New Wisconsin forests report shows continued growth
State timber volume grows, with greatest gain in white pine and declines in paper birch and jack pine
MADISON, Wis. -- The timber volume on Wisconsin’s 16.4 million acres of forest land continues to grow according to the Wisconsin DNR’s annual report published this spring. The greatest growth (by percentage) over the last 25 years has been in white pine. The report is based on 2018 data.
The forest has been getting older on average. Harvests have decreased (about 10% in annual volume down from 35 years ago). Tree mortality has increased as the forest has aged.
No Wisconsin county dominates acreage of trees in more than one major timber group.
If there were a forest acreage sweepstakes, the 2020 Wisconsin Forests Annual Report shows these counties lead lead (and are runners up) in species groups:
Pine: Jackson County, followed by Vilas and Bayfield.
Spruce and Fir: Oneida County, followed by Forest and Marinette.
Oak and Hickory: Marinette County, followed by Polk and Buffalo.
Maple, Beech: Forest County, followed by Sawyer and Langlade.
Aspen, Birch: Bayfield, followed by Douglas and Price.
Oak and hickory forests are growing on the largest proportion of Wisconsin forest land (about 25%), surpassing the maple, beech and birch group by a small margin, according to the report. Total acreage of forest land in the state stayed the same over the last 10 years, but total timber growing stock increased by nearly six percent from 2011-2018 as tree growth almost doubled harvest volume.
While wood volume on Wisconsin land is growing, some species’ volumes are experiencing dramatic long term decreases. Paper birch has shown the greatest decline over the last 35 years, showing a 58% decline in volume.
Because it’s an early rotational species and is relatively short lived that’s somewhat expected
In a maturing forest, Anderson said. Often these species follow disturbances like fires or clear cuts. There were six major forest fires in Wisconsin from 1977-1980, according to the Wisconsin DNR, so trees that followed are reaching full maturity.
Another species that is showing declining volume is jack pine --- also an early rotational species, Anderson said.