Common Name: Paper Mulberry

General Information

Broussonetia papyrifera is a deciduous shrub or small tree with a broad, spreading crown; it usually grows up to 9 metres tall, though in a suitable climate can reach 20 metres or more. The cylindrical bole can be 50 - 70cm in diameter[, ].
The tree is widely cultivated in temperate to tropical areas of eastern Asia for the fibre in its bark, there are many named varieties[, ]. Products made from the fibre are widely sold, especially in the Pacific Islands[]. Trees are coppiced annually for this purpose[]. The plant is also a very popular herbal remedy in the Orient, provides an edible fruit and has a range of other uses.
Broussonetia papyrifera has a very wide distribution, large population, is not currently experiencing any major threats and no significant future threats have been identified. The plant is classified as 'Least Concern' in the IUCN Red List of Threatened Species(2013)[].
Broussonetia papyrifera is a highly invasive species in the tropics, becoming weedy and difficult to remove after its introduction. Due to its excessive growth, it has become an agent of change in the whole ecosystem affecting native flora, human beings and causing economic losses. In Pakistan, for example, it was intentionally introduced to make the Islamabad (Capital) and Rawalpindi area green. But in less than 30 years it not only became highly invasive in the natural vegetation but also caused health problems in the human population. It is now commonly found in India and Pakistan at elevations from sea level to 1,000 metres, and has become highly invasive and a troublesome weed in many localities. Following invasion of an area, it excludes other species and it is very difficult to eradicate. Not only does it spread by seed, but if felled and uprooted it can maintain its presence by means of numerous suckers which grow from any portions of root left in the ground. Its growth is extremely fast and it quickly out-competes other species[].

Known Hazards

None known

Botanical References

, ,

Range

E. Asia - China, Japan, Korea, Myanmar, Thailand, Laos, Cambodia, Vietnam, Malaysia.

Habitat

Thickets, mountain ravines and forests[]. Dry or humid lowland woodland[]. Open areas, secondary forest, thickets, mountain ravines, along streams in deciduous forest, preferring moisture, at elevations up to 1,600 metres[].

Properties

Weed Potential	Yes
Conservation Status	Least Concern
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Deciduous Tree
Height	6.00 m
Growth Rate	Medium
Pollinators	Insect, Wind
Self-fertile	No
Cultivation Status	Cultivated, Ornamental, Wild

Cultivation Details

Broussonetia papyrifera is a very adaptable tree. It is found growing in tropical climates at elevations from sea level to about 2,000 metres, but its range also extends well into the temperate zone where mature plants can withstand temperatures down to about -10°c[]. It grows best in areas where annual daytime temperatures are within the range 15 - 28°c, but can tolerate 500 - 3,000°c[]. It prefers a mean annual rainfall in the range 800 - 2,500mm, but tolerates 500 - 3,000mm[].
Easily cultivated in a warm sunny position in any soil of reasonable quality[]. A drought resistant species once established[], thriving on poor sandy or gravelly soils[, ]. Another report says that it does not thrive on poor soils[]. Prefers a pH in the range 5 - 7.5, tolerating 4.5 - 8[]. The plant is tolerant to urban pollution (including airborne sulphur dioxide), moisture-sapping wind in hot and dry regions, and nitrogen loading near fertilizer factories[, ].
A fast-growing tree according to one report[]. Annual height increases of up to 2.6 metres have been recorded for young trees on good sites in the tropics, with an increase in bole diameter of 6 - 25mm[].
Trees are coppiced on a regular basis in order to provide young, long, clean shoots from which to strip the bark[].
With a 10-year rotation for pulp and paper production, annual yields of 8 - 12 tonnes per hectare can be expected in low rainfall areas and 21 - 30 tonnes in high rainfall areas[].
The leaves on the same tree can vary widely in shape and size[].
A dioecious species. Both male and female plants must be grown if seed is required.

Edible Uses

Fruit - raw[, , , ]. The fruit comprises a ball about 1.5cm in diameter with numerous small edible fruits protruding - there is not much edible flesh but it has a lovely flavour[]. Prolonged ingestion is said to weaken the bones[].

Leaves - cooked[]. The dried leaf contains 1% calcium carbonate[] (this report does not mention edibility).

Flowers[]. No more details.

Medicinal

The leaves are astringent, diuretic[]. They are used in the treatment of fluxes and gonorrhoea[].
The leaf juice is diaphoretic and laxative - it is also used in the treatment of dysentery[]. It is also poulticed onto various skin disorders, bites etc[].

The stem bark is diuretic, haemostatic[]. A decoction is used in the treatment of ascites and menorrhagia[].
A decoction of the twigs is used in treating eruptions, whilst the juice extracted from them is used in the treatment of anuria[].
The resinous sap found in the bark is used as a vulnerary, and in treating wounds and insect bites[].

The fruit is diuretic, mucilaginous, ophthalmic, stimulant, stomachic and tonic[, ].

The root is cooked with other foods as a galactagogue[].

Agroforestry Uses:

The plant establishes itself quickly on denuded and degraded sites in the form of a thick tree cover, fixing soils and preventing further erosion due to its dichotomous root system[]. It can be used as a pioneer species when restoring native woodland, or when establishing woodland gardens[].
When growing in areas polluted by heavy metals it has been shown to concentrate these metals in its tissues - especially lead, zinc and copper. It has a high potential for use in phytoremediation projects, either as a means of removing these metals or as a means of locking them up and helping to restore the fertility of the soil[].
It makes a good shelterbelt and windbreak[].
A mulch of the chopped leaves of this plant, applied at 4 tonnes per hectare, improves soil moisture and phosphorus content, leading to increased crop production[].

Other Uses

A fibre from the bark is of very good quality. It is used in making a very strong and high quality paper, cloth, rope etc[, , , ].
The cloth can be produced by beating strips of bark on a flat surface with a wooden mallet. A very fine cloth can be made in this way, the more the bark is beaten the finer the cloth becomes. Larger sizes can be made by overlapping 2 pieces of bark and beating them together[].
A leather substitute can also be made from the bark[].
When used for making paper, branches are harvested after the leaves have fallen in the autumn, they are steamed and the fibres stripped off. In humid areas this can be done without steaming the branches. The inner and outer bark are then separated by scraping (or simply peeling in humid areas) and the fibres are cooked for 2 hours with lye before being hand pounded with mallets. The paper varies in colour if the outer and inner barks are used together or separately[].

An oil from the seeds is used in soap and lacquer oil production[].

The plant has been investigated for its properties as a pesticide. The leaf powder, when fed to the cotton bollworm (Helicoverpa armigera) caused restriction in its pupation and adult emergence[].
The xylem contains an antifungal substance active against Fusariun species[]..

The tree (part not specified) produces a natural green to yellow-green dye[].

The light-coloured wood is straight and even-grained; soft, light in weight, brittle, not very durable. Easily worked, it is used for making items such as cups, bowls, packing cases, cheap furniture etc[, , , , , ].
The wood is used for fuel[].

Propagation

Seed - no pre-treatment is required. Sown in the autumn or spring in a greenhouse, germination usually takes place within 1 - 3 months at 15°c[]. When large enough to handle, prick the seedlings out into individual pots and grow them on in the greenhouse for at least their first winter, planting them out into their permanent positions in late spring or early summer, after the last expected frosts.
Cuttings of half-ripe wood, 8 - 12cm long with a heel, mid summer in a frame. High percentage[, ].
Cuttings of mature wood of the current season's growth, late autumn in a frame[].
Root cuttings in winter[].
Layering in spring[].