Bald Cypress knees

[markyscott]

FWIW, bald cypress grows IN water because it can, not necessarily because it wants to. Most serious bald cypress bonsai folks recommend NOT submerging the roots, because plunking a tree in a tub of water DOES NOT simulate swamp conditions. Water in swamps moves and circulates--albeit slowly, but it does move. Water in a tub doesn't. It staganates and becomes anaerobic, not a good thing for roots. Water in a container also heats up VERY quickly, which also drives out more oxygen. Swamp muck is deep and cool, not hot.

I grow mine in a couple of inches of water during the summer months, but I don't submerge them completely. It gives me some peace of mind and a small margin of error when I'm out of town and relying on my kids or the house sitter to water.

I wonder on what basis do the growers you are familiar with recommend not flooding their cypress trees. The only semi-serious study about the effect of flooding on bc growth rate I'm aware of is reported in an old BCI article: Chiplis, D., 1990, Effect of flooding on trunk diameter in bald cypress and its application as a bonsai technique, Bonsai Clubs International 29, p. 13-16. He conducted an experiment under semi-controlled conditions comparing trees exposed to different durations of flooding. During the course of the growing season he periodically measured trunk diameters of the trees in comparison to the control group. I haven't attempted to replicate the results myself, but the author reported a positive correlation between the duration of flooding and growth rate in his cypress trees. He stated that he measured up to a ~40% increase in growth rate for his bc that were flooded the longest and expressed a number of physio-chemical reasons why this is the case. I'd be interested to read any article you may be aware of that presented evidence to the contrary.

Scott

 

[Zach Smith]

I grow mine in a couple of inches of water during the summer months, but I don't submerge them completely. It gives me some peace of mind and a small margin of error when I'm out of town and relying on my kids or the house sitter to water.

I wonder on what basis do the growers you are familiar with recommend not flooding their cypress trees. The only semi-serious study about the effect of flooding on bc growth rate I'm aware of is reported in an old BCI article: Chiplis, D., 1990, Effect of flooding on trunk diameter in bald cypress and its application as a bonsai technique, Bonsai Clubs International 29, p. 13-16. He conducted an experiment under semi-controlled conditions comparing trees exposed to different durations of flooding. During the course of the growing season he periodically measured trunk diameters of the trees in comparison to the control group. I haven't attempted to replicate the results myself, but the author reported a positive correlation between the duration of flooding and growth rate in his cypress trees. He stated that he measured up to a ~40% increase in growth rate for his bc that were flooded the longest and expressed a number of physio-chemical reasons why this is the case. I'd be interested to read any article you may be aware of that presented evidence to the contrary.

Scott

Thanks for the reminder on the old Dan Chiplis article. I remember it well from back in the day.

Bald cypress sapwood is like a sponge, very light and porous, so you would expect that the more water you make available the more it would take, the more growth of the sapwood, the more water it would take, and so on. I have a small specimen I grew from seed germinated 13 years ago that grew for the first several years in poor conditions. I moved it about three years ago to a spot that gets flooded periodically (and gets more sun), and this has really accelerated the growth. Of course, this is no controlled experiment so there's nothing to compare to, but you'd be hard-pressed to argue that giving BC more water will have no effect.

I haven't pulled out the article to re-read it, but do you recall if Dan refreshed the water each week? For some reason that sticks in my head.

Zach

 

[Zach Smith]

Perhaps?: Baldcypress: The tree unique, the wood eternal, Brown, C.A. And Montz, G.A., 1986, Claitor's Publishing Division, Baton Rouge LA.

Scott

That's it! Much information in a little book.

Zach

 

[rockm]

The book "Baldcypress: The tree unique, the wood eternal, Brown, C.A. And Montz, G.A., 1986, Claitor's Publishing Division, Baton Rouge LA" is a MUST read if you're serious about BC.

It refutes the "constantly submerged is best" approach--in favor of research that says occasionally flooded trees do the best. The deeper the water a tree stands in the less likely it will develop knees and deeply ridged fluting on the trunk (in favor of a "hanging" or bottle-shaped flare). It also dispels the notion that knees are some sort of breathing aparatus. It is more in favor of starch storage for knees. There is indeed a lot of information in it and it can change your view of this species dramatically.

FWIW, I believe knees developing in containers has more to do with root congestion and cramping than submersion...I also still believe is is EXTREMELY rare in bonsai BC and not really reproduceable with some formula.

 

[markyscott]

Thanks for the reminder on the old Dan Chiplis article. I remember it well from back in the day.

Bald cypress sapwood is like a sponge, very light and porous, so you would expect that the more water you make available the more it would take, the more growth of the sapwood, the more water it would take, and so on. I have a small specimen I grew from seed germinated 13 years ago that grew for the first several years in poor conditions. I moved it about three years ago to a spot that gets flooded periodically (and gets more sun), and this has really accelerated the growth. Of course, this is no controlled experiment so there's nothing to compare to, but you'd be hard-pressed to argue that giving BC more water will have no effect.

I haven't pulled out the article to re-read it, but do you recall if Dan refreshed the water each week? For some reason that sticks in my head.

Zach

I was very happy to run across that article. I have a digital copy - pm me and I can email it to you. Dan reported topping off the water daily to keep the flood level constant, but did not report having changed the water as part of the experiment.

He claimed to observe what he believed to be the initiation of knee development on two of the flooded subjects. He also reported that his flooded subjects departed from his non-flooded control group in several other key ways: enlarged lenticels, appearance of "water roots", wider trunk fissures, etc...

Interestingly, Dan claimed that all of this was an adaptation to growth in anaerobic conditions. He noted that growth rate in his flooded subjects was the same as that of his control group for several weeks after flooding before he observed an increase in growth rate and suggested that this was the time-period over which the water became O[SUB]2[/SUB] depleted. He claimed that it was only after the water became depleted that the growth rates increased. Unfortunately, he did not report having measured O[SUB]2[/SUB] levels, so this claim is a bit speculative. But if correct, it suggests that changing the water regularly would not replicate his results.

Wish Dan was still around to talk to us about this. If you do have a chance to re-read his article, I'd be interested in your thoughts.

Scott

 

[markyscott]

The book "Baldcypress: The tree unique, the wood eternal, Brown, C.A. And Montz, G.A., 1986, Claitor's Publishing Division, Baton Rouge LA" is a MUST read if you're serious about BC.

It refutes the "constantly submerged is best" approach--in favor of research that says occasionally flooded trees do the best. The deeper the water a tree stands in the less likely it will develop knees and deeply ridged fluting on the trunk (in favor of a "hanging" or bottle-shaped flare). It also dispels the notion that knees are some sort of breathing aparatus. It is more in favor of starch storage for knees. There is indeed a lot of information in it and it can change your view of this species dramatically.

FWIW, I believe knees developing in containers has more to do with root congestion and cramping than submersion...I also still believe is is EXTREMELY rare in bonsai BC and not really reproduceable with some formula.

Agreed - this is a wonderful book - very well written and a thoroughly enjoyable read.

Scott

 

[rockm]

In addition to the book, the National Forest Service description and profile of the species is worth reading. There are some interesting tidbits on flooding and habitat in it, backed by research.

http://www.na.fs.fed.us/pubs/silvics_manual/Volume_1/taxodium/distichum.htm