Table 1 Characteristics of Norway spruce trees and site parameters from the first cycle of all state forest enterprise inventories in Lower Saxony. 29 324 Norway spruce trees from 23 145 sample plots were observed

Tree height [m]

3.7

14.6

21.8

27

47.3

dbh [cm]

7

16.8

30.5

37.9

104

Tree age [years]

20

41

54

77

199

Altitude [m]

0

90

307

475.2

947

Sum of topographic exposure indices [° × 1000] (DTM 90 m × 90 m resolution)

–84 560

–3108

1489

8135

89 208

Temperature sum during the vegetation period [°C]

833.6

1716.4

1996.6

2196.5

2456.8

Aridity index

24.8

37

44.8

54.6

87.5