تأثیر شیب زمین بر وسعت و شدت برهم‌خوردگی خاک جنگل در اثر عملیات چوبکشی زمینی (مطالعه موردی: جنگل ناو اسالم گیلان)

نوع مقاله: علمی- پژوهشی

نویسندگان

1 استادیار، گروه جنگلداری، دانشکده منابع طبیعی، واحد خلخال، دانشگاه آزاد اسلامی، خلخال، ایران

2 استادیار، گروه جنگلداری، دانشکده منابع طبیعی، دانشگاه گیلان، صومعه‌سرا، ایران

چکیده

یکی از عامل‌های کلیدی برای داشتن جنگل‌هایی با تولید مستمر، حفاظت از خاک جنگل است. در پژوهش پیش‌رو وسعت و شدت برهم‌خوردگی خاک جنگل در اثر خارج کردن تنه‌ها و گرده‌بینه‌های درختان قطع‌شده (m3/ha 20/5) در جنگل ناو اسالم گیلان بررسی شد. پس از اتمام عملیات چوبکشی، برهم‌خوردگی خاک از طریق نمونه‌برداری نقطه- خط‌نمونه و به ‌روش ارزیابی چشمی بررسی شد. نتایج نشان داد که حدود 2/6 ± 19 درصد از خاک منطقه در اثر چوبکشی دچار برهم‌خوردگی شده بود که 11/3 درصد آن با شدت کم و 7/7 درصد آن با شدت زیاد بود. وسعت و شدت برهم‌خوردگی خاک با افزایش فاصله از مسیرهای چوبکشی کاهش یافته بود، اما با افزایش شیب زمین افزایش پیدا کرده بود. وزن مخصوص ظاهری خاک در مناطق برهم‌خورده با شدت کم (g/cm3 1/29) و در مناطق برهم‌خورده با شدت زیاد (g/cm3 1/44) به‌ترتیب 2/4 و 14/3 درصد نسبت به مناطق شاهد افزایش یافته بود. وزن مخصوص ظاهری خاک مناطق برهم‌خورده با افزایش شیب زمین افزایش یافته بود، به‌طوری‌که در شیب‌های بیشتر از 50 درصد، وزن مخصوص ظاهری خاک 20/8 درصد نسبت به مناطق شاهد افزایش یافته بود. کاهش شدت برداشت، قطع و انداختن هدایت‌شده درختان و محدود کردن عملیات چوبکشی به شیب‌های کمتر از 50 درصد، ازجمله راهکارهای کاهش برهم‌خوردگی خاک در این جنگل‌ها است.

کلیدواژه‌ها


عنوان مقاله [English]

Effect of ground slope on extent and intensity of soil disturbance from skidder logging (Case study: Nav-e Asalem forest, Gilan province)

نویسندگان [English]

  • Farzam Tavankar 1
  • Mehrdad Nikooy 2
1 Assistant Prof., Department of Forestry, Faculty of Natural Resources, Khalkhal Branch, Islamic Azad University, Khalkhal, Iran
2 Assistant Prof., Department of Forestry, Faculty of Natural Resources, University of Gilan, Someh Sara, Iran
چکیده [English]

Protection of forest soil is one of key factors in having sustainable productive forests. In this research extent and intensity of soil disturbance due to extraction of logs of felled trees (20.5 m3/ha) were studied in Nav-e Asalem forest in Gilan province. After finishing the skidder logging operations, soil disturbance were studied by point-transect sampling method and visual assessing. Results indicated that about 19 ± 6.2 percent of surface soils were disturbed due to winching of logs that 11.3 percent of them disturbed with shallow intensity and 7.7 percent disturbed with deep intensity. The extent and intensity of soil disturbance were decreased by increasing distance from skid trail. The extent and intensity of soil disturbance were increased by increasing of ground slope. Soil bulk density in the shallow disturbed soils (1.29 g/cm3) and deep disturbed soils (1.44 g/cm3) were increased 2.4 and 14.3 percent, respectively, than control soils. Soil bulk density of disturbed areas were increased by increasing ground slope, so in slopes greater than 50 percent soil bulk density was increased 20.8 percent more than control soils. Including ways to reducing soil disturbance during skidder logging in the study area are reduction in harvest intensity, implementation of felling direction and skidder logging limitation to slopes less than 50 percent.

کلیدواژه‌ها [English]

  • Ground skidding
  • logging
  • selection cutting
  • soil bulk density
  • soil compaction

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