## 2 Nature and Characteristics of _A. altissima_
### Challenges and Limitations of Ailanthus Utilization  
Invasive alien species pose a significant threat to biodiversity conservation since they may disrupt ecosystem services, with subsequent socioeconomic and ecological implications that, in turn, affect human well-being. Global changes, such as rising temperature and anthropogenic disturbances, create favorable conditions for the introduction and expansion of invasive species, necessitating the proper management of this expansion and its impacts. [PERSON] et al. [104] evaluated the potential impacts of four invasive alien species (_Ailanthus altissima_, _Baccharis halimifolia_, _Impatiens glandulifera_, and _Pueraria montana_) on three ecosystem services in Europe: Food provisioning, soil erosion regulation, and maintenance of biological diversity. Wild species diversity, erosion regulation, food provisioning (crops and livestock), harvested wild goods, and tourism or recreation were found to be adversely affected, according to the risk analysis protocol applied. Species distribution models indicated a shift in distribution ranges towards the north and east of Europe for these invasive species. Bivariate analysis revealed that the invasive species _I. glandulifera_ and _A. altissima_ were identified to have the highest potential impact on the contribution of natural ecosystems to crop provision and on soil erosion control, with specific mechanisms of impact, such as altering soil nutrient cycling, affecting soil microorganisms, or producing allelopathic compounds. According to the models, Western Europe and the British Isles were identified as the most affected regions, while the Mediterranean region showed lower projected impacts due to the northwards expansion of invasive species [104]. Because of its invasive nature, the constraints and limitations of _Ailanthus_ use are triggered by a variety of socioeconomic concerns and ethical implications. To guarantee appropriate administration and usage, the following criteria must be carefully considered. First of all, the invasive habit of _Ailanthus_ can have a severe impact on native ecosystems by outcompeting native vegetation, affecting soil chemistry, and disturbing normal ecological processes. To prevent aggravating ecological imbalances, utilization initiatives must properly examine and manage these repercussions. Secondly, the quick growth and abundant seed production of _Ailanthus_ can result in the displacement of native vegetation species, and therefore, in a decrease in biodiversity and local food chain changes. This change of location has the potential to have a domino impact on ecosystem health and stability. Cross-breed between _Ailanthus_ and native species can result in hybridization, which may cause genetic pollution and put at risk the inherited characteristics of local plant populations. This has the potential to have long-term implications for ecosystem dynamics and evolutionary processes [18]. Furthermore, harvesting _Ailanthus_ for use may accidentally contribute to its spread since seeds can be dispersed during shipping and processing. This would raise the prospect of inadvertent introductions into new domains. Its root system can cause damage to pavements, archaeological monuments, walls, and other structures because it causes erosion of substrates, and this presents one of its most important problems. Its effect can be chemical due to the secretion of organic acids from the roots decomposing calcium bicarbonate, which is the main component of the limestone used as a building material, or it can be mechanical, by the increase of the pressure of the roots, either above or near the buildings [105]. Positive impact has also been detected, as analyzed in this review article, which should be considered for inclusion in management cost-benefit evaluations. _A.