Seed quality at tree species’ altitudinal limits

The low-temperature range limit of tree species may be determined by their ability to produce and disperse viable seeds, with processes such as flowering, pollen tube growth, fertilization, embryogenesis and seed maturation expected to be affected by cold temperatures. Kollas et al. investigate seed quality of nine broadleaved tree species harvested at their upper elevation limits in the Swiss Alps. Measuring morphological, physiological and phenological traits, they find hardly any differences between low- and high-elevation seed sources, and hence populations growing at their low-temperature limit exhibit similar seed quality to populations at lower elevations.