| Zone | Distribution of Energy content of Y. alpina in four age categories | ||||
| Young | Mature | Old | Dead | Totals | |
| A | 57,200 | 22,000 | 114,400 | 92,400 | 286,000 |
| B | 99,880 | 27,280 | 138,160 | 89,760 | 355,080 |
| C | 115,320 | 42,240 | 198,440 | 105,600 | 501,600 |
| Mean | 104,133 | 30,507 | 150,333 | 95,920 | 380,893 |