Highlights of Wisconsin's 2004 Forest Inventory and Analysis

Highlights of Wisconsin's sixth Forest Inventory and Analysis (FIA), completed in 2004, appear below. Previous inventories were completed in 1936, 1956, 1968, 1983 and 1996.

For those wanting more detailed information, the U.S. Forest Service provides a set of tools (exit DNR) that allows users to view FIA data online and generate tables and maps.

Definitions

• Seedlings-saplings: Trees less than 5 inches in diameter at breast height (d.b.h.).
• Poletimber: Softwood trees 5-9 inches d.b.h.; Hardwood trees 5-11 inches d.b.h.
• Sawtimber: Softwood trees greater than 9 inches d.b.h.; Hardwood trees greater than 11 inches d.b.h.
• Growing stock: All commercially valuable tree species greater than 5 inches d.b.h.
• Biomass: Aboveground weight of live trees 1-inch d.b.h. and larger. Biomass estimates are used to address issues such wildlife habitat, carbon storage, and the availability of wood fiber for fuel.
• Average annual net growth: Gross volume between 1996 and 2004 minus mortality over that period divided by the number of growing seasons.
• Average annual removals: Average volume of trees removed from growing stock each year due to timber harvests and land use changes.
• Average annual mortality: Average volume of trees that died each year due to insects, diseases and other natural causes.

Area of Forestlands and Forest Types

Thumbnails link to larger images.

Wisconsin's total forestland has remained stable since 1996 at 16 million acres, or 46% of the state's land area. Map provided by USDA Forest Service; beta version

• The maple/beech/birch, oak/hickory and aspen/birch forest types together make up about 70% of the state's forestlands.
• Maple/beech/birch remains the dominant forest type, composing 28% of Wisconsin's forests.

Area of Stand-Size Classes

• Acreage of the seedling-sapling stand-size class has decreased by 31% since 1996.
• The poletimber stand-size class has remained constant.
• Sawtimber acreage has increased by 33% since the last inventory.

Species Size Class Data (PDF, 4KB) provided by USDA Forest Service

Forest Ownership

2004 Forestland Ownership

• Patterns of forest ownership have changed little since 1996: In 2004, 68% of Wisconsin's forests were privately owned, mostly by individuals and families.

Volume of All Trees

• The volume of all live trees greater than 1-inch d.b.h. was 22.1 billion cubic feet in 2004.

Growing Stock Volume

• Growing stock volume on Wisconsin's forestlands was 19.7 billion cubic feet in 2004.
• Hardwood species made up 74% of net growing stock volume.
• Of the hardwoods, cottonwood/aspen had the largest net growing stock volume.
• Among softwoods, eastern white and red pines accounted for 51% of net growing stock volume.
• The growing stock volume of most major commercial tree species has increased since 1996, with the exception of jack pine, select red oak and aspen.

Sawtimber Volume

• Sawtimber volume on Wisconsin's forests was 54.8 billion board feet in 2004.
• Hardwoods accounted for 66% of net sawtimber volume.
• Of the hardwoods, select red oak had the largest net sawtimber volume.
• Eastern white and red pines made up 61% of net sawtimber volume among softwood species.

Biomass

• In 2004, the aboveground tree biomass in Wisconsin's forests was more than 593 million dry tons.
• 82% of total biomass was in hardwood species and 18% in softwoods.
• 58% of biomass was in the boles of growing stock trees.
• Private lands accounted for 70% of total tree biomass.

Growth, Mortality and Removals

• The average annual net growth of growing stock from 1996 to 2004 was 653 million cubic feet per year, or 3.3% of the current growing stock inventory on Wisconsin's forests.
• Average annual removals of growing stock from 1996 to 2004 were 346 million cubic feet per year, or 1.8% of the current growing stock inventory.
• Average annual removals from private lands exceeded removals from public lands.
• Average annual mortality of growing stock between 1996 and 2004 was 180 million cubic feet per year, or 1% of the current growing stock inventory.
• Average annual net growth of trees generally surpasses removals on both private and public forests, with the exception of jack pine (removals currently exceed growth) and white oak (removals equal growth).