The long-term storage of seeds is important for conserving native species, but its effectiveness depends on maintaining seed quality. This study assessed the impact of storage duration on seed quality in Alnus glutinosa (alder) and Betula pubescens (downy birch). Seed quality was evaluated using thousand-seed weight (TSW), moisture content (MC), tetrazolium (TZ) viability, and germination tests. Results from stored seed lots were compared with those from recently collected seeds. Moisture content, TZ viability, and germination were significantly affected by storage duration, although sensitivity analyses indicated that storage conditions, particularly lower temperature and airtight storage, may have contributed to improved seed viability in specific seed lots. A relationship between TZ viability and germination was observed, although this was influenced by zero values. Cold stratification improved germination in downy birch but did not compensate for reduced viability in older seed lots. These findings highlight the importance of storage conditions and species-specific pre-treatments and support the use of TZ testing as a rapid indicator of seed viability when used alongside germination testing. The results provide practical guidance for managing seed resources and maintaining reliable forest reproductive material supply.
Field et al. (Sat,) studied this question.