Arboriculture & Urban Forestry 34(6): November 2008 Arboriculture & Urban Forestry 2008. 34(6):379–385. 379 Assessing Urban Forest Structure and Health in Shenyang, China Zhu Hua Ning, Xing Yuan He, Chang Fu Liu, and Kamran K. Abdollahi Abstract. This article summarizes the assessment of the urban forest structure and health in central areas of Shenyang, China. Urban forest cover analysis was conducted using aerial photographs, satellite imagery, and a field survey of 282 plots as major study methods. Based on the location, function, and management objectives, the urban forests were classified into five cover types: landscape forests, ecologic forests, road forests, park forests, and commercial forests. Total tree cover in the study area is 7.85%. Most trees and shrubs are in good to very good health and have relatively small diameter at breast height and height. The major tree species are different in urban and suburban areas, which was the result of the natural occurrence of the species and manmade disturbances. Major recommendations for the future management include increasing urban forest cover, especially in the city center, east side, and outskirts; and increasing species diversity and urban forest connectivity. Key Words. Distribution; health condition; species composition; tree cover; urban forest structure. Over the past 10 to 15 years, urban expansion has been occurring more rapidly than at any time in China. Currently, approximately 41% of China’s people are living in cities, compared with 26% at the end of the 1980s, and the country is still rapidly urbanizing (Wu et al. 2008). Thus, city greening and urban forestry have become very important issues, because many Chinese cities have air pollution problems. Urban forest is one of the defining fea- tures of a city and a region. Proper urban forest structure and health are the cornerstones of urban forest sustainability, because they strongly influence the urban forest function and benefits. Urban forest structure and health assessment is highly important because it provides crucial characteristics of the green infra- structure (Smith et al. 2005). Many urban forest management questions could be quickly and effectively addressed using geo- spatial methods and tools (Ward and Johnson 2007). The geo- spatial tools can provide timely and extensive spatial data from which urban forest attributes can be derived such as land cover, forest structure, species composition and condition, heat island effects, and carbon storage. However, the ground survey meth- ods must be used along with the geospatial methods to increase the accuracy of the study results. To promote urban forestry and to obtain baseline information for better management decisions and practices, an urban forest assessment was conducted in central Shenyang, China. The as- sessment has many objectives and the objectives related to this article were to establish, for the first time in the history of Shenyang, permanent urban forest assessment plots for the first assessment and future assessments; to assess urban forest struc- ture such as urban forest cover, cover types, species composition, size, location, and distribution; and to assess the overall urban forest health. METHODOLOGY Study Area Shenyang is the largest city in northeast China. It is the capitol city and political, economic, and cultural center of Liaoning Province and is among the ten largest cities in China. It is also an important industrial base and a historical city with three UNESCO World Heritage Sites. As the host city of the 2006 International Horticultural Exposition and venue for the soccer matches of the 2008 Beijing Olympic Games, Shenyang has become the focus of worldwide attention. We selected the city of Shenyang for this study because it is representative of large- sized cities in China with a noticeable urban forest component. Shenyang is located in northeast China at 41°4744, 123°2653E. It is in the temperate zone and is greatly influenced by monsoons year round with an annual average temperature of 7°C to 8°C (45°F to 46°F) and precipitation of 510 to 680 mm (20.4 to 27.2 in). The natural forest soil is brown eluvial with a thick humus layer and high phosphorus and relatively low ni- trogen contents. The dominant forest species are Pinus tabuli- formis and Quercus mongolia. Pinus tabuliformis is the city tree of Shenyang. This study targeted the central area of Shenyang (Figure 1), which is comprised of 1,150 km2 (460 mi2) and is divided into two sectors, an urban area totaling 455.77 km2 (182.31 mi2) and a suburban area totaling 694.24 km2 (277.70 mi2). The central area and its two sectors are defined using the existing definition in China. The urban area is classified as the area within the third ring road, a circular loop on the outskirts of the city. The sub- urban area is classified as the area outside of the third ring road. The term suburban is defined somewhat differently than in the United States. The suburban area in the northeast of China is more rural in nature than suburban areas in the United States, because there are more agricultural lands and small farms than residential or bedroom communities with dense urban vegetation cover. Therefore, it is much like the city’s country- side fringe. Urban Forest Classification Various types of built-up areas have different effects on envi- ronmental conditions, urban forest structure, and management objectives. Thus, we should not treat urban areas as homoge- neous areas by combining all anthropogenic factors into one ©2008 International Society of Arboriculture
November 2008
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