برآورد بيوماس روزميني جنگل در جنگل هاي هيركاني با استفاده از داده هاي ماهواره اي

Estimation of Forest Above Ground Biomass in Hyrcanian Forests Using Satellite Imagery

زﻣﯿﻨﻪ و ﻫﺪف: اﻫﻤﯿﺖ ﺟﻨﮕﻞﻫﺎي ﺷﻤﺎل اﯾﺮان ﺑﻪ ﻋﻨﻮان ﯾﮑﯽ از ﻣﻬﻤﺘﺮﯾﻦ و ﺑﺰرﮔﺘﺮﯾﻦ ذﺧﺎﯾﺮ ﮐﺮﺑﻦ و ﻧﻘﺶ آن در ﺗﺮﺳﯿﺐ ﮐﺮﺑﻦ اﺗﻤﺴﻔﺮي در ﮐﺸﻮرﻣﺎن ﺑﺮﮐﺴﯽ ﭘﻮﺷﯿﺪه ﻧﯿﺴﺖ. ﻣﻄﺎﻟﻌﻪ ﺑﯿﻮﻣﺎس روزﻣﯿﻨﯽ اﯾﻦ ﺟﻨﮕﻞ ﻫﺎ ﺑﻪ ﻋﻨﻮان ﯾﮏ ﺿﺮورت ﺗﻠﻘﯽ ﻣﯽ ﮔﺮدد. در ﺳﺎلﻫﺎي اﺧﯿﺮ ﻣﻄﺎﻟﻌﺎت زﯾﺎدي ﺑﺎ اﺳﺘﻔﺎده از ﺗﮑﻨﻮﻟﻮژي ﺳﻨﺠﺶ از دور و ﺷﺎﺧﺺ ﻫﺎي ﻣﺨﺘﻠﻒ ﺑﺮاي ﻣﺤﺎﺳﺒﺎت ﺑﯿﻮﻣﺎس روزﻣﯿﻨﯽ ﺟﻨﮕﻞ ﻫﺎ اﻧﺠﺎم ﺷﺪه اﺳﺖ. ﻫﺪف ﭘﮋوﻫﺶ ﺑﺮآورد ﺑﯿﻮﻣﺎس ﺟﻨﮕﻞ ﻫﺎي ﻫﯿﺮﮐﺎﻧﯽ درﺷﻤﺎل اﯾﺮان ﺑﺎ اﺳﺘﻔﺎده از اﻃﻼﻋﺎت ﻣﺎﻫﻮاره SPOT6 ﻣﯽ ﺑﺎﺷﺪ. روش ﺑﺮرﺳﯽ: ﺑﯿﻮﻣﺎس روزﻣﯿﻨﯽ اﯾﻦ ﺟﻨﮕﻞ ﻫﺎ ﺑﺎ اﺳﺘﻔﺎده از ﺗﺼﺎوﯾﺮ ﻣﺎﻫﻮاره SPOT6 و ﻣﺪل ﻫﺎي رﮔﺮﺳﯿﻮﻧﯽ در ﺳﻪ ﻣﻨﻄﻘﻪ اﻧﺘﺨﺎﺑﯽ در اﺳﺘﺎﻧﻬﺎي ﺷﻤﺎﻟﯽ و در 2 داﻣﻨﻪ ارﺗﻔﺎﻋﯽ در ﺗﺎﺑﺴﺘﺎن 1395 ﺑﺮرﺳﯽ ﺷﺪ. ﭘﺲ از آن ﮐﻪ ﻣﻘﺎدﯾﺮ ﻣﺘﻮﺳﻂ ﺑﯿﻮﻣﺎس روزﻣﯿﻨﯽ ﺑﺮ ﺣﺴﺐ ﺗﻦ در ﻫﮑﺘﺎر ﺑﺎ اﺳﺘﻔﺎده از ﺑﺮداﺷﺖ ﻫﺎي زﻣﯿﻨﯽ ﻣﺤﺎﺳﺒﻪ ﮔﺮدﯾﺪ، از 3 ﺷﺎﺧﺺ ﭘﻮﺷﺶ ﮔﯿﺎﻫﯽ RVI ،NDVI و TVI ﺑﺮاي ﺑﺮآورد ﺑﯿﻮﻣﺎس ﺑﺮ اﺳﺎس ﺗﺼﺎوﯾﺮ ﻣﺎﻫﻮاره اي اﺳﺘﻔﺎده ﺷﺪ. ﯾﺎﻓﺘﻪ ﻫﺎ: ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد ﮐﻪ راﺑﻄﻪ ﺑﯿﻦ ﻣﻘﺎدﯾﺮ ﺑﯿﻮﻣﺎس روزﻣﯿﻨﯽ و ﺷﺎﺧﺺﻫﺎي ﭘﻮﺷﺶ ﮔﯿﺎﻫﯽ ﯾﮏ راﺑﻄﻪ ﺧﻄﯽ ﺑﻮده و ﺷﺎﺧﺺ NDVI در ﺳﻄﺢ ﺗﻤﺎﻣﯽ ﻣﻨﺎﻃﻖ ﺑﯿﺸﺘﺮﯾﻦ ﺳﻄﺢ ﻣﻌﻨﯽداري و ﺑﺎﻻﺗﺮﯾﻦ ﺿﺮﯾﺐ ﻫﻤﺒﺴﺘﮕﯽ ﺑﺎ ﺑﯿﻮﻣﺎس روزﻣﯿﻨﯽ را داﺷﺘﻪ اﺳﺖ. ﺑﻨﺎﺑﺮاﯾﻦ ﺑﻪ ﻣﻨﻈﻮر ﻧﻘﺸﻪ-ﺳﺎزي ﺑﯿﻮﻣﺎس روزﻣﯿﻨﯽ از رواﺑﻂ رﮔﺮﺳﯿﻮﻧﯽ اﯾﻦ ﺷﺎﺧﺺ اﺳﺘﻔﺎده ﺷﺪ. ﻧﺘﯿﺠﻪ ﮔﯿﺮي: ﺑﺮ اﺳﺎس ﻧﺘﺎﯾﺞ اﯾﻦ ﺗﺤﻘﯿﻖ ﻣﻘﺎدﯾﺮ ﺑﯿﻮﻣﺎس ﺑﯿﻦ ﺳﻪ ﻣﻨﻄﻘﻪ اﺻﻠﯽ ﺗﺤﻘﯿﻖ و در ﻃﺒﻘﺎت ارﺗﻔﺎﻋﯽ ﻣﯿﺎن ﺑﻨﺪ و ﺑﺎﻻﺑﻨﺪ داراي ﺗﻔﺎوتﻫﺎي ﻧﺴﺒﺘﺎً زﯾﺎدي ﻣﯽﺑﺎﺷﻨﺪ. ﺑﯿﺸﺘﺮﯾﻦ ﻣﯿﺰان ﺑﯿﻮﻣﺎس در ﻣﻨﻄﻘﻪ اﺳﺎﻟﻢ و داﻣﻨﻪ ارﺗﻔﺎﻋﯽ ﺑﺎﻻﺑﻨﺪ دﯾﺪه ﺷﺪه اﺳﺖ.

Background and Objective: The importance of the northern forests of Iran as one of the most important and largest carbon reserves and its role in atmospheric carbon sequestration in our country is evident. The study of the above ground biomass of these forests is considered as a necessity. In recent years, many studies have been carried out using remote sensing technology and various indices for forest above ground biomass estimations. The purpose of this study is estimating Hyrcanian forests above ground biomass in northern Iran using satellite data (SPOT 6). Method: In this research, above ground biomass of these forests using SPOT satellite images and regression models in three selected regions in the Northern provinces (Asalem, Sardaraboud and Kordkuy) and in 2 altitudes were investigated. After calculating the average above ground biomass per hectare using field plots, three vegetation indices NDVI, RVI and TVI were used to estimate biomass based on satellite imagery. Findings: The results showed that the relationship between above ground biomass values and vegetation indices was linear and the NDVI has the highest level of significance in all parcels and has the highest correlation coefficient with above ground biomass. Therefore, regression relations with NDVI were used in order to map the above ground biomass. Discussion and Conclusion: Based on the results of this study, the above ground biomass values between the three main study areas and in the elevation classes between the high lands and the middle land have a relatively large difference. The highest biomass in the Asalem region and the high lands has been observed.