Artocarpus heterophyllus
(jackfruit)

The following summary is from Witt and Luke (2017):

Description

Medium-sized evergreen tree [8–25 (–30) m tall]; stem straight, of diameter 30–80 (–200) cm, branching near the base, rarely buttressed; twigs sometimes covered with

minute hairs; crown dome-shaped, sometimes pyramidal, dense; exudes a white gummy latex when damaged.

Origin

Bangladesh, India, Malaysia.

Reason for Introduction

Food, fodder, medicine, shade and ornament.

Invades

Roadsides, disturbed areas, urban open spaces, forest edges/gaps and secondary forest.

Impacts

Has the ability to form dense stands, to the detriment of native flora and fauna.

Growth and Development 

Trees raised from seed start flowering at the age of 2-8 years. Clonally propagated trees produce fruit within 2-4 years from planting under favourable conditions. Clonal material reaches full production in Malaysia when the trees are 8-15 years old. In suitable environments, jackfruit trees bear flowers and fruits throughout the year, but usually there is a major harvest period, in April-August or September-December in Malaysia, January-May in Thailand and in the 'summer' in India. This implies that 3-6 months earlier, conditions were particularly favourable for flowering or fruit set. A load of growing fruit may suppress flowering and so accentuate seasonality of production. Whereas female flower heads are only borne on short shoots emerging from the trunk and main limbs, male heads are not restricted to these shoots; they also occur on shoots in the periphery of the tree canopy, particularly in vigorously growing trees. Male and female heads on a cauliflorous shoot develop almost simultaneously, the male head reaching maturity 3-5 days earlier. For the tree as a whole, male and female flowers open over a long period.

At anthesis, the male heads are dusted with sticky yellow pollen and emit a sweet scent which attracts small insects such as flies and beetles. These may be the pollinating agents, but few insects visit the female heads and in India pollination has been reported to be effected by wind. After anthesis, the male heads turn blackish and drop off. The fertilized female heads develop into mature fruits after 3 months or more, depending on the seedling or clone; at higher altitude or latitude it may take up to 6 months. Unfertilized flowers develop into strap- or string-like structures filling the spaces in between the developing fruitlets. A well-developed fruit may contain up to 500 seeds, each weighing 3-6 g. Germination is hypogeal, but unlike the breadfruit seedling, the cotyledons separate, thus allowing the plumule to emerge without any hindrance. New leaves take 12-15 days to expand. Extension growth in mature trees is slow (up to 3-5 cm per month), but it tends to be continuous.

Ecology 

In its original habitats, jackfruit was apparently found mainly in evergreen forests at altitudes of 400-1200 m. The tree extends into much drier and cooler climates than A. altilis (Parkinson) Fosberg (breadfruit) and A. integer (chempedak); it fruits up to latitudes 30°N and S in frost-free areas and bears good crops 25°N and S of the equator. However, jackfruit thrives in warm and humid climates below 1000 m. In fact, it has poor cold, drought and flooding tolerance, but moderate wind and salinity tolerance. The annual rainfall should be 1500 mm or more and the dry season not too prominent. The tree can be grown on different types of soil but performs best on deep, well-drained, alluvial, sandy or clay loam soils with pH 6.0-7.5.

Animal feed, fodder, forage

• Fodder/animal feed

Environmental

• Agroforestry
• Revegetation
• Shade and shelter
• Soil improvement

Fuels

• Fuelwood

Human food and beverage

• Beverage base
• Flour/starch
• Fruits
• Nuts
• Seeds
• Vegetable

Materials

• Carved material
• Dye/tanning
• Fibre
• Gum/resin
• Miscellaneous materials
• Rubber/latex
• Wood/timber

Medicinal, pharmaceutical

• Source of medicine/pharmaceutical

Furniture

Sawn or hewn building timbers

• For heavy construction
• For light construction

Woodware

• Industrial and domestic woodware
• Musical instruments
• Tool handles