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| LTER Sites > Andrews LTER > HJ Andrews Experimental Forest Research Site |
HJ Andrews Experimental Forest - Primary |
| Principal biome/main communities: |
| Temperate Forest (biome)
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| Disturbance Regime |
| Forest and stream ecosystems undergo progressive, slow change by processes such as succession and soil development. Abrupt changes are induced by disturbances such as fire, flood, wind, landslides, forest cutting, and road-building. The interplay of disturbances and succession drive ecosystem dynamics. We study the frequency, severity, duration, and spatial pattern of natural and management disturbance processes that dominate the disturbance regimes of the Andrews Forest and other parts of western Oregon. We also study effects of disturbances on biota and on ecological and watershed processes.
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| Description: |
When it was established in 1948, the Andrews was covered with virgin forest. Before timber cutting began in 1950, about 65% of the Andrews Forest was in old-growth forest (400-500 years old) and the remainder was largely in stands developed after wildfires in the mid-1800's to early 1900's. Clearcutting and shelterwood cuttings over about 30% of the Andrews Forest have created young plantation forests varying in composition , stocking level, and age. Old-growth forest stands with dominant trees over 400 years old still cover about 40 percent of the total area. Mature stands (100 to 140 years old) originating from wildfire cover about 20 percent. Wildfire was the primary disturbance in the natural forest; windthrow, landslides, sites of concentrated root rot infection, and lateral stream channel erosion were secondary disturbances.
Lower elevation forest are dominated by Douglas-fir, western hemlock, and western redcedar. Upper elevation forests contain noble fir, Pacific silver fir, Douglas-fir, and western hemlock. Low- and mid-elevation forests in this area are among the tallest and most productive in the world. Average heights are in excess of 75 m and a typical stand stores in excess of 600 megagrams of carbon per ha. These forests are also noteworthy for the large amounts of fine and coarse woody debris they contain. As elevation increases, Douglas- fir and western red cedar decline in importance and western hemlock is gradually replaced by Pacific silver fir. Non-forest habitats include wet and dry meadows, rock cliffs, and talus slopes.
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| Site Characteristics |
| Location Single Point |
| Latitude: +44.21184 |
| Longitude: -122.25589 |
| Location - Bounding Box |
| Latitude1: +44.282118 |
| Longitude 1: -122.260544 |
| Latitude 2: +44.197854 |
| Longitude2: -122.099675 |
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| Area (HA): |
6370 |
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High |
Low |
Mean |
| Elevation (M): |
1627 |
412 |
966 |
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| Research Site History |
| The H.J. Andrews Experimental Forest was established by the U.S. Forest Service in 1948. Over the more than 50 years since its inception, it has had a rich and diverse research history, with major research foci changing over time. Efforts in the 1950's concentrated on increasing efficiency of forest operations, such as regeneration, road engineering, and logging systems appropriate for old-growth forests. During the 1960's USFS scientists began a set of of experimental manipulations in small watersheds designed to study the effects of logging on hydrology, sediment loads and nutrient losses.
During the 1960's and 1970's, under the auspices of the NSF-funded International Biological Progam, collaborative research with scientists at Oregon State University began to examine the basic ecological processes that drive ecosystem functions in old-growth and managed forests and streams. These basic core studies have continued since the 1980's under NSF's Long Term Ecological Research Program (LTER). Since the 1990's, Andrews scientists have developed landscape level studies, and have begun testing methods of ecosystem management.
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