Mast seeding database compilation for conifer tree reproduction in North America (belonging to genus: Abies, Picea, Pinus, Tsuga). All data included in analyses met the criteria that they: i) had at least 6 years of mast seeding data for a species of coniferous tree in North America, ii) data were collected on a continuous scale (e.g., based on seed traps, visual cone counts, or cone scars), iii) occurred between 1960-2014, and iv) for a taxon to be included in the study, there was a minimum of 10 separate time series at the level of the genus. Data from distinct sites or on different species were included separately. Data are standardized to values between 0-100 for each dataset.

Summer temperature data are based on ClimateNA, including mean annual July temperatures from 1960-2014 for each location where there is mast-seeding data, and the difference in consecutive summer mean July temperatures.

Dataset collection - Mast-seeding: The dataset on annual conifer tree reproduction was largely based on an existing mast-seeding database (Pearse et al. 2017), augmented with additional data from literature searches and data repositories, and data from co-authors.

Data processing - Mast-seeding: Each dataset was standarized to values between 0 and 100 based on the range of seed set values within each record because units of seed set varied among studies.

Dataset collection - Summer temperature: We obtained climate data using ClimateNA v6.30, a software application that provides point-location climate data on a monthly, seasonal, and annual basis for a given year or time period over the entire continent of North America (Wang et al. 2016). We obtained July temperature data for all mast seeding dataset locations between 1958 (two years prior to our first year of mast-seeding data) to 2014.

Data processing - Summer temperature: Mean July temperatures and delta-T were calculated for each location where mast-seeding data were available. Delta-T is the difference in July temperature from year t-1 minus year t-2 (relative to the year of interest as year 't') based on Kelly et al. (2013).

See associated ReadMe files.