited March 24, 2016 by Opal92

[Phoenikakias]

Love that kind of chunky trunk of palmetto. I have observed similiar occuring on transplanted Washingtonia.

[Las Palmas Norte]

Wouldn't the deformities (narrow trunk sections) lead to compromise during stormy weather? Looks like the entire top could snap off in heavy weather.

Cheers, Barrie.

[Brian F. Austin]

On 7/7/2014, 3:14:26, Just Another Dave said:

No one really knows what triggers height growth but during that time in the establishment phase, the diameter increases to some nebulous maximum for that tree. As Tomlinson puts it, palms don't change diameter so they are 'over-built' when young and reach the limit of mechanical strength as height increases. Some tall palms pass the calculated buckling limit and change the mechanical properties of their stem. The way he puts it, its almost as if the palm 'knows' how tall it will grown in that environment and builds diameter to suit!

Is it safe to say that all things being equal as far as care and environment... a sabal seed planted directly in the ground will be bigger in the long term... than one started in a pot then transplanted?

[Turtlesteve]

I have noticed that in some areas of South Carolina, the native s. palmetto have on average thicker trucks and larger, more open crowns than the transplants (presumably all from Florida).  The difference was quite noticeable on Hunting island state park.  I don't know if this is consistent in the rest of the Carolinas or not.  I prefer the look of the wild ones, they have a little less of the Dr. Seuss "ball on a stick" look to them. 

Steve

[Brian F. Austin]

Hi Steve, I had to look up Hunting Island SP. Pretty cool place. Some good photos here...

http://maxi-scoots.com/scoot/index.php?topic=4413.0

this shot was really cool... it looks like the soil and sand had eroded to expose the mass of palmetto roots.... https://www.flickr.com/photos/dsrphotography/8240057850/ 

[Quasarecho]

I know this is an old discussion but very interesting. I'm new to the forum and a novice. I also thought there was an interesting observation about northernmost growing palmettos, that palmettos on the islands of North Carolina having trunks that were more stocky.  I'm a designer and sometimes look at things purely from an anesthetic viewpoint. I personally like the look of stockier, shorter trunks. I'm visiting the FL panhandle and these trees I saw tonight really stood out from everything else around. Nice stocky trunks.

[Brad Mondel]

Ones in the shade are skinny and ones in the sun are are thicker. That's the answer.

[Quasarecho]

Most in this area must have been started in the shade and brought in and planted in the sun. All seem to be skinny(ier). These in this parking lot all stood out because the have hefty trunks. I thought maybe they all came from the same area where genetics affected them.

Thanks.

Gary

[climate change virginia]

I think the farther north the palmettos are the skinnier the trunks are in sc and below the palmettos look full and poofy and in nc (excluding the outerbanks) and va beach they are WAY skinnier than anything you see in the deep south

[NCFM]

14 hours ago, climate change virginia said:

I think the farther north the palmettos are the skinnier the trunks are in sc and below the palmettos look full and poofy and in nc (excluding the outerbanks) and va beach they are WAY skinnier than anything you see in the deep south

I would have to disagree with that assessment. Some of the most robust trunked palmettos I've ever seen have been in NC. I'm still a bit confused on what all determines trunk thickness, but sun exposure and genetics seem to at least play some role. 

Native BHI palms:

 

 

Transplants growing in Emerald Isle, NC:

Shade grown:

More sun:

Full sun:

With this one (right), it appears that the palm was nursery or field grown in lower light conditions, and then began to develop a slightly thicker trunk once transplanted into full sun (notice kink):

 

 

Here is an older specimen in Southport, NC along with its offspring. All four have similar thickness:

This one in nearby Wilmington has a similar diameter and similar light conditions:

 

 

Edited January 5, 2021 by NC_Palm_Enthusiast

[Turtlesteve]

From what I have seen, the further south you go, the smaller they are.  And, I have seen thick ones in full sun or dense shade.

Perhaps this could reflect differences in soil quality and/or fertilization if there is a non-genetic component?