Just as frostbite occurs in humans, below-freezing temperatures can cause damage in plants, trees, and shrubs. If water has condensed on the leaves prior to freezing, the frost will appear white. In colder temperatures, however, the white frost that is normally visible will not appear. In both cases the real activity is beneath the surface, where water within the leaves and stems of delicate plantlife freezes, causing cell damage charactarized by a blackening of the leaves.
While all plants are effected by frost damage, it is most bothersome for citrus farmers, since the new buds on a fruit tree are exceptionally susceptible to the cold. Unprevented frost damage in a grove of orange trees can mean less fruit or product with weaker taste, as the cellular damage effects the growth process later in the cycle. The temperature at which the plant is damaged frequently depends upon its maturity, size, and durability. Keen farmers and gardeners watch the weather report carefully for signs of early or late frost.
To prevent frost damage, many farmers pay careful attention to the airflow, topography, and ground preparation of their orchards. The slightest change in the ground's ability to warm up with the sun's rays can greatly effect the lifetime of a plant. Once the winter hits, temporary solutions to the problem of frost include wind machines and orchard heaters. Some farmers will actually spray their crops with an irrigation system, as liquid water is warmer than frost. They may also attempt to increase warm air circulation by lighting fires or employing a helicopter to fly over their groves. As long as the cold weather doesn't stay, these quick fixes keep plantlife happy and healthy, so they're around to witness the kidnapping and selling of their young, who will someday meet terrible demise in the form of a fruit peeler or sharp knife. Oh, the horror!