تعیین تنوع ساختاری راشستان‌های آمیخته بخش گرازبن جنگل خیرود

نوع مقاله : علمی- پژوهشی

نویسندگان

1 دانشجوی دکتری جنگل‌شناسی، گروه جنگل‌داری و اقتصاد جنگل، دانشکده منابع طبیعی، دانشگاه تهران، ایران

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

3 دانشیار، گروه جنگل‌داری و اقتصاد جنگل، دانشکده منابع طبیعی، دانشگاه تهران، کرج، ایران

چکیده

کمی­‌سازی ساختار جنگل با عددی‌کردن اجزای مختلف آن به درک و فهم بهتر برای مدیریت بوم‌سازگان جنگل کمک می‌کند. در این پژوهش از یک شاخص مکانی غیرآشکار به نام شاخص جینی (Gini index) با هدف تجزیه و تحلیل ساختار توده و تعیین پارامترهای لازم برای همگنی و یا ناهمگنی ساختار توده استفاده شد. این مطالعه در پارسل­‌های 305، 306، 309، 310 و 311 بخش گرازبن جنگل خیرود با استفاده از داده‏‌های به‌دست آمده از اجرای یک دوره آماربرداری صددرصد انجام شد. با استفاده از پارامترهای تعداد درختان، تعداد در طبقه قطری، فراوانی نسبی تجمعی درختان و فراوانی رویه زمینی آن‌ها، شاخص جینی برای هریک از پارسل­‌ها محاسبه و منحنی لورنز آن‌ها ترسیم شد. نتایج نشان داد که شاخص جینی برای پارسل‌های 305، 306، 309، 310 و 311 به‌ترتیب 5/39، 66، 44، 82 و 74 درصد بود. همچنین، ساختار قطری پارسل‌­های 305 و 309 نزدیک به همگن، پارسل­‌های 310 و 311 نزدیک به ناهمگن و پارسل 306 نزدیک به حالت بینابینی داشتند. بنابراین، در منطقه مورد مطالعه می­‌توان از این یافته‌ها در موضوعات مدیریتی جنگل مانند مدل­‌سازی نزدیک به واقعیت توده‌­های طبیعی و چگونگی تنوع ساختاری آن‌ها به‌خوبی استفاده کرد.

کلیدواژه‌ها

عنوان مقاله [English]

Determining the structural diversity of mixed oriental beech (Fagus orientalis L.) stands in Gorazbon district, Kheyrud forest

نویسندگان [English]

  • Mohsen Javanmiri Pour 1
  • Mohammad Reza Marvie Mohadjer 2
  • Mahmoud Zobeiri 2
  • Vahid Etemad 3
  • Meghdad Jourgholami 3
1 Ph.D. Student, Department of Forestry and Forest Economics, Faculty of Natural Resources, University of Tehran, Karaj, Iran
2 Prof., Department of Forestry and Forest Economics, Faculty of Natural Resources, University of Tehran, Karaj, Iran
3 Associate Prof., Department of Forestry and Forest Economics, Faculty of Natural Resources, University of Tehran, Karaj, Iran
چکیده [English]

Quantification of forest structure and its various components helps to better understand the forest ecosystem and supports its improved management. Here, the Gini index were used as a spatial distribution index for evaluating the structural diversity. The main objective was to analyse the stand structure and determine the necessary factors for the structural heterogeneity and  homogeneity. This study was conducted in compartments 305, 306, 309, 310 and 311 in Gorazbon district, Kheyrud forest by means of a full calipering method. Then Gini index was calculated and finally the Lorenz curve was derived by using frequencies of stems, diameter class, as well as cumulative relative frequencies of trees and their basal area. The results showed Gini index values of 39.5%, 66%, 44%, 82% and 74%  for compartments 305, 306, 309, 310 and 311, respectively. In addiiton, the diameter structure for 305 and 309 compartments was shown to be close to homogeneity, whereas it was close to medium for compartment 306 and close to heterogeneity for compartments 310 and 311. Finally the use of Gini index and Lorenz curve was concluded to he helpful in reclecting the near-real structural diversity in natural beech stands.

کلیدواژه‌ها [English]

  • Forest structure
  • Gini index
  • Lorenz curve
  • quantification

مراجع

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