{'fraction_non_alphanumeric': 0.01993269479679006, 'fraction_numerical': 0.0038829924928811804, 'mean_word_length': 5.202247191011236, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Special feature: fir species and forests

In the northern hemisphere, firs (Abies species) are one of the dominant conifer species belonging to Pinaceae, which are distributed mainly in moist, temperate to subalpine and/ or sub-boreal forests and in forests in Mediterranean climate (summer-dry) regions. In many fir species, the saplings can establish on various kinds of microsites and are shade tolerant. These characteristics contribute to the abundance of the species in old-growth forests in many regions. Since fir species develop evergreen crowns in the canopy layers of forests, these species are important components in many forest ecosystems in Europe, North America, and Asia. With respect to silviculture, the wood of fir species is characterized by its relatively soft quality. Under ongoing environmental changes, information on the characteristics of fir species and forests is necessary for forest management and conservation of the species. In many regions, old-growth forests including fir species have been affected by human activity, resulting in the fragmentation of fir populations. Since fir species need both dry and moist conditions for pollination, the fragmented population under changing climatic regimes might be sensitive to extreme climate conditions during pollination. Additionally, the negative effects of browsing on saplings by ungulates have been reported in many regions. These issues have been recognized and discussed for various fir populations, particularly silver fir (Abies alba) in Europe. With the aim of addressing many questions about ecology, management, and conservation of fir species, we prepared a special feature on fir species and forests for Journal of Forest Research. The feature is based on presentations from an international conference, Abies 2016, organized by IUFRO WP 1.01.09 Ecology and silviculture of fir and the Boreal Forest Society, Japan. This IUFRO unit previously focused on the ecology and silviculture of silver fir in Europe only. The conference in Sapporo was the first fir conference outside of Europe. Approximately 50 presentations addressed the five main aspects of ecology and management of fir species in different countries and continents: the stand dynamics of fir forests, gene pool and provenances of fir species, vulnerability of fir species to a changing environment, silvicultural approaches in fir forests, and products and ecosystem services from fir species and forests. This special feature includes a review paper and two basic research papers, all highlighting current fir-forest management and its prospects for the future. Dobrowolska et al. reviewed current knowledge on silver fir (A. alba), particularly in relation to the genetics and paleobotany, the structure and dynamics of fir forests, and silver-fir ecology. They propose the adaptation of fir silviculture with regard to ongoing environmental changes and the expected responses of fir species. Sato et al. indicated an extending negative effect of a strong typhoon on A. sachalinensis trees in a natural mixed forest in Hokkaido in northern Japan. They concluded that a temporary disturbance of Abies trees by a strong wind can have a long-term influence on their stand dynamics. Oba and Yamada reported the contamination levels of Cs in the cones of A. firma affected by the Fukushima Daiichi Nuclear Power Plant accident in March 2011. They showed the different contamination levels between seeds and cone scales and suggested the difference in effects between strict seed feeders and cone feeders. These three papers are informative for the discussion of future management of forests with fir trees. We hope this feature will aid the further understanding of fir species and forests and will bring suggestions for resolving the issues of various forest ecosystems under ongoing environmental changes.