Japanese Knotweed in Remote Area

OBSERVATION I observed Japanese knotweed (Fallopia japonica) in a remote area at the north end of Harrison Lake late last year near Spring Creek, east of Tipella BC. There is a patch of this invasive species establishing on the west side of the the In-SHUCK-ch Forest Service Road (FSR) in a area where an old logging camp and out buildings were located. I have driven to the area along the In-SHUCK-ch FSR via Pemberton and also via the STS'AILES FSR from Harrison Mills many times and have never noted it anywhere along these routes. While this invasive has become relatively prevalent in Metro Vancouver and the Fraser Valley, the observation of it in this remote area is concerning.

BACKGROUND Japanese knotweed is an invasive plant that is native to East Asia and was introduced in Canada sometime in the early 1900's as a garden ornamental and quickly spread (Royal BC Museum). It is rapidly establishing in Metro Vancouver and the Fraser Valley and is out-competing native plants and other invasive plants like Himalayan blackberry.

Japanese knotweed is a herbaceous perennial that dies back each fall and emerges in the early spring. It is of particular concern because it spreads rapidly through seed dispersal and root systems that can extend 15 - 20 m laterally from the parent plant. This plant forms dense monocultures that displaces native vegetation communities. It thrives in disturbed and riparian areas and its shallow root system can destabilize stream banks making them vulnerable to erosion.

In the area where I observed the species there are several important salmon bearing streams including the Lillooet River, Sloquet Creek, Spring Creek, Douglas Creek, Tipella Creek, Fire Creek as well as Harrison Lake. Establishment of this invasive plant in these riparian corridors could have significant effects on the ecosystem and could potentially impact fish stocks due to destabilization of banks and introduction of sediments into these creeks. In addition, forestry is one of the main economic drivers in this area. Establishment of Japanese knotweed in cut blocks could have significant effects on regeneration of forests.

For additional information on Japanese knotweed in BC, see: http://www.fraservalleyweeds.com/ http://www.ssisc.info/home/knotweeds http://bcinvasives.ca/invasive-species/identify/invasive-species/invasive-plants/knotweed/

CONSULT: Abe Litz, RPF - Hedberg and Associates (Forestry). Thank you for the information. I was not aware of the presence of Knotweed at spring creek. This species is definitely one of our main species of concern from a forestry standpoint. The tough issue when managing knotweed (or any invasive on crown land) is determining who the party responsible for eradication would be. If this species was found in a recent cutblock where it can be reasonably assumed that the logging company contributed to the establishment of the species either through direct introduction or through practices which increased the probability of establishment then there would be a requirement for the licensee to report and control. In this case it sounds like the knotweed is a legacy of the old camp site and determining responsibility for management would be difficult. Currently the government approach for invasive species on crown land is to assign the responsibility to the tenure holder occupying the area of occurrence. More commonly, on untenured crown land the govt is relying on regional groups (regional invasive species councils – non-profit environmental groups) to co-ordinate the majority of identification/eradication/control methods. Their focus is primarily on areas such as public transportation corridors (highway shoulders, municipal parks, etc). To my knowledge no one is currently leading on invasive species control on crown forest land base.

Also I did check the FLNRO invasive species database (https://www.for.gov.bc.ca/HRA/plants/application.htm), there is no JK listed as occurring on the camp area. Under current regs it would be the responsibility of whoever has land tenure on the area to report to the IAPP program and to take the lead in control. Not sure who the tenure belongs to on the old camp site currently. The above web site is a good source of info for invasive species management.

From a forestry perspective this species is of high concern and we will actively manage operations in the area keeping in mind it does exist and we really do not want to see it spread into the adjacent forest harvesting landbase. Speaking generally, on all sites we are managing we will identify the presence of invasives on sites (cut blocks, new road construction, etc). During forestry operation pre-work start-up meetings on new sites we provide all contractors/logging crews with basic info about the risk of invasives and we prescribe and monitor to ensure machines moved to site are pre-washed before moving to a site so as to not transport seed or vegetative materials to the site. We also prohibit crews from dumping yard waste (single largest source of invasives movement into forest land base) on site and encourage clothing to be washed prior to site start up to limit the potential for introducing species. Specific to this infestation that you have discovered we would require any machinery working on the camp footprint to be thoroughly cleaned prior to movement/use at a new site, if a machine is moving through the camp area we would require no contact with identified infected site occurs.

I have also contacted the Fraser Valley Invasive Plant Council (Jeanne Hughes - Preferred), the Sea to Sky Invasive Species Council (Clare Greenberg), and the Douglas Nation to provide comment on the observation. I am hoping one of the invasive councils can provide information regarding treatment and am hoping the Douglas can provide some insight regarding when and how the species may have established in the area.