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Disturbance History of the Southern Appalachians. John Blanton, Forest Silviculturist USDA Forest Service Asheville, NC Upland Hardwood Silviculture Training Bent Creek Experimental Forest July 23, 2007.
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Disturbance History of the Southern Appalachians John Blanton, Forest Silviculturist USDA Forest Service Asheville, NC Upland Hardwood Silviculture Training Bent Creek Experimental Forest July 23, 2007
We will discuss 500 years of disturbance on 37 million acres in the Southern Appalachians;Discussion is based upon available literature, notably, the 1996 Southern Appalachian Assessment; Thanks to Dr. Scott Schlarbaum, Professor of Forestry at Univ. of TN at Knoxville, for his assistance and additional slides.
Occurrence of disturbances is irregular in both space and time. Fire History Reconstruction, Brush Mountain MEI: 4 yrs LEI: 1yr UEI: 8 yrs 82% Dormant Season Fires
Importance of understanding disturbance history • Human activities can cause or postpone certain types of disturbance. • Disturbances will always occur across the landscape at varying intervals. • The forests we have today are a result of past disturbances or lack of them.
Causes of disturbance: Fire 2000 & 2002: 7 million acres burned each year Average of 6 lightning fires/million acres occurs in SA’s
Causes of disturbance: Wind May 2003: 400 tornadoes in one week Since 1871: 14 hurricane-related windstorms in Southern Appalachians
Causes of disturbance: Wind With an aging, even-aged forest, the percentage of windthrow will increase (oak decline, heart rots)
Causes of disturbance: Wind Blowdown of individual trees: Perhaps 4-6% of acres could be affected in 200 years, including single treefalls
Causes of disturbance: Wind • Hurricane Hugo – 1989: high winds, microbursts in mtns. • Opal – 1995: 8” rain, 60-80 mph in NC mountains • Canopy gaps were 0.5-2.7 acres on Bent Creek • Within gaps, 28% of trees windthrown, nearly all uprooted • Black oak & scarlet oak most vulnerable to uprooting • At Coweeta, SO composed 6% density, but created 44% gaps
Landslides - saturated soils on steep slopes Hurricane Frances, 2004 Causes of disturbance: Water
Causes of disturbance: Ice Ice storms & wet snows (worse if vines are in trees) - 1993 blizzard: 24-48” snow, high winds, tornadoes in East - 1994, southeast states ice storm: 9 deaths, $3 billion - Yellow-poplar, black cherry, & VA Pine very susceptible
Causes of disturbance: Ice Hail alone Hail + insects
Causes of disturbance: Native Insects Southern Pine Beetle: From 2000-2003, 1.5 million acres in western NC
Causes of disturbance: Native Insects SPB: 75% of pine on Daniel Boone NF in KY was killed
Causes of disturbance: Native Insects Red oak borer in Ozark Mtns.in 2002: • Populations over 18 adults/m2 of bark • 300-500 borer attacks per tree instead of the usual 10 attacks • Oak decline on Ozark NF: 300,000 acres (over 400 sq mi) in 2001
Exotic forest pests in Eastern forests Butternut Canker Disease Dutch Elm Disease Before Chestnut Blight After
White and Black Oaks – Gypsy MothEastern White Pine – White Pine Blister RustAmerican Chestnut –Phytophthora cinnamomi, Chestnut Blight, Chestnut Gall Wasp, Asian Ambrosia BeetleSpruce (Eastern Hemlock) – Hemlock Woolly Adelgid Tree species recorded by Naturalist John Bartram’s first trip (1749) through Pennsylvania and their exotic pests (2007)
Sugar Maple – Pear Thrips, Asian Longhorned BeetleLinden –Basswood ThripsPitch Pine – Pine Shoot Beetle, Sirex woodwaspElm – Dutch Elm Disease (2 strains)Beech – Beech Bark Disease ComplexWhite Walnut (Butternut) -Butternut Canker Tree species recorded by Naturalist John Bartram’s first trip (1749) through Pennsylvania and their exotic pests (2007)
Causes of disturbance: Exotic Insects Gypsy moth: 80,000 acres of defoliation in Virginia in 2003 The cumulative effect is alteration of forests as we know them today.
Causes of disturbance: Exotic Insects Hemlock Woolly Adelgid: Most hemlocks will die within the next 5 years!
Causes of disturbance: Exotic Diseases Chestnut Blight • Up to one quarter of the dominant trees were chestnut • 1904 to 1950: American chestnuts on 9 million acres died
Causes of disturbance: Exotic Disease Phytophthora cinnamomi: Chestnut ink disease - By 1824, great losses of American chestnut on poorly drained soils. Littleleaf disease on shortleaf pine on poorly drained, eroded clay soils.
Oak Decline Complex: (age, site productivity, drought, insects, fungi, pollution): Older, even-aged forests (on N/P, 82% >60 years old) Loss of vigor predisposes trees to other agents Causes of disturbance: Age Armillaria Root Rot Two-lined Chestnut Borer
Causes of disturbance: Drought 2002: $10 billion in damages in 30 states; 1988: $40 billion in damages in central/eastern US; 1736, 1756, 1863, 1911, 1925, early-1930’s (Dust Bowl), 1954, 1956, 1977
Periods of History: Over 5,000 years ago, the climate continued to warm as the ice age ended. Population of Native Americans increased over time to 10-12 million (mostly along major rivers).
Native Americans & the North American Landscape Was the North American landscape undisturbed when the Europeans began colonization?
Native Americans & the North American Landscape Often viewed as nomadic hunter-gatherer tribes such as the Lakotas (Sioux) in the Great Plains
Native Americans & the North American Landscape In reality, there were a number of tribes with permanent villages, all dependent upon the surrounding land for food, water, and shelter.
Native Americans & the North American Landscape Agriculture Trees killed by fire
Paleoindian Period10,000 BC – 8,000 BC Nomadic Hunter – Gatherer Society
Archaic Period8000 BC - 1000 BC Hunter–Gatherer Society Small Villages
Woodland Period1000 BC - 1000 AD Village Gardener Society Domestication of plants including corn, sunflowers, squashes
Mississippian Period1000 AD - 1600 AD Highly structured society Development of large villages
Etowah Moundscirca 800 AD 54 acre site in northern Georgia Fortified cities led by high priest
Mississippian Period1000 AD - 1600 AD Substantial Agriculture
Iroquois Confederacy Maximum influence around 1680, controlling most of the northeastern United States and eastern Canada
Iroquois Confederacy Hunter – Agricultural Society
Iroquois Confederacy Planting the Three Sisters Squash (700 BC), Corn (800 AD), Beans (1200 AD)
Historic Period1600 AD - Present Hunter-Agricultural Society Eastern Tennessee and western North Carolina was occupied by the Cherokee Nation; the Chickasaws controlled hunting rights in west Tennessee.
Native Americans & Fire Early explorers and trappers often observed huge burned over or cleared areas with many dead trees
Native Americans & Fire Native Americans burned parts of the ecosystem to promote a diversity of habitats
Native Americans & FirePurposeful fires differed from natural or accidental fires Seasonality of burning Frequency of burning certain areas Intensity of fire
Native Americans used fire for: • Driving big game to improve hunting • Maintaining prairies or meadows for grass production (basket grasses, grain foods, habitat for grazing animals) • Clearing riparian areas to promote better habitat for beaver, muskrat, moose, and waterfowl • Felling trees and clearing wooded areas for crop and berry production
Native Americans used fire for: • Favoring plants such as strawberries, raspberries, and tobacco • Protecting medicinal plants by maintaining a burned area around them • Concentrating populations of insects for collection • Reducing pests like black flies, ticks, fleas, mosquitoes, rodents, and poisonous snakes
Native Americans used fire for: • Clearing brush and vines along travel routes and to increase accessibility into the forest • Depriving enemies of cover/ambush places • Signaling in war & announcing gatherings of tribes • Driving enemies away or burning them
Because burning was done frequently, fuel accumulations were low, and most fires burned only the understory, not killing the dominant trees. Native Americans & Fire Source: USDA Forest Service Chattahoochee-Oconee NF file photo
Pre-European Settlement1492 AD until 1607 AD Columbus, Ponce de Leon, Cortes, Verrezano, DeSoto, and other explorers introduced smallpox, measles, typhus, and malaria to North America, resulting in up to 90% mortality among Native American populations. Villages were abandoned, and canebrakes and agricultural fields in river bottoms reverted to forest.
Early European Settlement 1607 until 1880 – A Closed-Canopy Forest • Early colonial settlers and exploratory expeditions reported relatively complete coverage of closed-canopy forests from the Atlantic Coast westward to the Great Plains. • The open conditions written about by the early explorers like DeSoto were gone except near the remaining Native American villages.
Early European Settlement 1607 until 1880 – A Closed-Canopy Forest • Early colonial settlers began to clear the land for agriculture harvest the forest to export wood to Europe, as European forests had been exhausted of old growths or virgin timber. • Many of the forest products exported were related to construction of naval ships. • As European settlers moved into the Southern Appalachians during the 1700’s, their approach to land management, including agriculture and timber harvest, was much more intense than those of Native Americans.