By David Osborn

What Is Bamboo?
Bamboo is the generic, common term for a wide variety of different botanical geni and species of evergreen plants within the Gramineae, or Cereal Grass family, of which wheat, barley and corn, as well as a number of common grasses, are also members.  In other words, bamboo is basically a giant grass that has grown hard, fibrous and woody.  If you should have any doubt that bamboo is a cereal grass, just dig up a bamboo tree and a corn plant by their roots; they will look amazingly similar, and share many of the same morphological features.  The usual method of propagation for bamboo is for different stalks, or culms, to shoot up from underground rhizomes, and the various species of bamboo are classified either as clumpers, which shoot their culms up from a central clump rhizome, or runners, which shoot their individual culms up from a horizontally running underground rhizome.  Within the great number of grasslike plants that have been called bamboo there is incredible variety when it comes to characteristics like hardness or density, internode length, wall thickness, coloring or pigmentation, and other parameters.  Although the two terms are often used interchangeably, “cane” generally refers to bamboo species that are more slender, with a longer internode length, but not always. 

Amazing and Little Known Facts About Bamboo
Bamboo is one of the most useful and versatile plants known to man.  Throughout the long course of human history, and across many different times, lands and cultures, bamboo, in its many different varieties, has been used for food, medicine, cooking utensils, building materials, precision instruments, and of course, musical instruments, including various flutes from all over the world.  Bamboo is one of the fastest growing plants, and one of the quickest generators of green biomass on the planet, coming in a close second to hemp.  Although bamboo is notoriously vulnerable to splitting or cracking longitudinally along the length of its grain, it is otherwise one of the hardest and most durable materials in the world.  Bamboo will blunt and wear out whittling knives quicker than just about any other wood.  The individual fibers of bamboo have great tensile strength; when Thomas Edison was working on perfecting the electric light bulb, one of the first incandescent filament materials he found that worked, before he settled on tungsten, was a fiber of carbonized bamboo.

Within a grove or colony of bamboo, there is Yin and Yang, male and female.  Generally speaking, male bamboo culms are thicker and stouter, having more prominent nodes; they also tend to have but one small, thin branch with leaves sprouting out from each of its upper nodes.  On the other hand, female bamboo culms are generally thinner and more slender, with less prominent nodes, and have two fatter branches sprouting out from each node, with leaves.  When I was visiting my Shakuhachi teacher in Japan, a friend of his showed me the difference between male and female bamboo culms, juxtaposing noded pieces of each together in a sexually suggestive manner.  Although the usual method of bamboo propagation is via rhizome networks, which can be either running or clumping in nature, bamboo, having male and female culms, is a pollinating and germinating plant, and does bear seeds occasionally.  A bamboo grove comes to seed only after a great many years, and this coming to seed usually signals the imminent death of the grove, with new bamboo plants arising from its seeds.    

Bamboo and East Asian Culture, Spirituality and Philosophy of Life
So many items have been made from bamboo in the Orient that East Asian life and culture would be hard to imagine without it.  In the kitchen, we have cups and bowls, spoons and spatulas, and even chopping boards made of bamboo.  The cook herself might even stand on a wide diameter piece of bamboo that is split in half while cooking, as a kind of foot massage tool.  In the living room, bamboo might be built into the very woof and warp of many items, and more recently, even floor tiles have been made from laminated bamboo.  Bamboo is a hard, tough, durable material that can take a high polish; and so, precision instruments like mathematical slide rules, as well as various kinds of rulers, have been made from bamboo.  In the Japanese tea ceremony, the tool that whisks the Matcha into a green froth is exquisitely crafted from bamboo.  In China, Dim Sum dumplings of various sorts are often wrapped in bamboo leaves for their exquisite flavor.  And when you get sick, a tea made from bamboo leaves can lower certain kinds of fevers, and decocted bamboo shavings can help to eliminate certain kinds of phlegm. 

Bamboo is strong and straight, and grows quickly, shooting up almost overnight.  This is also how we should be in life, being straight, strong and forthright in our dealings with others, and shooting up quickly to establish ourselves, spread our influence and achieve our goals.  Bamboo is also one of the hardiest of plants, and can thrive virtually anywhere if given half a chance; gardeners often have to think twice before planting bamboo because, once installed, it often tends to be quite rambunctious and invasive.  Out of the hollowness of bamboo comes its great utility and versatility; this hollowness symbolizes humility, a virtue that makes us useful to others, and in the game of life.  As with Rabindranath Tagore’s little flute, if we are hollow and humble, the Divine Player can fill us with beautiful music.  In Japanese culture, there are three emblematic plants that symbolize the Japanese character: Shoh, Chiku, Bai.  Shoh is the hardy, evergreen Pine tree.  Chiku is the bamboo, which is also an evergreen.  And Bai  is the Plum tree, which is the very first tree to blossom, even when there is snow on the ground. 

And then, there are the nodes of bamboo, or those horizontal partitions that divide what would otherwise be the smooth, unbroken silhouette of its profile into knots that jut out.  They serve to divide the bamboo stalk or culm into discrete, measurable internodes or sections.  Without the nodes, bamboo would be weak and flimsy; with them, bamboo has character and strength.  And so, the bamboo nodes symbolize those difficult tests in life that we must pass through and grow beyond if our life is to have any power, durability and meaning, and if we are to develop any strength of character.  My Shakuhachi teacher, Iida Sesshu, told me that he could tell if a particular piece of bamboo was strong and hard, or weak and soft by looking at the strength and shape of its nodes.  Without limits or limitations that are imposed upon our life, which are voluntarily accepted and entered into, life would have no definition, no meaning – everything would just dissolve into the infinite.  That is the basic life message conveyed by the I Ching Hexagram number 60, Chieh, which is usually translated as “Limitation”, but whose Chinese ideogram literally depicts a bamboo node. 

Bamboo and the Flute Maker’s Art
Bamboo, being naturally hollow, is the perfect material for making flutes, since this hollowness saves the flute maker a lot of time in having to drill or ream out a bore.  Of course, bamboo has nodes, but these are quite thin on the inside, and can be reamed and sanded out without too much effort.  Besides requiring removal on the inside by the flute maker, bamboo nodes can also be problematic in that they are the main places from which undesirable irregularities in the bamboo culm’s shape and structure can develop in various ways.  Firstly, if a bamboo culm is to be crooked, this crookedness usually starts from one or more of the nodes, and crookedness is definitely NOT a desirable quality in a flute.  As one of my Shakuhachi teachers once told me wryly, “No (expletive deleted) likes a crooked bamboo.”  If a piece of bamboo should be markedly crooked, that does not necessarily disqualify it from being made into a flute.  Shakuhachi makers heat the crooked node up over a hibachi, or traditional Japanese charcoal stove, until its node is soft and flexible, then they straighten it out in a mechanical press. 

Another undesirable irregularity that can occur at or from a bamboo node is that of flutes, or longitudinal indentations in the bore, which can mar its cross-sectional cylindricality.  Again, these do not necessarily disqualify a particular piece of bamboo from being made into a flute, or even into a decent or even good one, but they do reduce the chances or probability of that outcome.  These longitudinal flutes or indentations in the bamboo internode usually accompany branches that branch off from the nodes, which happen mainly in the upper portion of the bamboo stalk, or tree.  Aside from outright crookedness or indentations arising from the bamboo nodes, the nodes can also introduce subtler kinks and irregularities in the inner bore of the instrument.  Smoothing out these inner kinks in the bore that happen at the nodes is one of the main objectives of the intricate bore work that is involved in the making of the Japanese Shakuhachi flute.  Regarding these kinks, the flute maker has three basic choices: tolerate or live with them if they’re not too bad (Chinese flutes); avoid the nodes altogether (Bansuri); or intricately sculpt the bore to smooth them out (Shakuhachi). 

One of the subtler qualities or attributes of bamboo when it comes to flute making is sonority, which could be defined as a species of bamboo’s ability to produce a musically pleasing sound and tone quality.  Although the qualities that have been most predominantly linked to a species of bamboo’s overall sonority have been those of hardness, density and resilience, there are also softer species of bamboo, often called “cane” or “reed” as well, that are also noted for their sonority and acoustical virtues.  Since the bamboo plant is a product of Nature, the natural setting from which the particular piece of bamboo was harvested is also very important in determining its hardness or softness, and its overall quality and sonority.  If you’re looking for hardness and density, resilience and durability in a piece of bamboo, your best bet is to go into the mountains, as it is most likely to be found in dry, rocky, well-drained mountain soil.  On the other hand, moist, wet or muddy, marshy ground is likely to yield bamboo that is unduly soft and pithy, or of inferior quality. 

Bamboo is, above all, a product of Nature, and the flute maker’s art can be defined as the fusion or integration of Art and Nature.  I would also venture to say that even the most seasoned flute makers would say that the best flutes in their experience came from pieces of bamboo that were naturally perfect as they were, and which required the least amount of work on them.  In this, a definite parallel could be drawn between the pieces of bamboo a flute maker has known and the relationships one finds in life, with the “naturals” being the best ones.  And so, flutes both big and small, or whatever their particular virtues, size and specifications, have tended to be made from the particular species of bamboo that most naturally fulfilled those particular flute making demands of overall  quality and texture, wall thickness, internode length and placement, and overall size and length.  Inside every good piece of bamboo is a flute, just waiting to be let out, so it can really sing.  This is the heart and soul of the flute maker’s art.

The Art of Protecting and Preserving Bamboo
As I said earlier, perhaps the greatest weakness or vulnerability of bamboo is its susceptibility to cracking longitudinally along the length of its grain.  Cracking can be a natural consequence of the drying process, which may not proceed in an even and uniform manner throughout the bamboo pole.  Bamboo as commonly available from a bamboo warehouse or dealer is only about half dried or cured, so cracking is a fairly common occurrence in bamboo bought from these dealers.  Accordingly, these bamboo dealers must be honest in saying that they can make no guarantee that a given piece of bamboo will not crack.  The various risk factors that can increase a piece of bamboo’s likeliness of cracking can be broadly differentiated into exogenous factors, which are mainly climatic in nature, versus endogenous factors, which are inherent to the piece of bamboo in question.

The exogenous climatic factors mainly involve wetness, or moisture, versus dryness, with dry being more inherently risky than wet.  Also, sudden climatic changes, not only of moisture levels but also of temperature and pressure as well, are risky for inducing cracking.  Wind is also a definite risk factor where cracking is concerned – even artificial wind, like that generated by an electric fan.  As for endogenous factors, how green or unseasoned / uncured is the piece of bamboo in question?  The greener the piece of bamboo, the more risk of cracking as the bamboo dries more thoroughly and completely, which may not happen in a uniform fashion.  Also, pieces of bamboo that are longer, bigger and thicker walled are more likely to generate the unequal torque-related forces that can lead to cracking than are pieces that are smaller, shorter or thinner walled.  Pieces of bamboo that are harder are also more likely to crack than pieces of bamboo that are softer, and therefore more flexible and pliable.  With these “specs” in mind, a piece of Shakuhachi bamboo is in the most danger of cracking if it is not well dried and cured, whereas the pipes of a Pan Flute, particularly the shorter ones, present a much lesser risk. 

So, what are the main ways of preventing cracking in bamboo, how can we treat bamboo in order to reduce or eliminate the risk of its cracking?  Briefly speaking, there are two basic ways: through heat or through oil or other sealing materials.  Heat treatments are basically drying the bamboo by baking it, and are a lot like the kiln drying of wood.  Oil and sealer treatments attempt to drastically slow down or stop the further drying of the bamboo by greatly reducing or stopping the rate of moisture evaporation from within the bamboo or keeping this natural drying or evaporation within more manageable levels.  Flute makers from around the world have been quite ingenious and resourceful when it comes to drying or curing their bamboo, and I will get into their particular methods and protocols in the pages that are relevant to those particular flutes.  But when it comes to processing bamboo that is bought from a bamboo dealer to reduce or eliminate the likelihood of its cracking, the following procedures should suffice:

First is the baking method.  For this, you must have an oven with an accurate temperature gauge or control, and an oven that is big enough so that the pieces of bamboo can be placed a safe distance from the heating elements, so the bamboo is not burned or seared.  Place the pieces of bamboo onto the racks, in the center of the oven, away from the heating elements, while the oven is cold; close the door.  Then, turn the oven on to low heat, to 150 degrees Fahrenheit; roast the bamboo at this temperature for an hour.  Next, turn the oven’s thermostat up to 200 degrees Fahrenheit for another hour.  Following this, turn the thermostat up to 250 degrees Fahrenheit for about a half an hour; another half hour with the temperature at 275 degrees is possible if you want a darker roast and color, but not necessary.  Then, keeping the door of the oven closed, turn off the oven and let the bamboo cool down naturally to room temperature overnight.  In my experience, this reduces the likelihood of bamboo cracking to near zero.  If a piece is to crack at all, in my experience, it will probably crack during baking, so you can promptly throw it out, and not waste any undue time and effort on it. 

The main drawback of the baking method is that pieces of bamboo that are too long, especially two feet (60 cm.) or longer, cannot be put into the oven.  If this is the case, then your next best option is to go the oiling route.  To do this, you must first ream out all the joints or nodes that you are going to ream out to make the flute in question, giving the “innards” of the bamboo, from which the lion’s share of the drying and evaporation proceeds, full access and exposure to the oil.  Pour oil into one end of the bamboo piece and pour it out, then do the same with the other end; even saturate the ends or cross sections or the bamboo grain with oil, so all the sensitive or vulnerable parts of the piece have been treated.  Different flute makers have their different preferences when it comes to oil, like Linseed oil from the hardware store (my personal favorite); Almond oil (Zamfir’s favorite) – or Olive oil, Sesame oil, Grapeseed oil (another good one), or even Castor oil (very moistening and penetrating).  Virtually any vegetable oil may be used.  Although the insides of the bamboo piece may initially be too moist and “gooey” to work on, in a few weeks or a month’s time, the oil will have thoroughly absorbed, and the piece will be thoroughly workable. 

If you should want a more thorough seal, then try mixing Linseed oil and Turpentine from your hardware store together in equal parts, and using that.  That works very well.  Or, you can use a sealer from your hardware store to seal the inside of the bamboo by pouring it in and pouring it out.  Or, take a long, thin piece of rag rolled around the end of a long, thin dowel stick and swab the insides of the bamboo thoroughly.  Some flute makers have combined both the oil and the baking methods by first oiling the bamboo, then baking it – some have even put aluminum foil around the oiled bamboo to seal the oil in while baking.  I have even known a Romanian Pan Flute maker who treated his bamboo pipes by deep frying them in hot oil!  You are free to experiment around and see what process, or combination of processes, works best for you.  After the baking and/or oil treatments have been completed, the bamboo is “stabilized”, and you can work on it whenever you want – or even put it in the closet to let it age.  Like fine wine, bamboo definitely improves with age.