Abstract: We conducted a survey on seedlings (height <1 m) and saplings (height ≥1 m, diameter at breast height <5 cm) in 20 gaps of Larix principis-rupprechtii plantations on Guandi Mountains, Shanxi to analyze regene-ration density, growth indicators, and spatial distribution of L. principis-rupprechtii seedlings and saplings under four gap sizes (<60 m², 60-120 m², 120-180 m², and ≥180 m²). The results showed that growth indicators (ground diameter, height) of seedlings and saplings and regeneration density of seedlings were highest in small gaps (14-60 m²). The sapling regeneration density was highest in medium gaps (60-120 m²), and sapling density exceeded seedling density in each size category. L. principis-rupprechtii seedlings and saplings exhibited favorable regeneration in small and medium gaps, while large gaps (120-180 m²) and extra-large gaps (≥180 m²) were unfavorable for L. principis-rupprechtii regeneration. L. principis-rupprechtii seedlings and saplings were mainly distributed within the canopy projection area and along the edge of canopy gap area. Controlling gap size within the range of 14-120 m² through artificial interventions, such as planting and thinning, could promote the regeneration of L. principis-rupprechtii.

Key words: kernel density estimation, spatial structure, expanded gap, regeneration of Larix principis-rupprechtii.