Investigation on some silvicultural and habitat characteristics of Quercus macranthera F. & M. at Semnan Province of Iran

Quercus macranthera is a dominant tree species of high elevation parts of north forests of Iran (Caspian region). It is distributed at high elevation area of Semnan and Shahrood cities of Semnan province at two types: 1. Scattered between 1700 and 2000 m. a.s.l. and 2. dense as dominant species between 2000 and 2500 m. a.s.l. and often on north aspects. In onder to study the silvicultural characteristics and site demands of this species, 42 sample plots were laid out on different land forms and geographical aspects, which In 34 plots, soil properties, including texture (clay, sand and loam), organic carbon, lime and acidity were studied. The results showed that pH varied between 5.2 and 8.1 and soil texture was almost sandy clay loam in all land forms, with an exception of clay loam on ridges. soil texture on north and east aspects was sandy clay loam, whereas on south and west aspects was loamy. Organic carbon percentage at three humid aspects (north, east and west) was 1.57, 1.69 and 1.95 %, respectively, whreas at south aspect was 0.48 % and significantly different from the other three aspects (p< 0.05). The maximum and minimum percentage of lime was 20 and 0.9 at south and west aspects, respectively with significant difference (p<0.01). The absolute maximum total height and diameter belonged to oak trees at flat land and north aspect, respectively. The greatest height and volume belonged to oak trees at 2200 to 2500 m. a.s.l. The absolute maximum volume belonged to an indivual oak tree (19.81 m3) on north slope. The maximum regeneration of oak trees was found at east aspect. Most of the forest species had the highest natural regeneration on north slopes.