Natural regeneration of Sogdian ash, Fraxinus sogdiana Bunge, in the floodplain of Sharyn River in Almaty region, Kazakhstan

The present study was carried out to find the natural regeneration patterns of Sogdian ash, Fraxinus sogdiana Bunge, in the fertile forests along the Sharin River in Almaty Province, Kazakhstan. We investigated factors affecting the establishment and growth of seedlings of this valuable species in the gradient of distance from the river. A systematic survey method with ۴۰ plots each ۲۰ × ۲۰ m۲ at different distances from the river was used to attain this goal. Data on seedling density in three different elevation classes, soil physico-chemical characteristics, light intensity, and health were carefully recorded and analyzed. The results showed that the distance from the river played a decisive role in the success of the natural regeneration of this species. The density of seedlings decreased from ۲۸۵۰ plants ha-۱ for the area within ۰-۵۰ m along the river up to ۲۹۰ plants ha-۱ in an area where distance from the river was more than ۱۵۰ m. Correlation analysis confirmed the existence of a significant correlation between distance from the river and seedling density, with a coefficient of -۰.۹۱. Soil properties including moisture (from ۳۲.۵% to ۱۲.۳%) and organic matter (from ۴.۵% to ۲.۱%) were also found to decrease by elevating distance from the river. On the other hand, the health of the seedlings beside the river was much better, and the proportion of healthy seedlings decreased from ۸۵.۵% close to the river to ۴۱.۲% at further distances. The growth rate of the established seedlings was also considerably higher beside the river, being ۲۸.۵ cm yr-۱ compared to ۱۲.۳ cm yr-۱ for the more distant plants. All these findings clearly suggest that maintaining the ecological conditions of the riverbank is crucially important for the continuation of the species, and also any change in the hydrological regime of the river can be considered a grave threat to the survival of this valuable ecosystem.

کلیدواژه ها:

Sogdian sparrowhawk ، Natural regeneration ، Sharin River ، Forest ecology