0-6 month-old seedlings	
Tree species	Target tree species (PIN, Pinus Banksiana, ou EPN, Picea mariana)
Target_pot	Target pot number
Seedling	Individual identification of seedlings (5 seedlings per pot, A, B, C, D et E)
MLS	Ground layer type (control, lichen, pleurozium, Sphagnum)
Donor_pot	Donor pot number
Root_biom	Root biomass expressed in g (dry weight)
Above_biom	Aboveground biomass expressed in g (dry weight)
Total_biom	Total biomass expressed in g (dry weight)
	
2 year-old seedlings	
Tree species	Target tree species (PIN, Pinus Banksiana, ou EPN, Picea mariana)
Target_pot	Target pot number
MLS	Ground layer type (control, lichen, pleurozium, Sphagnum)
Donor_pot	Donor pot number
Ini_biom	Root biomass expressed in g (dry weight)
Root_biom	Initial biomass expressed in g (dry weight)
Above_biom	Aboveground biomass expressed in g (dry weight)
Total_biom	Total biomass expressed in g (dry weight)
	
ECM 0-6 month-old seedlings	
Tree_species	Target tree species (PIN, Pinus Banksiana, ou EPN, Picea mariana)
Target_pot	Target pot number
Seedling	Individual identification of seedlings (5 seedlings per pot, A, B, C, D et E)
MLS	Ground layer type (control, lichen, pleurozium, Sphagnum)
Total_tips	Total number of root tips
ECM_tips	Number of mycorrhized root tips
ECM_rate	Ectomycorrhizal colonization rate (%)
	
Soil nutrients	
Experiment	Experiment (PIN, Pine experiment, ou EPN, Spruce experiment)
Target_pot	Target pot number
MLS	Ground layer type (control, lichen, pleurozium, Sphagnum)
NH4	Concentration in NH4 (mg/kg)
NO3	Concentration in NO3 (mg/kg)
P	Concentration in P (mg/kg)
K	Concentration in K (cmol(+)/kg)
Ca	Concentration in Ca (cmol(+)/kg)
Mg	Concentration in Mg (cmol(+)/kg)
Mn	Concentration in Mn (cmol(+)/kg)
Al	Concentration in Al (cmol(+)/kg)
Fe	Concentration in Fe (cmol(+)/kg)
Na	Concentration in Na (cmol(+)/kg)
	
Leachate content in N	
Experiment	Experiment (PIN, Pine experiment, ou EPN, Spruce experiment)
Donor_pot	Donor pot number
Date	Harvesting date (Date 0 : May 2015, Date 1 : June 2015, Date 2 : July 2015, Date 3 : August 2015, Date 4 : September 2015, Date 5 : October 2015)
MLS	Ground layer type (control, lichen, pleurozium, Sphagnum)
NH4	Concentration in NH4 (ppm)
NO3	Concentration in NO3 (ppm)
DIN	Concentration in Dissolved Inorganic N (ppm)
	
Leachate content in polyphenols	
Experiment	Experiment (PIN, Pine experiment, ou EPN, Spruce experiment)
Date	Harvesting date (Date 1 : September 2015, Date 2 : October 2015)
Donor_pot	Donor pot number
MLS	Ground layer type (control, lichen, pleurozium, Sphagnum)
Volume	Volume of leachate (mL)
C_polyphenols	Leachate content in polyphenols (mg/L)
	
Leachate content in usnic acid	
Experiment	Experiment (PIN, Pine experiment, ou EPN, Spruce experiment)
Donor_pot	Donor pot number
MLS	Ground layer type (control, lichen, pleurozium, Sphagnum)
C_usnic_ac	Leachate content in usnic acid (mg/L)