The chill hour requirements of female and male trees of Pistacia atlantica,
Pistacia palaestina and Pistacia khinjuk have been examined. This was carried
out through putting the studied cuttings in cool chamber for different perriods
of temperatur
es of 2 °C (550, 650, 750, 850, 950, and 1050 hours). The cuttings,
later on, were moved into growth chamber which offers temperature, moisture
and light similar to that available at the time of flowering season naturally.