بررسی عوامل تأثیرگذار بر خسارت برف زودرس در توده‌های طبیعی (مطالعۀ موردی: بخش پاتم)

نوع مقاله: مقاله پژوهشی

نویسندگان

1 دانشجوی دکتری مهندسی جنگل، دانشکدۀ منابع طبیعی، دانشگاه تهران، کرج، ایران

2 استاد گروه جنگلداری و اقتصاد جنگل، دانشکدۀ منابع طبیعی، دانشگاه تهران، کرج، ایران

3 کارشناسی ارشد جنگلداری، جنگل آموزشی و پژوهشی خیرود، دانشکدۀ منابع طبیعی، دانشگاه تهران، کرج، ایران

4 کارشناسی ارشد جنگلداری، ادارۀ منابع طبیعی و آبخیزداری، کلاردشت، ایران

چکیده

به‌منظور بررسی فاکتورهای مؤثر بر خسارت ناشی از برف زودرس در پارسل 10 بخش پاتم جنگل آموزشی خیرود، آماربرداری به‌روش تصادفی منظم با ابعاد شبکه (100 در 100 متر) با قطعات نمونۀ دایره‌ای 1000 متر مربعی به تعداد 46 قطعه نمونه انجام گرفت. در هر قطعه نمونه عواملی مؤثر شامل شیب عمومی قطعه نمونه، جهت جغرافیایی، ارتفاع از سطح دریا و عمق خاک، قطر برابرسینه و ارتفاع همۀ گونه‌های درختی بیشتر از 5/7 سانتی‌متر برداشت شد. خسارات به درختان به چهار نوع دستۀ ریشه‌کن شدن، شکستگی تنه، شکستگی تاج و خم شدن طبقه‌بندی و ثبت شد. نتایج تحقیق نشان داد که 1/28 درصد درختان خسارت دیدند که درصد هر یک از انواع خسارت‌های ریشه‌کن شدن، شکستگی تنه، شکستگی تاج و خم شدن به‌ترتیب 3، 4، 10 و 11 درصد بود. نتایج نشان داد که بین نوع خسارت و عوامل جهات جغرافیایی، شیب، ارتفاع از سطح دریا و عمق خاک اختلاف معنی‌داری وجود دارد. بیشترین خسارت درختان در دامنۀ شمالی، شیب کمتر از 15 درصد، ارتفاع (380-330 متر) و خاک‌های کم‌عمق و کمترین آن در دامنه‌های جنوبی رخ داده است. خسارت در دامنه‌های شرقی و غربی تقریباً برابر بوده است. بیشترین و کمترین درصد خسارت به‌ترتیب مربوط به گونه‌های توسکا و افرا است. عملیات پرورشی با تأثیر بر ساختار افقی و عمودی توده‌ها جهت کاهش ضریب قطری درختان، نقش مؤثری در کاهش شدت و وسعت خسارت برف بر درختان خواهد داشت و پایداری توده و درخت را بهبود می‌بخشد.

کلیدواژه‌ها


عنوان مقاله [English]

Study of the influencing factors on the early snow damage in the natural forest stands (Case study: Patom district in Kheyrud forests)

نویسندگان [English]

  • Hassan Samdaliri 1
  • Meghdad Jourgholami 2
  • Jafar fathi 3
  • Hamed Zalnezhad 4
1 Ph.D. student of forest engineering, Faculty of Natural Resources, University of Tehran, Karaj
3 Senior expert of kheyrud forest, Faculty of Natural Resources, University of Tehran
4 MSc student
چکیده [English]

In order to investigate the factors affecting damage caused by early snow in the compartment no. 10 in Patom district of Kheyrud forest research station, the sampling was conducted on a random grid (100 × 100 m) with 46 m 1000 circular sample plots. In each plot, effective factors including slope gradient of the plot, aspect, altitude (elevation), soil depth, diameter at breast height, and height of all tree species greater than 7.5 cm were recorded. Damages to trees were classified into four types including uprooting (tree throw), trunk fracture, crown fracture, and bending. The results showed that 28.1% of the trees were damaged, with damage of 3, 4, 10 and 11% for each type including uprooting (tree throw), trunk fracture, crown fracture, and bending, respectively. The results showed that there was a significant difference between the types of tree damage and some factors including aspect, slope, elevation, and soil depth. The highest percentage of tree damage occurred in the northern aspect, slope less than 15%, altitude of 330-380 m, and shallow soils depth, and the lowest occurred in the southern aspect. The damage on the eastern and western slopes was approximately similar. The highest and the lowest percentages of damage were related to alder and maple tree species, respectively. Thinning treatments affected the horizontal and vertical structure of the stands by reducing the slenderness coefficient of trees, which has a key role in reducing the severity of snow damage on trees, and improves tree and stand stability.

کلیدواژه‌ها [English]

  • Snow Damage
  • Bending
  • Trunk Fracture
  • Crown Damage
  • H/D Index
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