بررسی ارتباط عامل‌های پستی و بلندی با گسترش زوال بلوط در جنگل مله‌سیاه ایلام

نوع مقاله: علمی- پژوهشی

نویسندگان

1 استادیار پژوهش، مرکز تحقیقات کشاورزی و منابع طبیعی استان ایلام

2 مربی پژوهش، مرکز تحقیقات کشاورزی و منابع طبیعی استان ایلام

چکیده

بحران زوال بلوط در سال‌های اخیر موجودیت جنگل‌های زاگرس را به مخاطره انداخته و بر ساختار توده‌های جنگلی تأثیر گذاشته و پایداری آنها را دستخوش تغییر نموده است. شناسایی عامل‌های مؤثر بر گسترش این پدیده می‌تواند برنامه‌ریزان و متولیان حفاظت‌ این جنگل‌ها را برای کنترل بحران یاری نماید. در این تحقیق تأثیر ویژگی‌های محیطی توده‌ها بر پدیده زوال درختان بلوط ایرانی (Quercus brantii) در بخشی از جنگل‌های زاگرس جنوبی مورد ارزیابی قرار گرفت. برای این منظور تعداد 12 توده دچار خشکیدگی بلوط ایرانی در شرایط مختلف رویشگاه مله‌سیاه در قالب دو جهت شمالی و جنوبی، دو طبقه ارتفاعی و سه تکرار انتخاب شد. در هریک از توده‌ها یک خط ترانسکت تصادفی تعیین و تعداد سه قطعه نمونه مربعی 25 آری در طول هر ترانسکت مشخص و تمامی درختان آنها اندازه گیری شد. برای تجزیه و تحلیل اطلاعات با بهره‌گیری از نرم‌افزارهایSPSS  و  Excelدر قالب طرح بلوک‌های کامل تصادفی و آزمون فاکتوریل از روش‌های مقایسه میانگین‌ها استفاده شده است. نتایج نشان داد ویژگی‌های درختان از قبیل قطر، ارتفاع، طول تاج و سطح‌مقطع برابر سینه در جهت‌های مختلف دامنه و ارتفاعات مختلف از سطح دریا تفاوت معنی‌داری ندارد، با این حال جهت دامنه بر میزان خشکیدگی درختان دانه‌زاد اثر معنی‌دار داشت و عامل ارتفاع از سطح دریا بر خشکیدگی شاخه‌زادها اثر معنی‌دار داشت. میزان خشکیدگی در جهت جنوبی بیشتر از جهت شمالی و در ارتفاع پایین بیشتر از ارتفاع بالا بود. اثرات متقابل این دو عامل بر میزان خشکیدگی نیز معنی‌دار بود.

کلیدواژه‌ها


عنوان مقاله [English]

Influence of topography on Brant`s oak decline in Meleh-Siah Forest, Ilam Province

نویسندگان [English]

  • Jafar Hosseinzadeh 1
  • Ayyad Aazami 2
  • Mashaallah Mohammadpour 2
1 Assistant Prof., Research Division of Natural Resources, Ilam Agricultural and Natural Resources Research Center, AREEO, Ilam, Iran
2 Senior Research Expert, Research Division of Natural Resources, Ilam Agricultural and
چکیده [English]

During the last decade, oak decline has caused critical health issues within the Zagros forests in west Iran, which is currently approaching a threatening level with effects on stand structure and stability. Identifying the influential factors on the spread of this phenomenon can thus help forest planners and administrating units to control the crisis. This study aimed to assess different aspects influencing deterioration of oak trees with respect to stands environmental characteristics in the southern part of Zagros forests. For this purpose, 12 declined stand dominated by Brant`s oak (Quercus brantii) at different conditions in both the North and South aspects as well as two altitudes and three replications were chosen within Meleh-Siah forest site in Ilam province. A transect line was randomly assigned to each of the stands, along each or which three square plots (2500 square meter) were laid. Within the plots, all individual trees were inventoried. By using a randomized complete block and factorial design, methods were used to compare the mean values of the inventoried parameters. Although the results showed no significant difference between diameter, height, crown length and basal area of the stands along gradients of aspect and altitude, significant effect of aspect on decline rate in seed based trees as well as altitude on coppice trees were observed. The degree of decline in south aspect was greater than in north aspect. In addition, lower elevations showed larger effects than higher elevations. The interaction between two factors was also significant on the decline rate.

کلیدواژه‌ها [English]

  • Altitude
  • Ilam
  • Brant`s oak
  • decline
  • aspect
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