DOI: 10.5061/dryad.tx95x6b6r
title: Long-term soil warming drives different belowground responses in arbuscular mycorrhizal and ectomycorrhizal trees

description: The ability of trees to acquire soil nutrients under future climate
 conditions will influence forest composition and function in a warmer
 world. Rarely are multiple belowground carbon allocation pathways measured
 simultaneously in large global change experiments, restricting our
 understanding of how trees may shift their allocation of resources to
 different nutrient acquisition mechanisms under future climates.
 Leveraging a 20-year soil warming experiment, we show that ectomycorrhizal
 (EM) trees reduce mycorrhizal colonization and root exudation while
 increasing fine root biomass, while arbuscular mycorrhizal (AM) trees
 largely maintained their belowground carbon allocation patterns in warmer
 soils. We suggest that AM trees may be better adapted to thrive under
 global warming due to higher rates of nitrogen mineralization in warmer
 soils and the ability of their mycorrhizal symbiont to acquire mineralized
 inorganic nutrients, whereas EM trees may need to alter their belowground
 carbon allocation patterns to remain competitive as global temperatures
 rise.
description: # Long-term soil warming drives different belowground responses in
 arbuscular mycorrhizal and ectomycorrhizal trees
 [https://doi.org/10.5061/dryad.tx95x6b6r](https://doi.org/10.5061/dryad.tx95x6b6r) ## Description of the data and file structure ### Files and variables #### File: gcb\_data1.csv **Description:** This file contains the paired root exudation and root respiration data and traits associated with roots used for these measurements. This data can be used to generate Fig. 1b,c, Fig. 2., Fig. 3, Fig. S2, Fig. S3, Fig. S4, Table S1. In all files, cells labeled "NA" means that the measurement does not exist. | Column name | Definition | | :------------ | :------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | name | Name of sample as recorded on date of collection | | week | Sample collection timepoint 1-4. The data of each timepoint may be found in the Supplementary materials | | warm | Control ("C") or warmed ("W") plot | | myc | Arbuscular mycorrhizal ("AM") or ectomycorrhizal ("EM") root ID. Note this column does not always match the "name" column because the mycorrhizal type of some roots was reclassified after sample collection | | plot\_no | Subplot number within treatment (i.e. "16C" is subplot 16 within the control plot) | | ex\_blanked | Exudation rate after subtraction of "blank" cuvettes (ugC h-1), with negative values representing samples that were lower than the blank average | | root\_length | Total length of root used for exudation measurement (mm) | | root\_tips | Total # tips of root used for exudation measurement | | root\_sa | Total surface area of root used for exudation measurement (mm2) | | root\_mass | Mass of root used for exudation measurement (g) | | root\_vol | Total volume of root used for exudation measurement (mm3) | | d | Root tissue density (i.e. root\_mass/root\_vol) of root used for exudation measurement (g cm-3) | | diam | Average diameter of root used for exudation measurement (mm) | | srl | Specific root length (i.e. root\_length/root\_mass) of root used for exudation measurement (m g-1) | | ex\_length | Length-based exudation rate (i.e. ex\_blanked/root\_length) (ugC cm-1 h-1) | | ex\_tips | Exudation rate per root tip (i.e. ex\_blanked/root\_tips) (ugC tips-1 h-1) | | ex\_sa | Area-based exudation rate (i.e. ex\_blanked/root\_sa) (ugC cm-2 h-1) | | ex\_mass | Mass-based exudation rate (i.e. ex\_blanked/root\_mass) | | f\_resp\_conv | Root respiration rate (ugC h-1) | | resp\_length | Total length of root used for respiration measurement (mm) | | resp\_tips | Total # tips of root used for exudation measurement | | resp\_sa | Total surface area of root used for respiration measurement (mm2) | | resp\_mass | Mass of root used for respiration measurement (g) | | resp\_vol | Total volume of root used for respiration measurement (mm3) | | resp\_d | Root tissue density (i.e. resp\_mass/resp\_vol) of root used for respiration measurement (g cm-3) | | resp\_diam | Average diameter of root used for respiration measurement (mm) | | resp\_srl | Specific root length (i.e. resp\_length/resp\_mass) of root used for respiration measurement (m g-1) | | f\_length | Length-based respiration rate (i.e. f\_resp\_conv/resp\_length) (ugC cm-1 h-1) | | f\_tips | Respiration rate per root tip (i.e. f\_resp\_conv/resp\_tips) (ugC tips-1 h-1) | | f\_sa | Area-based respiration rate (i.e. f\_resp\_conv/resp\_sa) (ugC cm-2 h-1) | | f\_mass | Mass-based respiration rate (i.e. f\_resp\_conv/resp\_mass) (ugC g-1 h-1) | #### File: gcb\_data2.csv **Description:** This file contains the fine root biomass data which can be used to generate Fig. 1a | Column name | Definition | | :---------- | :---------------------------------------------------------------------------------------- | | Treatment | Warming treatment "Control" or "Heated" | | Plot | Subplot number | | Horizon | Soil horizon, for this analysis all organic ("O") | | rep | Replicate number of soil "brownies". Most subplots have 2 replicates but some have only 1 | | tEM | Dry biomass of EM transport roots (g m-2) | | aEM | Dry biomass of EM absorptive roots (g m-2) | | tAM | Dry biomass of AM transport roots (g m-2) | | aAM | Dry biomass of AM absorptive roots (g m-2) | | TotalAM | Total AM dry root biomass (g m-2) | | TotalEM | Total EM dry root biomass (g m-2) | | Abs | Total dry absorptive root biomass (g m-2) | | Transport | Total dry transport root biomass (g m-2) | | TRB | Total dry root biomass (g m-2) | #### File: gcb\_data3.csv **Description:** This file contains the mycorrhizal colonization data which can be used to generate Fig. 4 | Column name | Definition | | :---------- | :------------------------------------------------------------------------------------------------------------- | | name | Sample name. There are 4 replicates per subplot (A-1, A-2, B-1, B-2) | | myc | Arbuscular mycorrhizal ("AM") or ectomycorrhizal ("EM") roots | | warm | Control ("C") or warmed ("W") plot | | col | Mycorrhizal colonization rate as proportion of tips colonized for EM roots and % tissue colonized for AM roots | | plot\_no | Subplot number within treatment (i.e. "16C" is subplot 16 within the control plot) | #### File: gcb\_data4.csv **Description:** This file contains data on plot-averaged root strategies which can be used to generate Fig. 5 | Column name | Definition | | :---------- | :----------------------------------------------------------- | | Myco | Arbuscular mycorrhizal ("AM") or ectomycorrhizal ("EM" roots | | Treatment  | Control ("C") or warmed ("W") plot | | Plot | Subplot number | | Abs | Subplot-averaged absorptive root biomass (g m-2) | | Trans | Subplot-averaged transport root biomass (g m-2) | | Exudation | Subplot-averaged area-based exudation rate (ugC cm-2 h-1) | | col | Subplot-averaged mycorrhizal colonization rate (%) |