CC BY
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ЛЕСНОЕ ХОЗЯЙСТВО FORESTRY
UDC 528.9:630. *1
DOI: https://doi.Org/10.25686/2306-2827.2021.2.5
MONITORING CEDRUS LIBANI FORESTS CONSERVATION STATUS IN THE SYRIAN ARAB REPUBLIC USING GEOSPATIAL
TECHNOLOGIES
A. A. Ibrahim1, E. K. Koubaily1, A. M. Thabeet2
1Ecology and Forestry Department , Faculty of Agriculture, Tishreen University , Lattakia, Syria 2Department of Ecology and Forestry, Aleppo University, Syria E-mail: [email protected]
Advanced monitoring and mapping of forest areas using the latest technological advances in satellite imagery is an alternative solution for sustainable forest management compared to conventional ground measurements. Remote sensing products have been a key source of information and cost-effective option for monitoring changes in vegetation areas. The aim of this study is to assess the changes in conservation status of the natural stands of Cedrus Libani A. Richard (C. li-bani) in their only natural habitat in Syria, Slenfeh and Jawbat Burghal, during the period 19842014 by using Remote Sensing and Geographic Information Systems (GIS). 17 various Landsat images; Landsat 4, 5 and 8 and the Normalized Difference Vegetation Index (NDVI) were used during the period 1984-2014.The results showed a significant increase trend of NDVI for the natural stands of C. libani in Slenfeh and Jawbat Burghal during 1984-2014; which reflects the good health status of the natural Cedar stands in Syria and thus its ability to fruit and regenerate naturally especially when appropriate sylvicultural treatments are applied.
Keywords: Cedrus libani; conservation status; remote sensing; GIS; Landsat images; NDVI.
Introduction. Lebanon Cedar (C. libani A. Rich.) is of a principal importance from the historical, cultural, aesthetic, scientific, and economic perspectives. It is presently found primarily in the Taurus Mountain range of Asia Minor, Turkey. Historical records indicate extensive and magnificent forests of Lebanon cedar also existed in Syria and Lebanon; however, heavy cutting, burning, and goat grazing for the past 5,000 years
have left only small populations in Syria and Lebanon [1].
C. libani is confined to the Eastern Mediterranean region, forming in the past extensive and magnificent forests in Syria, Lebanon and Turkey, which were an important source of wood for successive human civilizations [2]. These populations have been genetically isolated since the last Quaternary glacial cycle; they have been
© Ibrahim A. A., Koubaily E. K., Thabeet A. M., 2021.
For eitation: Ibrahim A. A., Koubaily E. K., Thabeet A. M. Monitoring Cedrus Libani Forests Conservation StaTus in the Syrian Arab Republic Using Geospatial Technologies. Vestnik of Volga State University of Technology. Ser.: Forest. Ecology. Nature Management. 2021. No 2 (50). Pp. 5-12. DOI: https://doi.org/10.25686/2306-2827.2021.2.5
threatened by extinction since the 19th century [3]. According to the International Union for Conservation of Nature (IUCN) C. libani is classified as Low Risk and Near Threatened (LR/nt) [4], and though national records classified cedar as an endangered species (threatened) or near extinction [5]. In Syria, as a consequence of increasing human impact, C. libani populations are currently located in an extremely restricted area in the northern part of the Syrian coastal mountain range [6, 7].
Today in Syria, C. libani forests are degraded and scattered stands located only in Slenfeh and Jawbat Burghal areas in the northwestern part of the country, and C. liba-ni is accompanied by many shrubs and trees such as: Quercus cerris L. ssp. pseudocerris (Boiss.) Chalabi, Quercus libani Oliv., Q. infectoria Oliv., Ostrya carpinifolia Scop., Carpinus orientalis Mill, etc. [8]. Moreover, these remaining forests suffer from the severe scarcity of natural regeneration of C. libani, which means that their ability to continue self-regeneration is at risk [8].
The natural forest of C. libani may be actually threatened by the future effects of expected climate change, as Cedar populations will find no other place to extend to; they have already reached the highest elevations in mountainous regions [9, 10]. This makes the future of the C. libani forests unclear and uncertain, especially in view of the decline in the natural regeneration of this important forest species during the last years (approximately 50-60 year ago), thus maintaining population dynamics and improving their natural regeneration should be a priority for the conservation of C. libani [10]. This requires taking all the necessary precautions to protect the natural C. libani and to rehabilitate their degraded forest ecosystems. Growth dynamics over the last years and the affecting factors are required to perform the appropriate forest management planning which is primarily aimed at the development of the natural C. libani stands and preventing their degradation.
The use of satellite images at multiple spatial and temporal scales is important to study annual increment and natural regeneration after various disturbances (climate change, fires, land use change, volcanoes, etc.) over a given period of time through vegetation biomass indices or remote sensing indices [11, 12]. Numerous vegetation indices (VIs) utilizing spectral information as a way to monitor vegetation status and mapping process. The normalized difference vegetation index (NDVI) is the most common index for high-throughput screening [13]. The temporary NDVI images series are widely used in forest monitoring and growth conditions [14] and in the detection of the interrelationship between climate and forest ecosystems [15].
Remote sensing and GIS technology is currently playing an important role in the analysis of forest structure and natural regeneration mechanics, making a good approach to understand the long-term dynamics of the forest and the key factors influencing it and thus properly managing its forest structures and natural regeneration by understanding their responses to various forest management practices under the prevailing environmental variables, thus, making it possible to predict the response of these forest structures to forest management practices which will be applied in the future [16,17]
This research aims to monitor the conservation status of the remaining natural C. libani species by determining the general trend of changes in the health of the natural C. libani stands in Slenfeh and Jawbat Burghal by using NDVI index changes during the period 1984-2014 with the consideration of the changes in its local environment in order to produce a sustainable forest management plan.
Study Area. This research was carried out in the natural distribution area of C. liba-ni in Lattakia governorate of Syria, which has been declared as the "Cedar and Fir Protected Area" since 1996. The total area covers 1,350 ha. This protected area is located
(36° 10' to 36° 17' E; 35° 29' to 35° 41' N) in the northern part of the Syrian coastal mountain range on the eastern aspect (Slen-feh, Jawbat Burghal) (Fig. 1). C. libani trees grow naturally on the soil formed on the hard Jurassic limestone rocks; which are composed of hard limestone and dolomite calcareous formations [18]. The depth of the soil where the Cedar grows is between 15 and 105 cm and the soil pH is slightly acid [19]. Cedar forests are located in a cold humid bi-oclimatic zone on the eastern side of the Syrian coastal chain mountains from 900 m to 1,562 m above the sea in the Slenfeh and Jawbat Burghal areas [20]. The area size of the C. Libani in both Slenfeh and Jawbat Burghal determined to be 254.72 ha [21]. C. libani in Syria and Lebanon has suffered major deterioration in areas where the stands have been degraded and mixed with other tree species, accompanied by severe damage to natural habitats and soil erosion [8].
Methodology
1. Satellite images
The United States Geological Survey (USGS) Earth Explorer Landsat data archive (http://earthexplorer.usgs.gov/) was the source of 17 Landsat images with different sensors Landsat MSS, TM, and OLI_TIRS; that covers the area under study. These satellite images were level 1 systematic and terrain corrected (L1T/G) acquired in different years in summer and temporally covered the period 1984 - 2014 with the resolution of 30 m except Landsat MSS with the resolution of 60 m for the study site, which contained Path 174, Row 35 World Geographic System (WGS) (Table). The images were geometrically rectified to Universal Transverse Mercator (UTM), Zone 37 N, WGS 1984 Datum. The top-of-atmosphere (TOA) correction was applied to images to convert them to TOA reflectance by using the Spectral Radiance Scaling Method manually in ArcGIS 9.3 software [22].
Fig. 1. Location of the Protected Area Cedar and Fir, and the natural distribution of C. libani in Slenfeh
and Jawbat Burghal forests, Syria [21].
A collection of Landsat images for the study area
Satellite ID Sensor Spatial resolution (m) Acquisition date
Landsat 5 MSS 60 1984/7/4
Landsat 5 TM 30 1985/7/23
Landsat 5 TM 30 1987/7/29
Landsat 4 TM 30 1989/7/10
Landsat 4 TM 30 1990/8/30
Landsat 4 TM 30 1992/8/3
Landsat 5 TM 30 1999/8/15
Landsat 5 TM 30 2000/6/14
Landsat 5 TM 30 2002/6/20
Landsat 5 TM 30 2003/8/10
Landsat 5 TM 30 2006/7/17
Landsat 5 TM 30 2007/8/21
Landsat 5 TM 30 2009/6/23
Landsat 5 TM 30 2010/7/12
Landsat 5 TM 30 2011/7/31
Landsat 8 OLI TIRS 30 2013/8/21
Landast 8 OLI TIRS 30 2014/8/24
2. Field samples
The area of C. libani forest in Slenfeh and Jawbat Burgher divided into a square grid (200 x 200 m) by using ArcGIS 9.3 software and the final number of squares was 65. Then based on field observations and high resolution Google Earth images; the squares in which C. libani constituted more than 50 % from the total forest cover were taken as samples and identified by the global position system (GPS), so we had 9 sample plots of C. libani in Slenfeh and 39 sample plots in Jawbat Burghal. The coordinates of 48 sample plots centers were taken in GPS and were converted into a GIS point data layer by using ArcGIS 9.3 software.
3. The changes in the conservation status of the natural stands of C. libani during the period 1984 - 2014
The changes in the conservation status of the natural stands of C. libani were studied by calculating the Normalized Difference Vegetation index (NDVI) which extracted from the 17 Landsat images for the period 1984 - 2014. NDVI index is computed by the following equation [23]:
NDVI= (NIR-R)/(NIR+R).
The quotient represents the functional characteristics of the active plant that contrasts to the reflectance of the near infrared
and red bands; where NIR corresponds to the near infrared band, and R corresponds to the red band. The values of NDVI index vary according to the degree of absorption of solar radiation by chlorophyll in the red spectral band and its reflection in the infrared spectral band from electromagnetic radiation. NDVI values range between -1 and +1, and the high positive values represent dense and healthy forest such as broad leaf forests [24]. In contrast, NDVI values closer to -1 detect non vegetated surfaces such as bare soil, rocks, snow, and clouds [24].
The values of NDVI index of the sample plots centers were extracted by using ArcGIS 9.3. The trend and amount of NDVI index of the studied C. libani sample plots were determined during the period 1984 - 2014 by using SPSS (Statistical Package for Social Science) 15 pack program and ANOVA analysis (p < 0.05) by comparing the average of NDVI index values of all sample plots in the study period.
Results and discussion. NDVI values of C. libani stands in Slenfeh ranged from 0.433 as the lowest value for the year 1984 to 0.606 as the highest value for the year 2009 (Fig.2). For NDVI values of C. libani stands in Jawbat Burghal, the lowest value was recorded to be 0.422 in the year 1984 and the highest
value 0.588 in the year 2009 just like in Slen-feh exactly (Fig.3). The simple linear regression equation for the annual average of NDVI of the natural stands of C. libani showed a significant increase during the period 1984 - 2014 in Slenfeh and Jawbat Burghal; the annual increase of NDVI was 0.003 in Slenfeh (R = 0.66, P = 0.004) (Fig.2) and NDVI index increased by the same value (0.003) in the Jawbat Burghal (R = 0.62, P = 0.009) (Fig.3). The simple linear regression equation of NDVI explained 44 % of the variance in the actual values of this index in Slenfeh and 38 % of the variance in Jawbat Burghal (Fig. 2, 3) respectively. The calculated NDVI values are relatively low in the area under study due to the low number of field samples.
This result corresponds to the study of [25] about the changes in the annual and seasonal NDVI values of the natural stands of C. libani in Slenfeh and Jawbat Burghal and its relationship to climatic variables (temperature, precipitation) during the period 20042014 by using monthly MODIS NDVI satel-
lite imagery; the increasing trend of NDVI values of the C. libani stands was found in Slenfeh and Jawbat Burghal (0.006, 0.004 / year) respectively. Ismail F. [26] showed an insignificant increase in the value of NDVI index of Quercus cerris L. ssp. pseudocerris (Boiss.) Chalabi stands in Slenfeh - Syria during the period 2001-2011 with an increase of 0.008 / year.
The increasing trend of NDVI index of the natural C. libani stands during the period 1984-2014; reflects the good health status of these stands in its natural areas of Syria (Slenfeh and Jawbat Burghal) during the considered period. NDVI index is strongly associated with various biophysical properties such as biomass, leaf area index (LAI) and vegetation cover and strongly reflects the active solar radiation of photosynthesis and canopy closure of vegetation covers [27, 28]. NDVI values are sensitive to green vegetation even for low vegetation covered areas. This index is often shown to be related not only to canopy structure and LAI but also to canopy photosynthesis [29].
Fig. 2. The general trend of NDVI of C. libani natural stands in Slenfeh during the period 1984 - 2014
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Fig. 3. The general trend of NDVI of C. libani natural stands in Jawbat Burghal during the period 1984 - 2014
Our results may not be matched with the common local foresters' hypothesis that the drying of the Ghab Valley - Syria in 1954 [30] has reduced air humidity which may have adversely affected the vitality and physiology of the C. libani trees; thereby reducing its ability to fruit and thus, to natural regeneration, and especially that C. libani is the forest species that requires air humidity [31].
Conclusions. We conclude that the natural C. libani stands in Syria (Slenfeh and Jaw-bat Burghal) despite their decreasing area; are still in good health. Therefore, they are able to grow and regenerate naturally according to the structure and moisture content of these forests stands on the one hand, and the surrounding environmental conditions, especially the soil moisture, on the other. This requires immediate intervention to preserve and protect the
natural C. libani stands in Syria against all forms of violations especially over cutting and hunting; through an effective management plan that prioritizes the maintenance of the natural C. libani stands. Thus, maintaining population dynamics and regeneration of C. libani populations should be a priority matter for conservation managers in an effective management strategy.
In the future a study will be conducted to estimate the growth and productivity of C. libani in Slenfeh and Jawbat Burghal through field measurements. Moreover, a comparison with the calculated NDVI will be conducted to measure the correlation with climatic elements. However, using satellite images with high spatial resolution will be useful for monitoring changes in the natural environment of C. libani forest over time.
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The article was received 10.01.2021 Accepted for publication 12.05.2021
Informations about the authors
Abeer A. Ibrahim - Member of the teaching staff (demonstrator) at Tishreen University, Agriculture Faculty, Department of Forestry and Environment, Syria. Research interests - remote sensing of forest and GIS, studying the effect of forest structure on natural regeneration of forestry species. Author of 10 scientific publications.
Emad K. Koubaily - Professor in Department of Ecology and Foresty, Tishreen University, Syria. Research interests -forest mensuration, reforestation. Author of 10 scientific publications.
Ali M. Thabeet - Associat Professor in Department of Ecology and Foresty, Aleppo University, Syria. Research interests - remote sensing of forest and GIS, forest mensuration. Author of 21 scientific publications.
УДК 528.9:630. *1
DOI: https://doi.Org/10.25686/2306-2827.2021.2.5
МОНИТОРИНГ СОСТОЯНИЯ ЛЕСОВ КЕДРА ЛИВАНСКОГО В СИРИЙСКОЙ АРАБСКОЙ РЕСПУБЛИКЕ С ПОМОЩЬЮ ГЕОПРОСТРАНСТВЕННЫХ ТЕХНОЛОГИЙ
А. А. Ибрагим1, E. К. Кубайлы1, А. М. Tабиm2 кафедра экологии и лесного хозяйства, сельскохозяйственный факультет, Университет Тишрин, Латакия, Сирия
2Кафедра возобновляемых природных ресурсов, сельскохозяйственный факультет, Университет Халеба, Алеппо, Сирия E-mail: [email protected]
Ключевые слова: Cedrus libani; природоохранный статус; дистанционное зондирование; ГИС; изображения Landsat; NDVI.
АВТОРСКОЕ РЕЗЮМЕ
Введение. Дистанционный мониторинг и картографирование лесных территорий с использованием новейших технологических достижений в области спутниковых изображений является альтернативным решением для устойчивого лесопользования по сравнению с традиционными наземными измерениями. Материалы дистанционного зондирования представляют собой важный источник информации для мониторинга изменений в растительном покрове. Целью данного исследования явилась оценка изменений в статусе сохранности естественных насаждений кедра ливанского (Cedrus libani) в их единственной естественной среде обитания на территории Сленфех и Джавбат Бургал Сирийской Арабской Республики (САР) за 1984-2014 гг. с помощью дистанционного зондирования и ГИС. В работе были использованы 17 изображений нормализованного дифференцированного вегетационного индекса (NDVI) по данным Landsat 4, 5 и 8 за исследуемый период. Результаты показали значительную тенденцию к увеличению NDVI для естественных насаждений кедра ливанского на территории Сленфехе и Джавбат-Бургале САР в период 1984-2014 гг. Выводы. Естественные насаждения кедра в Сирии находятся в устойчивом состоянии и, следовательно, способны к естественному лесовозобновлению и росту, особенно при применении соответствующих лесоводственных мероприятий.
Информация об авторах
Ибрагим А. А. - преподаватель кафедры лесного хозяйства и окружающей среды, сельскохозяйственный факультет, Университет Тишрин (Сирия). Область научных интересов -дистанционное зондирование леса и ГИС, изучение влияния структуры леса на естественное возобновление лесных пород. Автор 10 научных публикаций.
Кубайлы E. К. - профессор кафедры экологии и лесоводства, сельскохозяйственный факультет, Университет Тишрин (Сирия). Область научных интересов - лесная таксация, лесовосстановление. Автор 10 научных публикаций.
Табит А.М. - доцент кафедры возобновляемых природных ресурсов, сельскохозяйственный факультет, Университет Халеба (Халеб, Сирия). Область научных интересов -дистанционное зондирование леса и ГИС, лесная таксация. Автор 21 научной публикации.
