Effects of tree density and herbaceous plants on tree seedling survival across the growing and non-growing season in a temperate forest

•Both tree neighbors and herbaceous plants affected tree seedling survival.•Conspecific adult neighbors had a negative effect on shade-tolerant seedlings.•Herb removal improved the survival of newly germinated and shade-intolerant seedlings.•Effects of tree, herbaceous neighbors and herb removal were seasonally dependent.•Herb removal offsetting the negative effects of conspecific adult neighbors.