Adaptability and growth rate of various conifers under rainfed conditions in Arasbaran region

In order to rehabilitate abandoned forest lands, and prevent soil erosion in sloping areas, 12 conifer species were planted under rainfed conditions. Sufficient solar radiation and adaptability of conifers for poor nutrient environment were two reasons for selection of these species. The experiment was conducted in 1994 in two locations. The experimental designs in Kalaleh (northern slope) and Hareh Sar(southeastern slope) were repeated in simple rectangular lattices with four replicates, and triple rectangular lattices with three replicates, respectively. Thirty-six seedlings were planted in each experimental plot. Seedling interval distance in Kalaleh and Hareh Sar were 2x3.5 and 2x3 m, respectively. Planted species included: Pinus pinea L., Cupressus sempervirens L. var. horizontalis, Pinus eldarica medw., Pinus nigra Link var. austriaca, Pinus sylvestris L. (Yugoslavian origin), Cuppressus arizonica Green, Picea abies, Pinus nigra Link var. pallasiana, Pinus nigra Link var, caramanica Pinus brutia Ten, Larix decidua Mill, and Cedrus atlantica mamett. Survival rate in 1994-96, height and diameter of seedlings were measured during 1995 and 1996. Then the relative height and diameter growth rate of the species were calculated. Since Cedrus atlantica seedlings were not available at the beginning of the experiment, plantation of this species was completed in 1996. Statistical analyses of relative growth rate of height and diameter were therefore conducted as randomized complete block design in each location. Since the effects of incomplete blocks for survival rate in both locations were not significant, the final analysis for this character was also conducted as a randomized complete block design in 1996. Furthermore, combined analysis of data of two locations for all of the characters were done and means were compared using Duncan's test. There was significant differences between the two locations with respect to the survival rate and relative growth of plant diameter. The mean percentage of the survival rate and relative growth of diameter in Kalaleh (northern slope) and Hareh Sar (southeastern slope) were 92.71, 36.92, and 64.24, 21.56, respectively. Even though differences between the locations, in relative growth of plants were not statistically significant, the relative height growth in the northern slope was 6.91% higher than that of the southeastern slope (26.4 compared to 19.49). There were significant difference among species within each of the locations, and in the average of two locations, with respect to the survival rate and relative height growth. There was not any significant differences among species with respect to the relative diameter growth. Species of Pinus eldarica, Cuppressus arizonica, Pinus nigra var, pallasiana, and Pinus brutla observed the highest percentage of the survival rate based on the location's average. Except the Picea abies and Cedrus atlantica, the survival rate of other species ranged from 90 to 100% in the location of Kalaleh. On the ether hand, in Hareh Sar, only the Pinus eldarica, Cuppressus arizonica Pinus nigra var. austriaca, and Pinus brutia showed the survival rate greater than 90%. With respect to the relative height growth, Pinus nigra var. austriaca was exclusively different than other species and stayed in first place with the percentage of 46.71 in Kalaleh, 74.47 in Hareh Sar, and a mean of 47.1 as compared to all other species. Kalaleh was superior to Hareh Sar because it was located on the northern slope which provides sufficient moisture content, solar radiation, and better regulation of water balance.