Forest Floor Bamboo pages
pastoral farms in New Zealand.
Bamboos are used extensively around the world for many purposes, amongst them stock fodder, erosion control and shelter. In New Zealand the main economic use of a bamboo so far has been in planting Bambusa oldhamii for horticultural shelter. There are many other species of bamboo already in New Zealand, that are suitable for planting on pastoral farms for economic gain. Their use has so far been limited by a lack of knowledge and in some cases, by a scarcity of plant material.
There are two basic types of bamboo: clumping and running. Bambusa oldhamii, the main shelter variety in New Zealand, is an example of a clumping type, along with all other Bambusa species. It forms a dense clump that gradually expands outward, so these types are more suitable for compact lines of shelterbelt, or when space is limited. The running varieties, on the other hand, spread by the advancement of underground rhizomes that may grow up to 10 metres each year in suitable conditions. They form more or less dense stands depending on the species, and the more vigorous running species are capable of covering several acres. The running types are very suited to erosion control due to their fibrous and tough root systems that can bind an unstable surface together. Less initial planting material is required to establish a running variety. For many reasons I regard running varieties to be most suitable for pastoral operations, especially extensive pastoralism.
Bamboos sometimes die after flowering heavily in old age. All the plants in a clonal line of one species may flower at once, then possibly die, thus potentially causing economic loss where they are relied upon. It is not known what causes this "gregarious flowering", but there is a tendency for it to occur in a cyclic pattern. The length of a cycle may range from a few years to over one hundred years, depending on the species. Although stands can often be re-established from seed, it is important to select species that have long flowering cycles or that are less likely to die when they flower. An effective strategy against possible gregarious flowering followed by death is to plant more than one variety on a site. In addition, many bamboos are shade tolerant and thus can be combined in mixed plantings with other types of plants such as tall shelter trees, including Pinus radiata.
Bamboos tend to be highly nutritious and stock love to get at them. However three points must be noted in relation to their edibility. Firstly several species of bamboo (mostly tropical ones) contain hydrocyanic acid in their new shoots, noticeable as a bitterness. This substance can cause poisoning if eaten in sufficient quantity, but is easily removed by boiling for human consumption. In some parts of the world (mainly the tropics), bamboo shoots are routinely protected from cattle for this reason, until the shoots have grown to full height, when they leaf up and the leaves are highly nutritious (more or less depending on the time of year). Many other types of plant that stock regularly eat contain small levels of toxins, it is only if they eat too much at once that there is any danger of adverse effects. Some species of bamboo are much less toxic than others, e.g. Phyllostachys species (especially P. aurea which is edible raw by humans). Shoots of several Phyllostachys species are eaten by dairy cows without any adverse effects.
Secondly, many bamboos are too tall for stock to reach the foliage and too strong for the stems to be pushed or trampled down. These must be chopped down and transported to stock (or thrown over the fence) to provide fodder. This is done overseas (typically with clumping Bambusa spp.) to provide large yields of high quality fodder during a drought. A possible alternative is to cut a stand, or part of it, to the ground regularly, to maintain low bushy growth, and then to graze occasionally. Next to a hedgerow of bamboo, some species have stems which grow outwards and curve over to within reach of stock. Some species are either short enough for stock to eat or they are relatively soft stemmed and easily pushed over.
This brings me to my third point, that stock can seriously damage stands of the less vigorous varieties if allowed to graze too often. Stands must be allowed to recover from heavy grazing otherwise they will dwindle, and they must be well established before any stock are allowed near. This means that the most vigorous varieties should be selected for grazing and also that stock can effectively be used to control even the most vigorous types of bamboo from spreading.
When used for the purposes of erosion control, bamboo must be allowed to establish to maturity on a site before it is grazed, if it is suitable to graze at all. Its productivity will reach a maximum when site and species and management are properly matched. Grazing must always be kept to a minimum to allow the stand to maintain vigour. Regular grazing may not be compatible with erosion control, but sporadic light grazing may help rejuvenate old dense stands. A recommended management regime would be to allow one or more vigorous running species to establish in a fenced off gully, by planting at intervals and using stock to control it from spreading beyond the fence lines. During a severe drought it may be cut down for fodder (large species) or stock allowed in for short periods. If enough planting material is available cheaply enough, it is advisable to plant lines of plants (at 3 - 10 metre spacing) to facilitate quick establishment. Clumping varieties may be planted even closer.
Planting material may be limited in several ways. Seedlings grown in containers are the easiest to establish, but are seldom available. Viable divisions off an established clump may be rather large, thus making transport difficult. It may be more economic to plant lots of small divisions, allowing for some failing to strike. The timing of propagation is critical, so division must take place at certain times of year so as not to interfere with shooting or rhizome development. The best time for transplanting most species is early Spring, with mid Autumn being suitable if good growing conditions exist to enable establishment before frosts. Container grown stock may be planted at any time of year, but in all cases the plants must not be allowed to dry out during the first few weeks of establishment. In most cases young plants are less hardy to extremes of climate than established plants.
As they are generally slow to establish, bamboos need a high standard of weed control around them for the first 1 - 3 years. The safest foliage applied herbicides for around bamboos are selective broadleaved weed killers, such as methabenzthiazuron (Tribunil) or clopyralid (Lontrel). The safest soil applied residual herbicide is oxadiazon (Foresite). In no cases should these be applied closer than 1 metre to a bamboo. Irrigation and fertilisation will greatly improve speed of establishment. A suitable balanced fertiliser (eg NPK 6-6-6, preferably slow release) should be applied in early spring.
Drains at least 600 mm deep and containing water will limit the spread of bamboos, as will stock, and most are very susceptible to herbicides, especially ones that kill grass. Mowing or slashing will easily control the spread of bamboo if done at, or shortly after the time when they are sending up new shoots, and breaking off the soft new shoots with one's foot is also effective.
In summary, the best varieties of bamboo suitable for planting on pastoral farms (especially extensive pastoralism) are running ones. A variety that is to be grazed, harvested for fodder, or used for erosion control must be vigorous and strongly running both to establish and recover quickly, and also to cope with possible droughts and poor soils. Thus a variety should be selected that is known to thrive in the climatic and environmental situation that it is to be grown in. A high standard of post-planting care is required, although big plants are increasingly hardy. A range of species (at least 2) should be planted together to hedge one's bets, considering both a range of bamboos and a mixture of bamboo and tree species. Properly sited and attended, the right bamboos can yield large amounts of high quality drought fodder, a regular small supply of fodder from shoots or trimmings, excellent erosion control, low shelter to 15 metres, quality wood, and aesthetic appeal.
The following are a list of bamboo species that are available in NZ and suitable for one or both of grazing and erosion control:
Arundinaria hindsii - deeply and rapidly running, tough rhizomes, stems 4-7 metres tall by 15-25mm thick. Tolerates poorer soils, frost to -6 degrees C. Deep roots (to at least 1.5 metres) are more likely to withstand drought and recover quickly from harvest or grazing than A. japonica.
Recommended for erosion control, proven effective in NZ, especially when planted on contour to stabilise slips. Last flowered 1960 (NZ), cycle probably over 50 years.
Arundinaria japonica - stems 2 - 5 metres tall by 20 mm thick, forms dense upright thicket, spreads slowly but shade tolerant and potentially invasive, prefers moist soil, tolerates wind, frost to -8. Flowering cycle 25 - 80 years, last flowered 1983. May die if soil becomes too dry, but otherwise suited to erosion control.
Sasa palmata (syn. Arundinaria palmata) - Deep rooting, moderately rapid running, stems 2 - 3 metres tall by 6 - 12 mm thick, relatively weak stems that tend to sprawl over. Tolerant of wet conditions, supposedly not drought tolerant but I have seen it thrive on top of a Northland clay ridge. Large leaves, good potential for grazing. (related Sasa paniculata used for pasture for horses and sheep in Japan)
Phyllostachys aurea - (fishpole bamboo) - rapidly running on loose soil, this bamboo has a reputation as an invasive and difficult to control plant in suburban gardens where neglected. Stems 3 to 8 metres tall by 20 - 40 mm, shoots edible by humans even raw, shallow rooting but drought and wind hardy, frost tolerant to at least -10. Recommended for erosion control and for underplanting farm shelterbelts that are grazed both sides, successful companion to Pinus radiata. Stands usually survive flowering.
Phyllostachys mitis - vigorously running, establishes an open thicket quite quickly for bamboo. Stems 6 - 20 metres by 40 - 100 mm. Tolerates drought, poor soil and wind, frost to -10. Edible shoots in late spring. Flowering cycle about 60 years.
Suitable for erosion control and for shelterbelts grazed both sides, by itself or as underplanting.
Phyllostachys edulis- Stems 6 - 20 metres by 50 - 125 mm, hardy once established, edible shoots in mid Spring. Quality wood for crafts. Suitable for erosion control, but not as strongly running as P.mitis, aurea, or bambusoides. Economically valuable in China and Japan, mainly for edible shoots and timber, the most cultivated variety in China. Flowering cycle 59 years.
Phyllostachys bambusoides - (giant timber bamboo) - slow to establish, but the main species used for construction scaffolding and building overseas, ie quality wood of large dimensions. Highly valued by the Japanese. Stems 8-16 metres by 80 - 120 mm. Edible shoots. Flowering cycle reputedly 120 years, last flowered in NZ 1960. Survives -6 degrees.
Phyllostachys nigra- (black bamboo) Stems to 8m by 30mm, reasonably easy to establish but runs slowly, forming a dense stand.
Valuable ornamental as a stand and for craft timber. Flowering period estimated at 60 years, last flowered 1930's (ie due soon, therefore not reccommended)
Arundo donax - (not a bamboo, but a giant reed grass) - leafy stems 4 - 8 m tall by 20- 50 mm thick, remaining soft for longer after shooting than most bamboos thus having good potential for stock fodder. Tolerates moderate drought and salinity, frost to -6. Good for erosion control. Established stands rejuvenated by cutting back to ground level. Establishes to a dense spreading thicket if unmanaged.
Page last updated: 20/05/02