Study On Forest Quality Improvement Planning Of Coastal Saline-alkali Land In Hekou District Of Dongying City,Shandong Province

The urbanization and the continuous development of the economy and society have made the contradiction between environmental construction and economic development increasingly sharp.The construction of urban forests has become an important means for most cities to cope with urban environmental problems.However,as a coastal city with the characteristics of saline-alkali,it is subject to the harsh natural conditions of saline-alkali land.Its urban forests are generally characterized by monotonous forests,poor growth,poor landscape effects,and fragile ecosystems.In order to solve the current situation that the quality of forests in coastal saline-alkali cities is generally low and the forest landscape is poor,the paper studies the selection of forests with improved saline-alkali land improvement and forestry construction in Hekou District,Dongying City,Shandong Province.Using literature research,case analysis,field research and design research methods,the paper proposes a scientific and rational conceptual planning plan for urban forest quality improvement in Hekou District.The planning plan will solve the problem of low forest quality in coastal saline-alkali land in Hekou District and effectively enhance urban landscape.Quality is of great significance.The main planning results achieved are as follows:1.The coastal saline-alkali land is a type of land that is distributed in the coastal or estuary delta,with soil salinity above 0.1%,pH value of 7-9,and only salt-tolerant plants can be grown under natural conditions.The coastal saline-alkali soil is divided into mild according to soil salinity and alkalization degree[salt content 0.1%-0.2%,alkalinity 5%-10%],moderate[salt content 0.2%-0.4%,alkalization Degrees 10%-15%(20%)]and severe[salt content 0.4%-0.6%(1.0%),alkalinity 15%(20%)-20%(30%)]3 grades.The area of saline-alkali land in the estuary area accounts for more than half of the land area of the whole area.The degree of salinity is mainly moderate to heavy,and the pH value is about 8.5.For the improvement of coastal saline-alkali soil,physical,chemical,biological and other improved methods are commonly used.Based on the basic characteristics of coastal saline-alkali soil,the comprehensive technology is proposed to solve the problem and approach of forest quality improvement in coastal saline-alkali soil.2.The paper collected and sorted out 119 kinds of salt-tolerant plant resources suitable for planting in the region.According to the salt and alkali resistance of plants,39 species were severely salt-tolerant plants(salty tolerance 0.6%or more),moderate salt-tolerant plants(resistant 36 kinds of salinity 0.3%-0.6%),44 kinds of mild salt-tolerant plants(salt tolerance 0.3%or less).According to the life style of plants,there are 40 species of arbor trees,including 4 species of evergreen trees and 36 species of deciduous trees;28 species of shrubs,including 8 species of evergreen shrubs and 20 species of deciduous shrubs;47 species of herbaceous plants,including 18 species 1-2 years old herb and 29 perennial herbs;4 species of vine.The landscape effects and value of the collected salt-tolerant plants were evaluated from the perspectives of plant size,shape and color.3.The paper summarized three urban greening construction modes that can improve the forest quality of coastal saline-alkali land:the ecological garden city construction mode of Tianjin Development Zone,the construction model of Caofeidian plant landscape and the construction mode of coastal industrial city landscape of Huanghua City.4.The paper put forward the concepts and principles that should be followed in urban forest quality improvement planning in Hekou District,the main directions and suggestions of planning,and the main technical modes and parameters that can be used in planning and design.5.The paper proposed the main selected tree species in the forest quality improvement plan of Hekou District,including 10 kinds of backbone trees,20 kinds of road greening trees,16 kinds of shelter forest greening trees,22 kinds of garden greening trees,35 other main tree species,10 kinds of lawns and ground cover plants..6.The paper determined that the overall layout structure of the forest quality improvement plan in Hekou District is the forestry ecological backbone framework with "two belts and three networks" as the main body and the urban forest construction function system based on "one ring,two axes and multiple zones".The forestry layout structure is an ecologically livable pattern in which the ecological forests,protective forest corridors and landscape nodes of the whole district are connected in series.7.The paper divided the green area of Hekou District into two types of green areas:plaque-type green space(including park green space,wetland,production green space,protective green space,residential green space)and corridor-type green space(including road green space and riverbank green space).Select typical cases in different types of green space,such as Chengdong Forest Park,Chengbei Wetland Park,Forestry Industrial Park,G340,etc.,and analyze and discuss from three aspects:regional overview,forest quality improvement measures and plant configuration design.The district,practical and operative conceptual planning plan is expected to achieve a forest coverage rate of more than 35%in the urban area of the estuary,an urban greening rate of more than 42%,and a per capita park green area of the urban area of more than 18 m2.