Coffee plants

Coffea species are shrubs or small trees native to tropical and southern Africa and tropical Asia. Coffee plants were discovered in Africa and eventually disseminated to countries throughout the world. Despite this diversity, only two species are actually of great importance in the world market, C. arabica L. and C. canephora Pierre.

All coffee species are woody evergreens, but the plants range in size from small shrubs to trees more than 10 meters tall. All coffee trees consist of an upright main shoot (trunk) with primary, secondary and tertiary lateral branches.

Leaves vary in color from yellowish to dark green, with touches of bronze or purple. coffee leaves are generally thin, shiny and waxed, elliptical in form and conspicuously veined. They typically grow in pairs that are opposite to each other on the branch.

A study of the effect of shade on the growth and production of coffee in Ethiopia showed that the shade stimulated changes in the physiology of coffee plants, including increasing photosynthesis and adding leaf area indexes.

Thus, the coffee plantations under shade have a larger and heavier coffee production compared to those without shade. Shade also increases the dry matter of coffee fields, which means it plays a role in storing carbon stocks.

The white flowers appear in small bunches at the nodes. After pollination, a fruit develops into a cherry about 3/8 to 5/8 inch (10 to 15mm) long containing two seeds (the coffee beans). Technically, the flowers form on the one-year-old wood that is only slightly hardened.

The fruit of the coffee plant is typically described as a drupe: a fleshy, indehiscent fruit with a pericarp that is clearly differentiated into an exocarp, mesocarp and endocarp.
Coffee plants

Altitude preference for coffee tree

Coffee quality is determined by organoleptic characteristics (cup quality), physical appearance and chemical constituents. Coffee from high altitude with open or medium shade and early to middle harvest periods had a superior bean quality.

As coffee species do not tolerate large changes in seasonality, yet do not flourish in very hot conditions, altitude is also an important factor. For every 100 m, temperature decreases on average by 0.6 °C. Higher altitudes in tropical regions, therefore, offer a cool environment where the yearly temperature does not fluctuate drastically, providing an ideal climate for coffee cultivation.

Air temperature factors have a direct effect on the growth of coffee plants, especially the formation of flowers and fruits and sensitivity to disease attacks. In general, high temperatures are affected by the altitude of the sea surface.

While the height of the appropriate place for the growth of Arabica coffee is 1000-2000m above sea level, whose temperature conditions range from 15 °C to 24 °C, and for the Robusta coffee <700 meters above sea level, whose temperature conditions range from 24 °C-30 °C.

C. canephora prefers a hotter climate and is more adapted to the lowlands (below 900 m altitude), though quality improves with altitude.
Altitude preference for coffee tree