So there's plenty of talk of bamboo backings, but never any discussion of the different species of bamboo. According the the oh-so-reliable wikipedia post, there are 70+ genera and around 1,450 species currently known with a striking level of variety. I would guess most of what we use for bamboo backings are from timber bamboos of the genus Phyllostachys. Within this genus are many species, including the timber species Bambusoides (also called 'Japanese Timber Bamoo'), Edulis (also called 'Moso'), Vivax (no other name i've heard), and many others. These three I mentioned in descending order of culm (what the 'canes' are called before they're cut down) strength. Japanese Timber is often used for scaffolding because of it's incredible strengh, and Vivax will break because of a heavy snow (they are all evergreen, so snow weighs down the leaves a lot).
From what i've read, this is due to wall thickness, though very little has been said of wall density. I would assume Vivax, being sooo much thinner walled, would need denser walls to support a 70' tall plant. Boo backings are often planed down, so I wouldn't expect the original thickness to matter as much, assuming the plant is of sufficient diameter/thickness to start with, any more being unneccessary.
Another boo backing post talked about node weakness, and these different species have different nodes, which may have an effect. Also, many commercial bamboo cane sellers bake the stuff first, which removes starches that may attract pests who would eat it all up. I don't know if this would effect breaking strength, but it certainly could.
Anybody here grow/harvest their own? I have 3 species in pots, though none would grow large enough for backings even in perfect conditions. There are plenty that are currently grown in the USA (available at nuseries all over) that could potentially make backings. In addition to the species listed above, you could look at Parvifolia, and some variants of the species Nigra, specifically the variant called 'Henon'. The variant "Megurochiku" seems to have very long internodes in photos (i don't have any, so i can't say from looking at one in person) which may be of interest. These all have different charachteristics and different preffered climates. Despite the general idea that bamboo will take over everything, it isn't hard to control if you aren't lazy and know how to take care of it going in. in fact, most people will have a much bigger problem with the whole plant dying during harsh winters, but there are ways to help that as well. Much of the "it will take over!" mindset comes from misidentifying japanese knotweed as bamboo. It looks kinda similar, but isn't bamboo, and yes it will totally take over. Sure hard to kill, too. On that topic, lucky bamboo isn't bamboo either. It looks like it kinda, but its not related.
Anyone with lots of land in a good climate zone and lots of time to kill could probobly do some good bow backing tests. or you could just buy the canes. There are planty of other species from the tropics (not from the phyllostachys genus) that grow huge and could be backings, but those don't really grow too far north so I've ignored them.
Arrows seem to be from different species, also not from the genus phyllostachys. River cane is actually a North American native form of bamboo, called Arundinaria Gigantea. An arrow species commonly grown as houseplants/hedges is Pseudosasa Japonica, also called Japanese Arrow Bamboo. I have one in a pot that I just got, so it's not big but it is unusually straight growing. Bamboo tends to kink slightly at the nodes, or have bulging nodes, but this doesn't. I can see why the japanese name is "Yadake". Ya meaning arrow, dake meaning bamboo. or so I read.
If you're going to harvest yourself, it seems you have to wait 3-5 years or so after the right size shoot grows for best strength. In the meantime, the plant will send up new shoots, and you will actually help the plant by removing the older, less photosynthesizing culms. The old shoots come out of the ground at final diameter, grow to final hight in a couple months, and never grow bigger ever again, so if you see the right diameter arrow shoot comming up, it will be the right diameter in 3-5 years, too. Just don't let it die.
Much more information available at bamboogarden dot com and needmorebamboo dot com. They are nurseries with an awesome amount of free information and pictures. bambooweb dot info is also a good source of information, i think its got a forum, too. Also, word of caution, if you're going to grow your own, don't buy seeds. They are usually a little bag of lies. Bamboo rarely flowers, (every 50-130 years depending on the species, though there are some flowering more often) so you will probobly get moso seeds no matter what the package says, and growing them can be extra tricky.
Has anybody tried comparing species or even got a species ID from backings? All bamboo should be super strong in tension, but there must be variablity, right?
