Seasonal dynamics of organic components in fresh foliar litters at different gap positions in an alpine forest on the eastern Tibetan Plateau

Purpose The organic components in fresh litters are important chemical traits for evaluating the initial quality that controls decomposition of plant litter. This study aimed to assess the seasonal dynamics and drivers of organic components in four dominant fresh litters and their variations at different gap positions in an alpine forest on the eastern Tibetan Plateau. Materials and methods We measured the water- (WSE), organic- (OSE), acid-soluble extractables (ASE) and acid-unhydrolyzable residues (AUR) in fresh litters of fir (Abies faxoniana), cypress (Sabina saltuaria), azalea (Rhododendron lapponicum), and cherry (Cerasus duclouxii) at the gap center, gap edge, and under the closed canopy over 1 year in an alpine forest. Results and discussions The contents of organic components significantly varied among litter species and collecting time, and the ASE content also showed significant variations among gap positions. Manganese (Mn) was negatively related to the OSE content, and dissolved organic carbon (DOC) was the most significant factor affecting WSE and AUR contents. Magnesium (Mg) was the factor of great magnitude that significantly influenced the ASE content, and the correlation coefficient between Mg and ASE in the gap center was higher than that in other gap positions. Conclusions The contents of organic components were markedly controlled by litter species over time, and ASE content varied significantly after gap formation. The seasonal dynamics of these organic components were strongly mediated by litter nutrients, such as Mg, Mn, calcium (Ca), and nitrogen (N), while DOC was a significant factor controlling WSE and AUR contents in fresh litters in this alpine forest.

Automated summary

This study assessed the seasonal dynamics and driving factors of organic components in fresh litters in an alpine forest on the eastern Tibetan Plateau. Organic component contents significantly varied among litter species and collecting time, with significant variations in ASE content among gap positions. Nutrients like Mg, Mn, Ca, N, and DOC were found to play significant roles in mediating the seasonal dynamics of organic components in fresh litters.