| Criterion 2 Indicator 12 |
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| Rationale |
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The Area and Growing Stock of Plantations of Native and Exotic Tree Species
Forest plantations may indicate the creation of an ecologically simplified forest. In Oregon, it has been popular for about 30 years to plant live tree seedlings in a harvested area, in order to increase the number of commercially desirable trees and decrease the length of time it will take to grow trees to a harvestable size again. One indicator of forest management intensity is the acreage in forest plantations, and the amount of growing stock, or timber, in these plantations.
In Oregon, tree seedlings are grown from seeds taken from native tree species located in the same geographic area and elevation zone where they will be planted. During treeplanting, many naturally established seedlings are left to become crop trees. Unlike tree plantations on flatter ground in other regions, tree plantations in Oregon are rarely tilled. Due to all these techniques, Oregon’s tree plantations generally retain a broad mix of the native species. Tree plantations may have a different percentage of the various native tree species than a natural stand would have, but Oregon’s tree plantations generally do have most or all native tree species that are found in naturally regenerated stands of similar ages.
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| Can This Indicator Be Quantified |
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There are few or no records that show exactly which stands have been regenerated through planting and which have been regenerated though natural seeding. Therefore, for this indicator we developed estimates by using a combination of sources. We developed separate estimates for western and eastern Oregon.
According to a survey of private forest landowners conducted by the Oregon Department of Forestry, 88 percent of younger stands in western Oregon (excluding the interior counties in southwest Oregon) have been planted, and about 47 percent of the younger stands in the interior portion of southwest Oregon have been planted. We used these numbers and information from the federal forestry-related databases (see Indicator #11) to estimate the acres and growing stock in plantations in western Oregon.
The table below shows the results. In western Oregon, about 3.8 million acres of planted forests have about 4.7 billion cubic feet of growing stock.
Table 12-1. Acres and growing stock (by volume) in forest plantations, in western Oregon
| Western Oregon |
| Minus Jackson and Josephine Co.’s Plantations (88% of Stands less than 30 Years Old) |
| Owner |
Acres |
Growing Stock (MCF) |
| Federal |
824,786 |
1,351,679 |
| Industry |
1,651,016 |
1,066,646 |
| NIPF |
508,384 |
548,539 |
| Other |
309,689 |
191,115 |
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| Jackson and Josephine Co.'s |
| Plantations (47% of Stands less than 30 Years Old) |
| Federal |
369,229 |
1,344,765 |
| Industry |
74,915 |
92,859 |
| NIPF |
95,069 |
115,816 |
| Other |
21,014 |
19,802 |
| Total |
3,854,101 |
4,731,221 |
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In eastern Oregon, most forest land is managed using uneven-aged silvicultural systems that rely on natural regeneration. As the productivity of the forest increases, landowners report that it is more common for them to plant stands. We estimate that about 590,000 acres of eastern Oregon forests are planted. Because most of these forests are young and grow slowly, very little growing stock is associated with the planted stands in eastern Oregon.
Table 12-2. Acres and growing stock (by volume) in forest plantations, in eastern Oregon
| Eastern Oregon |
Plantations |
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| Site Class |
% Planted |
Acres |
Growing Stock (MCF) |
| 3+ |
87% |
113,896 |
37,723 |
| 4 |
69% |
179,740 |
49,364 |
| 5 |
41% |
199,243 |
47,331 |
| 6 |
17% |
99,980 |
23,770 |
| Total |
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592,861 |
158,187 |
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| Trends |
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The number of acres reforested in Oregon has declined by 36 percent since 1990. The most recent data shows that 158,600 acres were reforested in 1997.
Figure 12-1. Number of acres reforested in Oregon, 1990-97
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Much of the decline in reforestation is due to the decrease in timber harvesting during the same period (See Indicator #13). The annual timber harvest in Oregon declined from over 6.2 billion board-feet in 1990 to 4.1 billion board-feet in 1997. The decline was due mainly to decreases in timber sales from federal lands, resulting in a decline in reforestation on those same lands.
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| Data Source and Availability |
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The following data sources were used for this indicator.
Hansen, Mark H., and Thomas Frieswyk, Joseph F. Glover, John F. Kelly. 1992. The eastside forest inventory data base: user’s manual. USDA Forest Service North Central Forest Experiment Station, Saint Paul, MN. General Technical Report NC-GTR-151. 48 pp. Forest inventory and analysis data records, USDA Forest Service.
Lettman, Gary, and Linc Cannon. 1998. Oregon forest management intentions survey. Oregon Department of Forestry, Salem, OR.
Oregon Department of Forestry. Annual reports.
http://www.odf.state.or.us/annual_reports/AR_Home.htm
Woudenberg, Sharon W., and Thomas O. Farrenkopf. 1999. The westside forest inventory data base: user’s manual. Forest inventory and analysis data records, USDA Forest Service.
The Timber Harvest Report and Oregon Forest Management Intentions Survey are both available from the Oregon Department of Forestry. The Timber Harvest Report is produced annually. Data from the Eastside Forest Inventory Database is reported in a consistent manner with the Westside Forest Inventory Database, and is available from the FIA program responsible for the state’s inventory. The data are available from 1994 on.
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| Reliability of Data |
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Data from the Timber Harvest Report are reliable and consistent from year to year. Forest inventory data are reliable.
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| Scale |
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All data are statewide in scale
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| Recommended Action for Data Collection |
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None.
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| Definitions |
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Plantation — A stand of timber reestablished through the planting of tree seedlings. In Oregon, most planted stands are 30 years or younger, and are intensively managed for fiber production.
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| Selected References |
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None.
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