مونيتورينگ فنولوژي راش ايراني در جنگل‏هاي طبيعي با استفاده از داده‏هاي ماهواره‏اي درشمال ايران (مطالعه موردي حوزه 21 استان گيلان)

Monitoring of Iranian Beech Phenology in Natural Forests Using by Satellite Data in North of Iran (Case Study 21 Basin, Guilan Province)

در اين مطالعه فنولوژي گونه راش در سه محدوده ارتفاعي (400 تا 700 متر، 700 تا 1000 متر و 1000 تا 1300 متر )، در دو جهت (شمالي و جنوبي) و در منطقه كوهستاني جنگلي واقع در حوزه 21 استان گيلان مورد بررسي قرار گرفت. در مجموع 6 قطعه نمونه يك هكتاري انتخاب و در هر قطعه نمونه 100 اصله درخت سالم علامتگذاري و در ماه‏هاي مختلف سال در دفعات متعدد مورد بازديد قرار گرفت و مشاهدات در جداول مربوط درج گرديد. همچنين از تصاوير سنجنده LISSIII-IRS در طول دوره مطالعه استفاده گرديد. پس از تصحيح هندسي با دقت كمتر از 5/0 پيكسل و تصحيح اتمسفري تصاوير با توليد شاخص NDVI مراحل فنولوژيك گونه راش ايراني مورد پايش قرار گرفت. نتايج نشان مي‏دهد ظهور برگ و گلدهي از هفته سوم فروردين تا هفته اول ارديبهشت، شروع ريزش برگ اوايل هفته چهارم آبان و پايان ريزش برگ اواخر هفته اول آذر مي‏باشد. همچنين كليه برداشت‏هاي فنولوژيكي پس از تبديل به گذشت روز از سال مورد تجزيه قرار گرفتند نتايج نشان داد كه كليه سطوح مورد بررسي شامل سال، ارتفاع، جهت و گونه از لحاظ صفات فنولوژيكي مورد بررسي داراي اختلاف معني داري با همديگر بودند. حداكثر مقدار NDVI 6/0 در مرحله كامل شدن برگ و افزايش NDVI به مقدار 31/0 مرحله ظهور برگ و كاهش NDVI به مقدار 33/0 مرحله خزان برگ در گونه راش ايراني را نشان مي‏دهد.

In this study, beech phenology in three altitudinal range (400 to 700 m, 700 to 1000 m and 1000 m to 1300), in both aspect (North and South) and in the mountainous forested areas located in Guilan province, 21 were studied. A total of six-hectare plots in each plot selected 100 healthy trees marked in different months and years were visited several times and observations were inserted in the relevant tables. Also LISSIII-IRS satellite images during the study period were used. After geometric correction accuracy of less than 0.5 pixels and atmospheric correction of images produced in NDVI Iranian beech phenological stages were monitored. Results indicate the emergence of leaves and flowering of the third week of April to first week of May, beginning of leaf loss in early October and the end of the fourth week of leaf loss in December is the first weekend. All interpretations of the phonological days after the passing of years into the analysis results showed that were reviewed included in all levels, altitude, direction and types of phonological characteristics of studied were significantly different from each other. Correlation matrix was calculated based on the traits that a significant negative correlation between rainfall and average temperatures of leaf emergence, flowering and the rate of emergence was scored. Correlation between average temperatures complete with leaves, falling leaves, the rate and amount of flowering fruit week was also significant and negative. Maximum NDVI 0.6 complete leaf stage and increase the value of NDVI 0.31 leaf emergence stage and reduce the NDVI value of 0.33 phase Autumn beech leaves in Iran shows.