تنوع‌گونه‌اي در اشكوب‌هاي درختي و علفي و ارتباط آن با برخي مشخصه‌هاي توده جنگلي راش در جنگل‌هاي هيركاني(مطالعه موردي: جنگل سوادكوه- مازندران)

Species Diversity in Tree Strata and Its Relation to Some Features of Beech Stand in Hyrcanian Forests (Case study: Savadkooh,Mazandaran)

زﻣﯿﻨﻪ و ﻫﺪف: ﺗﺮﮐﯿﺐ ﮔﻮﻧﻪﻫﺎي درﺧﺘﯽ ﯾﮏ ﻣﺸﺨﺼﻪ اﺳﺎﺳﯽ ﺑﻮمﺳﺎزﮔﺎن ﺟﻨﮕﻞ ﻣﯽﺑﺎﺷﺪ و ﯾﮏ ﻫﺪف ﻣﻬﻢ ﺑﻮمﺷﻨﺎﺳﺎن آﮔﺎﻫﯽ از ﻋﻮاﻣﻞ اﺻﻠﯽ اﺳﺖ ﮐﻪ اﻟﮕﻮي ﺗﻨﻮع زﯾﺴﺘﯽ را ﺗﻮﺿﯿﺢ ﻣﯽدﻫﻨﺪ. ﺳﺎﺧﺘﺎر ﻋﻤﻮدي ﺟﻨﮕﻞ ﯾﮑﯽ از و ﯾﮋﮔﯽﻫﺎي ﺟﻨﮕﻞ ﺑﻮده ﮐﻪ در ﻣﺪﯾﺮﯾﺖ ﺑﻮمﺳﺎزﮔﺎن ﻣﻮرد ﺗﻮﺟﻪ ﻣﯽ-ﺑﺎﺷﺪ.ﻫﺪف از اﯾﻦ ﺗﺤﻘﯿﻖ ﺑﺮرﺳﯽ ارﺗﺒﺎط ﺗﻨﻮعﮔﻮﻧﻪاي در اﺷﮑﻮبﻫﺎي درﺧﺘﯽ ﺑﺎ ﺑﺮﺧﯽ ﻣﺸﺨﺼﻪﻫﺎي ﺗﻮده ﺟﻨﮕﻠﯽ راش در ﺟﻨﮕﻠﻬﺎي ﺳﻮادﮐﻮه ﻣﺎزﻧﺪران ﺑﻮده اﺳﺖ. روش ﺑﺮرﺳﯽ: در ﺗﺤﻘﯿﻖ ﺣﺎﺿﺮ، ﺑﻪ ﺟﻤﻊآوري داده ﻫﺎ از 24 ﻗﻄﻌﻪﻧﻤﻮﻧﻪ 400 ﻣﺘﺮ ﻣﺮﺑﻌﯽ در ﯾﮏ ﺷﺒﮑﻪ آﻣﺎرﺑﺮداري 100×150 ﻣﺘﺮ در ﺗﻮده ﺟﻨﮕﻠﯽ راش)Fagus orientalisLipsky( در ﺷﻤﺎل اﯾﺮان)ﺳﻮادﮐﻮه( در ﺳﺎل 1392 اﻗﺪام ﺷﺪ. ﺷﺎﺧﺺ ﻏﻨﺎيﻋﻠﻔﯽ و درﺧﺘﯽ) ﺷﻤﺎرش ﺗﻌﺪاد ﮔﻮﻧﻪ(، ﺷﺎﺧﺺ ﺗﻨﻮع و ﯾﮑﻨﻮاﺧﺘﯽ در اﺷﮑﻮبﻫﺎي درﺧﺘﯽ و ﻋﻠﻔﯽ ﺑﺮاي ﻫﺮ ﻗﻄﻌﻪﻧﻤﻮﻧﻪ ﻣﺤﺎﺳﺒﻪ ﺷﺪ. ارﺗﻔﺎع ، ﻗﻄﺮ ﺑﺮاﺑﺮ ﺳﯿﻨﻪ و ﻗﻄﺮ ﺗﺎج درﺧﺘﺎن راش ﻫﺮ ﻗﻄﻌﻪﻧﻤﻮﻧﻪ اﻧﺪازهﮔﯿﺮي ﺷﺪﻧﺪ .ﻫﻤﭽﻨﯿﻦ ﺿﺨﺎﻣﺖ ﻻﺷﺒﺮگ و ﻫﻮﻣﻮس در ﻣﺮﮐﺰ و ﭼﻬﺎرﺟﻬﺖ ﻗﻄﻌﻪﻧﻤﻮﻧﻪ ﻣﻮرد اﻧﺪازهﮔﯿﺮي ﻗﺮار ﮔﺮﻓﺘﻨﺪ. ﯾﺎﻓﺘﻪ ﻫﺎ: ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد ﮐﻪ ﺗﻮده ﺟﻨﮕﻠﯽ ﻣﻮرد ﻣﻄﺎﻟﻌﻪ ﺷﺎﻣﻞ 7 ﮔﻮﻧﻪ درﺧﺘﯽ راش، ﻣﻤﺮز، ﺷﯿﺮدار، ﺗﻮﺳﮑﺎيﯾﯿﻼﻗﯽ، اﻓﺮاﭘﻠﺖ، ﻧﻤﺪار و ﮔﯿﻼسوﺣﺸﯽ اﺳﺖ. ﺗﻌﺪاد 23 ﮔﻮﻧﻪ ﻋﻠﻔﯽ ﻣﺘﻌﻠﻖ ﺑﻪ 21 ﺧﺎﻧﻮادهﮔﯿﺎﻫﯽ در زﯾﺮاﺷﮑﻮب درﺧﺘﺎن ﺟﻨﮕﻠﯽ ﺷﻨﺎﺳﺎﯾﯽ ﺷﺪﻧﺪ. اﺧﺘﻼف ﻣﻌﻨﯽدار ﺑﯿﻦ اﺷﮑﻮبﻫﺎي درﺧﺘﯽ از ﻧﻈﺮ ﺷﺎﺧﺺ ﻏﻨﺎ و ﺗﻨﻮع ﮔﻮﻧﻪاي ﻣﺸﺎﻫﺪه ﺷﺪ 0.01

Accepted: 2018.10.24 Received: 2016.10.24 Abstract Background and Objective: Tree species composition is a major feature of forest ecosystems and understanding the major factors that clarify patterns of diversity is an important objective for ecologists. The aim of this study was to investigate the relationship between species diversity in tree layer and some features of beech stand in savadkooh forest. Method: Field data from 24 circular 400 m2 sample plots in the inventory grid of 100 m × 150 m were used in beech stand. For characterizing tree-layer diversity, tree-layer species richness (SR), Shannon–Wiener diversity index and Hill's evenness index were used. Herb-layer species richness (herb-layer SR) was estimated in each plot. Diameter (DBH) and height, also crown diameter in beech trees were measured per sample plot. In addition, litter and humus layer thickness were measured at center and cardinal points of sampling points. Findings: Result showed a total of 7 tree species were recognized in 24 plots. Totally, 23 herbaceous plants belonging to 21 families were found distributing in different plots within forest which higher life form was presented by Hemicryptophytes. There was a significant difference between dominant and co-dominant layers regarding to tree species richness (SR) and Shanon-weaver diversity index (P<0.01), and higher mean values belonged to the dominant layer. The herb-layer richness correlated significantly with litter thickness, whereas there was no correlation between other factors. SR of tree layer was negatively and significantly correlated with DBH and Height of beech trees and Shanon’s diversity and Hill’s evenness indices of tree layer were negatively correlated with beech frequency. Discussion: In general, it can be stated that the highest indicators of richness and tree diversity are observed in the upper floors of the target population, which can be due to competition, the nature of the tree species. It is recommended in forestry operations, the diversity of tree species in different floor to be considered. Keywords: Beech Forest, Diversity, Herb-Layer, Hyrcanian region, Tree strata