Moso bamboo

General information about Phyllostachys pubescens

1 General description of moso bamboo ( Phyllostachys pubescens)

1.1 Moso bamboo's biological characteristics

Character of Ph. Pubescens

Culms over 20 m tall, 6--18 cm in dbh. Internodes at midculm reaching 40 cm in diameter. Culm wall thick, young culms dense pubescent, thickly pruinose; on the culm without branching , culm annulus indistinct, sheath annuals slightly convex with deciduous setae; sheath scar prominent, sheath thickly covered with brown hair and dark brown specks; sheath auricles short, with developed humeral hair; sheath ligule short and broad, bow-shaped, with both sides drooping; sheath blade green, long triangular or lanceolate; leaves narrow and small, 4-11 cm long, 0.5-1.2 cm wide. Shoot period end of March and beginning of April. The most important bamboo species for culm and shoot production. The shoot is delicious, eaten fresh, or processed as canned food or dried food. The culm is used for processing in manufacturing or used wholly (Wang 1987; Zhu 1994).

1.2 Growth of moso bamboo

Moso bamboo is a monopodial bamboo. Its growth includes the growth of rhizome, culm (shoot® culm formation® timber quality) and stand (Hui 1996).

Rhizome growth

Rhizomes grow mostly horizontally and undulating in top 15-40 cm soil. A rhizome is composed with rhizome tip, rhizome body and rhizome handle, all come from the growth of rhizome tip. Rhizome tip grows 5-6 months and alternatively with shooting, from April or May to the end of October, the growth peak is between July to September.

Shooting and its growth

From July to September the lateral buds of rhizomes differentiate to shoot buds that grows slowly in length and mostly in diameter by its cell division. In winter the shoot buds turn into greater shoots, namely winter-shoots. In March or April the temperature begins to increase, winter-shoots come up. The shooting stage lasts 40-45 days and its peak is about 15 days.

It takes 50 days from the emergence of shoots from soil to new culms. The tempo of height growth of shoots is a S-curve, namely slow-fast-slow rhythm. The mean dairy growth rate of young culms is 30-50 cm, the biggest is greater than 100cm.

Before the emergence of shoot from soil the number of nodes is definite. After that, internodes elongate by the cell division of intermediate tissue. Young culms are formed by elongation of internodes. At the beginning of young culm growth the upward growth rate is small, but the horizontal growth rate of the internode is pronounced. Thereafter the internodes under the soil stop growing and bamboo roots begin growing at a large number into root system. At the same time the internode growth accelerates until its peak time. At peak time internodes grow fast and steadily, at this time the culm sheaths at the base of culm begin to fall, the upper braches begin to spread and the culm growth rate slows down. At the end the top of young culms bend, its branches spread fast, young culm growth rate slows down till ending. When all the sheaths have fallen and all branches and their leaves have unfolded, a new culm has beens developed. Thereafter the height, diameter and volume of culm are stable and do not change noticeably, but the quality of culm will change, it has three stages:

the stage of timber quality improvement(new culm to 5 years old): A young culm, supported by a strong rhizome, is vigorous. With age increase, root system development and leaf exchanging, chlorophyll, sugar, and other organic matter become richer and richer. At that time the physiological activities are the strongest and it reach the peak time of rhizome growth and shooting. Meanwhile in the cells water content decreases and dry substances increase, cell walls become thicker, as the result the lignification of the culm is complete.
stable stage(5-9 years old): metabolism of the culm stabilizes with rich nutrients and active physiological activities.

c. declining stage(after 9 years old) : The bamboos are aging and declining in physiological activities, because of the substance consumption of respiration and substance transportation, the culm weight, mechanical strength and nutrients content are gradually declining, so culm quality declines.

Stand growth

Grove growth habit can been classified as two types: on-andoff year groves and even year ones.

Onandoff year grove

Most of moso groves in China are onandoff year groves. In an on year the grove shoots in a large quantity compared to an off year in which it shoots relatively few. In an off year the grove mainly develops rhizomes and exchanges leaves. On year and off year appear alternatively.

Even year grove

In an even year grove shooting and rhizome growth occur each year at a relatively equal quantity.

1.3 Moso bamboo's distribution

The natural habitat of Ph. Pubescens extends approx. 23°30'--32°20' N and 104°30'--122° E. It grows at elevations between 10-1700 m above sea level, most of the area is less than 800 m and in the hills and mountains. Those provinces are Zhejiang, Fujian, Jiangxi, Hunan, Hubei, Sichuan, Anhui, Jiangsu, Guizhou, Guangdong, Guangxi, Yunnan and Shan'xi. The central forest area of Ph. Pubescens is between 25°--30° N and 110°--122° E. 81.2% of the moso' total area is in province Zhejiang, Fujian, Hunan and Jiangxi. Fig 311 gives the distribution map of moso bamboo in China (Forest Division Office of Forestry Ministry 1992).

Widrlechner (1997) published "Hardness Zones in China". In comparison with the hardness zones, moso bamboo is located in zone 7, 8 and 9. Zone 7, 8, and 9 have mean annual minimum temperature -17.7-- -12.3, -12.2-- -16.7, and -6.6-- -1.2 °C respectively.

At its vertical distribution moso bamboo distributed higher in connected mountains than in isolated mountain, as well as higher in higher mountain than in lower mountain. Moso distributed mainly in hills and mountains in the form of pure stands or mixed stands, and is planted sporadically on plain and platform. The best suitable distribution is in the low mountains with the sea level of 500 -- 800 m.

1.4 Site requirement for Phyllostachys pubescens:

Climate

Moso' distribution belongs to subtropical monsoon climate. The mean annual temperature varies 15--21° C, with mean temperature of the coldest month being 1--12° C, and that of the warmest month 26--29° C. Moso bamboo can withstand - 18 -- - 20.9 °C in the winter. The annual Precipitation is between 800--1800 mm. The restricted factors for moso' distribution are the annual precipitation in the north (<800 mm) and the mean annual temperature in the south (>21° C) .

The key factor for moso bamboo growth is rainfall. It is optimal for moso bamboo when the rainfall reaches 400 - 600 mm by shooting time. A drought in Autumn affects shoot bud division and conduct, consequently production decreases the next year.

Soil and geology

In moso bamboo distribution zone the soil types are red soil ® yellow soil ® yellowish-brown soil from the south to north or from low elevation to high elevation. Red soil is the dominant soil type in this area. The suitable conditions are as follows:

60 cm deep fertile loam, pH = 4.5 - 7.0

moist but specially not having accumulated water in soil

When > 0.1% salt content or pH > 8.0, moso bamboo grows badly.

Topography refer mainly direction of slop, gradient and elevation. South slope is better than north slope, south east slope better than north west slope. Mountain valley, the foot of a mountain, and gentle slope are suitable to moso bamboo growth.