Does bamboo absolutely, always, split?

[anthropisces]

I read, on the sites of suppliers of bamboo poles, that it will, in time, always split. Does it really always split over time?

Even if splitting is a sporadic event, it would seem to dramatically limit bamboo usage.

If this is the case, how can the mechanical properties be counted on for the structures being built?

[Mark Meckes]

Hi anthropisces,
"Our bamboo is guaranteed to split" is a form of disclaimer that some suppliers use ... in case a split does occur. Also some bulk processed bamboo may have some cracks due to a number of reasons such as the price a vendor is prepared to pay, quality of materials, intended market use and other reasons mentioned below ...

Even if splitting is a sporadic event, it would seem to dramatically limit bamboo usage.

If this is the case, how can the mechanical properties be counted on for the structures being built?

Different bamboo species differ in the manner a crack or split may occur, which can additionally vary according to regional growing conditions, age of harvest, drying processes, treatments and storage methods prior to or during use etc.

In some instances cracks in bamboo may be only skin deep and only cosmetic annoyances, like what can happen with wooden posts and beams in buildings, and don't affect the integrity of the structure.
In other situations, or species which can split wide open from end to end, it is better to employ preventative measures or to use the bamboo for the many other applications requiring the use of split portions.

Usually a structure should be built with load bearing allowances exceeding what it is intended to carry should any member fail.
However we are generalizing here, and in the real world other materials including wood or other products are used in combination with bamboo for building large permanent structures.
If the goal is to build solely with bamboo, then one must be very selective in the bamboo materials and joinery techniques used.

Mark

[ShmuBamboo]

I cut and store all of the dead canes from my bamboo gardens here and use them all over the ranch outdoors. Over time and exposure to the elements they tend to split, vertically at first. This has little effect on what I use them for. Over a longer time they get weaker and split horizontally, uaually at the nodes. At that time they need to be replaced. But I do not use them for structural purposes. I use them mostly for making trellis and for supporting deer fencing, and for staking plants. I have a pinot noir vineyard with golden bamboo stakes used for training the vines. We also have thousands of commercial bamboo stakes used for tubing newly planted 10,000 or so trees that we have planted here in the past 5 years. Thay last as long as needed, usually, then they rot.

[Mark Meckes]

If the commercial bamboo used for staking your trees have fairly flush (not prominent nodes),
... then it is most likely Pseudosasa amabilis (http://www.bamboocraft.net/bamboo/showgallery.php?cat=599) - Tonkin Cane (Formerly Arundinaria amabilis)
This is possibly the most extensively imported bamboo, culmsumed in great quantities by the horticultural and floricultural industries.

The long term weakest point for bamboo is where it makes contact with the ground, which is why I always 'cheat' when making fences etc, beginning with metal garden stakes from which I attach bamboo vertically and horizontally, providing long lasting fences and other garden structures.

Mark

[ShmuBamboo]

Well, for staking grapes I stick the golden canes in the ground. They only need to last a few years until the grapes form up good trunks to the lower wire. You are probably right about the commercial stake boo species. Minimum node width. We get them in huge bagged bundles at a commercial tree supply place in Eugene. They are from asia. We lace two of them into each of the plastic tree savers and shove them into the ground when it is wet here (planting season is in January/February when most conifer trees species are dormant). They are designed to hold up for a few years, and by then the trees have outgrown the plastic sleeves. The plastic breaks down in the sunlight and the bamboo rots away.

For deer fencing I have come up with several uses for longer canes from my black and golden boos. I lash them to 6 ft t-posts and use them for extending the posts for 8 ft deer mesh. Cheap/strong long poles. I also use them for making deer fence doors and for running along the bottom of deer fence to keep the deer from nosing their way up through the fences. We have 3 types of deer and elk here year round. So my orchard, vineyard and berry/rose gardens are all in fenced areas. Lest they get eaten overnight. The bamboo is pretty much deer-proof. One of the few plants that are around here. And the second major reason I grow them here (#1 is that they are bullet-proof, and my girlfriend has a brown thumb). The boos are not sheep-proof though... when they get out they head stright for the bamboos groves. Yum yum!