تحلیل ساختار تیپ های مختلف در جنگل های ناو اسالم گیلان با استفاده از شاخص های نزدیک ترین همسایه

ارزﻳﺎﺑﻲ ﺳﺎﺧﺘﺎر ﺟﻨﮕﻞ ﺑﻪ ﻋﻨﻮان ﻳﻜﻲ از ﻣﻨﺎﺳﺐﺗﺮﻳﻦ اﺑﺰارﻫﺎ در ﻣﺪﻳﺮﻳﺖ ﻧﻮﻳﻦ ﺟﻨﮕﻞ در ﻧﻈﺮ ﮔﺮﻓﺘﻪ ﻣﻲﺷﻮد. در اﻳﻦ ﺗﺤﻘﻴﻖ ﺳﺎﺧﺘﺎر ﮔﻮﻧﻪﻫﺎی درﺧﺘﻲ ﺗﻴﭗﻫﺎی راش، راش- ﻣﻤﺮز و راش- اﻓﺮا ﺟﻨﮕﻞﻫﺎی ﻫﻴﺮﻛﺎﻧﻲ ﻣﻮرد ﺑﺮرﺳﻲ و ﻣﻘﺎﻳﺴﻪ ﻗﺮار ﮔﺮﻓﺖ. ﺑﻤﻨﻈﻮر اﻧﺠﺎم اﻳﻦ ﺗﺤﻘﻴﻖ 5 ﻗﻄﻌﻪ ﻧﻤﻮﻧﻪ ﻳﻚ ﻫﻜﺘﺎری در ﻫﺮ ﻳﻚ از ﺗﻴﭗﻫﺎی ﻣﺬﻛﻮر ﺟﻨﮕﻠﻲ ﻧﺎو اﺳﺎﻟﻢ ﮔﻴﻼن ﻛﻪ از ﻟﺤﺎظ ﺷﺮاﻳﻂ ﻣﺤﻴﻄﻲ ﻫﻤﮕﻦ ﺑﻮدﻧﺪ، آﻣﺎرﺑﺮداری ﺷﺪﻧﺪ و ﺷﺎﺧﺺﻫﺎی ﻣﻴﺎﻧﮕﻴﻦ ﺟﻬﺖ، زاوﻳﻪ ﻳﻜﻨﻮاﺧﺖ، آﻣﻴﺨﺘﮕﻲ، اﺑﻌﺎد ﻗﻄﺮ ﺑﺮاﺑﺮ ﺳﻴﻨﻪ و ارﺗﻔﺎع و ﻓﺎﺻﻠﻪ ﺗﺎ ﻧﺰدﻳﻚﺗﺮﻳﻦ ﻫﻤﺴﺎﻳﻪﻫﺎ ﻣﺤﺎﺳﺒﻪ ﺷﺪﻧﺪ. ﻧﺘﺎﻳﺞ ﺣﺎﺻﻞ از ﺷﺎﺧﺺﻫﺎی ﻣﻴﺎﻧﮕﻴﻦ ﺟﻬﺖ و زاوﻳﻪ ﻳﻜﻨﻮاﺧﺖ، ﻧﺸﺎن-دﻫﻨﺪه ﻣﻮﻗﻌﻴﺖ ﻣﻜﺎﻧﻲ ﺗﺼﺎدﻓﻲ ﺑﺮای درﺧﺘﺎن ﺳﻪ ﺗﻴﭗ ﻣﻮرد ﺑﺮرﺳﻲ ﺑﻮد. ﻧﺘﺎﻳﺞ ﺷﺎﺧﺺ آﻣﻴﺨﺘﮕﻲ، اﺧﺘﻼط ﻛﻤﻲ را ﺑﺮای ﺳﻪ ﺗﻴﭗ ﻣﻮرد ﺑﺮرﺳﻲ ﻧﺸﺎن داد. ﻧﺘﺎﻳﺞ ﺑﺪﺳﺖ آﻣﺪه از اﻳﻦ ﺷﺎﺧﺺ ﻧﺸﺎن داد ﻛﻪ ﻏﺎﻟﺒﺎ ﮔﻮﻧﻪ fagus orientalis دارای رﻗﺎﺑﺖ درون ﮔﻮﻧﻪای و ﺳﺎﻳﺮ ﮔﻮﻧﻪﻫﺎی ﻣﻮرد ﺑﺮرﺳﻲ دارای رﻗﺎﺑﺖ ﺑﻴﻦ ﮔﻮﻧﻪای ﻣﻲﺑﺎﺷﻨﺪ. ﻣﻴﺎﻧﮕﻴﻦ ﺷﺎﺧﺺﻫﺎی اﺑﻌﺎد ﻗﻄﺮ ﺑﺮاﺑﺮ ﺳﻴﻨﻪ و ارﺗﻔﺎع،ﺷﺒﺎﻫﺖ ﻧﺴﺒﻲ ﺗﻴﭗﻫﺎی ﻣﻮرد ﺑﺮرﺳﻲ را ﻧﺸﺎن داد. ﻧﺘﺎﻳﺞ ﺣﺎﺻﻞ از اﻳﻦ دو ﺷﺎﺧﺺ ﻏﺎﻟﺒﻴﺖ ﻧﺴﺒﻲ ﮔﻮﻧﻪﻫﺎی acer velutinum و alnus subcordata و ﻣﻐﻠﻮﺑﻴﺖ ﮔﻮﻧﻪﻫﺎی cerasus avium و ulmus glabra را ﻧﺸﺎن دادﻧﺪ. ﻧﺘﺎﻳﺞ ﺣﺎﺻﻞ از ﺷﺎﺧﺺ ﻓﺎﺻﻠﻪ ﺗﺎ ﻧﺰدﻳﻚﺗﺮﻳﻦ ﻫﻤﺴﺎﻳﻪﻫﺎ ﻧﺸﺎندﻫﻨﺪه ﺗﺮاﻛﻢ ﺑﺎﻻی درﺧﺘﺎن در ﺗﻴﭗ راش ﻧﺴﺒﺖ ﺑﻪ ﺳﺎﻳﺮ ﺗﻴﭗﻫﺎی ﻣﻮرد ﺑﺮرﺳﻲ اﺳﺖ. ﻣﻘﺎﻳﺴﻪ ﺳﺎﺧﺘﺎر ﮔﻮﻧﻪﻫﺎی ﻣﺸﺎﺑﻪ در ﺗﻴﭗﻫﺎی ﻣﺨﺘﻠﻒ، ﺑﻴﺎﻧﮕﺮ ﻋﺪم وﺟﻮد اﺧﺘﻼف ﻣﻌﻨﻲدار ﺑﻴﻦ آنﻫﺎ از ﻧﻈﺮ وﻳﮋﮔﻲﻫﺎی ﻣﻮﻗﻌﻴﺖ ﻣﻜﺎﻧﻲ، اﺑﻌﺎد ﻗﻄﺮ ﺑﺮاﺑﺮ ﺳﻴﻨﻪ و ارﺗﻔﺎع و ﺗﺮاﻛﻢ درﺧﺘﺎن ﺑﻮد و در آﻣﻴﺨﺘﮕﻲ ﮔﻮﻧﻪﻫﺎی carpinus betulus ،fagus orientalis و alnus subcordata در ﺗﻴﭗﻫﺎی ﻣﻮرد ﺑﺮرﺳﻲ اﺧﺘﻼﻓﺎت ﻣﺸﺎﻫﺪه ﺷﺪ. ﺷﺎﺧﺺﻫﺎی ﺑﻜﺎر رﻓﺘﻪ در اﻳﻦ ﺗﺤﻘﻴﻖ اﺑﺰار ﺑﺴﻴﺎر ﻣﻔﻴﺪی ﺟﻬﺖ ﺗﺤﻠﻴﻞ ﺳﺎﺧﺘﺎر ﺗﻴﭗﻫﺎی ﻣﺨﺘﻠﻒ و ﻫﻤﭽﻨﻴﻦ وﻳﮋﮔﻲﻫﺎی ﺑﻮمﺷﻨﺎﺧﺘﻲ ﮔﻮﻧﻪﻫﺎی درﺧﺘﻲ ﻫﺴﺘﻨﺪ.

Analysis of different type’s structure in Nave Asalem-Gilan forests by using nearest neighbor indices

The quantitative description of forest structure can be regarded as one of the most usable working tools in modern forest management. In this study, the structures of trees species in Fagus, FagusCarpinus and FagusAcer types were investigated and compared in Hyrcanian forests. In order to do this research, five plots oneha inventoried in each forest types Nave Asalem Gilan that were homogeneous environmental conditions, and Crancod (ver. 1.4) software was employed to calculate the Mean directional, Uniform angle, Mingling, DBH dominance and Height dominance and Distance to nearest neighbours indices. The result of mean directional and uniform angle indices showed a random positioning for the trees in the studied types. The result of mingling index showed a low mixture for three studied types. The result of this index indicated an intraspecific competition for Fagus orientalis and an interspecific competition for other species. The average value of DBH and Height dominance indices showed a relative similarity among the studied types. The result of these indices showed that some species such as Acer velutinum and Alnus subcordata are dominant and species including Cerasus avium and Ulmus glabra are dominated. The comparing of similar species structure in different types showed a non significant difference for positioning, DBH and height dominance and tree density features.