Data to review the effects of biotic and abiotic variables, and experimental treatments on tree seedling recruitment in temperate and subtropical species

This dataset compiles information from a systematic review of experimental
studies investigating the effects of seed priming techniques, seedling
treatments, and biotic and abiotic modifiers on tree seedling recruitment
in temperate and subtropical biomes. It includes data extracted from 266
peer-reviewed articles. From these, 91 articles published between 1961 and
2023, encompassing 104 independent studies and 1,114 observations, were
retained after screening as the basis of our review and synthesis. For
each observation, the dataset records details on study characteristics
(e.g., location, taxa, and research aims), treatment and modifier types
(including their levels, duration, and intensity), control conditions, and
response variables related to seed and seedling performance (e.g.,
germination, survival, growth, and fitness traits). Treatments are
categorized into 54 specific treatment categories, further grouped into
broader study aim categories (biotic modifiers, abiotic modifiers, seed
treatments, and seedling treatments). Response variables are likewise
organized into six categories based on life stage and type of response.
Treatment effects are standardized into four directional outcomes
(positive, negative, non-significant, or variable) relative to control
conditions, enabling cross-study comparison. The dataset supports a
structured synthesis of heterogeneous experimental evidence on the drivers
of tree seedling recruitment.