**3. Climate and weather**

The timing of phenological events can be quite sensitive to environmental conditions mainly climatic [2, 4, 5]. For example, an advance of leaf budburst and blooming for could be caused by warming an drought in spring and this could be for two weeks earlier than usual, whereas cold and moisture could exceptionally could equally delay them. Thus, weather and climate controls the timing of phenol-phases which vary among years [2]. Effectively, climate cyclic variations are the controlling variables of phenol-phases timing. In plants, bud-burst, leaf-expansion, abscission, flowering, fertilization, seedset, fruiting, seed dispersal and germination all take place in due season [6].

On the one hand weather is limited to a very short period of time from one day to less than week and it includes atmospheric conditions of a region, such as temperature, precipitation, humidity, wind, and sunshine. The climate of a region, on the other hand, concern a long period more than thirty years commonly defined as the conventional period for climatic studies. Climate consists of the generally-prevailing weather conditions for this period and in a large geographic region. For example, Santa Barbara, California is characterized by a Mediterranean climate – warm, dry summers and cool, moist winters. There are, however, daily and weekly changes in the weather that can rapidly change the temperature, sunshine, and wind conditions [2]. Nonetheless, there is no steady rhythm for all years particularly in the context of recent climate changes. This would not be tolerated by some species and therefore they are likely been extinguished and rarified in many regions.
