Table 1 Summary statistics of the candidate predictors

H₂Osat_1990

Relative water saturation in soil 28 Feb 1990

0.95

1,167

0.12

Meteorology

H₂Osat_1999

Relative water saturation in soil 26 Dec 1999

0.98

1,167

0.12

Meteorology

wind50

Wind50 (maximum gust speed in m/s with exceedence probability of 0.02, wind model KAMM)

38.12

1,165

3.08

Meteorology

wind90

Wind90 (maximum gust speed in m/s on 28 Feb 1990, wind model KAMM)

35.89

1,165

4.00

Meteorology

wind99

Wind99 (maximum gust speed in m/s on 26 Dec 1999, wind model KAMM)

35.62

1,165

3.39

Meteorology

PreviousStormDamage

Previous storm damage (yes/no)

0.19

1,167

0.39

Previous storm damage

relcumRemovals

Cumulative removals in percent of total volume production

0.34

1,167

0.16

Removals

relRem

Relative removed volume

0.14

1,167

0.12

Removals

relRem_10yr

Average relative removed volume during past 10 years prior to intervention

0.13

1,167

0.09

Removals

relRem_prevTh

Relative removed volume of previous intervention

0.13

1,167

0.12

Removals

relRem_sched

Relative removed volume of scheduled thinnings

0.09

1,167

0.11

Removals

Rem

Absolute removed volume per ha (in m³)

55.60

1,167

53.86

Removals

Rem_prevTh

Absolute removed volume of previous intervention per ha (in m³)

52.21

1,167

55.54

Removals

Rem_sched

Absolute removed volume per ha of scheduled thinnings (in m³)

35.32

1,167

44.14

Removals

ThQuot

Thinning quotient

0.74

1,167

0.33

Removals

ThQuot_10yr

Average thinning quotient during past 10 years prior to intervention

0.73

1,167

0.26

Removals

ThQuot_prevTh

Thinning quotient of previous intervention

0.71

1,167

0.34

Removals

ThQuot_sched

Thinning quotient scheduled thinnings

0.67

1,167

0.56

Removals

ThQuot_yrs

Thinning quotient/years since previous thinning

0.02

1,167

0.03

Removals

yrssince_prevTh

Years since previous intervention

4.90

1,167

1.97

Removals

acidicSoil

Strong acidity in upper soil (<40 cm; yes/no)

0.17

1,161

0.38

Soil

CaCO₃

Free CaCO₃ in upper soil (<30 cm; yes/no)

0.11

1,161

0.31

Soil

shallowSoil

Restricted rooting depth (bedrock < 40 cm; yes/no)

0.07

1,156

0.25

Soil

StabPt

Site risk score (stagnant water × 3 + restricted rooting × 2 + CaCO₃ + acidity)

0.62

1,156

1.03

Soil

deepLoam

Loam >70 cm depth without bedrock or stones (yes/no)

0.44

1,167

0.50

Soil

heavyClay

Over 50 % clay horizons in the upper 70 cm (yes/no)

0.03

1,167

0.18

Soil

waterloggedSoil

Stagnant water in soil (<70 cm; yes/no)

0.07

1,161

0.25

Soil

Species

Main tree species (Douglas-fir: N = 531, Norway spruce: N = 636)

Nominal

1,167

Species

hd100

h100/d100 ratio

0.70

1,167

0.07

Stand density

hd100_5rel

Relative 5-year  h100/d100 ratio

1.01

1,167

0.10

Stand density

hd100_relnorm

Relative normalized h100/d100 ratio

0.98

1,167

0.10

Stand density

hd100_relnorm_5rel

Relative 5-year normalized h100/d100 ratio

1.00

1,167

0.09

Stand density

stockDegr

Stock density

0.88

1,149

0.21

Stand density

D100

Mean quadratic diameter of 100 largest trees per ha

35.13

1,167

9.90

Stand dimension

Dg

Mean quadratic diameter

27.25

1,167

9.73

Stand dimension

G

Basal area per ha (in m², trees with dbh > 6.5 cm)

32.32

1,167

9.43

Stand dimension

H100

Dominant height

24.52

1,167

7.17

Stand dimension

Hg

Mean height

22.72

1,167

7.18

Stand dimension

N

Number of stems per ha (trees with dbh > 6.5 cm)

676.15

1,167

388.95

Stand dimension

stand_age

Age of main tree species

50.20

1,154

29.87

Stand dimension

V

Standing volume per ha (in m³, trees with dbh > 6.5 cm)

410.02

1,167

201.19

Stand dimension

Dist_2ForEdge

Distance to westward forest edge in m (≤340 m)

304.52

1,166

79.33

Topography and site

elevation

Elevation above sea level (m)

567.16

1,166

210.78

Topography and site

Topex8w

Topex (distance 1,000 m, west weighted, 8 cardinal directions)

21.82

1,165

29.97

Topography and site