مقايسه رشد صنوبر اورامريكن روي خاك هاي مختلف جلگه غرب مازندران

A Comparison of Populus X. euramericana Growth on Different Soils in Western Mazandaran Plain

In order to compare the growth in 16-year-old Populus X. euramericana (Dode) Guinier (clone I-214) trees in different soils, seven plantation sites of 5 x 5 m tree spacings were chosen in western Mazandaran plain, north of Iran. In each site three transects (replications) of 20 x 33.3 m area were taken in a randomly designed experiment, while and diameter at breast height (d.b.h.) as well as height for all trees within transects were determined. Soil in sites after physio-chemical analysis, was classified into four types, namely, podzolic brown grayish of much organic matter (A), brown forest (B), podzolic brown grayish (C) and pseudoglay (D). Averages in annual growth of d.b.h., height, basal area (b.a.) in ha, and volume (in ha.), based on soil type, were computed and statistically analyzed (at a level of 1% probabilty). The results demonstrated that, except height growth which was statistically equal (168-174 cm) in A, B as well as in C soils, other characteristics of d.b.h. (1.6-1.7 cm), b.a. (1.3-1.5 m2/ha) and volume growth (16.4-17.1 m^3/ha) were greater in A and B than in C and D soils. The measured figures were the lowest in D type soil. It can be concluded that, A and B soils are more favorable for growing Populus X. euramericana clone I-214 in western Mazandaran plain, and therefore its plantation is recommended, preferably, on these soils.