Effects of pure and mixed Caucasian alder (Alnus subcordata C. A. Mey.) and eastern cottonwood (Populus deltoides Marsh.) plantations on carbon sequestration and some physical and chemical soil properties

This study investigated effects of pure and mixed plantations of Caucasian alder (Alnus subcordata C. A. Mey.) and eastern cottonwood(Populus deltoides Marsh.) on carbon sequestration and some physical and chemical soil properties. The stands across the test site were planted in 1996 under randomized complete blocks design at four replications and five treatments at Chamestan Forest Station. The treatment consisted of five pure and mixed eastern cottonwoodand Caucasian alder stands (pure eastern cottonwood, pure Caucasian alder, mixed Caucasian alder and eastern cottonwoodstands at three different levels: 50+50 %, 33+67 % and 67+33 %, respectively). Combined soil samples were taken at two depths including 0-15 and 15-30 cm. The results showed no significant difference in carbon sequestration rates amongst the treatments at both soil depths, except for pH which was significantly different at soil surface layer (P<0.05). There was a significant (P< 0.01) positive correlation between organic carbon and nitrogen, whereas negative correlations were observed between soil organic carbon and soil bulk density and carbon to nitrogen ratio. Furthermore, presence of Caucasian alder species showed positive effect on the amount of carbon and other soil properties. However, longer term investigations are required to achieve better results.