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Our Shifting Hardwood Resources Change Hasn’t Slowed Growth |
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Editors Note: The USDA Forest Service recently released an update on the state of U.S. forests which includes the first full set of current statistics since 2002. All data in this article are from Forest Resources of the United States, 2007.
In the past five decades, the hardwood resources of the United States have grown and changed significantly. U.S. hardwood growing stock was just 184 billion cubic feet (BCF) in 1953, but has most recently been estimated at 402.8 BCF in 2007, an increase of 119%. While the growth has been spread across all states and regions, distribution of growing stock and species mix have undergone a number of changes. More Concentrated in the North In 1953, the Northern regions (see Table 1 for regional definitions) held 41.7% of all U.S. hardwood growing stock. Today an even greater percentage of the U.S. hardwood resource grows in the Northern states. Thanks to a 165% volume increase in the North Central and 139% volume increase in the Northeast since 1953, the Northern region now contains 47.6% of hardwood growing stock in United States. While growing stock volume increased in the South and West during the same time period, it was at a much smaller rate. The North continued to gain a larger share of growing stock between 1997 and 2007, primarily due to volume reductions in the Southeast region (Figure 1). In the past ten years, the Southeast is the only region to experience a decline, losing 1.5% of its growing stock. Missouri led all states in rate of growth between 1997 and 2007, while Florida lost nearly a quarter of its hardwood growing stock (Figure 2). Northeast In the past decade growth in the Northeast has been just enough to maintain a 25.6% share of U.S. hardwood growing stock. Pennsylvania has experienced the most absolute volume growth in this region over both the past 54 years and past decade. Rhode Island has experienced the highest percentage growth over both those time periods, despite recording the smallest absolute volume growth since 1953. The least amount of growth in the past decade has come from the northernmost states of Vermont, New Hampshire and Maine. Hardwood growing stock declined 0.8% in New Hampshire between 1997 and 2007 and grew only 0.7% and 6.8% in Vermont and Maine respectively. North Central Since 1953, Michigan has had the largest hardwood volume growth in the region, but its growing stock was virtually unchanged between 1997 and 2007. In the last decade, Missouri had the largest gains in absolute volume, accounting for more than half of the region’s 14.2 BCF increase. Other than Michigan, Minnesota was the only other state in the region to lose growing stock between 1997 and 2007. Southeast All the regional growing stock reductions between 1997 and 2007 came in Georgia and Florida. Florida stands out the most, losing 24.4% (1.5 BCF) in just ten years. The major factor in reduced growing stock in Florida was land use change as the state’s population has grown. The University of Florida Extension estimates that annual forest loss is 80,000 acres due to land being converted to residential and other uses. While continued loss of forestland is a concern, the good news is that hardwood growing stock on remaining forestland is increasing by 98 million cubic feet annually. The decline in Georgia was about half the volume of Florida, but because Georgia has always had more hardwoods, the rate of decline was only 4.5%. Despite the 10-year decline, Georgia has had the highest rate of growth in the Southeast since 1953. Like Florida and other Southeastern states, Georgia has experienced an above average urbanization rate since 1990. While forestland increased in the state between 1997 and 2007, much of this growth was in pine plantations. South Central Among the South Central states, Tennessee’s hardwood resources have increased the most in volume, both since 1953 and in the last decade. Oklahoma was the only state in the region without at least 1.5 BCF in growth between 1997 and 2007; growing stock there declined by 1 million cubic feet. Western Hardwood growing stock volume in the Western states has gradually been increasing, but remains only 10.1% of the U.S. resource, the same share it held in 1997. The majority of hardwood growing stock in the West is still along the Pacific Coast. Species Trends As U.S. forests are changed by land use, forest pests, fire and other forces, the species mix changes as well. Grouped together for reporting purposes, Tupelo and Black Gum were the only eastern hardwood species to decline in volume of growing stock between 1963 and 2007. The rate of decline for these species was slightly greater in the last decade than in the previous two decades. Although all other species grew between 1963 and 2007, some have outgrown others and now make up a higher percentage of U.S. growing stock. Between 1997 and 2007, Beech growing stock declined 7.7%, while Walnut had the largest growth rate at 54.6% (Figure 3). However, combined these species make up only 3% of Eastern hardwood forests. Maples Increase Between 1977 and 2007, Soft Maple became more prominent in Eastern U.S. forests, more than doubling in volume, which led all hardwood species. In 1963, Soft Maple made up just 6.5% of U.S. growing stock, but by 2007, it made up 10.6%. The volume of Hard Maple has also nearly doubled since 1977, but its growth rate tapered off some in the past decade, possibly due to increased removals to satisfy consumers’ newfound taste in cabinet style. Hard Maple made up 4.2% of growing stock in 1963 and accounted for 6.7% in 2007. Maple’s increased prevalence in the forest is the result of forest succession due to the society’s current preference to avoid clear cutting. Maple species are among the most shade tolerant in the forest, allowing them to thrive and multiply easily even under the canopy of mature forests. Oaks Less Dominant Red Oak remains the most common species found in U.S. Forests, growing in volume by 38.2% since 1977. However, Red Oak’s share of the forest declined from 20.2% in 1977 to 19.1% in 2007. Our July 14, 2006 article “Will Mother Nature Fix Red Oak Markets?” detailed the reasons Red Oak is becoming less dominant. “Public concern about forest management practices has worked against Oak since the first Earth Day in 1970,” we wrote. “By the 1990’s, the silvicultural treatments required to regenerate Oak and help it out-compete more aggressive sun-loving species (primarily clearcuts and fire) were all but removed from foresters’ toolkits by litigious environmental groups. An uninformed public wanted to have its cake (ban clearcutting and burning) and eat it too (have access to Oak lumber).” (The entire July 14, 2006 article is now available on our blog—www.hardwoodreview.blogspot.com) Similar to Red Oak, White Oak growing stock volumes have grown 39.8% since 1977, but the species fell from 16.5% of Eastern hardwood growing stock in 1977 to 15.4% in 2007. As in intermediately shade tolerant species, the same principals that are working against Red Oak’s dominance in Eastern U.S. forests also apply to White Oak. Aspen/Cottonwood Scarcer As shade intolerant species, Cottonwood and Aspen are most effectively regenerated through clearcutting. As noted with Red Oak, absent implementation of these forestry techniques, their existence in U.S. forests will decline. Between 1997 and 2007, Aspen/Cottonwood was one of three species groups to show declines in growing stock volume. Aspen/Cottonwood growing stock declined 933 million cubic feet in the ten-year period—losing nearly one percentage point of its share of Eastern hardwood forests. Reduction of Aspen/Cottonwood growing stock in the North Central and South Central regions overwhelmed small amounts of growth in the Southeast and Northeast. Poplar Gains Buck Trend As a shade intolerant species, Poplar would have been expected to lose some of its share of eastern U.S. forests and have a slow rate of growth for growing stock. However, Poplar volumes increased in all four eastern regions between 1997 and 2007. Poplars’ 6.6-BCF increase in growing stock and resulting 31% 10-year growth rate trailed only Red and White Oak in volume and Walnut in rate of growth. Poplar gained a full percentage point of Eastern forest share in the last 10 years, making it the 4th most prominent hardwood species in 2007. Outgrowing the Borer? We’ve written several articles about the Emerald Ash Borer (EAB) and its long-term impact on Ash. While there have been massive diebacks of Ash related to EAB, its spread had not yet had a widespread impact at the time the data were generated, so growing stock increased 23.4% between 1997 and 2007. Growth in the two northern regions, where EAB activity is most concentrated, increased by 26.6% since 1997. Ash’s share of North American forests has been growing since 1963 and the past 10 years were no exception. Ash increased its share of North American forests from 4.4% in 1997 to 4.8% in 2007. While the Ash growth rate is encouraging, EAB continues to spread and 1997-2007 may be the last 10-year period we see Ash growing stock increase in some time. Confirmation of Sustainability In the past decade, the U.S. has added 51 BCF of hardwood growing stock, during the same 10-year period in which modern sawmill production peaked. Not only that, but the existing growing stock is remaining in forests longer, slowly shifting the average tree diameter larger. Nearly half (47%) of all hardwood growing stock is between 11 and 18.9 inches in diameter, and the volume of hardwood trees with diameters 19 inches or greater has tripled from 26 to 81 BCF since 1953. The U.S. hardwood resource is not only sustainable, but in the next decade, it has enough extra capacity to maintain healthy growth while providing large volumes of lumber to countries around the world without similarly abundant resources. |
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| The information in this article is From the editors of Hardwood Review
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