Variation in abundance of trees originating from sapling banks facilitates the coexistence of two Abies species in a wave‐regenerated forest

Abstract

AbstractThe contribution of sapling banks to the coexistence of species with different shade tolerance under the “wave regeneration” regime has not been researched extensively. This study first assessed spatial and temporal variations in the relative dominance of two Abies species, Abies veitchii and Abies mariesii, with different shade tolerance in a wave‐regenerated forest. Second, we present the age structure and its spatial variation in young Abies stands (sapling stage) to exhibit the prevalence and variability of regeneration from sapling banks (defined as trees established 10 years before canopy opening). The relative dominance of A. mariesii, the more shade‐tolerant species, compared to that of A. veitchii, did not change over a period of 10 years, irrespective of stand developmental stages, indicating the importance of initial dominance in determining the local species composition. The tree ages at the sapling stage were significantly higher for A. mariesii than for A. veitchii. Approximately, 30% of all trees were likely to arise from a sapling bank, and 86% of them were A. mariesii. Age structure significantly varied between 5 × 5 m quadrats; some quadrats were dominated by A. mariesii originating from sapling banks, while others were dominated by A. veitchii that were established at the time of canopy opening. These results indicate that regeneration from sapling banks contributes to the dominance of A. mariesii and that the spatial variation in the abundance of trees originating from sapling banks is essential for the coexistence of A. mariesii with A. veitchii.