Pests and diseases affect the early natural regeneration of the oak (<i>Quercus aliena</i> var. <i>acuteserrata</i>) population

Insects and pathogens interact with plant species, influencing the natural regeneration of plant populations. However, the mechanisms by which they mediate the early regeneration process remain unclear. Herein, we evaluated the pest and disease status of 380 Quercus aliena var. acuteserrata seedlings and its effects on their photosynthetic and physiological properties in the Qinling Mountains, China. Results indicated that 243 seedlings were affected by pests and diseases, mainly in the 0−20 cm height range, and the affected leaf area was mainly in the range of 0−60%. Biology and soil factors were the primary drivers of these conditions, with canopy density being a largely influencing factor. Disease significantly decreased the chlorophyll content (Chl), net‐photosynthesis ( P n ), stomatal conductance ( G s ), intercellular CO 2 concentration ( C i ), and transpiration rate ( T r ) in seedlings but increased malondialdehyde (MDA) and soluble sugar content. The light‐response curve varied among pests, diseases, and healthy seedlings. Pest stress prompted the seedlings to maintain high levels of photosynthesis unlike the effects seen with diseases. Our findings highlight the impact of biotic factors on forest natural regeneration and contribute to enhancing healthy forest management and promoting sustainable development.