Altitude:
Lismore is one of Australia's largest coffee growing regions
Overseas literature often sets firm guidelines on altitudes for coffee growing. Zimbabwe literature recommends an altitude of 900 to 1200 metres above sea level. These altitude recommendations are made to either guide prospective growers to areas of suitable temperature and rainfall or are used to delineate areas where arabica coffee develops high acidity. Acidity, an important factor in determining coffee quality, is favoured by the cool growing conditions of high altitudes.
Australian experiences partially conflict with these guidelines. The coffee research and development program has found that coffee grown in northern New South Wales has good acidity due to its southern latitude rather than its altitude. In North Queensland, temperature data is a more reliable indicator of coffee performance and quality than altitude, although quality has generally improved with altitude. Good quality arabica coffee has been produced at altitudes of 15 to 700 metres in areas of North Queensland. In Australia, altitude recommendations are made only to define areas which have suitable temperature and rainfall ranges.
Aspect and slope:
Aspect influences temperature and wind protection;
- In northern New South Wales growers prefer northern slopes for warmth and protection from cold south-east winds.
- In North Queensland wind protection is more important than aspect.
- Natural or planted windbreaks are essential for coffee production due to the trees being sensitive to wind damage.
- Flat ground is preferred for machine-harvesting, however hydraulic levelling on the machine allows it to harvest up-and-down slopes of up to 15% and side slopes of 6% to 8%.
Recommended Australian growing areas:
The site and environmental requirements of coffee detailed above define the areas most suitable for coffee production in Queensland and New South Wales;
- In Queensland, coffee has been grown commercially along the tropical coast and on the Atherton Tablelands inland from Cairns.
- In New South Wales commercial plantings have been confined to the far north coast and the northern rivers region. The sites in New South Wales represent the southern most limit for commercial coffee production in the southern hemisphere.
Areas of commercial coffee production in Australia:
The yearly temperature and rainfall patterns for two representative sites of commercial coffee cultivation in Australia are shown in the graph below. Note the rainfall pattern in Mareeba is close to ideal for manipulating flowering and ensuring dry conditions for harvesting. Dry conditions from September to November allow the trees to be purposely water-stressed and then rewatered to promote uniform flowering. Dry conditions from May to July ensure a dry harvest season, aiding mechanical harvesting. The temperature pattern indicates that for several months of the year the Mareeba site has maximum temperatures and diurnal fluctuations higher than ideal for coffee. This has resulted in lower yields, smaller bean size and poorer coffee quality compared with other areas of the Atherton Tablelands with milder temperatures.
In the Tweed Valley in northern New South Wales, the spring rainfall pattern is not ideal for manipulating flowering and may also disrupt harvesting. However, the milder temperatures during cherry ripening (June to September) favour extended cherry life and more even ripening and greatly assist mechanical harvesting. The milder temperatures are also more suitable for vegetative growth, favouring high yields and good bean size and quality. A comparison of yield, bean size and quality of coffee grown at various sites throughout Queensland and New South Wales is given in Informed Farmers article titled ‘Coffee Cultivators.’
Trial plantings to define areas suitable for machine-harvested coffee production in Queensland and northern New South Wales suggest that the most suitable sites in Queensland are the frost-free areas of the southern Atherton Tablelands (Walkamin to Atherton), the fertile, well-drained coastal soils of the Palmerston Valley in North Queensland, and the Bundaberg/Childers district in southern Queensland. In northern New South Wales, frost-free level or gently sloping (up to 10%) areas of the Richmond and Tweed valleys are the preferred sites.
