I am intrigued by how this plant developed a twin trunk. It is the first that I have noticed here in the San Francisco Bay Area, though it is possible that I may have overlooked it before on another plant. This plant is a Dicksonia Antarctica, which is slower growing than the Cyathea plants. As a result, there are fewer plants in the stores with trunks large enough for a twin trunk to be noticeable. It is possible that other smaller, younger Dicksonia have the same attribute, but since the trunk is smaller it is less noticeable.
In an online web search, I found some discussion of this situation on a gardening website based in the UK. There are probably more gardeners with Dicksonia plants in London than in the sf Bay Area. So the chances of this coming up in the sf area may just be statistically less. If any readers have some experience with this, can you please comment or send me an email so that we might correspond and share experience ?
Well, at this time, I have more questions....
(1) does a twin trunk indicate two plants or is it one plant?
There is some debate on the uk site, with some suggesting that this is two seedlings that sprouted close together. There seemed to be another possibility that it may be a plant that started out from one seedling, and that at some point the trunk divided in two.
(2) is it better for the health of the plant to keep it as is, or at some point to separate the trunks ?
Some suggested in uk that it looks better separated, and that a twin trunk plant would have croziers from one side unfurling into an existing from from the other side. Are these more aesthetic issues that we as observers might be imposing on a plant that might just continue to grow in some way?
(3) what will the plant look like if it continues to grow with this element ?
It seems possible that a twin trunk plant could grow so with a symmetry that would be aesthetically pleasing. Would the two sides compete with each other, until one side becomes larger than the other?
(4) is there some advantage that a twin trunk plant might have in a 'wild' natural environment?
Here in Northern California, we are accustomed to seeing something similar especially with redwood trees. In fact, redwoods grow a 'family' in a circle often, with the trunks connected to one another sometimes. So would there be some reproductive advantage or added resiliency to such a plant?
At this time, I plan to observe the growth pattern of the twin trunk Dicksonia, and document it with fotos and notes here on this website. Please stay tuned for more entries on this story. And thanks for your interest in this topic !