Agroforestry systems in Vietnam

In the uplands of Vietnam, agroforestry in various forms is widely used by farmers and forest enterprises. Of the total land area, 70% is upland and almost 30% of the population lives in upland areas. Almost all of the 54 ethnic minority communities are found in the upland areas.

Vietnam

System	Region
Farm-based agroforestry
Homegardens and von ao ca chuong	all regions
Fruit orchards, including coconut-based gardens	all regions
Forest/crop/irrigated rice	hilly and mountainous areas
Woodlot	mostly midland areas
Commercial crops under multipurpose tree species
-tea	midlands and uplands
-coffee	central and southern
	midlands and uplands
-black pepper	central and southern
	midlands and uplands
-other agricultural crops
Agricultural crops under commercial trees
-rubber	central and southern
	midlands and uplands
-cashew nut	coastal and midland areas
-fruit trees	all regions
-cinnamon	central and northern regions
Hedgerow and contour planting	central and northern regions
	(SALT)
Forest-based agroforestry
Shifting cultivation/fallow upland areas
Taungya
-timber production	northern midlands and
	uplands
-paper pulp production	central and northern
	midlands and uplands
Accelerated pioneer climax series	all regions

Upland use

Total upland area	24.5 million ha
· Arable land	5.4 million ha
Cultivated	3.5
-Perennials	0.6
-Rice	1.4
-Annual crops	1.5
Pasture	0.3
Others	1.6
Forest land	19.1 million ha
Forested	9.3
-Natural forest	8.7
Planted forest	0.6
Deforested	9.8
Upland population	19 million
Ethnic minorities practicing shifting cultivation	2 million
Average household size	7 persons

Farm-based agroforestry systems

Homegardens

The homegarden is a traditional agroforestry system found throughout Vietnam from the lowlands to the highlands. On a relatively small piece of land around the house (usually only about 0.5 ha, but occasionally up to 5 ha), the land is used as efficiently as possible to produce a wide variety of products. Fruit, vegetables, root crops, fish, livestock, fodder, fiber, medicine, small timber fuelwood and various minor products are grown in a multilayered structure. Seed and seedlings for propagation are often obtained from the family or neighbor's gardens. One kind of tree or crop may be dominant and the homegarden may be named accordingly, e.g., coconut garden. Although the size of individual homegardens is small, their cumulative effect can be very important in watershed and natural resource management on a community or regional scale.

One very common type of homegarden is the so-called von ao ca chuong or rung von ao ca chuong (RVAC) system, combining forest trees, fruit trees, fishpond and livestock in an integrated farming system.

Factors influencing species composition

soil conditions.	available labor.
local climate.	household needs.
household economy.	farmer skills and preferences.
	Iocal markets.

RVAC system in Tuyen Quang

Species found in Vietnamese homegardens

Fruit trees	Root crops
jacktruit	cassava
banana	sweet potato
orange	taro
lemon	canna
pomelo	yam
grapefruit
papaya	Vegetables
sapote	squash
longan	soybean
litchi	pumpkin
starfruit	Chinese
coconut	cabbage
cashew nut	squash
durian	spinach
rambutan	black pepper
avocado	carrot
guava	mungbean
water apple
custard	Others
apple	peanut
cumquat	sugarcane
mangosteen	pineapple
langsat	ginger
jujube	medicinal
	plants
Others
coffee	Animals
cacao	fish
bamboo	pigs
rattan	goats
mulberry	chickens
tea	ducks
cinnamon	cattle
Melia spp.	deer
forest trees	silkworms
	bees

Advantages

· ecologically/economically stable.
· Iow labor requirements.
· Iow level of pests and diseases.
· familiar to farmers (traditional).

Limitations

Quality and availability of seedlings are not yet fully established.

Forest/crop/irrigated rice

Forest/crop/irrigated rice systems are often established in hilly and mountainous areas. A natural forest or plantation crowns the site and is usually managed by state. forest enterprises or community groups. In some places, the upper part of the system includes a water reservoir which is to irrigate the lower areas and to generate electricity. Vegetables or cash crops are grown on terraces or along contour lines and the irrigation system allows farmers in the valley to grow paddy rice.

Advantages

The spatial arrangement of the components enables their positive interaction, thereby optimizing the overall production of the area.

Even distribution of work and income throughout the year.
Diversity of locally available products.

Limitation

The system requires good relations and cooperation between farmers, farmers' cooperatives and the forestry agency or group managing the forest This can be difficult in newly established communities.

Woodlot

Woodlots have been successfully established on underutilized or degraded land, using fast-growing trees, especially nitrogen-fixing multipurpose species.

Along with the rehabilitation of wastelands, these woodlots supply fuelwood, small timber and other minor products for local consumption. Beekeeping and livestock grazing are often practiced in the woodlot. Agricultural crops can be intercropped during the establishment of the woodlot tree species. State lands, as well as financial and technical support, have been allocated to individual farmers for plantations.

Advantages

Simple management (monoculture, regular arrangement).
Can provide windbreak and soil protection.
Aesthetic improvement to the landscape.
Intercropping is possible during woodlot establishment.

Limitations

Sufficient planting material not available.
Requires extension support.
Pests and diseases.
Uncertain distribution of work responsibilities and income on state lands.

Commonly used woodlot tree species

Acacia auriculiformis
A. mangium
Cassia siamea
C. fistula
Erythrina spp.
Eucalyptus tereticornis
E. camaldulensis
Gliricidia septum
Melia azedirachta

Cash crops under multipurpose tree species

Cash crops, such as coffee, tea and black pepper, can be grown under trees which provide shade and other forms of support to the crops. Tree species commonly used in these systems are Pinus kesya, P. merkusii, Cassia siamea, Leucaena leucocephala, Gliricidia sepium, Pterocarpus indicus, Moringa oleifera, Manglieta glauca, Aleurites fordii, T. candida and cinnamon. Although the trees do not provide the major income from these systems, their contribution to farm income can still be important. They also serve various other purposes.

Advantages

Protection and support of agricultural crops through windbreaks, shade and possible nitrogen fixation provided by trees.

Improved soil protection through contour planting.

Increased soil cover by tree litterfall.

Diversification, which improves food security.

Limitations

· Crops such as coffee or tea are dependent on international market fluctuations.
· Practice requires much skill and technical expertise.
· Trees may affect cash crop productivity.

An agroforestry system from Lao Cai province (northern Vietnam)

Agricultural crops under commercial trees

Several agroforestry systems use the space between commercial tree crops to intercrop agricultural crops (annuals). This intercropping is usually limited to the first few years of plantation establishment (e.g., rubber plantations, or fruit orchards of cashew nut, mango or jackfruit) until the tree canopy closes. This is usually done by a farm family who manages the plantation for another landowner (usually a state enterprise).

Advantages

Potentially high income.
Tree cover improves soil protection.

Limitations

Labor intensive
Allows for cultivation of agricultural crops only during establishment.
High investment costs.

Intercropping during the establishment of cinnamon plantations

A common practice of the ethnic Zao people is to intercrop during the establishment of a cinnamon plantation. The plantation is often established on steep slopes (>25 degrees) under natural forest with a crown cover varying from 50-70 %. Cinnamon requires 2000mm of evenly distributed annual rainfall, generally warm and humid conditions and good soils. Usually, the eastern side of a slope is used for this practice.

Initially 2000-3000 cinnamon seedlings per hectare are planted under the shade of the forest trees after clearing shrubs.

In the first 3 years, upland rice and cassava may be intercropped.

After 2-4 years, the trees of the natural forest are thinned to provide more light.

When the cinnamon is 6-7 years old, a second thinning of the natural forest trees is carried out.

At the age of 8-10 years, most forest trees are cut and the cinnamon becomes the dominating tree in the system.

When the cinnamon trees are 20-25 years old, they then reach their mature harvest age.

Cutting of most forest trees

Hedgerow and contour planting

Various combinations of techniques have evolved to allow cultivation on steep, sloping terrain without causing serious soil erosion. In Vietnam, within the last decade, farmers have adapted the SALT (Sloping Agricultural Land Technology) technique, originally developed in the Philippines. Locally suited species, like Tephrosia shrubs and Indigofera trees, have been incorporated. By the use of a very simple A-frame, farmers are able to mark out the contour lines of the slope. Along these contour lines, physical measures may be applied to enable cultivation, including construction of terraced fields and stone embankments. On the edge of the terraces, rows of woody perennials are grown. In Central Vietnam, trees are also planted on the contour lines, together with grasses and other crops. Natural terraces will gradually form as the tree rows form a barrier which prevents soil and plant material from washing down the slope.

Advantages

Soil and water control.
Diversified production.
Income throughout the year.
Increased yields.
Green manure can improve soil fertility.

Limitations

Labor intensive.
High investment for seed/seedlings required.
Training of farmers required.
Difficulties in marketing newly introduced products or crops.
Farmer reluctance to adopt the new system.

Sequence of SALT practice in Lang Son province

Initially, forest trees are planted at the top of the slope (generally 15-25 degrees) and cash crops such as pineapple and hill rice are planted. At the foot of the hill, forest trees (such as Manglieta) are inter-planted with rattan.

After 2 years, barrier crops such as Tephrosia spp. and pineapple are planted along the edges and waterdiverting ditches are constructed, creating natural terraces over time.

Depending on water availability, fruit trees, tea, staple food crops or other crops can be planted on the terraces.

Food crops

Forest-based agroforestry systems

Shifting cultivation

Shifting cultivation, or slash and burn, is practiced extensively by more than two million people from more than 50 different ethnic groups in the hilly and mountainous areas of Vietnam. On a patch of upland forest, farmers slash shrubs and other low vegetation and then burn it. Hill rice is then grown for two to three years. The field is then abandoned and the farmer moves to another site to repeat the process. In the past, the farmer returned to a site only after 10 to 20 years, depending on the recovery rate of the fallowed fields. Rice yields were reported from 2000 kg/ha in the first year to 900 kg/ha the third year in central and northern Vietnam. However, today this fallow period is often reduced to 5-7 years, resulting in much lower yields. In some places, cassava is cultivated for 1-2 years after the first two years of rice cultivation. But this practice leaves the soil without any cover for 34 months following each harvest, causing severe erosion. Besides these two crops, farmers may also cultivate corn, bamboo and various tree species, such as Manglieta or Melia.

Traditionally, shifting systems were sustainable because population pressure was low and enough time was allowed for the forest to regenerate. However, with today's rapidly growing population, this system has been cited as a major cause of deforestation in Vietnam.

Advantages	Limitations
Low cost.	Large land area needed.
System is familiar to farmers.	Soil erosion after burning.
	Leads to deforestation.
Simple technology.	Low yields.
Integrated part of local culture.	Extensive weeding initially needed.

Agricultural farming cycles on the hillslope

Taungya

The taungya system allows venous intercrops to be grown (until the tree canopy closes) between newly established tree rows in forest plantations. This system has been used for many contract reforestation projects throughout Vietnam as a means to rehabilitate degraded natural forest lands. These contracts between state forestry enterprises and rural households often include technical support, such as the introduction of new species, supply of seedlings and fertilizers, training in planting and intercropping techniques, as well as financial support. The contracts also specify land tenure and duration and percentage of benefits to the farmer from the clearing, thinning and harvesting operations to be undertaken. The forest trees may be grown for either timber or paper pulp production.

Advantages

Reduced management costs for plantation owner.
Provides additional cropland to farmers (in the initial stages).
Ecological benefits of reforestation.

Limitations

Short agricultural cropping period.
Farmers must have other land.
Requires some management skill.
Requires a guarantee for the sale of the forest product.

Taungya system for timber production

Fast-growing trees Acacia auriculiformis, A. mangium or Cassia siamea are planted at a density of 1250 trees/ha (2m x 4m spacing) for fuel wood and small timber production in a 10-year rotation.

Timber species Hopea odorata and Dipterocarpus alatus are planted with a density of 312 trees/ha (4m x 8m spacing).

Cash crops are interplanted in the alleys between rows of forest trees during establishment.

Taungya is also practiced by several state forestry enterprises to produce pulp for paper production. In these systems, each family plot is divided into 20 parts that are gradually planted with EucaIyptus and Acacia species in an 8- to 10year cycle and intercropped with annual cash crops.

Degraded land restoration by sequential planting accelerated pioneer climax series system

Reforestation has been proposed as the most promising stategy to rehabilitate degraded upland soils and make them more productive and ecologically balanced. The accelerated pioneer climax series (APCS) system has been applied in reforestation of marginal lands in the midhills and uplands of central and southern Vietnam. Experiments with APCS were carried out in Vietnam as early as the 1920s. Although reforestation is the major aim, intercropping of agricultural crops is possible during certain phases.

APCS is based on the ecological principle of natural succession, which relies on pioneer species that have the ability to adapt to adverse conditions. These species will improve the microclimate and soil conditions of a particular site, making it favorable for the establishment of less-sturdy climax species. Natural succession is a slow process, but it can be accelerated considerably through planting pioneer species and interplanting climax species. Variations of this practice focus on different species and planting distances. There are two main phases:

Phase 1. The establishment of dense stands of fast-growing species to eliminate "cogon grass" (Imperata cylindrica) and to produce short-cycle fuelwood and roundwood. This involves high tree densities (2000-3300 trees per ha) to eliminate light-demanding grasses within two years after planting. Species commonly used are Acacia auriculiformis, A. mangium, Indigofera teysmanii and Gliricidia septum. Four years after establishment, the trees are thinned to remove one out of every four rows for fuelwood and small-pole production. Crops and dipterocarp species are then planted in the alleys between the double rows of pioneer trees. At years 8 and 12, the pioneer species will be gradually cut and removed, providing more light for the climax species and space for growing crops.

Phase 2. The establishment of mixed plantation with pioneer, intermediate and climax tree species. Pioneer species may be Indigofera teysmanii, intermediate species are Acacia auriculiformis, or Cassia siamea; and climax species include Dipterocarp species, like Dipterocarpus alatus, D. dyerii and Hopea odorata. Planting densities follow these guidelines: pioneer species—1666 trees/ha, intermediate species—833 trees/ha and climax species—278 trees/ha.

Objectives of APCS

To quickly rehabilitate wasteland and denuded hills
To produce fuelwood and small timber for local consumption
To make the site favorable for the climax forest species

Objectives of APCS

The three species planted are:

The pioneer species (Indigofera teysmanii) which is cut every two years for fuelwood production. This species grows fast and coppices well.

The intermediate species (Acacia auriculiformis) which is gradually thinned every six years, providing fuelwood, poles and small timber.

The climax species (Dipterocarpus alatus or Hopea odorata) which is expected to develop for 60 years before harvest for timber.

Advantages

Environmental

Follows the principle of natural succession.

Promotes tree diversity (at least two species are planted).

Recovers grassland areas, which were formerly dipterocarp forests.

Improves the microclimate and provides immediate cover.

Protects upland soils from erosion.

The pioneer trees improve soil conditions, particularly the soil's biological and physical properties.

The growth performances of the intermediate and climax species are improved and are much better than in pure stands.

Strengthens the nutrient cycling process, thereby restoring the productivity of the upland tropical forest ecosystem.

Socioecono mic

Thinnings from the pioneer and intermediate species can be good sources of fuelwood, roundwood, fodder, mulch, organic fertilizer and small timber for local consumption.

Acceptable to local people since the practice allows participating farmers to get different products shortly after establishment until the end of the climax species rotation.

Cost-effective, especially on open grasslands, since the pioneer and intermediate trees quickly suppress light-demanding grass.

Limitation

Willingness of farmers to accept this system to rehabilitate degraded lands or on commununal lands.