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BALD HILL OAK RESTORATION

Integrated Resource Management, Consulting Foresters and Restoration Ecologists
Introduction: The City of Corvallis, Parks and Recreation hired Integrated Resource Management in partnership with the Nature Conservancy to restore the oak woodlands at Bald Hill Park. Bald Hill Park is located on the west end of the urban growth boundary in Corvallis, Oregon. It is a popular park for trail hiking and running, horseback riding, and provides views of the surrounding city. The park is ecologically significant for its mosaic of oak habitat including wet and dry prairie, savanna, woodlands, and riparian forest.

The planning stages began with several site visits and assessments in September 2003. Treatments were initiated in early October 2003 and completed by November 3, 2003. Pretreatment photo monitoring points were installed in October 2003 to assess treatment effects on plant structure and composition. These points were permanently located and GPS coordinates recorded. Post treatment re-measurement of these plots will occur in May-June 2004 and on an ongoing basis as further treatments are applied.

Efforts have already been initiated at Bald Hill to restore the oak mosaic; a continuum of oak habitats including wet and dry prairies flowing into savanna and woodland. This habitat arrangement offers a high degree of diversity favoring both edge and open oak dependent species. Restoration efforts funded by this grant focused on expanding these treatments with the objective of recreating savanna conditions at spatial scales adequate to support home range habitats of open oak dependent species including acorn woodpecker, white breasted woodpecker, and neo-tropical species including lazuli bunting, black headed grosbeak, and Bullock's oriole. Prairie/grassland dependent species including vesper sparrow will also benefit from this work, which is expanding the prairie openings at the west end of Bald Hill. In addition to birds, the western gray squirrel, listed as threatened in the state of Washington, was a species considered during restoration planning. Nest trees were protected during thinning and continuous canopy (escape) cover was maintained around portions of nest trees. Thinning treatments were design to improve the long-term mast producing capacity of the area. A resource that is very important to a host of bird and mammal species.

Goals and Objectives: The following project goals were complete by November 2003.

  • Removed 11 acres of false brome, Armenian blackberry, and English Hawthorne.
  • Thinned 8 acres of oaks to open woodland tree density
  • Created 4 acres of wildlife wood piles.
  • Seeded approximately six acres with native grass and annual forbs.
  • Restored four acres of savanna density habitat to conditions favorable for associated bird species.
  • Restored understory on seven acres of woodland oak forest.
  • Tilled and seeded six burn piles to ameliorate soil degradation from burning brush and cut trees from past treatments.

Methods/Activities : IRM used two implements on its Lightfoot™ machine including the: Fecon Bullhog for brushing and mowing implement to remove non-native species and competing understory brush; and Tree Shearer to thin and remove small diameter trees. Removing the non-natives, competing brush and small trees, will provide better habitat and growing conditions from native oak populations. Herbicides were used to eradicate non-native species. These areas were then re-seeded with native grasses and forbs. Brush mowing decreases the fire danger to the surrounding community, thereby creating a fire resilient ecosystem. Prescribed burning will occur every 5 to 10 years to maintain a fire resilient ecosystem.

    Herbicide Application
  • Sprayed all false brome with glyphosate (2%) with surfactant within treatment area.
  • Sprayed blackberry, rose and Hawthorne with garlon and surfactant within treatment area.
    Fecon Bullhog Brushing and Tree Mastication Treatment Prescriptions
  • Bullhog all non-oak vegetation (<5" dbh) within treatment unit
  • Bullhog all oak trees <4" dbh marked with blue paint.
  • Till/mulch burn piles (3-4" deep) with Fecon (general locations were posted on a map).
  • Till blackberry patches (3-4" deep) where feasible.
    Tree Shearer (thinning)
  • Cut and whole tree skidded all "blue" marked trees to designated landings for firewood processing.
  • Slopes too steep for the machine were hand felled and jackpotted.
  • Left 3 coarse wood piles/acre (130 ft3/pile (1 cord) of logs 10' and at least 5" small end diameter.

Lessons Learned: Follow-up treatments and weed control are critical in the restoration process. The use of certain herbicides such as round-up and glyphosate led to the success of control blackberry and false brom without damaging native grasses.

Further Information: Contact Marc Barnes, Integrated Resource Management, marc@irmforestry.com or by phone at (541) 929-3408. For additional oak project work visit IRM's website at www.irmforestry.com. At the City of Corvallis contact Parks and Recreation, Steve DeGhetto, stephen.degehetto@ci.corvallis.or.us or by phone (541) 766-6918..

Bald Hill Park: Oak woodland stand before thinning

Bald Hill Park: Oak woodland stand after thinning

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