Journal of Spatial Analysis Environmental Hazards

fa ارزیابی ارتباط خشکیدگی جنگل و خشکسالی با استفاده از مدل های آماری در استان ایلام Assessing the relation ship between forest drying and drought using statistical models in illam province تخصصي Special پژوهشي Research <div style="text-align: justify;"> در این مطالعه ارتباط بین خشکیدگی درختان بلوط ایرانی و خشکسالی در استان ایلام بررسی شده است. هدف اصلی تحقیق معرفی مدلی مناسب از روابط بین خشکیدگی بلوط و خشکسالی می باشد بنابراین از شاخص‌های SPI و NDVI وآماره شاخص موران و آماره رگرسیون خطی و تصاویر ماهواره‌ای مودیس و لندست در تحلیل ارتباط خشکیدگی جنگل‌های ایلام با خشکسالی‌های رخ داده در منطقه استفاده شده است. داده‌های بارش 93 ایستگاه باران سنج در طول دوره آماری تحلیل شد و با توجه به ضرایب خشکی شاخص SPI لایه های پهنه بندی خشکسالی استان ایلام برای دو سری زمانی سالهای 2000 تا 2009 و سال‌های 2010 تا 2019تهیه شد. لایه‌های رستری سبزینگی از تصاویر ماهواره‌ای مودیس برای سری‌های زمانی ذکر شده تهیه شد. نتایچ تحلیل آماره موران همبستگی معناداری بین شاخص SPI و شاخص NDVI در بعد فضایی و مکانی نشان داد. به روش تصادفی ساده 143 نقطه خشکیدگی بلوط در ابعاد 30 مترمربع که هر نقطه معادل یک پیکسل سایز بود با دستگاه GPS ثبت و با شبیه سازی در تصاویر ماهواره‌ای، لایه نقطه‌ای خشکیدگی بلوط استخراج شد. هرچند رگرسیون خطی بین نقاط خشکیدگی بلوط استخراج شده با نتایج شاخص SPI و آماره موران معنی دار بود، اما نتایج ارتباط شاخص NDVI و آماره موران تاثیر روند خشکسالی در ابعاد مکانی و زمانی بر روند خشکیدگی بلوط با تحلیل فضایی و رگرسیون غیر خطی از معناداری و تبیین آماری مناسب تر و دقیق تری برخوردار است. بنابراین این روش در تحلیل خشکسالی و خشکیدگی بلوط مطلوب تشخیص داده و معرفی شد. </div> Introducing the appropriate model of oak forest and drought relations in Ilam province Introduction The forest ecosystems of the Zagros vegetation region have a very long history of exploitation in various forms. The material of the Zagros vegetation region is Iranian oak. In recent years, a significant proportion of oak forests have dried up or have experienced drought. Although the main cause of drought in these forests has not been determined yet, in the preliminary studies, factors such as climate change, increasing dust, increasing drought periods, pest infestation and disease, high user changes have been cited as reasons for drought in the Zagros forests. (Hosseinzadeh and Pourhashemi, 1396). Iran's location in the arid and semi-arid zone of the world (sub-tropical region) has often been associated with fluctuations in climatic and atmospheric elements and under the influence of atmospheric currents, synoptic patterns, irregularities in precipitation and temperature patterns (Rahmati, 2016; 1383). Comparison of the effect of climatic variables on healthy masses and affected by the decline of oak in Khorramabad city based on rainfall and temperature data using Pearson correlation coefficient, on annual growth rings of oak trees Effectiveness of drought of oak trees from both series In general, healthy trees have been more affected by monthly and seasonal temperatures and have shown the highest coefficient of correlation with the temperature of the region (Naseri Karimvand et al., 2016). , And the Standardized Rainfall Index (SPI) and the correlation between these two indicators in assessing and monitoring drought in different areas of Isfahan province, the results showed that NDVI plant index can be a good alternative to climatic indicators in drought assessment and monitoring) with the conclusion and colleagues, 2011: 79). Data and Method So from SPI and NDVI indicators and Moran index and statistical regression statistics and satellite images of Modis and Landsat have used to analyze the relationship between dieback of Ilam forests and happened drought in the region. The precipitation data of 93 rain gauge stations were analyzed during the statistical period and according to the dry coefficients of SPI index, drought zoning layers of Ilam province were prepared for two time series of 2000 to 2009 and 2010 to 2019. Greenery's raster layers were prepared from Modis satellite imagery for the mentioned time series. The results of analysis of Moran's statistical showed a significant correlation between the SPI index and the NDVI index in spatial dimensions. By a simple random method, 143 points of oak dieback with dimension of 30 m 2 , which each point was equivalent to a pixel-size, were recorded with a GPS device, and by simulating in satellite imagery, the droplet layer of oak dieback was extracted. Result and Discussion What is debatable about the results of the implementation of methods for obtaining drought ranges and its relationship with oak drought points or masses is that the results of the models show a statistically close and direct relationship between drought and oak drought. . The general trend of oak drought and drought in these two decades has been from the southeast to the northwest of Ilam province, with increasing temperature and decrease in rainfall in the southern and eastern regions of the province and increasing rainfall and decrease in temperature in the central and northwestern regions of Ilam province. The data of the synoptic stations are consistent. Analysis of satellite imagery and declining greenery in the models although the study was aimed at meteorological drought and precipitation fluctuations, but spatial changes of arid points and masses in the province were adapted to field visits and human intervention, especially in the southeast with agriculture. Under the rubble and the remnants of the dried trees, the ax has been placed on the roots of these trees, and this trend is spreading in almost other parts of the arid areas of the province. Therefore, due to the irregularity in the pattern of precipitation and temperature of the research country (Rahmati, 2016; Zandi Army, 2004) and the effect of monthly and seasonal نشریه تحلیل فضایی مخاطرات محیطی، سال نهم، شماره 1، بهار 1401 2 temperature on the growth and decline of oak trees in the study (Naseri Karimvand et al., 2016) and other related research and The flooding situation in the basins of Ilam province, the rainfall, the impermeability of the soil and their erosion, and finally the lack of moisture in the months before the oak trees grow in the soil and the increase in temperature in the dry season, which leads to reduced humidity and eventually greenery. Variables affecting oak drying in linear regression are not responsive, but more accurate results will be obtained in multivariate regression, although regression analyzes are spatially empty, and X and Y represent a one-way, quantitative analysis based on the number of dried trees with pixel counts. Drought range is measured which this defect in SPI method despite its spatial and statistical analysis using Moran statistical index due to non-compliance in the coefficients of this index with the range of changes in Moran statistical analysis in statistical analysis is a more appropriate explanatory coefficient than The regression models showed but at a lower level than the NDVI method it placed. The advantage of NDVI method with Moran statistical analysis is the relationship between pixel and pixel, ie in spatial analysis, all pixels that have green changes have been analyzed in the same domain of spatial changes with oak trees. High results and higher statistical explanation coefficient were obtained than other models. Conclusion Although linear regression between extracted oak dieback points with SPI and Moran statistical indicators was significant, but the relationship between NDVI index and Moran statistic has the effect of independent variable of drought trend in spatial and temporal dimensions on the dependent variable process of oak drought with spatial analysis. And nonlinear regression has a more appropriate and accurate statistical significance and explanation. So this method as desirable method has been introduced for analyzing of drought and oak dieback. Keywords: Ilam province, oak forest drought, drought, Moran index استان ایلام, خشکیدگی جنگل, خشکسالی, مدل آماری Ilam province, oak forest drought, drought, statistical models 1 20 http://jsaeh.khu.ac.ir/browse.php?a_code=A-10-464-2&slc_lang=fa&sid=1 SHAMSOLLAH ASGARI شمس اله عسگری shamsasgari@yahoo.com 100319475328460010632 100319475328460010632 Yes Assistant Prof, Soil Conservation and Watershed Management Research Department, Ilam Agricultural and Natural Resources Research and Education Center, Agricultural Research, Education and Extension Organization (AREEO), Ilam, Iran خش تحقیقات منابع طبیعی و آبخیزداری، مرکز تحقیقات و آموزش کشاورزی و منابع طبیعی استان ایلام، Tayeb Raziei طیب رضیئی tayebrazi@yahoo.com 100319475328460010633 100319475328460010633 No Associate Prof, Soil Conservation and Watershed Management Research Institute (SCWMRI), Agricultural Research, Education and Extension Organization (AREEO), Tehran, Iran پژوهشکده حفاظت خاک و آبخیزداری، سازمان تحقیقات، آموزش و ترویج کشاورزی، MohamadReza Jafari محمدرضا جعفری mg_jafari@yahoo.com 100319475328460010634 100319475328460010634 No Assistant Prof., Research Division of Natural Resources, Ilam Agricultural and Natural ResourcesResearch Center (AREEO), Ilam تحقیقات منابع طبیعی و آبخیزداری، مرکز تحقیقات و آموزش کشاورزی و منابع طبیعی استان ایلام، Ahmad Hosini احمد حسینی ahmad.phd@gmail.com 100319475328460010635 100319475328460010635 No Assistant Prof., Research Division of Natural Resources, Ilam Agricultural and Natural ResourcesResearch Center (AREEO), Ilam, تحقیقات منابع طبیعی و آبخیزداری، مرکز تحقیقات و آموزش کشاورزی و منابع طبیعی استان ایلام،