برآورد تغييرات مكاني ضخامت لاشبرگ در سري يك و دو توده‌هاي جنگلي طبيعي و دست كاشت عرب داغ گلستان

Estimation of spatial variation of litter thickness in series one and two of natural and planted forest stands in in the Arabdagh area

با توجه به اهميت ضخامت لاشبرگ در تنظيم ميكروكليما و خصوصيات فيزيكي، شيميايي و زيستي خاك، تنظيم تبادلات ورودي و خروجي خاك، تحول و تداوم توده هاي جنگلي و بررسي وضعيت ميزان آن در توده هاي دست كاشت و شرايط محيطي مختلف، اين مطالعه با هدف برآورد ضخامت لاشبرگ و تهيه نقشه توزيع مكاني آن از طريق مقايسه روش هاي مختلف ميان يابي قطعي و زمين آماري در منطقه جنگلي عرب داغ واقع در شمال شرق استان گلستان انجام گرديد. مواد و روش ها: اطلاعات ضخامت لاشبرگ در 422 قطعه نمونه دايره اي با مساحت 400 مترمربع در قالب شبكه خوشه اي منظم با ابعاد شبكه 600×400 (هر خوشه 5 قطعه نمونه با فواصل 100 متري) از توده هاي سوزني برگان (كاج بروسيا، زربين، سرو نقره اي، كاج بادامي، كاج اروپايي)، پهن برگان (آزاد، ممرز، انجيلي، افراپلت) و مخلوط پهن برگان و پوشش درختچه اي و بوته اي (سياه ال، سياه تلو، انار وحشي) جمع آوري گرديد و پس از آناليز اوليه در نرم افزارهاي آماري، بانك اطلاعاتي مكاني و توصيفي آنها در محيط GIS تهيه شد. سپس به منظور توليد نقشه موضوعي ضخامت لاشبرگ، كارايي روش هاي مختلف درون يابي EBK، OK، RBF، LPT، LDW و Co-kriging مورد مقايسه و آناليز قرار گرفتند. اعتبارسنجي متقابل براي ارزيابي دقت تكنيك هاي مختلف درون يابي به وسيله ضريب تبيين (R2)، ميانگين خطاي نسبي (MRE)، ميانگين خطاي اريبي (MBE)، ميانگين خطاي مطلق (MAE) و ميانگين مجذور مربعات خطا (RMSE) انجام شد.يافته ها: نتايج اين پژوهش نشان داد بيش ترين ضخامت لاشبرگ در توده هاي پهن برگ طبيعي و كم ترين ضخامت در تيپ سوزني برگ سرو نقره اي در منطقه بوده است. هم چنين در گروه پهن برگ، تيپ خالص آزاد بيش ترين تغييرات ﺿﺨﺎﻣﺖ ﻻﺷﺒﺮگ را داﺷﺘﻪ )1/09 ﺳﺎﻧﺘﯽ ﻣﺘﺮ( و ﺗﯿﭗ ﺧﺎﻟﺺ ﻣﻤﺮز ﺑﺎ ﮐﻢ ﺗﺮﯾﻦ ﻣﻘﺪار اﻧﺤﺮاف ﻣﻌﯿﺎر )0/27 ﺳﺎﻧﺘﯽ ﻣﺘﺮ(، ﺗﻘﺮﯾﺒﺎً ﺿﺨﺎﻣﺖ ﺛﺎﺑﺘﯽ را ﻧﺸﺎن داد درﺣﺎﻟﯽ ﮐﻪ در ﮔﺮوه ﺳﻮزﻧﯽﺑﺮﮔﺎن ﺗﯿﭗ ﻫﺎي ﮐﺎج ﺑﺮوﺳﯿﺎ ﺑﯿﺶ ﺗﺮﯾﻦ ﺗﻐﯿﯿﺮات ﺿﺨﺎﻣﺖ ﻻﺷﺒﺮگ را ﺑﻪ ﻧﻤﺎﯾﺶ ﮔﺬاﺷﺖ. ﻧﺘﺎﯾﺞ اﯾﻦ ﻣﻄﺎﻟﻌﻪ ﻧﺸﺎن داد ﮐﻪ روش درون ﯾﺎﺑﯽ زﻣﯿﻦ آﻣﺎري ﮐﻮﮐﺮﯾﺠﯿﻨﮓ ﻣﻌﻤﻮﻟﯽ ﺑﻪ ﺗﺮﺗﯿﺐ ﺑﺎ ﻣﺪل ﻫﺎي ﻧﻤﺎﯾﯽ )0/783(، ﮐﺮوي )0/789( و ﮔﻮﺳﯽ )0/791( ﺑﺎ داده ﮐﻤﮑﯽ ﺳﻄﺢ ﻣﻘﻄﻊ در ﻫﮑﺘﺎر ﺑﺎ ﺣﺪاﻗﻞ ﺟﺬر ﻣﺮﺑﻌﺎت ﺧﻄﺎ و ﺑﯿﺶ ﺗﺮﯾﻦ ﺿﺮﯾﺐ ﺗﺒﯿﯿﻦ، ﻗﺎﺑﻠﯿﺖ ﺑﻬﺘﺮي در ﻣﻘﺎﯾﺴﻪ ﺑﺎ روش ﻫﺎي درون ﯾﺎﺑﯽ ﮐﺮﯾﺠﯿﻨﮓ )0/8 ﺗﺎ 0/817( و ﻗﻄﻌﯽ )0/875 ﺗﺎ 1/05( در درون ﯾﺎﺑﯽ ﺗﻮزﯾﻊ ﻣﮑﺎﻧﯽ ﺿﺨﺎﻣﺖ ﻻﺷﺒﺮگ اﮐﻮﺳﯿﺴﺘﻢ ﺟﻨﮕﻠﯽ ﻣﻨﻄﻘﻪ ﻋﺮب داغ دارد. ﻧﺘﯿﺠﻪ ﮔﯿﺮي: ﺑﺎ ﺗﻮﺟﻪ ﺑﻪ ﺗﺄﺛﯿﺮ ﺿﺨﺎﻣﺖ ﻻﺷﺒﺮگ ﺑﺮ روي ﺑﺮﺧﯽ از ﻓﺎﮐﺘﻮرﻫﺎي ﺗﻮده و روﯾﺸﮕﺎه ﻣﺎﻧﻨﺪ زادآوري، ﮐﯿﻔﯿﺖ و ﻧﻔﻮذﭘﺬﯾﺮي ﺧﺎك و ﺷﺪت ﺑﺮﺧﯽ از آﺷﻔﺘﮕﯽ ﻫﺎي ﻃﺒﯿﻌﯽ راﯾﺞ در ﻣﻨﻄﻘﻪ ﻣﺎﻧﻨﺪ آﺗﺶﺳﻮزي و ﻧﺘﺎﯾﺞ ﺣﺎﺻﻞ از اﯾﻦ ﭘﮋوﻫﺶ، روش ﻣﯿﺎنﯾﺎﺑﯽ ﮐﻮﮐﺮﯾﺠﯿﻨﮓ ﻣﻌﻤﻮﻟﯽ ﺑﺎ ﻣﺪلﻫﺎي ﻧﻤﺎﯾﯽ و ﮔﻮﺳﯽ در ﻣﻘﺎﯾﺴﻪ ﺑﺎ ﺳﺎﯾﺮ روش ﻫﺎ، ﺑﻪ دﻟﯿﻞ دﻗﺖ و ﺻﺤﺖ ﻧﺘﺎﯾﺞ ﺑﻪ دﺳﺖ آﻣﺪه ﻣﯽﺗﻮاﻧﺪ در ﺗﻌﯿﯿﻦ ﺿﺨﺎﻣﺖ ﻻﺷﺒﺮگ ﺗﻮدهﻫﺎي ﺟﻨﮕﻠﯽ و ﻫﻢ ﭼﻨﯿﻦ ﻣﺪﯾﺮﯾﺖ ﻃﺮحﻫﺎي ﭘﺮورﺷﯽ و ﺟﻨﮕﻞ ﮐﺎري ﻣﺸﺎﺑﻪ ﮐﺎراﯾﯽ ﺑﯿﺶ ﺗﺮي داﺷﺘﻪ ﺑﺎﺷﺪ.

Background and purpose: the importance of litter thickness in the regulation of microclimate and the physical, chemical and biological characteristics of the soil, the regulation of soil input and output exchanges and evolution and continuity of forest stands and the study of its nature in natural endemic hardwood and planted forests and different environmental conditions is an essential issue. In this study, different techniques of interpolation were analyzed and compared to estimate the spatial variability of litter thickness in the Arabdagh area located in Northeast Golestan province. Materials and Methods: Litter thickness data were collected in 422 sample plots with an area of 400m2 using a systematic cluster network (400×600m, each cluster includes 5 plots with a distance of 100 meters) in different hardwood, softwood tree stands and shrub&herb lands including Pinus brutia, Cupressus sempervirens var. horizontalis, Pinus pinea, Pinus sylvestries and broad-leaved species such as Zelkova carpinifolia, Carpinus betulus, Acer velutinum, Parrotia persica and mixed broadleave. Then, after an initial analysis of the data in statistical software, their spatial and descriptive database was prepared in GIS environment . In order to produce litter thickness thematic map, the efficiency of different interpolation methods of EBK, OK, RBF, LPT, LDW and Co-kriging were compared. Cross-validation was performed to evaluate the accuracy of different interpolation techniques by the coefficient of determination (R2), mean relative error (MRE), mean error (MBE), mean absolute error (MAE) and root mean square error (RMSE). Results: The results of this study presented that the highest thickness of the litter was in the natural broad-leaved stands and the lowest thickness in the Cupressus arizonica type in the region. Also, in the broad-leaved group, the pure type of Zelkova carpinifolia had the most changes (1.09 cm). While, in the needle-leaved group, the Pinus brutia type showed the most variation in the thickness of the litter. The results of this study showed that the Co-kriging interpolation method with the exponential (0.783), spherical (0.789) and Gaussian (0.791) models using the auxiliary data of Basel area per hectare and with least-squares error and the highest coefficient of determination had high capability Compared to kriging (0.8 to 0.817) and deterministic models (0.875 to 1.05) in spatial distribution interpolation of litter thickness in Arabdagh region. Conclusion: Due to the effect of litter thickness on some stand and habitat factors such as regeneration , soil quality and Permeability and The intensity of some natural disturbances in the area such as wild fire, it is recommended to take an effective step in managing plan and forestry projects by evaluating it. Due to the effect of litter thickness on some factors of habitat and habitat such as regeneration, soil quality and permeability and the severity of some common natural disturbances in the region such as fire and the results of this study, the Co-kriging interpolation method with the exponential and Gaussian models compared to other methods, due to the accuracy of the results can be more effective in determining the litter thickness of forest stands as well as managing similar stands and afforestation plans.