Forests:
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Topics to cover, in addition to fragmentation above, related to forest trends.
Since I work for the US Forest Service, and am a forest ecologist, more is given on this topic.
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But most animal species also are dependent in some way of forests as well.
This gives the numbers, with 90% of bird, amphibian, and fish species and 80% of mammal and reptile species being found on forest land.
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Old growth forests were, for the most part, harvested by 1920, especially in the East.
Pacific Northwest forests and UP Michigan forests cut heavily after 1920 until quite recently.
Meyer WB. 1995. Past and present land use and land cover in the USA. Consequences. Spring 1995:25-33.
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The forest changes (not virgin forests) for Illinois are shown, going from 13.8 million acres in 1820 down to 3.02 million in 1924, and then back up to 4.33 million acres in 1998.
Iverson LR. 1991. Forest resources of Illinois what do we have and what are they doing for us? Pages 361-374 in Symposium Proceedings Our Living Heritage. Illinois Natural History Survey Bulletin 34, Champaign, IL.
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History does indeed repeat itself
Deforestation rates in tropics are following same pattern as it did about a century earlier in Illinois
We have to be careful how we deal with tropical countries undergoing deforestation because we did it first!
Iverson, L.R., G.L. Rolfe, T.J. Jacob, A.S. Hodgins, and M.R. Jeffords. 1991. Forests of Illinois. Illinois Council on Forestry Development, Urbana, and Illinois Natural History Survey, Champaign. 24 pp.
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US Forest Service Forest Inventory data shows the amount of forestland in each state.
Prairie states aptly named; highest forest percentages in New England and West Virginia.
Prasad, A. and L.R. Iverson. Unpublished map produced from USDA Forest Service Forest Inventory and Analysis data.
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A map showing the distribution of forest types according to classified AVHRR data.
Lots of aspen-birch in Lake States, mostly oak-hickory elsewhere.
But these too are changing and could dramatically change in future.
Zhu Z, Evans DL. 1994. U.S. forest types and predicted percent forest cover from AVHRR data. Photogrammetric Engineering and Remote Sensing 60:525-531.
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Total area of forest land in the US has been stable since early part of 20th century.
Distribution of forest land has been shifting, however.
http://www.fs.fed.us/pl/rpa
USDA Forest Service. 2001. 2000 RPA assessment of forest and range lands. FS-687. USDA Forest Service. Washington, D.C. 78 pp.
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The US demand and consumption of timber products has steadily increased except for 1930s and early 1980s (generally follows economy).
Fuelwood consumption was initially high, then decreased during 1960s and early 1970s until the oil embargo, and has increased again since.
Big rise in pulp products throughout, and more recently with plywood and chip products.
http://www.fs.fed.us/pl/rpa
USDA Forest Service. 2001. 2000 RPA assessment of forest and range lands. FS-687. USDA Forest Service. Washington, D.C. 78 pp.
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Volume per acre has increased each decade since 1953 in the north and south (both east); not much change in West.
Secondary forests in East are growing more rapidly than being cut.
http://www.fs.fed.us/pl/rpa
USDA Forest Service. 2001. 2000 RPA assessment of forest and range lands. FS-687. USDA Forest Service. Washington, D.C. 78 pp.
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Growth-removal ratios give indication of sustainability of the timber resource: a ratio of 1 means the same amount is growing as is being harvested.
Hardwoods generally have higher ratios than softwoods.
Overall, ratios have been in 1.2 to 1.55 range, and now, nearly 50% more wood is grown than is being removed.
http://www.fs.fed.us/pl/rpa
USDA Forest Service. 2001. 2000 RPA assessment of forest and range lands. FS-687. USDA Forest Service. Washington, D.C. 78 pp.
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The Rocky Mt. region now has a ratio over 4.5
The south ratio has been declining (heavier harvest partially because of shutdown in Pacific Northwest).
Some project the ratio in the South to go below 1.0 in next couple of decades.
The North is largely secondary growth and has been growing nearly twice that of harvest since the 1950s.
http://www.fs.fed.us/pl/rpa
USDA Forest Service. 2001. 2000 RPA assessment of forest and range lands. FS-687. USDA Forest Service. Washington, D.C. 78 pp.
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Considered by ownership, the ratio shows a dramatic recent spike, to over 5.0 in national forest lands.
Forest industry lands generally have had ratios below 1.0.
http://www.fs.fed.us/pl/rpa
USDA Forest Service. 2001. 2000 RPA assessment of forest and range lands. FS-687. USDA Forest Service. Washington, D.C. 78 pp.
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Trends in wild forest fires show that, although 2000 was the major fire year since the 1950s, there were many more acres burned per year in years preceding Smoky Bear.
50 years of effective suppression has put us in difficult situation now.
That, combined with many more humans living in the wildland interface, causes problems.
http://www.fs.fed.us/pl/rpa
USDA Forest Service. 2001. 2000 RPA assessment of forest and range lands. FS-687. USDA Forest Service. Washington, D.C. 78 pp.
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Along with the (mostly Western) issue of forest fire danger due to excessive fuel buildup, is the issue of maple takeover in the East.
It too is at least partially the result of 50 years of fire suppression.
Trends in Ohio wood volume 1968-1991 show large increases in maples, yellow poplar, and black cherry, with concommitant reductions in oak and hickory.
Iverson LR, Dale ME, Scott CT, Prasad A. 1997. A GIS-derived integrated moisture index to predict forest composition and productivity in Ohio forests. Landscape Ecology 12:331-348.
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Another way to show this is the 'oak bottleneck' diagram, where there are plenty of oaks in the seedling size class as well as the canopy trees, but very few in the sapling size class.
As these maple saplings grow and mature, they will replace the oak canopy trees.
Regeneration is not presently successful, so management options are needed to help regenerate oaks.
Sutherland E., Sutherland S., Hutchinson T., Yaussy D. Oak bottleneck. Unpublished work of USDA Forest Service Project 4153 in Delaware, Ohio.
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We have been studying the role of prescribed fire in the oak-dominated communities of southern Ohio for 7 years.
Though the fires do a good job of topkilling the maple saplings, we are finding that fire alone does not sufficiently open the canopy for oak growth into the canopy.
http://www.fs.fed.us/ne/delaware/4153/ffs/Ohio_Hills_Study_Site.htm
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RWU NE-4153, USDA Forest Service, Northeastern Research Station, Delaware, Ohio, USA
Delaware, OH Home
