Juniperus drupacea is an eastern Mediterranean mountain tree with a disjunct geographical range. We hypothesized that this disjunct occurrence (the Pe

The climate drives species distribution and genetic diversity; the latter defines the adaptability of populations and species. The ongoing climate crisis induces tree decline in many regions, compromising the mitigation potential of forests. Scientific‐based strategies for prioritizing forest tree populations are critical to managing the impact of climate change. Identifying future climate refugia, which are locations naturally buffering the negative impact of climate change, may facilitate local conservation. In this work, we conducted the populations' prioritization for Castanea sativa (sweet chestnut), a Neogene relict growing in the Caucasus global biodiversity hotspot. We generated genetic and ecological metrics for 21 sites in Georgia and Azerbaijan, which cover the natural range of sweet chestnut across the region. We demonstrated that climate primarily drives the pattern of genetic diversity in C. sativa, proved with a significant isolation‐by‐environment model. In future, climate change may significantly reorganize the species' genetic diversity, inducing even some genetic loss, especially in the very distinct eastern fringe of the species range in Azerbaijan. Based on our combined approach, we mapped populations suitable for ex situ and in situ conservation, accounting for genetic variability and the location of future climate refugia.

This account presents information on all aspects of the biology ofAesculus hippocastanumL. (horse‐chestnut) that are relevant to understanding its ecological characteristics and behaviour. The main topics are presented within the standard framework of theBiological Flora of the British Isles: distribution, habitat, communities, responses to biotic factors, responses to environment, structure and physiology, phenology, floral and seed characters, herbivores and disease, history and conservation. Aesculus hippocastanumis a large deciduous tree native to the Balkan Peninsula. Native populations are small (<10,000 trees total) and apparently in decline, but the tree has been widely planted in gardens and streets across Europe and other temperate areas from the 17th century onwards. It was voted theUK's favourite tree in a 2017 poll. As a British neophyte, it is occasionally naturalised in open wooded habitats. Horse‐chestnut is renowned for the beauty of its large (up to 30 cm long), upright panicles of white flowers, and for the large seeds (up to 42 g each) used in the formerly common children's game of “conkers.” More recently, the triterpene glycosides, extractable from various plant parts but especially the seeds, have been widely used in medicine. In much of Europe, horse‐chestnut is affected by chestnut bleeding canker (caused byPseudomonas syringaepv.aesculi), the horse‐chestnut leaf minerCameraria ohridellaand the leaf blotch fungusGuignardia aesculi. The canker is likely to lead to death of <10% individuals, but seeds of plants infested with the leaf miner are 40%–50% smaller, which may affect long‐term establishment in non‐planted areas.