Table 2 Summary statistics of response variables tested shown here with largest effect sizes at top and diminishing effect sizes toward bottom of table

1st year root length

Control

19.7

18.9

20.5

0.536

0.03*

Warmed

20.0

19.2

20.8

1st year Root:Shoot length

Control

6.3

5.6

7.0

0.489

0.36

Warmed

6.5

5.8

7.2

Standard height change

Control

6.1

4.9

7.3

0.253

0.15

Warmed

5.1

3.9

6.4

Cotyledon No.

Control

11.5

10.4

12.5

0.171

0.76

Warmed

11.5

10.4

12.6

1st year shoot length

Control

3.3

2.7

4.0

0.155

0.58

Warmed

3.3

2.6

3.9

Phenology PC1

Control

0.7

0.4

1.0

0.107

0.13

Warmed

1.0

0.7

0.0

1st year stem length

Control

2.2

1.2

3.1

0.083

0.76

Warmed

2.1

1.1

3.2

Early needle length

Control

2.5

2.1

2.8

0.080

0.60

Warmed

2.5

2.2

2.9

Morphology PC1

Control

0.8

− 0.4

1.9

0.060

0.96

Warmed

− 0.6

− 1.7

0.5

2016 DRC

Control

3.8

3.5

4.2

0.030

0.62

Warmed

4.3

4.0

4.6

2017 DRC

Control

4.1

3.9

4.2

0.020

0.43

Warmed

4.1

4.0

4.3

4th year (harvest) root mass

Control

4.0

2.6

5.4

0.020

0.50

Warmed

4.0

2.5

5.5

4th year (harvest) Root:Shoot mass

Control

0.6

0.5

0.8

0.019

0.78

Warmed

0.6

0.5

0.8

2018 height

Control

13.5

11.5

15.5

0.015

0.89

Warmed

13.4

11.3

15.6

2017 height

Control

9.5

8.9

10.0

0.015

0.41

Warmed

9.4

8.9

9.9

Mycorrhizal richness

Control

3.0

2.7

3.4

0.012

0.02*

Warmed

3.2

2.9

3.5

2018 DRC

Control

5.4

4.9

5.9

0.010

0.22

Warmed

5.6

5.1

6.1

2018 spectra PC1

Control

1.0

0.7

1.2

0.008

0.01*

Warmed

0.9

0.6

1.2

2016 height

Control

8.6

7.2

10.0

0.004

0.67

Warmed

9.2

8.0

10.5

4th year (harvest) shoot mass

Control

6.5

5.2

7.9

0.004

0.35

Warmed

6.6

5.1

8.0

2017 spectra PC1

Control

− 0.1

− 2.2

2.0

0.001

0.58

Warmed

0.1

− 2.4

2.6