Meet FRED
The FRED Initiative began as an international collaboration of root ecologists with an overarching goal of improving our understanding and model representation of fine-root traits and processes. To meet this goal, we looked to the long and rich history of observations of belowground plant traits, with a specific focus on fine roots, to serve as a solid foundation for our current understanding and as fuel for the next generation of measurements. The Fine-Root Ecology Database (FRED) was born (Iversen et al., 2017). In the years since, FRED has been used to understand and model root trait variation across the world.
The first FRED
The first version of FRED (FRED 1.0) was released to the broader public in February 2017 (data citation: Iversen et al., 2016). FRED 1.0 housed more than 70,000 root trait observations from more than 800 data sources. It represented more than 300 root traits, along with associated ancillary data related to site, vegetation, edaphic, and climatic conditions from across the globe.
FRED was popular! Over the course of 1 year, FRED 1.0 was downloaded more than 200 times to address a number of questions related to modeling, local site or species measurements, and broad trait relationships across species or sites. A pre-release of FRED (FRED 0.0) was incorporated into the fourth version of the TRY database (TRY 4.0); the FRED-TRY synergy increases the representation of belowground plant traits in TRY and facilitates above- and belowground trait linkages.
Meet FRED 2.0
FRED 2.0 was an improved version of his older brother (data citation: Iversen et al., 2018), with 50% more root trait observations, particularly in the categories of root anatomy, architecture, chemistry, and morphology. FRED 2.0 had more than 105,000 observations of more than 300 root traits, with data collected from more than 1200 data sources. The ancillary data increased concurrently with increased root trait observations.
Meet FRED 3.0
FRED 3.0 became available in February 2021 (data citation: Iversen et al., 2021). FRED 3.0 had more than 150,000 observations of more than 330 root traits, with data collected from more than 1400 data sources. FRED 3.0 had 45% more root trait observations than FRED 2.0, particularly in the categories of root anatomy, morphology, and microbial associations; ancillary data on associated site, vegetation, edaphic, and climatic conditions from across the globe have also increased concurrently. This version of FRED was encoded into database form (Microsoft Azure), and we developed a User Interface (programmed using Vue.js for the user interface and Node.js for interface with the data) that allowed users to filter the observations in FRED according to their scientific needs.
Meet FRED 4.0 - Available Now!
FRED 4.0 was released in October 2026, with more than 200,000 observations of more than 230 root traits and data collected from more than 2,000 data sources. FRED 4.0 has ~40% more root trait observations than FRED 3.0, particularly in the categories of root system, chemistry, and morphology. The release of FRED 4.0 also includes significant increases in geographic regions that have long been underrepresented in global data sets, notably in the tropical low latitudes (e.g., Cordeiro et al., 2025). Ancillary data on associated site, vegetation, edaphic, and climatic conditions from across the globe have also increased concurrently with root trait observations.
Please cite FRED 4.0 as well as the original data source where possible.
Acknowledgements
We thank A. Shafer Powell and J. Katie Baer for their assistance with FRED data harvesting, Chris DeRolph for his assistance with GIS mapping, Les Hook for his assistance with best data management practices, and Dave Connerth, Derek Brownlee, and Zach Edwards for their assistance with FRED database development and programming as well as this website.
Funding source
This work is supported by the Biological and Environmental Research program within the Department of Energy's Office of Science.