Chapter II: The Nature of the Plant and Its Cultivation

In order more thoroughly to know and appreciate bamboo, one must consider the nature of the plant. Though we wish to avoid any unnecessary references of a purely botanical character, we feel it is almost impossible to impart an understanding of the economic factors that enter into its cultivation without first entering into a discussion of some of its more important characteristics. 

In the first place, bamboo is a tree-grass. It possesses all the essential characteristics that mark a grass. A brief analysis will suffice to establish the fact. We must expect from it, therefore, the behavior and habits peculiar to grasses, creeping grasses especially. At this point let us consider a matter of terminology. It is customary to refer to the standing. canes and poles of bamboo as culms. It may have been noticed that the standing culms of some bamboos form dense clumps, while others stand more or less widely separated in groves and forests. Morphologically, culms are not stems. Unlike the culm, the real stem is practically solid, and grows into a tortuous many-branched system that spreads beneath the surface of the ground in all directions. From its joints on alternate sides spring the jointed hollow culms like branches of a tree. The stem is generally called a rhizome. The elongation and branching of the rhizome continues year after year; and in this way the forest grows in extent. 

Roots radiate from the nodes of the rhizome and also from the base of the culms. Everyone who has lived in the Far East or the tropics is familiar with the characteristic jointed appearance of bamboo, the branched upper parts, and the waving plumes of foliage, so that no further discussion along these lines is necessary. The particular point we wish to make from these few statements is that owing to the physical connection between many culms, sometimes between whole forests, the bamboo is a very large and very extensive plant. If an entire forest is to be considered one plant, naturally the treatment accorded it will from this point of view differ from that based on the conception that separate culms are separate plants. This fact is of obvious economic significance. 

The reasons for this statement may be made clear with a few illustrations arising from scientific investigation. It is clear from our premise that what affects one part of the plant is likely to affect the whole. Passive environmental conditions, however, must be excluded because, being prevalent generally in any one region, they act equally on all animals and plants in that region, and, therefore, if species will respond to those conditions similarly in greater or less degree regardless of individuality, the fact of whether or not in the case of bamboo the culms are individuals or part of a physiological whole is not demonstrated. Too extensive cutting of the culms, though immediately affecting only individuals, results in the general production of smaller shoots and smaller culms. A good example of this may be seen on the hillsides of Mokanshan, in Chekiang province, particularly on the foreign properties. As this is a summer colony, the place is deserted in winter, being left in the hands of a few Chinese caretakers who make something on the side by selling canes cut from these places. The culms as a result become smaller each year, averaging not over three inches in diameter, while those of the same species in other localities, where the thinning process has been carried out with care, average five to six inches. In any producing district, if the former is the practice, there will result an economic loss which can only be compensated by a change of treatment. Fairchild in his interesting account of bamboo forest culture in Japan explains that scientific cutting throws the strength of the plants into a comparatively few large culms and gradually increases the height and strength of the forest. This certainly points to the physiological unity of the grove and must be considered in any economic discussion. 

Another economic factor of importance in the life-history of bamboo is the extraordinary rapid growth of the culms. Bamboos vary in height from a few feet to l00 and 120 feet. An example of the latter is the giant bamboo, Dendro calamus giganteus, of the Asiatic tropics. A tall deciduous forest tree or a giant conifer takes two or three hundred years to grow to similar proportions, but it is a fact that a single culm, depending on the kind, will reach its full height in from 40 to 60 days. Indeed the growth-rate is so rapid that it is measurable by the hour. Lock in his measurements of the growth-rate of giant bamboos says that the greatest growth observed for 24 hours was 46 centimeters, while the greatest recorded growth per hour was 23 millimeters. Growth was found to be more rapid by night, and seems to be at all times affected by external factors, rainfall, temperature, and wind. The curve of growth by day follows closely that of the percentage of moisture in the air. 

The conical bud when ready to spring upward from the node of the rhizome swells until it is thicker than the rhizome. Because of its tender character, it is well protected with sheathing bracts, which originate from the joints already formed within the bud. The thickness of the bud at its widest part is an indication of the probable diameter of the future culm. In the shoot the nodes seem to be the first parts developed. In a longitudinal section they are seen to lie flat one on top of the other like a pile of plates, with the pith between them larger and thicker on the bottom and tapering off to the smaller and thinner at the top near the growing point. When elongation commences, the growth activity is centred entirely in the internodes, all internodes taking part for a time nearly simultaneously but in ascending order, the lowest as usual completing its growth first. As the nodes draw away from each other, the pith breaks, and the characteristic hollow-spaces of the internodes develop. It is this co-operative growth of the internodes which brings about the tremendous upward push of the shoots. Just as remarkable is the fact that before a culm has attained its height, its diameter has already been determined; in fact, not six inches behind the growing point may its final thickness be observed. Beyond this point growth is in one direction only. The size of the culm therefore, cannot be said to increase with age. 

As each internode reaches its full length, the sheathing bract generally drops off, exposing the dark green culm. The wood is soft and may easily be cut with a knife. If cut down at this stage, however, the culm will dry out, shrinking to a more shell and badly warping at the same time. This is because it is 80 per cent water. In three to five years the fibres of the culm, if left, will harden sufficiently to allow of cutting. To insure perfect preservation of form and strength, it is better, however, to wait until the culm turns yellow. This may take ten to twenty years, depending on the kind of bamboo. Of the many useful and interesting characteristics already mentioned, its rapid growth is perhaps the most economically important, as well as the most surprising. 

The last though not by any means the least important fact of its life history which has a real economic bearing is its habit of gregarious flowering. Some bamboos flower annually or sporadically here and there, but a great many burst simultaneously into flower over the whole countryside, and only after an interval of many years. The flowering itself is not so important as the events which follow it. After a simultaneous flowering the entire crop of culms from the youngest to the oldest turns yellow and dies. It is a sign of maturity hastened into expression by favorable environmental factors. This simultaneity is due to the fact already brought out, namely, that the whole forest is one plant. There may be a preliminary flowering of a few culms; then the entire forest bursts into bloom. As a grass it follows the habit of grass. Wheat, oats, barley live a vegetative life for a time; then they reach maturity, flower, and die. 

Let us first consider the economic importance of the flowering. Perhaps its most important aspect is the production of seed. It may either fall to the ground to produce new rhizomes and a few years later a new generation of normal-sized culms, or it may be gathered and eaten like rice. In the natural course of things, the first alternative takes place. Thousands of seeds fall to the ground and the surviving seedlings eventually develop independent rhizome systems which interweave with adjacent rhizomes. The seedling culms of the first year are small and whip-like, giving place in the following years to increasingly larger ones till finally the characteristic size is reached. But it must be borne in mind that it takes three to five years for this to take place, and in the interim the bamboo industry of that particular region is inactive. Either bamboo must be imported or the people must wait for the flowering. 

In China and India there is a saying to the effect that bamboo flowers only when there is going to be a famine so that the people may come to gather the seed for food. Aug. Henry tells of an incident about thirty year, ago which happened near Ichang, During a visit to that district he came upon quantities of dead canes standing in a large tract of coniferous forest. He was informed that this particular species had flowered three years before and produced seed which had been gathered by the mountaineers and used as food. Mr. Shaw Stewart, the collector of Canara on the Western Coast of India, states that in 1864 there was a general flowering of the bamboo in the Soopa jungles, and a very large number of persons, estimated at 50,000, came from the Dharwai and Belgaura districts to collect theseed. Each party remained about ten to fourteen days, taking away enough for their own consumption during the monsoon months, as well as some for sale, and adds that "the flowering was a most providential benefit during the prevalent scarcity."' A student reported that six years ago in Hunan in the district of Hung Shan Hsien (衡山县). there was a famine, but the bamboo flowered and saved the people. Enough was gathered for food and some in addition for sale in the markets. 

There is, however, another less happy side to this wholesale production of seed. Hackel reports that calamity as well as benefit may follow in the wake of a general flowering of bamboo. He says that in Brazil as well as in India, the sudden production of great masses of rich grain in widespread localities serves to increase the available food-supply for rats and mice to such an extent that they multiply to extraordinary numbers. After consuming all the fruit of the bamboo they naturally overflow into the neighboring fields and devour the crops. The German colonies in Rio Grande du Sul and Santa Catharina were visited by this plague at intervals of about thirteen years, which apparently represents the periodicity of the particular species covering that region. 

It is evident that as a rule bamboos do not flower often, but require many years to mature, after which they flower and die. Those which do not exhibit gregarious flowering may have had their periodicity disturbed by certain external factors which in one case retarded and in another hastened it. Upon close analysis, however, it would be seen that the characteristic periodicity in the case of individual plants was still maintained, that the seeming breakdown of periodicity was due to the presence of several different plants of the same species. Hereditary specificity combined with response to external conditions may account for this. The extensive overlapping of flowering periods serves to keep up the illusion. The remarkable phenomenon of gregarious flowering is the most convincing evidence of the physiological unity not only of the immediate bamboo forest alone, but also of such cuttings and offshoots that may have been taken away. Messrs. A. and C. Riviere relate an instance of comprehensive gregarious flowering in Europe. In 1867 flowers began to appear on two clumps of Arundinaria japonica in the Bois de Boulogne. At the same time they were noticed on the same species in the nursery gardens of Messrs. Thibaut and Keteleer at Sceaux, at Marseilles in the pleasure grounds of M. Paulin Talabot, and in other European collections. Stranger than this, across the Mediterranean the plants of A. japonica in the Government gardens of the Hamma at Algiers were observed to be flowering; not only the old canes but the young shoots also. It was found upon investigation that the whole of the plants then in cultivation in Europe and at Algiers were but off-springs of the parent plant introduced by Siebold in 1850, There are other instances reported. Sir Joseph Hooker states that cultivated plants of Chusquea abietifolia, a climbing bamboo, flowered at Kew gardens simultaneously with the wild ones of Jamaica. In China the same thing has doubtless happened, but accurate accounts are not available, or at least have not yet come to light. It is remarkable how far-reaching the effects of a single flowering may be. 

Though the rhizome usually dies with the culms, there are many instances recorded where it has not been entirely exhausted by flowering, but has recovered in certain parts sufficiently to put forth new shoots and begin anew. This dos not do away, however, with thee dearth of building materials consequent upon the flowering of the bamboo. Just the same, it makes the people realize what part bamboo plays in their lives. The wiping out of a bamboo forest by whatever means is a real loss, and its recurrent happening must be looked upon as an economic factor in the business and domestic life of the community. Nevertheless, it must not be overrated. It is only a temporary loss, and then again the event is comparatively rare. Some of the intervals are 10, 15, 30, 32, 35, and 60 years, according to the species, in comparison with which the life of man amounts to but little more. During his life he stands one or two chances at the most of experiencing a general flowering of his crop of bamboo. In general, nothing much is said about it, or the scarcity of data on the flowering periods of our bamboos would not be so evident. In buying land the question of whether the bamboo crop may be a total loss next year does not enter into the negotiations. At the time of the flowering, however, one can scarcely overlook the fact that the loss involved is a most inconvenient handicap to the community. 

Given a tract of land that is covered with a good stand of bamboo, the Chinese farmer shows his regard for his forest wealth by taking particular pains to mark each culm with his Chinese character to insure at least a nominal immunity from theft. If he gave as much thought, however, to the cutting of shoots and culms as he does to the preservation of his personal property, he would reap a crop of canes that in size and value would more than pay him for his extra trouble and anxiety. What is really needed is an improved forest technique for bamboo, as carefully worked out as it is for the deciduous and evergreen forests of Europe and America. This is necessary in order to preserve a maximum growth and constant supply of culms. Owing to the tremendous demand for bamboo, it is perfectly natural that the farmers should seek to satisfy that demand, just as far as it is to their advantage to do so. With trade coming their way, the temptation to extend their cutting lo younger culms in order to send down to the market a larger number is too strong, and the result is overcutting. This is decidedly weakening to the plant, as the leaf-bearing culms are its synthetic organs. There is a zero point in the relations between the production of new shoots and the cutting of old culms beyond which the farmer cannot go without impairing the normal life of the plant. It is impossible to keep up the production of normal full-sized shoots when cutting goes beyond the zero point and upsets the balance. It is" the old problem of commercializing natural resources without regard for the future. In this case, however, our attitude must be more concerned than that of the men who have watched with regret the passing of the great forests of North America through ruthless cutting. With the ordinary deciduous or coniferous forest the treatment of an individual tree does not injure those standing by; if anything, its removal is an advantage, since, as a result, there is more light, more space, and more available supplies of food materials in the soil. But as has been stated, the nature of the bamboo plant demands that less casual attention be paid to the cutting; that since a single culm is but a shoot of a far-reaching plant, intelligent principles be used in handling that culm, lest the whole forest suffer. 

There is good evidence that this is a fault regularly displayed by the Chinese farmer, and the effects may be observed by anyone interested enough. Two patches only are known on the whole of Mokanshan, near Hangchow, Chekiang province, where Phyllostachys pubescens, locally known as Mau tsok, 毛竹, the largest lumber bamboo in the Yangtse valley, has reached its finest development; one is in the Mt. Clair district on the Tucker property, the other is on the south slope of the mountain beyond the Camp. The culms in these groves average five to six inches in diameter, but they are positively watched and guarded. Over the rest of the hillsides the culms though labelled are undersized, averaging at most two to three inches in diameter; and stumps are everywhere to be seen. Furthermore, these stumps by measurement indicate that the culms which in the past stood in their places were thicker. The region round Shanghai is not essentially bamboo-growing country, but there are many isolated groves, chiefly of Phyllostachys bambusoides, which are productive. These show the same trend as the others, but in lesser degree, probably because we are here deal- ing with a smaller bamboo. The fault lies not so much with the farmer as with the agent to whom he sells his standing crop. The latter cuts the whole lot, leaving only a few undersized culms to carry on until the plant can recuperate and re-establish itself. After four years he will begin cutting again, and then after the grove has grown beyond his own needs, he again contracts for the whole stand. One must consider also the annual picking of the early shoots as or before they appear above the ground. These are good to eat and are sold in the markets for a good price. Altogether, we have a grove which promises well but never produces more than undersized culms. The explanation is over-cutting. 

There is one further illustration of the effects of over-cutting. It is a regular practice in green-houses where bamboos are grown in tubs or pots to cut back not only the culms but also the rhizome, so that the culms may not become too large. Clumps of bamboo growing on restricted areas in the garden are treated by force of necessity in the same way, with always the same result. 

Some mention has been made of the cutting of bamboo shoots. The young shoots of some bamboos are very edible, and they form one of the chief items of vegetable diet in the Far East at certain times of the year. They possess a crisp juicy flesh, like that of a potato or of certain kinds of apples. Foreigners in the Orient enjoy them as much as the Chinese themselves. In fact, the demand for shoots has grown so much that canning factories have been established at Ningpo and Amoy. Now bamboo shoots may be enjoyed at any time of the year. Annual exports of bamboo shoots from Foochow to Amoy are estimated at 80,000 catties. The current price is about $2.50 per 100 calties. Like eggs in China, all shoots gravitate toward the tinning factories. The temptation to the farmer is obvious, and the result is increasingly smaller shoots, as in the case of the culms. Therefore, in considering better methods of cultivation in China to increase the production of bamboo and to secure greater benefit thereby to the country, the question of cutting must be considered seriously. 

To sum up, cutting should not be for the sole purpose of obtaining an immediate return. Some thought should be expended on the future. Cutting should therefore be in the nature of a thinning process. Just as appropriate trimming and pruning will increase the yield of certain trees, so with bamboos scientific cutting will not only in time yield a large immediate crop, but also by throwing the strength into fewer culms will gradually increase the height and strength of the forest, and will assure an increased yield for the future. In the scientifically treated groves of Japan and elsewhere, all shoots that are left to grow up are labelled with the year so that the age of the culm in each case is known and none are cut down before they are hard. The proper age for cutting is eight or nine years. When a recently planted grove of bamboo becomes thick and dense, that is not necessarily the time to begin cutting. Some thinning may have to be done, but ordinarily the grove does not begin to produce before eight years. After that lime if accurate records of the ages of the culms have been kept, the cutting of them alone will have effected a sufficient thinning. 

In regard to cultivation, the native practice in China deserves attention. In the Yangtse valley as the winter draws on and the wheat has been successfully started, the farmers turn their attention to various side-lines and specialties. In some villages it may be basket-making, in others, the weaving of certain kinds of figured silk. But among the various duties performed during the slack season which are more or less cognate to the business of farming, are the raising of winter vegetables and the cultivation of the bamboo patch. The soil over the area occupied by the bamboo is dug up and the clods of earth pulverized after which fertilizer is put on. The fertilizer most used is creek mud. During the low tides of winter and the accompanying dry season the water in the ponds and canals is very low. The bottom mud of these ponds is very rich in necessary mineral food making substances ; so by using it, the farmer not only gets a good fertilizer but also secures the extra advantage of ponds dredged clear of the muck which has silted down into and nearly filled them during the rainy seasons. Manure fertilizers are also used with success. Horse and cow manure is also worked into the ploughed up earth and afterward covered with leaves in some of the foreign garden and parks. This protects them from frost in winter and, by preventing evaporation, keeps the underground stems moist in summer. One chemical fertilizer has been approved for bamboo cultivation. The formula for this compound is as follows: three parts super-phosphate of lime, one part ammonium sulphate, and one part calcium sulphate. Five hundred kilograms are sufficient for one hectare, which is a little over two acres. The application, however, must be made three times; the first time around February l0, the second time when the shoots are about three meters high, and then a month later. 

We come now to the important subject of the propagation of the bamboo. Propagation is accomplished in four different ways : first, by the natural way, by seed; second, by division; third, by cuttings at the base of the culm with or without the rhizome attached; fourth, by cuttings of the rhizomes. A fifth process, propagation by layering, is available in the case of the autumn-growing or tender bamboos. 

Propagation by seed, although the natural method, is the least efficient. In the first place, the intervals between flowering periods are usually so long that seeds are rare. If the spread of bamboos had depended entirely on seed distribution, there would have been considerably fewer groves than now. Furthermore, they would have been crowded out by the more recent and more quickly-maturing plants. In the second place, the ravages of rodents as described above and the tremendous gathering of the seeds by the people reduce the possible productivity. The seedlings succeed best if they can be sheltered and cared for, but in nature the chances for this are rare and accidental, and consequently what is not scratched up by animals or trodden down by men may wither from lack of moisture, poor light, or deficient soil. Undoubtedly quantities of seedlings do survive and produce forests, a phenomenon which has been witnessed by many observers, but even then it takes years for the embryo forest to become truly productive. From the economic standpoint this is hardly a desirable method of propagation. 

The second method, that of multiplication by division, is the one carried out locally in the Yangtse valley, where the distance over which the divisions are to be carried is not great. The process is simple enough. A clump of two culms one or two years old with a length of connecting rhizome is lifted with as much earth as can be carried and planted direct on a new site. With proper moistening and top-dressing with manure and leaves, the buds on the nodes of the rhizome or at the base of the culms will grow and produce new culms and new rhizomes in the next spring. If twenty or thirty pairs of these culms are planted out at distances of two feet, a whole forest can be started immediately, and in four years the new rhizomes will be spreading out, becoming entangled in an extensive underground mat, and sending up normal culms which in a short time will be ready for use. The economic saving is obvious. Whereas three or four years are wasted in developing and establishing rhizomes from seeds before even fair-sized culms begin to appear, and that only after an infrequent -periodical flowering, from transplanted divisions with a rhizome already present and buds already formed the preliminary periods of development are eliminated. In other words, we start with something and time is saved. Moreover, divisions and cuttings are likely to be more vigorous. A still more important consideration is the fact that we do not have to wait for flowering to take place. Usually about the ninth or tenth month of the Chinese calendar is the season for this kind of propagation. 

In the vicinity of Luchow in the province of Szechwan bamboos are propagated by cuttings of the base of the culm with the rhizome attached. This is usually done before the shoots come up. A short section of one or two year old rhizome is dug up with one young culm attached, which is cut off five feet from the ground. The underground parts are encased in mud and when planted are sunk deep enough so that the two or three lowest nodes of the culm are completely covered. Care must be taken that the newly planted cutting is well watered. 

Propagation by cuttings of the rhizome alone is a still more simple process. Lengths of from six to eight inches are planted at a depth of four to six inches in rich loam and watered well during the summer. The cutting should always be from the growth of the preceding year, for these contain the buds still in a living condition, Shoots from the nodes of these will appear the following spring as in the preceding cases. " 

Locally, propagation by the second method is more convenient though not any more effective than by the third. Also, there is some advantage in carrying along a leaf-bearing culm inasmuch as the nutrition of the plant will not then be unduly disturbed. For transportation to distances, however, because of their small bulk, the third and fourth varieties of cuttings are found to be more economical. The difference between the third and fourth is that a better start may be had by the former. Since the spread of the bamboo plant primarily depends on the growth of the rhizome, the sooner the new rhizome commences fo grow the sooner will the plant become productive. New rhizomes spring from a node of the old rhizome where the base of a culm is attached. Transplanting with a piece of the culm attached, therefore, is of some advantage. 'Without the culm, as in the fourth method of propagation, sufficient time will be required first to pro- duce a few small culms and then a new rhizome bud will develop. Practical- ly a year is gained by using the third method. Certainly from many points of view, principally because it combines the good points of both the second and fourth, the third commends itself to commercial use, The practice in general then is to make cuttings of whatever kind from the young parts of the plant. Moisture is of prime necessity at all times. Transplanting may be done in the first, second, eighth, ninth and tenth month of the Chinese calendar and when the shoots do come up, great care must be exercised not to jar them or trample on them lest they be injured and cease to grow. In this case a whole year's growth will be lost. 

After the shoot has attained its growth, it is pretty sure to survive. It has, however, one enemy against which provision should be made. Wind is very destructive, not directly but through the lashing of neighboring culms. The wood of the new culm is soft and cannot stand continued strain or sudden shock. Consequently, before a heavy typhoon wind the desperate lashing of the hardened whip-like tops of the older culms either breaks off or permanently injures the growing-point or beats down and destroys for further use the young culm. In order to provide for this emergency the custom is to trim the drooping tops so that less surface is left for the wind to catch, and the culm like a shaft rises straight to the cut end. The same thing is done to bamboos which inhabit the mountain sides at higher altitudes. Here snows are frequent during the winter. If the tops were not cut off, the added weight of the snow on the tips would be disastrous. The culms would buckle lower down and even though they lived to harden, they would be useless for anything but fuel. The culm does not break clean off but, owing to the unequal strain due to bending, several longitudinal splits occur, usually in the internode, which suffers the greatest strain and in consequence collapses, Trimming results in a tremendous economic saving, for even though the weak terminal sections, which are useless anyway, are cut off, the lower parts which bear foliaceous branches will continue to harden and when the time is ripe will be fit for use. There is still one further reason for pruning the tops. In such species of bamboo as are especially productive of edible shoots as Phyllostachys mitis, Riv. (Kiangnan 江南竹) , it pays to cut off the top of the culm because this diverts more of the plant energy into sprout production. Accompanied by proper soil treatment, this procedure brings in greater returns, as not only is there as a result a larger number of fleshy sprouts to be had in April and May the regular time for cutting, but the number of winter shoots which though smaller command a higher price will be greater also. 

The practices employed in the cultivation and general treatment of bamboo in China, as has been shown, are outgrowths of custom and the experience of generations. They are mostly good, but by scientific study and standardization they could certainly be improved with beneficial results. The experience in India, the Philippine Islands, and Japan shows this. At present in China no specific instruction in bamboo forestry is offered in the schools of Agriculture or Forestry. Even knowledge of the facts is still in a vague and disorganized state. At Canton, investigations are being carried out by Prof. McClure of the Canton Christian College. The Nanking University Forestry School has one graduate student pursuing the study of bamboo solely. The rest of the contributions are chiefly from independent observers or from outside sources. The Chinese Government Bureau of Economic Information has investigated bamboo to a certain extent, but with the tremendous field which this organization has to cover, it is obvious that not much of a comprehensive nature has been done along this particular line. Moreover, any comprehensive survey demands the co-operation of specialists. We repeat that to put the bamboo industry of China on a productive basis proportionately equal to that of other Eastern countries, a special forest technique worked out scientifically needs to be developed and taught along with other subjects like sericulture and animal husbandry.