Status of English Ivy (Hedera helix) Removal
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English ivy infests approximately 100 acres in the North District, mostly in Jedediah Smith Redwoods State Park and adjacent NPS lands. Mapping was performed in summer 2000, and removal of heavy infestations began in the fall. State park project clearances for areas in Jed have been written and approved; national park clearances are in process (one submitted for approval, one in draft review). In the current fiscal year, 4000 hours have been spent clearing and maintaining 10 of acres of ivy, plus the campground area. The first of three years of NRPP grant money was received in April.
For the most part, infestations occur at park edges. Aubell, the west end of Highway 199, Kings Valley Road, Highway 197 (North Bank Road), its junction with Highway 199, and the Hiouchi area are all infested to some degree. Aubell, as a developed site with a small, non-fruiting infestation, has not received crew time for removal. All other areas have been visited with a crew. I separate large areas into several fronts for attack. We work each front for a couple of weeks, and then we move to another site. This method allows work on many edges, and prevents over-trampling. I usually do re-sprout and light infestation work myself, which also cuts down on trampling and increases efficiency (crews do better removing heavy infestations).
With the onset of spring, cleared areas are rebounding quickly. Redwood sorrel (Oxalis oregana), Hedge nettle (Stachys sp.), native blackberry (Rubus ursinus), and various ferns are the first natives to appear. In most areas, other exotics have not colonized. Where creeping buttercup (Ranunculus repens) is present, it establishes a carpet on bare soil. The problem was too prevalent at some places on the Hampson Property (junction 199 and Parkway, the burn site for west end 199 ivy), which was buttercup and chickweed where it was not ivy, but around Camp Lincoln the buttercup will continue to be pushed back to the lawn edge. The lawn of the Hiouchi Information Center has filled in the open area where ivy once grew, and the forested slope is a mix of natives and exotics. At the east end of HIC and around housing at Jed Campground the CNPS list 4 heart-leaf twayblade (Listera cordata) has returned following ivy removal.
Much of the 100 acres is not heavily infested, so we are more than one-tenth of the way through with removal. An upcoming contract with the CCC will mean steady crew time and lots of land cleared. I hope to see the entire acreage visited by the end of the year.
