A Pilot Project to Propagate Native Black Cottonwood
along Willow Creek, Camas County, Idaho
Prepared by: Jack E. Williams, Bureau of Land Management, 1997
| Background and Proposal
Cottonwoods are an ecologically important and aesthetically pleasing component of the riparian community along Willow Creek and many other streams in the West. Unfortunately, along many streams, including Willow Creek, recruitment of young black cottonwoods (Populus tricarpa) has decreased and only patches of older trees remain. Causes of this decline vary, but include grazing of young trees by livestock or wildlife, or lack of periodic high flow events that facilitate natural seedling establishment. Artificial propagation provides one way to increase production of young plants. Cuttings can be taken from remnant mature trees in the watershed in order to perpetuate the genetic integrity of remaining trees. The Forest Service and BLM have implemented such a project to restore native black cottonwood along Bridge Creek in central Oregon. The project involves taking cuttings from trees in the watershed, allowing the cuttings to root-out, and then planting stock into fenced exclosures. A small, pilot effort is proposed for Willow Creek to test the efficacy of native cottonwood restoration along Willow Creek. Because of the small size and low cost of this pilot effort, it could rather easily be undertaken by high school students with some oversight and assistance from agency staff. If the pilot effort is successful, additional small projects could be completed to restore cottonwoods to selected sites or a larger propagation effort for the watershed could be undertaken. Even if no additional projects are conducted beyond the pilot effort described herein, a young grove of cottonwoods could be established to insure that the species is maintained within the watershed. Procedures and Materials With permission from the Forest Service, approximately 30 cuttings would be taken from several cottonwood trees growing on Sawtooth National Forest lands along Willow Creek. Cuttings would be taken prior to leaf budding from stems at least 2 years old (lower branches trimmed as needed). Cuttings from young recent sprouts should be avoided as hormones for proper root and leaf development may be lacking (Roger Rosentreter, BLM, personal communication). Cutting would probably be taken during late March to early April 1997. Cut ends would be dipped into a fungicide and root stimulant (B vitamin) solution and then planted into 6" diameter 2 1/2-ft long sections of PVC pipe filled with sandy soil and vermiculite mixture. One or more internodes must be buried into the soil so that root formation can occur. Long sections of PVC pipe encourages vertical root formation. The bottom end of the pipes would be partially seated with duct tape. These PVC containers would be placed in a sunny location and watered. If feasible, a trench could be dug for the cuttings, which would allow watering from the trench to encourage proper root formation. Cuttings would be especially well watered until root growth is observed at which time watering would decrease. During April to May 1998, rooted cuttings would be planted into four small (approximately 6 x 10 ft.) fenced exclosures on the McNee property. Fencing would protect cuttings from herbivory by deer, elk or other wildlife. Plantings would be monitored and maintained as necessary. Until plants are fully established, maintenance could include weeding, watering, and fence repair. Materials needed for this pilot project include approximately 75 feet of 6" diameter PVC pipe, soil, fungicide/vitamin solution, and approximately 140 feet of fencing materials. Staff from the Bureau of Land Management (BLM) have volunteered to assist in taking cuttings and planting stock. School students would primarily be responsible for growing stock, constructing fenced exclosures, monitoring planting, and performing necessary maintenance. |
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