Table 1 Summary of forest structure and environmental data from 1923 compared to 2001–2010. The smaller size classes (15 to 30 and 30 to 60 cm DBH) were adjusted from one third of the plots (those sampled in 1936) to bring the density down to estimated 1923 levels, as described in Methods. The environmental variables were averaged across all historical sample transects and FIA plots (2001–2010) using long-term average values from 1981 to 2010
Forest structure and data | 1923 | 2001–2010 |
|---|---|---|
Trees per hectare 15 to 30 cm DBH | 45.1 | 180.2 |
Trees per hectare 30 to 60 cm DBH | 40.4 | 113.1 |
Trees per hectare 60 to 91 cm DBH | 20.5 | 24.7 |
Trees per hectare >91 cm | 22.0 | 8.7 |
Total trees per hectare | 128.0 | 326.7 |
Total basal area (m2 ha−1) | 43.1 | 42.1 |
Mean Abies:Pinus ratio | 0.6 | 0.5 |
Mean elevation (m) | 1840.8 | 1740.0 |
Mean annual precipitation (mm) | 1402.8 | 1427.0 |
Mean annual temperature (°C) | 15.4 | 16.3 |