FUNDAMENTAL RESEARCH ON TYPIFICATION
OF BAMBOO STANDS
  In order to manage bamboo stands efficiently, it is necessary to understand the different types. Watanabe (1968) proposed that this typification needed to take into account life form, propagation form, growth form and culm size (Figure 1). By establishing a number of types of stands, it is possible to consider their management, irrespective of the species and genotypes, because each ecological type can be managed according to the ecology.

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Fig. 1 Typification of bamboo forests by Watanabe, 1986
STAND STRUCTURE
  Following basic studies by Numata et al. on density and distribution of plants within stands and the application of theoretical considerations of dispersion of populations (Lloys, 1967, Iwao, 1968), the parameters mean crowding and mean density can be measured and plotted.
  It is possible to determine the m-m relation, where m indicates "mean crowding" and m indicates "mean density", and the dispersion pattern of population can be discussed by the relationship between m and m. A number of patterns emerge, e.g m=m means a random distribution, but m>m means an aggregate distribution. Also, the m-m relation can be expressed by the equation of m = + m.
  Application of this measured dispersion provides an objective, quantitative description of the stands and this assists greatly in deciding management options for selective cutting. This quantification has been applied to the ecological types (Watanabe 1986), especially to those natural stands which are not managed.
  Figs. 2 and 3 show examples of stand, structure of standing bamboo, and its dispersion patterns using the m-m relation. In the case of a long term non-managed Phyllostachys bambusoides stand in Kyoto, as shown at Fig. 2, the dispersion pattern shows

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  Fig. 2: Distribution of standing bamboos (left) and m - m relation (right) in Phyllostachys bambusoides stand, Kyoto by Watanabe, 1987

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  Fig.3: Distribution of standing bamboos and clumps (left) and m - m relation (right) in Thyrsostachys siamensis forest Kanchanaburi, Thailand by Watanabe, 1987.
  almost poisson, or random distribution with small colonies existing.
  Since temperate Phyflostachys bambusoides bamboo tends to form a diffuse - form stand, the pattern of random distribution with randomly distributed small colonies must be normal under natural or nearly natural conditions. Knowing the dispersion pattern of standing bamboo is important for control of stand density in actual management.
  Fig. 3 shows the stand structure of standing bamboos and clumps in a tropical clump-form stand, and its dispersion pattern by m-m relation of Thyrsostachys siamensis in Kanchanaburi, Thailand. The stand is composed of scattered large and small sized colonies and can be subjectively seen. However, m-m relations shows the structure to comprise compact clumps in a somewhat aggregated distribution.
  It could be thought that tropical clumping bamboo has a tendency to distribute clumps at random, which is the same character as shown in individual clums distributed at random in temperate bamboo. An aggregate distribution of compact clumps might be, however, not ideal when looked on dispersion pattern.
  Wider application of the m-m relation to determine stand structure can be expected to have important applications on the sustainable management of stands.
PRODUCTIVITY
  Ueda (1960, 1963) investigated the productivity of temperate
Table 1 : Annual production of culms by selective cutting method in diffuse-form stands in Japan.
Species Site Number (no/ha) Fresh wt. (ton/ha) Dry wt. (ton/ha)
Phyllostachys pubescens

 

Phyllostachysbambusoides

 Good Ordinary Poor

Good Ordinary Poor

 500
800
1,000

1,200
1,700
2,000

 19.0
13.0
6.0

14.0
9.0
5.0

 11.4
7.8
3.6

8.4
5.4
3.0
Note. Dry weight was estimated by fresh weight as 40% of water content.
Table2:Above-ground biomass in  diffuse-form stands.
Species DBH Density

Dry weight

(cm.)
(no/ha)		 Culms (ton/ha) Branches (ton/ha) Leave (ton/ha) Total
(ton/ha)		 References
8.3 4,500 40.6 7.3 3.1 51.0 Suzuki,
P.pubesrens 9.3 5,100 49.2 9.2 4.2 62.6 1976
9.2 8,800 87.6 12.5 5.5 105.6
P.pubescens 7.0 6,120 36.5 8.2 3.5 48.2 Kao,Y.-P.,
9.4 5,120 63.5 11.0 4.8 79.3 1986
P.{iuhescms 9.6 3,700 43.2 8.3 3.9 55.4 Wang, T., 1981
P.bambusoides 2.6 18,300 12.6 3.5 3.3 19.4 Watanabe
2.9 22,000 23.2 7.1 6.9 37.2 et al., 1978
P.banibusoides 5.4 7,250 25.5 4.4 1.9 31.8
5.5 10,750 41.3 7.0 3.1 51.4 Wantanabe,
5.6 12,800 52.1 8.7 3.9 64.7 1983
3.1 15,800 17.3 4.4 1.4 23.1
3.9 16,800 29.3 7.1 2.4 38.8
4.5 10,400 28.3 6.5 2.6 37.4 Watanabe &
P.bambusoides 4.5 6,700 15.7 3.8 1.6 21.1 Ueda,1976
5.0 8,800 27.8 6.6 2.4 36.8
7.2 8,900 61.2 13.7 6.0 80.9
8.7 4,800 55.2 12.4 5.4 73.0
3.0 26,200 28.0 5.4 3.8 37.2
P.nigra v. 3.6 18,000 28.0 5.8 3.4 37.2 Suzuki &
henonis 3.8 23,800 40.0 7.4 6.0 53.4 Uchimura,
4.4 15,200 36.6 7.2 4.4 48.2 1980
6.6 13,800 73.6 12.6 9.2 95.4
  stands under various degrees of cultivation and measure dannual production. To the  data of Ueda in Table 1 have been added dry weight production,estimated as 40% of water content in fresh weight.
  Productivity studies are now more focused on the ecosystem and estimation of biomass. Uchimura (1972) looked at biomass in P. baniusoides stands which were recovering from flowering. Since that study, biomass estimations have become more routine.
  The above-ground biomass in temperate Phyllostachys stands in Japan and Taiwan are summarised in Table 2. In dealing with production in the material cycling of ecosystems, the production is usually expressed by weight in a definite area and period. This production is called productivity.
  Net production is the newly produced biomass in a certain period. Few studies have been reported to date, but these are summarised in Table 3. More research is required because productivity is greatly affected by species, genotype1 G X E interactions and management.

Table3:Net production in diffuse-form stands.
Species DBH (cm) Density (na/ha) Net production (ton/ha, yr)
Culms BralKte Leave SheaBis Total		 References
8.3 4,500 5.0 0.9 3.1 1.2 10.2
P.pubescens 9.3 5,100 8.3 1.5 4.2 1.6 15.6 Suzuki,1976
9.2 8,800 6.0 0.9 5.5 1.7 14.1
P.pubescens 7.0 6,120 5.3 1.1 2.3 0.5 9.2 Kao, et al.
9.4 5,120 10.8 2.1 2.2 0.5 15.6 1986
P.pubescens 9.6 3,700 9.1 1.8 3.0 13.9 Wang,1981
P.bambusoides 5.5 10,750 14.3 2.3 3.9 1.2 21.7 Watanabe,1983
5.6 12,800 9.7 1.6 5.2 1.7 18.2
3.0 26,200 3.6 0.7 2.3 * 6.6
P.nigra 3.6 18,000 3.6 0.7 2.0 * 6.3 Suzuki &
v. henonis 3.8 23,800 4.9 0.9 3.6 * 9.4 Uchimura,
4.4 15,200 5.0 1.0 2.7 * 8.7 1980
6.6 13,800 6.0 1.1 5.2 * 12.3
Note:*Sheaths are included with leaves.
STAND DENSITY
  An extremely important aspect of sustainable management is the control of density in stands. In order to maintain consistent high yields each year, density has to be controlled.
  Ueda (1960) measured stand densities (Table 4) and Uchimura (1972) developed a plot of stand density and average diameter of stand, which permitted the theory of density control based on the adoption of a density index.
Table 4: Stand density of diffuse-form stands.
Species Site Number (no/ha) Fresh wt. (ton/ha) Drywt. (ton/ha)
 

Phyllostachys pubescens

 Good 4,000 154 92
Ordinary 6,000 96 58
Poor 8,000 51 31
 

Phyllostachys bambusoides

 Good 8,000 93 56
Ordinary 12,000 53 32
Poor 15,000 39 23
Note:Dry weight was estimated by fresh weight as 40% of water content
Table 5: Stand density and determination of crop per ha in stands of Pyllostachys bambusoides.
Mean of

D.B.H. (cm)

 Stand

density

 Determination of crop
3 40,000±6,000
4 22,000±2,500 Unproductive stand (Small diam. Stand)
5 15,000±2,000
6 10,000±l,500 Ordinary stand (Medium diam. Stand)
7 7,500±l,200
8 5,500±l,000
9 .4,500±500 Productive stand (Big diama. Stand)
10 3,500±500
Note: Original table showed stand density per 0.1ha.
  Regarding stand density, Uchimura (1972) also showed standard determination of crop per definite area in Phyllostachys bambosoides (Table 5). These data, based on modern ecology, are valuable for sustainable management. Uchimura (1994) has recently published a Japanese book introducing the value of this type of research to the general public.
FLOWERING
  During the 1960's and 1970's, stands of Phyllostachys bambusoides flowered simultaneously throughout Japan, causing a panic in bamboo industry. Hence, it is very important to have data which give information on the genetic trait of flowering in the sense that time intervals can be predicted. Watanabe et al.(1981) recorded time intervals, as in Table 6.
  It is a very important problem how stands biologically and ecologically recover from the destruction by flowering. Figure 5 shows the recovery from a flowered stand, which had been well managed and had adequate density control and fertiliser application. Dry weight increment of culm during 5th to 12th years after flowering increased year by year, and reached a maximum at the 11th year. This confirms the old Japanese saying that flowering is like a "ten year withering disease."
Table 6: Exact records of flowering interval
Species Country interval
(years)
Bambusa arundmacea (bambos) Brazil 31-32
Btimbtisa arundmacea (bambos) India 45
Dcndrocalamus strictus Cuba 44
dendrocolamus strictus Taiwan 47
Guadua trinii Argentina 30
Phyllostachys dulcis U.S.A. 43
Phyllostachys pubescens Japan 67
Thyrsostachys oliveri India 48

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Fig .4 :Full density curve and stand densety index of phyllostachys reticulata.

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Fig.5: Incenent of standing crop in recovering from floweringin phyllostachys bambusoides stands.
JAPANESE RESEARCH IN OTHER COUNTRIES
  Much research by Japanese scientists has been reported on tropical bamboo forests. The pioneer was Ueda (1960, 1966) and he reported fundamental research in natural bamboo forests in southeastern Asia. His recommendation (1966) on bamboo resources for pulp and paper making in Thailand was a landmark at the time.
  After that, many papers on tropical bamboo forests have been published from Japan. For example, Watanabe (1972) reported on afforestation using mixed bamboo seedings with leguminous tree seedings. Table 7 shows the result of a plantation of mixed Thyrsostachys siamensis seedling with Cassia fistula seedling in Kanchanaburi, Thailand. Even though the results were obtained after two growing seasons, the benefit of the nitrogen fixing is obvious. Wider use of such mixed plantings on poor soils in tropical areas will promote the growth of bamboo at lower cost.
Table 7: Growth aspect of Thyrsostachys siamensis and Cassia fistula seedings by mixed plantation after the second growing season
                                          Thyrsostachyssiamensis                                          Cassia fistula

Plot

 		Survival Bamboo newly produced Survival Growth
rate No/hole Ave.D Ave.H   Volume rate Ave.D Ave.H     Volume
  (%) (No.) (mm) (cm) (m3) (%) (mm) (cm) (irf)
A 95.8 1.2 3.9 49 11   - - - -
B - - - - - 91.7 9.2    49 54
C 83.3 3.5 6.6 84     243 - - - -
D - - - - - 100.0   17.9 98 378
E 87.5 1.9 4.2 54 23 95.8 5.8 37 19
F 72.9 3.4 7.9 110 374 95.8 9.9 66 129
Plot A= Planting of T. siamensis seedling
Plot B= Planting of C.fistula seedling
Plot C= Fertilising in addition to A
Plot D= Fertilising in addition to B
Plot E= Planting mixed T. siamensis with C.fistula seedling
Plot F= Fertilising in addition to E
Table 8 : Growth nf' culms, branches and leaves of Bambusa vulgaris propagated by cutting.
                      Stage of culm development
Characteristics

First year     

   Second year

1 2   3 4 5 6 7
Culms:
No. of culm (pc) 1 2 2 3 3 5 2
Length (m) 1.20 2.43 4.26 5.43 6.28 8.44 8.85
Diameter' (cm) 0.95 1.15 2.43 3.10 4.10 4.89 4.88
Green weight (gm) 10.5 69.65 445.03 1522.20 2651.0 5650.1 5414.97
Moisture content (%) 10.15 10.29 32.21 41.47 43.66 45.46 51.27
No. of node (pc) 8 12 21 30 33 38 35
Branches"
Maximum length (m) - 0.91 1.49 2.45 2.53 3.45 3.93
Green weight (gm) - 54.7 360.6 1300.5 1743.2 3923.6 3805.7
Moisture content (%) - 9.44 34.10 48.4 50.62 54.00 60.00
Leaves**
No. of leaves (pc) - - 306 2281 3566 6442 4753
Green weight (gm) - 29.5 354.6 693.9 2135.9 1623.1
*Diameter measured at 30 cm above the ground level.

**No data available ar the initial stages of elongationin the first year of observation.
  Various papers on ecological characteristics, productivity and propagation of Philippine bamboo have also been reported by Japanese scientists (Suzuki & Jacalne, 1986, Uchimura, 1978a & 1978c). Experiments on rhizome cuttings (offset) and culm cuttings of Philippine bamboo by Uchimura (1978a & 1978c) are reported in Table 8.

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