Managing salinity stress in Eucalyptus spp.: trait variation, mechanistic insights, and implications for salt-affected landscapes

Salinity is a growing global concern, aggravated by climate change and human activities, with severe impacts on forests and biodiversity. This review critically examines the following key points: (1) the systematic impacts of salinity on forestry and ecosystem functioning; (2) the multilevel mechanistic responses of Eucalyptus species, clones, and genotypes, emphasizing their operational deployment in salt-affected landscapes; and (3) the potential of contemporary genetic technologies and environmental strategies to enhance plant resistance. Although responses vary among taxa, salinity tolerance is generally mediated through an integrated physiological and molecular framework, and substantial intra- and interspecific variation offers a solid foundation for targeted selection, hybridization, and genetic improvement. While genetic transformation and large-scale application of omics approaches remain technically challenging, recent advancements in breeding and management practices provide effective pathways for developing salt-tolerant planting material. Importantly, most current knowledge comes from controlled studies on juvenile material, highlighting the need for long-term field validation. Despite this limitation, the Eucalyptus genus represents a strategic resource for afforestation, reforestation, and ecological restoration of salinity-affected regions. Future research should prioritize field-level validation, genotype-environment interactions, and translating molecular insights into scalable silvicultural practices that strengthen forest resilience under increasing salinity stress.