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Fig. 1. Map of all sites where biomass sampling was undertaken.

Table 1. Characteristics of the studied stands.
Variable Renfors Degerön Kulbäcksliden Gagnet Lillarmsjö Unbyn
Altitude (m a.s.l.) 190 175 170 125 220 20
H100 (m) a) 18 20 20 24 21 19
Latitude (ºN) b) 64.21 6415 64.17 63.26 63.97 65.69
Longitude (ºE) b) 19.70 19.67 19.62 16.79 19.30 21.58
Soil c) Loamy sand Sandy loam Loamy sand Sandy loam Sandy loam Silt loam
Mean annual precipitation
(mm) d) 		700–800 700–800 700–800 700–800 700–800 600–700
Growing season length
(days) e) 		120–150 120–150 120–150 150–180 150–180 150–180
a) H100 site index (dominant height at 100 yrs of age) for Pinus sylvestris L. according to definitions by Hägglund and Lundmark (1977).
b) Latitude and Longitude are given in degrees and decimals of degrees (WGS84).
c) Soil textural classes are specified according to the definitions of Hägglund and Lundmark (1987).
d) Annual precipitation mean values from the meteorological period 1961–1990 (2014).
e) Defined as the number of days for which the daily mean temperature was > 5 °C mean values from the meteorological period 1961–1990. (Growing season length 2014).
Table 2. Arithmetic mean diameter at breast height (dbh), dominant height (defined as the mean height of the 100 largest trees per hectare), basal area, and number of stems for the different sites considered in this work, for trees > 1.3 m in height.
Variable Year Renfors Degerön Kulbäcksliden Gagnet Lillarmsjö Unbyn
dbh (mm) 1997–1998 24 16 26 38 38 33
2002 29 20 27      
2010   42 61      
Dominant height (m) 1997–1998 5.2 4.2 5.1 6.0 7.1 7.2
2002 9.7 6.0 9.3      
2010   10.0 12.7      
Basal area m2 ha–1 1997–1998 10.0 7.0 11.4 21.1 21.2 23.9
2002 20.3 18.0 20.3      
2010   32.0 26.7      
No. of stems ha–1 1997–1998 13 500 24 900 13 800 18 330 12 140 20 375
2002 17 400 34 000 18 300      
2010   14 460 4060      
Table 3. Number of sample trees per dbh a) class and height class for each species.
Height (m) dbh (cm) N Total
0–2 2–4 4–6 6–8 8–10 10–12 12–14 14–16 16–18 18–20 20–22
Scots pine
1.3–3 11 18                   29
3–5   15 20 2               37
5–7   3 9 13 7             32
7–9       2 11 3 2         18
9–11           2 2 2       8
11–13               1 1 1 1 2
Total 11 36 29 17 18 5 4 3 1 1 1 126
Norway spruce
1.3–3 7 8                   15
3–5   8 12 1               21
5–7     7 11 2             20
7–9         5 1           6
9–11           2 1         3
11–13               1 1     2
13–15                     1 1
Total 7 16 19 12 7 3 1 1 1 0 1 68
Birch
1.3–3 11 2                   13
3–5 2 24 2                 28
5–7 1 4 12 6               23
7–9     4 9 7             20
9–11         1 1           2
11–13                        
13–15                        
Total 14 30 18 15 8 1           86
a) dbh, diameter at breast height
Table 4. Number of sampled trees for each site per year and species.
Site Year Scots pine Norway spruce Birch
Degerön 1997 20 6 15
Renfors 1997 18 6 12
Kulbäcksliden 1997 18   12
Lillarmsjö 1998 13 11 13
Gagnet 1998 8 8 8
Unbyn 1998 8 10 6
Degerön 2003 9 6 6
Renfors 2003 10 6 8
Kulbäcksliden 2003 11 6 6
Degerön 2010 5 3  
Kulbäcksliden 2010 6 6  
Total   126 68 86
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Fig. 2. Biomass sampling tree showing the positions of discs and strata.

Table 5. The parameter estimates of the compiled biomass models for pine, spruce and birch (ln(kg)). dbh is diameter at breast height (cm) and h is tree height (m). The standard error is given in parentheses. View in new window/tab.
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Fig. 3. The effect of tree height on pine branch biomass at a given diameter (6 cm) using the NEW, Marklund (1988) and Repola (2009) biomass models.

Table 6. The ratio between biomass estimates obtained using the NEW and Marklund’s models (RATIOM) and the NEW and Repola’s models (RATIOR).
  Pine Spruce Birch
RATIOM RATIOR RATIOM RATIOR RATIOM RATIOR
Stem 0.99 0.90 0.85 0.84 1.13 1.13
Branches 0.80 0.97 0.61 1.00 0.69 0.93
Foliage 1.07 1.77 1.10 1.66   17.63
Total abv. 0.92 0.94 0.83 0.87 0.93 1.08
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Fig. 4. The ratio between stem biomass estimates (pine and spruce) obtained from the NEW and Marklund’s (1988) models (RATIOM) and the NEW and Repola’s (2008, 2009) models (RATIOR).

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Fig. 5. The ratio between branch biomass estimates (pine and spruce) obtained from the NEW and Marklund’s (1988) models (RATIOM) and the NEW and Repola’s (2008, 2009) models (RATIOR).

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Fig. 6. The ratio between foliage biomass estimates (pine and spruce) obtained using the NEW and Marklund’s (1988) models (RATIOM) and the NEW and Repola’s (2008, 2009) models (RATIOR).

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Fig. 7. The ratio between stem and branch biomass estimates (birch) obtained using the NEW and Marklund’s (1988) models (RATIOM) and the NEW and Repola’s (2008, 2009) models (RATIOR).