The trait observations included in FRED 2.0 have been collected from many different types of roots. You may want to consider selecting only a subset of these root measurements for your analysis (for example, living roots only, absorptive fine roots only, or first-order roots only).
In addition to important root traits such as diameter (or diameter class) and color, ancillary root sampling metadata can facilitate accurate comparisons of root traits within- and among species by indicating whether roots were:
- Fine roots, coarse roots, belowground stems, rhizomes, a mixture of these organs, or the total root or belowground system [Column ID F00055]
- Within a specific range of root diameters [Column ID F00949 and F00950]
- A given age [Column ID F00061]
- Associated with a specific root functional class (e.g., absorptive or transport fine roots, or a mixture of both) or heterorhizy class (e.g., fibrous or pioneer roots) [Column IDs F00060 and F00066]
- Associated with a specific root order (generally 1-7) [ Column ID F00056] or a range of root orders [Column IDs F00057 and F00058]
- Ordered according to a centripetal or centrifugal numbering scheme [Column ID F00059]
- Living or dead (or a mixture of both) [Column ID F00064]
- Collected from a given soil depth [Column ID F00985]
In turn, ancillary data associated with plant growing conditions indicate the conditions under which the root traits were measured, for example, whether roots were:
- Collected from plants growing in situ (i.e., under field conditions), in pots, or in hydroponic solutions [Column ID F01156] and if plants were grown indoors or outdoors [Column ID F01158].
- Collected from across observational gradients, or from experimental treatments that included nutrient, water, temperature, elevated [CO2], burning, disturbance, girdling, or light manipulations and their associated controls [Column ID F01159].
These are only a few of the many ways in which the root trait observations in FRED 2.0 can be organized for comparison.