Abstract: In the process of secondary forests restoration on the eastern Qinghai-Tibet Plateau, the regeneration of Minjiang fir (Abies fargesii var. faxoniana) is of critical importance. Key challenges in regeneration include securing a stable seed supply and ensuring seedling survival; however, research on the seed ecology of these species remains limited. This study collected cones and seeds of Minjiang fir from seven sites distributed along four elevations on the eastern Qinghai-Tibet Plateau. We compared the coefficient of variation and diversity, conducted multiple comparisons, examined correlations, and analyzed seed vigor and germination across elevations and crown directions. The results showed that: (1) Cones length and weight were 5.98 ± 1.36 cm and 29.06 ± 12.39 g. Seed size was 11.2 ± 1.9 mm, and the weight of 1,000 seeds was 8.86 ± 2.31 g. Seed vigor averaged 19.05% and germination rate was 17.61%. (2) With increasing elevation, the morphological traits of cones and seeds first increased, peaked at 3,300 − 3,600 m, and then decreased. Trait variations were less pronounced than at other elevations, and diversity analysis revealed weaker differentiation, with more stable seed trait expression. Furthermore, cone and seed traits near the timberline areas are significantly smaller than those in adjacent lower elevation zones. The 3,300–3,600 m elevation zone appears to be the most suitable habitat for Minjiang fir. (3) Seed vigor and germination rate followed unimodal distribution patterns. Seeds at 3,900 and 3,300 m germinated faster than 3600 m, whereas seeds at 3,000 m took the longest time to initiate germination. Seeds at higher elevations exhibited faster post-initiation germination but later initial germination and a lower final germination rate. (4) Seed vigor and germination rate are positively correlated with cone length, cone weight, seed length, seed weight, tree height, diameter at breast height, and crown direction, and negatively correlated with elevation and the number of seeds per cone. Cone weight had the highest contribution to seed vigor and germination (21.5%), followed by elevation (18.39%). Minjiang fir growing on the sunny side of the crown exhibited better cone and seed traits, including larger, plumper seeds. This study validates the mid-elevation peak pattern of Minjiang fir with increasing elevation and can help understand the regeneration of coniferous trees in high-mountain areas.

Key words: Abies fargesii var. faxoniana, Cone and seed, Elevation, Crown direction, Diversity analysis, Germination