Tree responses, tolerance and acclimation to stress: Does current research depend on the cultivation status of studied species?

The patterns of tree-related stress research depended on their cultivation status and were statistically highly significant in all analyses. Non-cultivated tree species were studied more, cited more often, by authors from differing countries, with emphasis on different tree processes, stress types and research areas, and published in different journals. From 2001–2014, 4128 articles in 586 different academic journals dealt with tree stress. A majority of journals published stress-related research either on cultivated or on non-cultivated tree species. The articles were averagely cited 17 times, the five dominant journals being Acta Horticulturae, Tree Physiology, Trees—Structure and Function, Forest Ecology and Management and PLoS ONE. Research was published by authors from 109 countries, authors from China, USA, Spain, Brazil and Italy being the most productive. International collaboration was present in 21 % of the articles. A total of 1141 tree species were studied from 366 genera. The dominant species studied were Olea europaea, Malus x domestica, Pinus sylvestris, Prunus persica, Picea abies. Around ¾ of the articles were single species studies. Water stress, followed by drought stress, salt stress, abiotic stress, and environmental stress were the most studied types with over 90 % articles dealing with a single stress type. Physiological and ecophysiological research of trees exposed to stress dominated, followed by molecular biology and biochemistry, genetics, ecology. Tree growth was the most studied process/activity, followed by photosynthesis, gene expression, stomatal conductance and water status. An increase in “-omics” type research was observed in recent years in cultivated tree research.