Provenance variation in germination and seedling growth of Abies guatemalensis Rehder

The Guatemalan fir, Abies guatemalensis (Rehder), is an endangered conifer from Central America listed within CITES. Illegal harvest of branches from natural forests for Christmas tree production is one of the main threats, and thus plantations are recommended as suitable conservation strategy. Currently, plantation trees suffer from insufficient quality which could be improved by selecting more suitable provenances. This paper analyses differences among nine seed provenances of A. guatemalensis for a set of traits important for seedling production; source populations were selected from montane natural forests at 2600–3400 m a.s.l. The provenances were evaluated during the first year of establishment in one nursery and two common gardens within the natural altitudinal range at the centre of the distribution range in Guatemala. Time-to-germination, germination percentage, seedling survival, height, flushing and number of secondary branches were examined. There were significant differences among provenances for all traits. Two provenances showed superior germination and growth characteristics; one had the highest germination percentage and the densest distribution of secondary branches, and the other produced tallest seedlings. In contrast, all provenances from the edge of the distribution range in Guatemala had delayed time-to-germination, and reduced germination and growth. The results indicate considerable variation among provenances for germination and seedling characteristics. The traits investigated in this study should be included for appropriate provenance selection to improve seedling quality for Christmas tree plantations. We recommend a number of contrasting seed sources to maintain conservation interest in various natural forests for seed production.