Indiana's Forest Resource in 2011
by Joey Gallion
The U.S. Forest Service Forest Inventory and Analysis Program (FIA), in cooperation with the Indiana DNR has been taking measurements on research plots across Indiana since the 1950s. Comprehensive reports of previous inventories are dated 1950, 1967, 1986, 1998, 2003, and 2008. These reports, along with annual data, may be viewed via the National Forest Inventory and Analysis website (http://www.fia.fs.fed.us/).
° The area of Indiana's forests continued to show a net increase, a trend that began in the 1960's. Increases in the width of narrow wooded strips and the conversion of cropland and pasture to forest land were greater than losses from development of forest land for agriculture or urban/suburban expansion.
° Average annual net growth exceeded harvest by a 3 to 1 margin between 2006 and 2010. As a result of the increased acreage and growth exceeding harvest, the volume of trees growing in Indiana continued to increase.
° Indiana had an estimated 84 million less trees in 2010 than in 2003. This decrease was found in the small diameter categories, while all trees 7” and greater gained in total numbers.
EXTENT OF INDIANA'S FORESTS
° The area of forestland in Indiana has been increasing since the 1960's. Timberland increased from 3.896 million acres in 1967, to 4.775 million acres in 2010. In 2010, forestland represented 20.6 percent of the total land area in Indiana.
° Brown County has the most forested acres with more than 166 thousand acres of forestland.
° Private landowners are the largest ownership group in Indiana, owning 84.5 percent of all forestland in 2010. The Federal government is the largest public owner of timberland with nearly 8 percent while the State owned 7 percent. Private landowners held 4.034 million acres, the State owned 339 thousand acres, the Hoosier National Forest owned 195 thousand acres, and the Dept. of Defense owned 89 thousand acres.
COMPOSITION OF INDIANA'S FORESTS
°95.2 percent of the total area of forestland is classified as hardwood forest types. The primary hardwood forest types in Indiana are oak-hickory with 3.5 million acres, elm-ash-cottonwood with 596 thousand acres, and maple-beech with 326 thousand acres.
° The area of sawtimber-size stands increased as Indiana's forests continued to mature and increase their average diameters. As the area in sawtimber sized stands increased, the area in poletimber-size stands decreased. In 1998, sawtimber-size stands accounted for 3.17 million acres. By 2010, sawtimber-size stands represented 3.66 million acres.
° In 2010, only 32 percent of the timberland in Indiana was considered fully stocked. Stocking is a measure of how well trees occupy a forest. The goal of most forest managers is to maintain the forests in a fully stocked condition for optimum growth. There are opportunities to improve the growth rate and the overall health and vigor of Indiana's forestlands through increased management. Only 2 percent of the stands were considered overstocked. However, stocking rates could be increased on nearly 70 percent of the forestland in Indiana.
° Indiana has some of the most productive forest soils in the United States. Sixty-three percent of Indiana’s forestland has the potential to produce more than 85 cubic feet of wood per acre per year. As a comparison, Illinois, Kentucky, Michigan and Ohio have 41%, 25%, 23% and 13% respectively of their forestland capable of producing 85 cu. ft. per acre per year. With Indiana’s high growth potential, timberlands should be fully stocked in order to produce maximum volume.
Number of Trees
° The hard maple group (sugar and black maple), with over 354 million trees, was the most abundant species group. Eastern redcedar, with around 64 million growing-stock trees in 2010, was the most abundant conifer.
° The number of all live trees was estimated to be 2.2 billion in 2010. With a 2010 population of 6.48 million people, Indiana had about 340 trees for each citizen.
° Between 2003 and 2010, beech, hard maple, sweetgum, ash, and black walnut were among the species groups that increased in the total number of trees.
° Oaks are of special concern in Indiana. Between 2003 and 2010, the total number of trees in all oak species groups decreased by about 21 million trees.
° The number of all live trees on timberland in Indiana decreased by an estimated 84 million trees from 2003 to 2010. The decrease was found in the smallest diameter categories. There were 115 million less trees in the 1-3 inch diameter class while all classes above 7 inches gained in the total number of trees.
° Total net volume of trees 5” and above was nearing the 10 billion ft3 in 2010.
° Average volume per acre has increased from about 680 ft3 per acre in 1950 to 2,188 ft3 per acre in 2010. The high volume per acre is a reflection of stocking rates and high growth-to-removal ratios. Average volume per acre increases with stocking rates.
° The increase in volume shows the dominance of large stands and trees. As these forests mature, regeneration will favor shade-tolerant species such as maples and beech. Regeneration of shade intolerant species such as oaks will decline without significant disturbances.
° While the total volume of red and white oak has been increasing, the percentage of the State's total volume represented by oak has declined because of greater increases in volume by other species. In 1950, red oak represented more than 20 percent of Indiana's total volume. However, since the 1986 inventory, red oak has represented only about 15 percent of total volume. The situation was similar for white oak. This implies a shift in dominance from oaks to other species.
° In 2010, sawtimber volume in Indiana totaled 35.3 billion board feet measured with the International 1/4-inch rule. Of this volume, 30 percent was in trees with d.b.h. of more than 21 inches.
° The species groups with the most sawtimber volume include red oaks, yellow-poplar, white oaks, hickories, hard maple, ashes, and soft maple. All of these species groups had more than 2 billion board feet of sawtimber volume.
° Between 2003 and 2010, all hardwood species groups increased in sawtimber volume except for basswood. The greatest increase in sawtimber volumes occurred in the yellow-poplar, soft maple, hard maple, hickory, and ash species groups...all gaining more than 500 million board feet.
° Soft maple increased by 86 percent. Hard maple, ash, yellow-poplar, and hickory all increased from 20 to 32 percent. The red and white oaks, while still gaining, only increased by 6.7 and 4.6 percent respectively.
° The percentage of sawtimber in the highest quality classifications (grades 1 and 2) increased from 26 percent in 1986 to 47 percent in 2010.
GROWTH, REMOVALS, AND MORTALITY
° Between 2006 and 2010, Indiana's average annual net growth of growing stock was 279 million ft3. This equates to an average annual net growth rate of 58 ft3 per acre for each of the 4.8 million acres of forestland in Indiana. Net growth rates are gross growth minus mortality.
° Hardwoods accounted for 97 percent of Indiana's total average annual net growth. Yellow-poplar (48.7 million ft3) and hard maple (28.8 million ft3) had the largest average annual net growth from 2006-2010.
° Average annual mortality was 109.6 million ft3 from 2006-2010 or 23 ft3 per acre for each of the 4.8 million acres of forestland in Indiana. With an average annual mortality rate of 23 ft3 per acre and a net growth rate of 58 ft3 per acre, Indiana averaged a gross growth rate of 81 ft3 per acre during that time period (gross growth equals net growth plus mortality). If mortality can be decreased through increased management, the additional growth could be available for harvest. However, limited mortality provides coarse woody material for protecting Indiana's water systems and a variety of wildlife habitats.
° From 2006-2010, the greatest mortality occurred in elm, black oak, and white ash. Elm mortality was primarily due to Dutch elm disease. Emerald Ash Borer (EAB) played a major role in the ash mortality. Mortality on other species was due to a combination of old trees reaching the end of their life span, natural competition with other trees, flooding or drought, and a variety of diseases and insects.
° Indiana's average annual removals (roundwood products, logging residues, and other removals such as land-use changes) from 2006-2010 were 93.8 million ft3; or an average annual removal rate of 19.7 ft3 per acre for each of the 4.8 million acres of forestland in Indiana. This removal rate represents less than 1 percent of the total volume in Indiana.
° Currently, Indiana’s growth-to-removal ratio is 2.97. A net growth-to-removal ratio of 1.00 indicates that the volume of net growth (gross growth minus mortality) equals that being removed. Indiana is growing nearly 3 times more volume than is being removed annually. We have an opportunity to increase harvest rates without threatening long-term sustainability.
LITERATURE CITED / REFERENCES
Web citation: Miles, P.D. 2012. Forest Inventory EVALIDator web-application version 1.5.00. St. Paul, MN: U.S. Department of Agriculture, Forest Service, Northern Research Station. [Available only on internet: http://apps.fs.fed.us/Evalidator/tmattribute.jsp]
Joey Gallion is the Forest Inventory Program Supervisor for the Indiana DNR Division of Forestry.