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. 2011 Aug 24;40(6):672–682. doi: 10.1007/s13280-011-0173-1

Table 2.

Tree characteristics of the studied clusters in 1997 and 2010, for small trees (trees <30 mm at DBH and higher than 1.3 m), large trees (trees >30 mm at DBH) and all trees (all trees higher than 1.3 m)

Small trees Large trees All trees
1997 2010 1997 2010 1997 2010
Mean SD Mean SD p Mean SD Mean SD p Meana SD Meana SD ta p
Mountain birch
 Mean diam. (mm) 5.4 7.2 4.6 6.2 0.23 27.3 33.8 29.2 35.7 0.005 16.5 24.3 15.7 26.2 −0.45 0.66
 No. of trunks (ha−1) 826.6 1695.5 804.3 1364.1 0.86 252.7 429.7 300.7 496.4 0.008 1079.2 1069.8 1105.0 1081.3 0.21 0.83
 Basal area (m2 ha−1) 0.15 0.33 0.13 0.22 0.39 0.79 1.26 0.99 1.54 <0.001 0.94 0.93 1.12 1.10 2.98 0.004
 TDW (kg ha−1) 544 1216 461 808 0.39 2741 4384 3452 5330 <0.001 3285 5216 3914 5968 2.92 0.005
Willow
 Mean diam. (mm) 1.7 5.8 0.3 2.7 0.038 11.4 18.0 11.1 19.4 0.83 10.3 16.4 10.9 19.2 0.35 0.73
 No. of trunks (ha−1) 13.8 49.7 0.9 7.2 0.047 9.0 22.5 7.9 26.7 0.55 22.7 23.0 8.9 9.0 2.20 0.032
 Basal area (m2 ha−1) <0.01 0.02 <0.01 <0.01 0.09 0.01 0.04 0.01 0.05 0.82 0.02 0.02 0.01 0.01 −0.91 0.37
 TDW (kg ha−1) 15 64 1 9 0.09 49 142 51 173 0.83 64 174 52 173 −0.94 0.35
Alder
 Mean diam. (mm) 0.4 3.2 0.2 1.0 0.45 2.0 11.3 2.3 12.6 0.19 2.0 11.1 1.3 7.0 −1.43 0.16
 No. of trunks (ha−1) 0.5 3.8 9.31 65.5 0.27 9.4 67.4 11.4 83.4 0.32 9.9 10.0 20.7 21.0 1.09 0.28
 Basal area (m2 ha−1) <0.01 <0.01 <0.01 <0.01 0.30 0.04 0.32 0.06 0.45 0.30 0.04 0.04 0.06 0.06 1.03 0.30
 TDW (kg ha−1) 0.9 6.8 1.7 13.2 0.30 148.7 1104 208.0 1553 0.30 150 1111 210 1566 1.03 0.30
Rowan
 Mean diam. (mm) 1.0 4.5 0 0.09 2.7 13.7 1.2 6.5 0.40 3.7 14.3 1.2 6.5 −1.41 0.16
 No. of trunks (ha−1) 7.9 53.8 0 0.26 0.2 0.7 0.2 1.4 0.68 8.0 8.1 0.23 0.24 −1.16 0.25
 Basal area (m2 ha−1) <0.01 0.01 0 0.22 <0.01 <0.01 <0.01 <0.01 0.62 <0.01 <0.01 <0.01 <0.01 −1.56 0.12
 TDW (kg ha−1) 7 43 0 0.22 2 10 1 6 0.64 8 44 1 6 −1.54 0.13
Pine
 Mean diam. (mm) 0.4 2.88 0 0.32 0 0 0.4 2.8 0 0 −1.00 0.32
 No. of trunks (ha−1) 0.5 3.8 0 0.32 0 0 0.5 0.5 0 0 −1.00 0.32
 Basal area (m2 ha−1) <0.01 <0.01 0 0.32 0 0 <0.01 <0.01 0 0 −1.00 0.32
 TDW (kg ha−1) <1 5 0 0.32 0 0 <1 5 0 0 −1.00 0.32
Other Tree species
 Mean diam. (mm) 0.1 1.0 0 0.32 0 0 0.1 1.0 0 0 −1.00 0.32
 No. of trunks (ha−1) 0.5 3.8 0 0.32 0 0 0.5 0.5 0 0 −1.00 0.32
 Basal area (m2 ha−1) <0.01 <0.01 0 0.32 0 0 <0.01 <0.01 0 0 −1.00 0.32
 TDW (kg ha−1) <0.1 0.7 0 0.32 0 0 <0.1 0.7 0 0 −1.00 0.32
All Trees
 Mean diam. (mm) 5.9 7.4 4.7 6.2 0.050 26.6 32.2 29.0 33.8 0.006 14.8 20.5 15.7 22.6 0.66 0.51
 No. of trunks (ha−1) 849.6 1702.9 814.5 1374.8 0.78 271.1 448.7 320.3 514.9 0.009 1120.8 1112.0 1134.8 1111.6 0.11 0.91
 Basal area (m2 ha−1) 0.15 0.34 0.13 0.22 0.29 0.84 1.35 1.07 1.69 <0.001 1.00 1.00 1.19 1.18 2.84 0.006
 TDW (kg ha−1) 568 1235.9 464 812.4 0.29 2940 4701.5 3712 5862.6 <0.001 3507 5520 4176 6476 2.78 0.007

Paired t-tests were based on all 61 clusters, df = 60. Bold figures denote significant changes in tree variables between 1997 and 2010

aThe mean diameter for all trees was weighted as small and large trees, respectively, were measured on different plot size

Number of trunks is the mean number of trunks based on all clusters

Basal area is the mean basal area based on all clusters

TDW is Total dry weight (kg ha−1) and corresponds to mean tree biomass per hectare