The cashew tree

Botanical classification

Rank	Classification
Kingdom	Plantae
Clade	Tracheophyta (vascular plants)
Clade	Angiosperms (flowering plants)
Clade	Eudicots
Order	Sapindales
Family	Anacardiaceae
Genus	Anacardium
Species	A. occidentale

Origin and spread

The cashew tree is native to the coastal cerrado of northeastern Brazil — modern-day Ceará, Piauí, and Rio Grande do Norte states. Pre-Columbian indigenous peoples (Tupi-Guarani) named it "acaju" (from which both "cashew" and the Portuguese "caju" derive). The Portuguese encountered cashew trees in the early 1500s.

From around 1560, Portuguese traders carried cashew seeds and seedlings on their trade routes — primarily to East African colonies (Mozambique, Tanzania) and to Portuguese India (Goa). From these initial seeding points, the species spread across the tropical belt over the following centuries: West Africa, the Indian Western Ghats, Southeast Asia, the Caribbean.

Today, cashew is grown commercially in 60+ countries. Ivory Coast, India, Vietnam, Tanzania, Brazil, Mozambique, Benin, Ghana, and Nigeria are the major producers.

Tree morphology

• Form: Spreading, multi-branched evergreen. Canopy diameter often exceeds tree height.
• Trunk: Short, crooked, often branching low. Bark is rough and brown.
• Height: 6-14 metres typical; can reach 20m in optimal conditions. Many commercial varieties dwarf to 4-6m for easier harvest.
• Leaves: Simple, alternate, leathery. 10-20cm long, ovate to obovate. Glossy green.
• Flowers: Small (5-10mm), greenish-yellow to pink, fragrant. Borne in terminal panicles. Polygamomonoecious — both bisexual and male flowers on the same tree.
• Roots: Deep taproot + extensive lateral root system. Allows drought tolerance.

Growing conditions

• Climate: Tropical to subtropical, latitudes 25°N to 25°S. Optimum temperatures 20-35°C; tolerates 0-45°C briefly.
• Rainfall: 600-3000mm/year. Tolerates dry periods well. A pronounced dry season during flowering improves yields.
• Soil: Tolerant of poor soils. Prefers well-drained sandy or sandy-loam soils with pH 4.5-6.5. Cannot tolerate waterlogging.
• Elevation: Sea level to 1000m. Below 700m optimal for fruit set.
• Wind: Light-to-moderate wind exposure is fine; severe wind damages branches.

Productivity

• First yield: 3-5 years after planting (grafted trees can fruit at 2-3 years)
• Commercial maturity: 8-10 years
• Productive lifespan: 30-40 years; trees can live 60+ years total
• Yield per tree: 5-25 kg of raw cashew nut (RCN) per year at maturity. Optimal management can exceed 50kg.
• Density: 100-200 trees/hectare typical
• Yield per hectare: 500-2000 kg RCN/hectare/year typical; intensive cultivation can reach 4000+ kg/ha.

The harvest

Cashew apples ripen and fall from the tree when fully mature. Traditional harvest is by hand-picking fallen apples (with the attached drupe) from the ground. Mechanical harvest exists but is uncommon — the asynchronous ripening means many passes through the orchard are needed.

Harvest seasons by region:

• Northern Hemisphere — India, Vietnam, West Africa: Feb–Jun (peak Mar–May)
• Southern Hemisphere — Brazil, Tanzania, Mozambique: Aug–Jan (peak Oct–Dec)

This counter-seasonal pattern allows year-round RCN supply through combined sourcing.

Pests and diseases

• Tea mosquito bug (Helopeltis spp.) — major pest in Africa and Asia. Damages flowers and young fruits.
• Cashew stem borers — bore into trunk/branches; can kill trees
• Powdery mildew — particularly in humid conditions during flowering
• Anthracnose — affects flowers and young fruits
• Cashew apple flies — damage ripening fruit

Cashew tree in non-commercial contexts

• Ornamental — planted in tropical gardens for foliage and unusual fruit
• Erosion control — Portuguese originally planted cashew in Goa to bind eroding laterite slopes; still used this way globally
• Shade — broad canopy provides shade in tropical agroforestry systems
• Wood — soft, light wood; used for low-grade construction, packing crates, paper pulp