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Modelling the Form Factor of Palestine Oak Maquis “Quercus calliprinos Webb.”, Grown on the Eastern Versants of Coastal Mountains-Syria

نمذجة معامل الشكل لماكي السنديان العادي Quercus calliprinos Webb. النامي على السفوح الشرقية للجبال الساحلية - سورية

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 Publication date 2015
and research's language is العربية
 Created by Shamra Editor




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This study aims to construct a mathematical model to calculate the form factor of Palestine Oak Maquis grown on the eastern versants of coastal mountains. The form factor model can help foresters to precisely estimate the volume of tree and forest stands. In the year 2014, 129 oak shoots of various ages and sizes, located in natural stands of different densities and site qualities covering all conditions of region grown on, were felled. Diameters at different heights of the felled shoots were measured; shoots volumes and volumes of equivalent cylinders were calculated, and consequently the values of shoot form factor were computed. The dataset was randomly split into two parts, 70% (90 shoots) of the data for constructing form factor model and 30% (39 trees) for model validation. Several form factor models were developed using the non-linear regression equations in the statistical program SPSS. Best fit to the data was selected and value of the coefficient of determination adjusted (R²adj) was about 0.77. The model has been validated using several statistical methods, the relative bias of the best model ( e%) was ca. -3.6 %, while the value of model accuracy ) % x m ) was 15%. In order to obtain lower value of model relative bias and higher value of accuracy, it’s recommended to use a larger database comprising all distribution areas of oak Maquis in Syria.


Artificial intelligence review:
Research summary
تهدف هذه الدراسة إلى تصميم نموذج رياضي لحساب معامل الشكل لأخلاف السنديان العادي الموجود على السفوح الشرقية للجبال الساحلية في سوريا. تم جمع البيانات من 129 خلفة متنوعة في الأعمار والقياسات خلال عام 2014. تم قياس أقطار الأخلاف على ارتفاعات مختلفة، وحساب حجومها وحجوم الأسطوانات المكافئة لها، ومن ثم الحصول على قيم معامل الشكل. استخدمت 70% من البيانات لتصميم النموذج و30% لاختبار جودة النموذج. تم تطوير عدة نماذج رياضية باستخدام معادلات الانحدار غير الخطي في برنامج SPSS، وتم اختيار أفضلها بناءً على قيمة معامل التحديد المعدل (R²adj) التي بلغت 0.77. أظهرت اختبارات الجودة أن النموذج الأفضل يمتلك متوسط نسبي لخطأ النموذج يبلغ -3.6% ودقة تبلغ 15%. توصي الدراسة باستخدام قاعدة بيانات أوسع لتحسين دقة النموذج.
Critical review
دراسة نقدية: تعتبر هذه الدراسة خطوة مهمة نحو تحسين تقدير حجوم الأشجار والمجموعات الحرجية في سوريا، خاصة في ظل نقص الدراسات المتعلقة بمعامل الشكل للسنديان العادي. ومع ذلك، يمكن توجيه بعض الانتقادات البناءة. أولاً، الاعتماد على بيانات من منطقة جغرافية محددة قد يحد من تعميم النتائج على مناطق أخرى. ثانياً، رغم أن الدراسة توصي باستخدام قاعدة بيانات أوسع، إلا أنها لم تقدم خطة واضحة لكيفية تحقيق ذلك. أخيراً، كان من الممكن أن تكون الدراسة أكثر شمولية إذا تضمنت تحليلاً للعوامل البيئية الأخرى التي قد تؤثر على معامل الشكل.
Questions related to the research
  1. ما هو الهدف الرئيسي من الدراسة؟

    الهدف الرئيسي من الدراسة هو تصميم نموذج رياضي لحساب معامل الشكل لأخلاف السنديان العادي على السفوح الشرقية للجبال الساحلية في سوريا.

  2. كيف تم جمع البيانات اللازمة للدراسة؟

    تم جمع البيانات من 129 خلفة متنوعة في الأعمار والقياسات خلال عام 2014، وتم قياس أقطار الأخلاف على ارتفاعات مختلفة، وحساب حجومها وحجوم الأسطوانات المكافئة لها.

  3. ما هي أفضل قيمة لمعامل التحديد المعدل (R²adj) التي تم الحصول عليها؟

    أفضل قيمة لمعامل التحديد المعدل (R²adj) التي تم الحصول عليها هي 0.77.

  4. ما هي التوصية الرئيسية التي قدمتها الدراسة لتحسين دقة النموذج؟

    التوصية الرئيسية هي استخدام قاعدة بيانات أوسع تشمل جميع مناطق انتشار السنديان العادي في سوريا لتحسين دقة النموذج.


References used
ADEKUNLE V. A. J, NAIR K. N., SRIVASTAVA A. K., SINGH N. K. Models and form factors for stand volume estimation in natural forest ecosystems: a case study of Katarniaghat Wildlife Sanctuary (KGWS), Bahraich District, India. Journal of Forestry Research, 24(2), 2013: 217−226
ALTRIELL D, BRANTHOMME A, TAVANI R. Assessing growing stock and stock changes through multi-purpose national forest monitoring and assessment, FAO Forest Resources Assessment Programme Working paper, Rome,2010
CHÁIDEZ J. N. Allometric equations and expansion factors for tropical dry forest trees of Eastern Sinaloa, Mexico. Tropical and Subtropical Agro-ecosystems, 10, 2009, 45−52
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