تحقیقات جنگل و صنوبر ایران (Sep 2008)
Phenological study of different Poplar clones Populus euramericana and Populus deltoides in Karaj collection during 1986 - 2004
Abstract
Poplar collection project was carried out in frame of the national project for gathering native and exotic poplar clones and establishing of selection nursery, using 57 different species and clones in year 1984 in the Alborz research center, Karaj. Five seedlings from each clone (two years old) were planted in lines with 5m×8m spacing. During the study years, more new clones from five poplar sections were gradually added to the pervious ones. Therefore, the total number of poplars in the collection became to 69 samples. Irrigation, weed control and branch pruning have been done during growing seasons. Phenological studies of different Poplar clones have been done from mid December to mid February, every year. In the first three months of growing season, phenological phenomena have been observed and recorded by binocular, twice a week and during the other months it has been done once a week. In this paper, we revealed information of phenological study for 28 Populus euramericana and Populus deltoides clones. Results showed that vital activity in poplar trees starts between late February until late April and ends up between late October until middle of December. Vital phenomena (blooming, flushing, maturity and dispersal of seeds and leaf fall) have appeared in different times among different clones and different years depending on air temperature. By checking of blooming and flushing dates during the study period we can conclude that the beginning of the vital activities tends from April to March and from March to February. This means that spring begins sooner in the last years of the experiment. In the other word, the length of the growth season during these years has been increased by several days in Kkaraj climatic conditions.
