Latitude

The temperate zone extends from approximately 35 to 60 degrees north and south of the equator, and the region has four distinct seasons—winter, spring, summer, and fall. Temperate fruit species have an endodormancy, or rest requirement, that can be satisfied under the climatic conditions of only this region, and, consequently, this factor limits the growth of these species to this zone. Dormancy is overcome by exposing the plants to a chilling period (at 4 to 7°C) in winter. The length of exposure needed to overcome endodormancy varies with species (and even cultivars within a species) but on average ranges from 400 to 1,200 hours for peaches and 800 to 1,500 hours for apples and pears. Although the winter hardiness of the different temperate species (and cultivars) varies, most cannot withstand the extreme winter cold encountered in areas beyond the latitude of the temperate zone. This is another factor limiting their growth to this region.

Although the temperature of a location is primarily a function of latitude, it is also strongly influenced by altitude. The temperature drops approximately 3.5°C for every 500 meters increase in altitude. As a result of this, the peak of Mt. Kilimanjaro in Tanzania, which lies three degrees south of the equator at a height of 5,895 meters, has year-round snow cover, and regions in the Himalayan mountain range are major producers of temperate fruit crops.

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