Mast seeding records in North American Pinaceae and summer temperature data (1960-2014)

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.

Methods
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).

北美冷杉属（Abies）、云杉属（Picea）、松属（Pinus）、铁杉属（Tsuga）针叶树繁殖大年结实（Mast seeding）数据库汇编。所有纳入分析的数据需满足以下标准：i) 针对北美某针叶树物种，至少具备6年的大年结实观测数据；ii) 数据采用连续尺度采集（例如基于种子陷阱、视觉球果计数或球果疤痕计数）；iii) 数据采集时段为1960年至2014年；iv) 若某类群需纳入本研究，则其在属级水平下至少需包含10条独立的时间序列。不同采样站点或不同物种的数据集将单独纳入分析。所有数据集均被标准化至0至100的数值区间。

夏季气温数据源自ClimateNA平台，包含各大年结实观测点位1960年至2014年的年平均7月气温，以及连续两年夏季7月平均气温的差值。

研究方法
数据集采集——大年结实：本研究的针叶树年度繁殖数据集主要依托已公开的大年结实数据库（Pearse等，2017）构建，并补充了通过文献检索、公共数据仓库获取以及合作者提供的额外观测数据。

数据处理——大年结实：由于不同研究中结籽量的计量单位存在差异，我们以每条记录内的结籽量值域为基准，将各数据集标准化至0至100的数值区间。

数据集采集——夏季气温：我们通过ClimateNA v6.30获取气候数据，该软件可为北美大陆任意年份或时间段提供月、季、年度尺度的点位气候数据（Wang等，2016）。我们获取了所有大年结实观测点位在1958年（即本研究首个大年结实数据年份的前两年）至2014年期间的7月气温数据。

数据处理——夏季气温：针对所有具备大年结实数据的观测点位，我们计算了其7月平均气温与ΔT。其中ΔT指以目标年份为"t"时，t-1年与t-2年的7月气温差值，该计算方法参考Kelly等（2013）的研究成果。