GEOLOGY

Detailed explanation-1: -Nut and fruit trees (except for citrus) need a specific number of chill hours each winter to regulate their growth. If a tree doesn’t experience enough chill hours in the winter the flower buds might not open at all in spring, or they might open unevenly. In addition, the production of leaves may also be delayed.

Detailed explanation-2: -A chill hour is the amount of chilling received by a plant at 45 degrees F. The chilling requirement is the total number of hours required during the winter for a particular cultivar to induce the tree to break dormancy and produce flowers.

Detailed explanation-3: -“Low-chill” varieties, required in warm-winter climates, are defined by Dave Wilson Nursery as those varieties requiring 500 or fewer chill hours. For coastal southern California, low-chill varieties are considered to be those requiring less than 300 hours.

Detailed explanation-4: -Almonds (Prunus dulcis) It is the earliest deciduous fruit and nut tree to bloom in spring, due to its relatively low winter chilling requirement and quick response to warm growing temperatures.