## 2 Nature and Characteristics of _A. altissima_  
### Ecology and Distribution of A. altissima  
_A. altissima_ is a deciduous tree with a wide range of ecological tolerances, including tolerance to drought, pollution, and a variety of soil types. It is a fast-growing, climate-tolerant species that prefers warmer and drier environments, although it can also survive in a variety of habitats of a wide temperature- and air humidity-range, while it seems to withstand drought, using a highly effective mechanism for saving water with reduced water loss from leaves and reduced root hydraulic conductivity [12]. It is noticeable that in several regions of Asia with harsh and adverse climatic conditions and poor soils, this species holds a key role in the local economy and is characterized as a kind of multiple-purpose species. It reproduces both sexually and asexually, with the latter being the main mechanism of spread [12]. This tree species can reach up to 25-30 m in height and has a distinctive appearance, with smooth gray-brown bark, large pinnate leaves, and clusters of small yellow-green flowers that develop into samara fruit. _A. altissima_ has both dioecious and hermaphroditic forms, with male and female flowers produced on separate trees, while hermaphroditic flowers are produced on the same tree. It can rapidly colonize disturbed areas and form dense thickets, competing with native vegetation. The tree has been found to exhibit allebotathic effects, releasing compounds that can inhibit the growth of other plant species. Allelopathy is the ability of a plant to release chemicals that inhibit the growth of other nearby plants. It also has a high level of insect herbivory, with several species of insects feeding on the tree's leaves, stems, and fruits [12; 16; 17]. Nowadays, it can be found in many parts of the world, including Europe, Asia, Africa, and North and South America. Distribution data for _A. altissima_ can be collected from several global databases, such as (A) the Global Biodiversity Information Facility (GBIF),(B) Centre for Agriculture and Biosciences International (CABI), (C) the Global Invasive Species Database (GISD), and (D) Delivering Alien Invasive Species Inventories for Europe (DAISIE). [PERSON] and [PERSON] [18] investigated the distribution and changes in abundance of _A. altissima_ (Miller) Swingle, in a southwest Ohio woodlot. The study involved sampling of _A. altissima_ population in a 12.6-hectare woodland from 1978 to 2006. It was concluded that this species was present in the study area throughout the study period, with a high initial abundance and a subsequent decline in population density over time. This decline in population density could be attributed to natural factors, such as competition with other species or mortality due to disease or insects. It was also revealed that it was most abundant in disturbed areas of the woodland, such as along the edges and in degraded areas that had been previously logged or cleared. Generally, this species is commonly found in disturbed habitats, such as roadsides, vacant lots, and abandoned fields. It can also invade natural ecosystems and outcompete native plant species [12]. The tree produces an extensive root system that can contribute to its ability to grow in a wide range of environmental conditions, including nutrient-poor soils and areas with high levels of pollutants [19]. It was suggested that the species has a high capacity for colonizing disturbed habitats, and its presence in the study area could be attributed to previously applied land-use practices [18]. [PERSON] and [PERSON] [20] investigated the population structure of the invasive tree species _A. altissima_ and the role of land-use history and management practices in shaping its distribution. The study was conducted in an urban area of northern Italy and involved sampling 37 populations of this species across different land-use types.