1

Fig. 1. Schematic map of the experiment showing the four main plots, 16 sub-plots, and four combinations of treatments: non-fertilised + conventional harvest (C + CH), non-fertilised + whole-tree harvest (C + WTH), fertilised + conventional harvest (F + CH), and fertilised + whole-tree harvest (F + WTH).

Table 1. Degrees of freedom for the variables and their respective error terms included in the GLMs.
Source   df
Intercept Hypothesis 1
Error 2
Fertilisation Hypothesis 1
Error 2
WTH Hypothesis 1
Error 10
Block(Fertilisation) Hypothesis 2
Error 10
Fertilisation * WTH Hypothesis 1
Error 10
Table 2. Estimated amount of biomass and N and C/N-ratio in branches, foliage, and total slash on fertilised and non-fertilised plots. Statistics from One-Way ANOVA. The N concentrations and C/N-ratios of branches and foliage were not testable due to absence of within group variation.
  Control Fertilised P
Branches (Mg ha–1) 17 25 0.019
N concentration in branches 0.43 0.49  
N in branches (Mg ha–1) 0.07 0.12 0.012
C/N in branches 115 101 -
Foliage (Mg ha–1) 17 22 0.015
N concentration in foliage 1.23 1.30  
N in foliage (Mg ha–1) 0.21 0.30 0.007
C/N in foliage 41 36 -
Slash (Mg ha–1) 34 47 0.018
Total N in slash (Mg ha–1) 0.29 0.43 0.009
N in slash (%) 0.9 0.8 0.004
C/N in slash 60 55 0.003
2

Fig. 2. Nitrate concentrations in soil water (mg NO3-N l–1). The abbreviations are: non-fertilised plots with conventional harvest (C + CH), non-fertilised plots with whole-tree harvest (C + WTH), fertilised plots with conventional harvest (F + CH), fertilised plots with whole-tree harvest (F + WTH), and average standard error (se mean).

Table 3. Precipitation (P), and total drainage in clear-cut (control and fertilised), and intact control (C), and fertilised plots (F), respectively (mm per year).
  P Clear-cut C F
2004 860 620 400 350
2005 490 360 170 150
2006 730 450 240 210
2007 840 700 340 290
Mean 730 530 290 250
3

Fig. 3. Drainage (mm month–1) and cumulative nitrate leakage (kg N ha–1) at 0.5 m depth in the soil after clear-cutting in December 2003. The abbreviations are: non-fertilised plots with conventional harvest (C + CH), non-fertilised plots with whole-tree harvest (C + WTH), fertilised plots with conventional harvest (F + CH), fertilised plots with whole-tree harvest (F + WTH), fertilised (F), and control plots (C) that were not clear-cut in 1994. Double arrows to the right indicate final standard error for the respective series.

Table 4. Statistics for effects of fertilisation and whole-tree harvest (WTH) on the levels of aluminium, calcium, DOC (dissolved organic carbon), DON (dissolved organic nitrogen), potassium, magnesium, ammonium, nitrate, phosphate, and pH in soil water. Effects significant at the 0.1 level in bold.
  Fertilisation WTH Fertilisation x WTH
P P P
Aluminium 0.647 0.176 0.055
Calcium 0.698 0.060 0.557
DOC 0.251 0.057 0.488
DON 0.132 0.076 0.668
Potassium 0.001 0.015 0.258
Magnesium 0.051 0.019 0.054
Ammonium 0.419 0.016 0.057
Nitrate 0.821 0.007 0.012
Phosphate 0.538 0.957 0.239
pH 0.429 0.042 0.071
4

Fig. 4. Average soil water concentrations (mg l–1) of Al, Ca, DOC (dissolved organic carbon), DON (dissolved organic nitrogen), K, Mg, ammonium, nitrate, and pH, that were significant (P<0.1) in the GLM (Table 3). Bars represent from left non-fertilised plots with conventional harvest (C + CH), fertilised plots with conventional harvest (F + CH), non-fertilised plots with whole-tree harvest (C + WTH) and fertilised plots with whole-tree harvest (F + WTH).Error bars show ±2 standard errors.

5

Fig. 5. a) Mean dry weight (g m–2) for Deschampsia flexuosa (dark grey), Rubus idaeus (light grey), and other species (white), b) Mean amount of N (g m–2) for D. flexuosa (dark grey), R. idaeus (light grey), and Pteridium aquilinum (white) in non-fertilised plots with conventional harvest (C + CH), fertilised plots with conventional harvest (F + CH), non-fertilised plots with whole-tree harvest (C + WTH), and fertilised plots with whole-tree harvest (F + WTH). Error bars show ±2 standard errors.

Table 5. Pearson correlations between concentration of nitrate in the soil water (for 2007 and mean value for the whole period of measurement), weight of the biomass of the forest-floor vegetation, amount of N in the biomass of the forest-floor vegetation as continuous variables, and whole-tree harvest (WTH) and fertilisation as binomial variables. Partial correlation between concentration of nitrate in the soil water, weight of the biomass of the forest-floor vegetation, and amount of N in the biomass of the forest-floor vegetation with WTH and fertilisation as control variables. Correlations significant at the 0.1 level in bold.
Correlation     2007 Mean Biomass
Pearson Biomass r –0.189 0.224 1.000
p 0.535 0.423 .
Biomass – N r –0.254 0.546 0.798
p 0.402 0.035 <0.001
WTH r –0.108 –0.478 0.232
p 0.724 0.072 0.405
Fertilisation r –0.256 –0.034 0.201
p 0.398 0.906 0.472
Partial Biomass – weight r –0.187 0.399 1.000
p 0.582 0.177 .
Biomass – N r –0.229 0.697 0.794
p 0.499 0.008 0.001
Table 6. Soil compartment nitrogen mass balance (kg N ha–1) for the first four years following clear-cutting
  C + CH C + WTH F + CH F + WTH
Input to soil
Atmospheric deposition 36 36 36 36
Slash – branches 70 14 120 24
Slash – foliage 210 42 300 60
Vegetation litter a) 44 72 74 59
Total input 360 164 530 179
Output from soil
Uptake in vegetation a) 73 120 123 98
Leakage 55 61 82 38
Total output 128 181 205 136
Change in storage 232 –17 325 43
a) The maximum vegetation biomass each year was assumed to increase linearly from 0 in 2003 to measured amounts in 2007 and to form litter the year following its production. Thus the vegetation litter includes biomass produced during 2004 to 2006 and uptake in vegetation includes biomass produced during 2004 to 2007. The C/N ratio of vegetation biomass was assumed constant.