Ecosystem development of coastal forest on planting bases: the role of initial soil properties

The results indicate that soil physical and chemical constraints of planting bases strongly influence the direction of vegetation–soil feedbacks. Sites with lower soil hardness, better aeration, and less severe acidity promoted a ‘positive feedback’ loop, supporting root development and stable litter retention, which led to litter layer formation and nitrogen accumulation in the soil. Nitrogen stocks in the litter layer were 9.23, 4.06, and 0.56 g N m⁻² at the high-, moderate-, and low-growth sites, respectively, and total N stocks in the litter layer and 0–10 cm mineral soil decreased in the same order, from 78.10 to 61.73 and 37.02 g N m⁻².

Conversely, the site with poor growth was characterized by severe soil compaction, poor aeration and drainage, and strong acidity. Despite substantial litterfall inputs, this site failed to retain litter or accumulate nitrogen, likely because surface runoff prevented litter layer formation. This resulted in a ‘negative feedback’ loop that maintained a nutrient-poor state.

Although planted trees can function as ecosystem engineers by supplying nutrients via litterfall, this potential depends critically on appropriate initial soil physico-chemical conditions and subsequent litter retention.</p>