control plot

Quantifying the structure of forest stands by quantifying their different components helps to better understand for the management of different components of the forest ecosystem. One of the most important reasons for the structure quantification is that the forest structure is related to the habitat of many plant species, the modeling and reconstruction of the forest based on its structural characteristics, and the forest structure is an important source of information for forest dynamics, aesthetics and wood production. Therefore, in this research, the structural characteristics of two stands managed by single-selection and shelterwood methods were compared with the control stand.

In order to conduct this study, three plots including plot No. 3 with single-selection method, plot No.  13 with shelterwood method and plot No. 10 (control plot) were selected in Alandan forests, Mazandaran province. To study the structural features of forest stands, circular sample plots with an area of ​​1000 m2 were used (21, 14 and 25 sample plots in (In the plots of single-selection, shelterwood and control plot, respectively and a total of 60 sample plots). The inventory was conducted in a systematic-randomly method with a grid size of 200 × 150 m. To investigate the regeneration condition, a 1 m2 micro-plot in the center of the sample plot and its four main directions were used. In order to investigate the soil properties, sampling was performed by a combined method at a depth of 0-10 cm in the center of the large sample plot and the four main directions. Percentage of soil texture (including sand, silt and clay), moisture content, bulk density, pH, EC, percentage of organic carbon, percentage of organic matter, percentage of lime, total nitrogen, absorbable phosphorus and absorbable potassium were measured in the laboratory.

The results showed that the average number of trees per hectare was 206, 209 and 358 in the single-selection, control and shelterwood plots, respectively; which had a volume of 428.22, 477.14 and 373.3 sylve, respectively. The average percentage of moisture, percentage of organic carbon and percentage of organic matter in the single-selection was 49.4%, 4.7% and 8.2%, respectively; while, in the control and shelterwood plots they were 44.12 and 43.24%; 3.4 and3.28%; and 5.9 and 5.66%, respectively. The bulk density was 1.72 g/cm3 in the shelterwood plot; while, its amount in single-selection and control masses plots 1.22 and g/cm3, respectively.

In general, the results of this study showed that the implementation of different silvicultural methods such as the shelterwood and selection methods have different effects on the structure, regeneration, and physical and chemical properties of the soil.