Table 1. Descriptive statistics including mean, standard deviation (sd), minimum (min), maximum (max) and piece count (n) of the length, mid-diameter and volume over bark (ob) of the Norway spruce logs that were investigated regarding blue-stain development for the trial campaigns in summer 2020 and spring 2021 at both sites, Jagerbauerngraben (JBG) and Krampen (KRA). | ||||||||||||

summer.JBG | summer.KRA | spring.JBG | spring.KRA | |||||||||

length [cm] | mid-diameter [cm _{ob}] | volume [m ^{3}_{ob}] | length [cm] | mid-diameter [cm _{ob}] | volume [m ^{3}_{ob}] | length [cm] | mid-diameter [cm _{ob}] | volume [m ^{3}_{ob}] | length [cm] | mid-diameter [cm _{ob}] | volume [m ^{3}_{ob}] | |

mean | 406.50 | 31.54 | 0.32 | 204.10 | 29.21 | 0.14 | 405.75 | 34.14 | 0.38 | 404.17 | 33.92 | 0.37 |

sd | 2.65 | 4.34 | 0.09 | 1.29 | 2.08 | 0.02 | 1.57 | 4.64 | 0.10 | 2.53 | 4.13 | 0.09 |

min | 401.00 | 24.93 | 0.20 | 202.00 | 26.40 | 0.11 | 402.00 | 26.55 | 0.22 | 399.00 | 26.20 | 0.22 |

max | 410.00 | 38.40 | 0.47 | 207.00 | 33.75 | 0.18 | 408.00 | 42.68 | 0.58 | 407.00 | 42.15 | 0.57 |

n | 24 | 48 | 24 | 24 |

Table 2. Time scheme of sampling for both trial campaigns 2020 and 2021. T0 marks the date when the Norway spruce logs were stored at the trial sites. T1–T8 represent the sampling dates, on which log slices were cut to investigate blue-stain development. | |||||||||

sample date ID | T0 | T1 | T2 | T3 | T4 | T5 | T6 | T7 | T8 |

storage time 2020 (days) | 0 | 7 | 14 | 22 | 29 | 37 | 43 | 50 | 56 |

sample date 2020 | Jul. 14th | Jul. 21st | Jul. 28th | Aug. 05th | Aug. 12th | Aug. 20th | Aug. 26th | Sept. 2nd | Sept. 8th |

storage time 2021 (days) | 0 | 38 | 46 | 53 | 60 | 67 | 74 | 81 | 88 |

sample date 2021 | Apr. 3rd | May. 11th | May. 19th | May. 26th | Jun. 2nd | Jun. 9th | Jun. 16th | Jun. 23rd | Jun. 30th |

Table 3. Descriptive statistics including mean, minimum (min), maximum (max) of daily mean temperature, average relative humidity and daily precipitation for the trial sites Jagerbauerngraben (JBG) and Krampen (KRA) for the trial periods Jun. 26th (KRA) and Jul. 7th (JBG) 2020 to Sep. 8th, 2020 and Mar. 4th (JBG) and Mar. 19th (KRA) 2021 to June 30th, 2021, during which the development of blue-stain on Norway spruce logs was investigated. For precipitation the sum is also presented. | ||||||||||||

2020 | 2021 | |||||||||||

Jagerbauerngraben (JBG) | Krampen (KRA) | Jagerbauerngraben (JBG) | Krampen (KRA) | |||||||||

daily mean temperature [°C] | average relative humidity [%] | daily precipitation [mm] | daily mean temperature [°C] | average relative humidity [%] | daily precipitation [mm] | daily mean temperature [°C] | average relative humidity [%] | daily precipitation [mm] | daily mean temperature [°C] | average relative humidity [%] | daily precipitation [mm] | |

mean | 14.86 | 87.68 | 6.35 | 14.95 | 87.26 | 4.24 | 6.57 | 79.82 | 1.80 | 7.95 | 77.89 | 2.08 |

min | 8.63 | 70.36 | 0.00 | 9.09 | 67.66 | 0.00 | –5.64 | 50.31 | 0.00 | –4.39 | 59.39 | 0.00 |

max | 19.78 | 100.00 | 40.20 | 20.29 | 97.34 | 50.80 | 23.11 | 99.43 | 18.40 | 20.92 | 94.26 | 19.10 |

sum | 361.80 | 241.40 | 213.80 | 216.20 |

Table 4. Descriptive statistics of the density of the Norway spruce log slices, that were used to quantify blue-stain development, including the results of Tukey’s HSD test, mean, standard deviation (sd), minimum (min), maximum (max), the 5th,50th and 95th percentiles for the four datasets from both trial sites JBG and KRA and both trial campaigns in 2020 and 2021. The significance letters “a”, “b” and “c” in the Tukey’s HSD row indicate significant differences between the datasets with a confidence level of 0.95. | |||||

density [kg m^{–3}] | |||||

summer.JBG | summer.KRA | spring.JBG | spring.KRA | overall | |

Tukey’s HSD | a | b | b | c | |

mean | 375 | 438 | 444 | 464 | 431 |

sd | 46 | 40 | 36 | 31 | 51 |

min | 319 | 368 | 380 | 400 | 319 |

5% | 327 | 378 | 395 | 414 | 340 |

50% | 364 | 432 | 440 | 463 | 431 |

95% | 454 | 505 | 507 | 517 | 509 |

max | 560 | 594 | 570 | 531 | 594 |

n | 96 | 96 | 96 | 96 | 384 |

Table 5. Summary of the results of the ANCOVAs, which tested the effect of the mean daily temperature sum to which the Norway spruce logs were exposed, on the percentage of sapwood that was discolored by sap-staining fungi, taking site effects, season effects and interactions into account (LI, ME, MDTS = mean daily temperature sum, R^{2} = coefficient of determination, σ^{2} = variance of the residuals, τ_{00} = variance of random effects, RMSE = root mean square error, AIC = Akaike’s information criterion). | ||||||

Predictors | Linear Interactions (LI) | Mixed Effects (ME) | ||||

Estimates | CI | p | Estimates | CI | p | |

MDTS | 0.04 | 0.04 – 0.05 | <0.001 | 0.03 | 0.03 – 0.04 | <0.001 |

site [JBG] | –5.33 | –7.39 – –3.28 | <0.001 | |||

site [KRA] | –5.36 | –7.40 – –3.32 | <0.001 | |||

season [summer] | –5.25 | –7.88 – –2.63 | <0.001 | |||

site [KRA] × season [summer] | 13.72 | 10.25 – 17.19 | <0.001 | |||

Random effects: | ||||||

σ^{2} | 18.88 | |||||

τ_{00} | 0.00 _{site} | |||||

31.61 _{season} | ||||||

Observations | 384 | 288 | ||||

R^{2} / R^{2} adjusted | 0.756 / 0.753 | |||||

Marginal R^{2} / Conditional R^{2} | 0.643 / NA | |||||

RMSE | 8.40 | 4.32 | ||||

AIC | 2736.701 | 1692.266 |

Table 6. Summary of the results of the non-linear least square regression analysis, which tested the effect of the mean daily temperature sum to which the Norway spruce logs were exposed, on the percentage of sapwood that was discolored by sap-staining fungi (R^{2} = coefficient of determination, RMSE = root mean square error, AIC = Akaike’s Information Criterion). | |||||

Non-Linear (NL) | |||||

Term | Estimates | Std.error | t-statistics | p | CI_{95} |

a | 43.87 | 6.85 | 6.40 | <0.001 | 30.37, 57.36 |

b | –662.17 | 71.81 | –9.22 | <0.001 | –803.63, –520.70 |

Observations | 288 | ||||

R^{2} | 0.56 | ||||

RMSE | 4.48 | ||||

AIC | 1687.284 |