Survey and Inventory Noxious Weed Program 2001


This survey was focused on the possibility to create Integrated Vegetation Management (IVM) Program in the Bridge-Seton Watershed. Such a program is complex to implement due to constant evolution of herbaceous species and herbicides related information. However the Bridge-Seton Watershed area is mostly isolated which probably allows an easier management of noxious weed infestation than other areas. Co-operation between all people related to infested area is needed in order to avoid that untreated and unmanaged areas keep recontaminating treated areas.


It is often hard for herbicides application unit to find the assigned location due to constant evolving situation and re-evaluation. A new numerical identification system has been created to help next weed inventory records to identify specific polygons on maps. A table of abbreviations used in the identifying numbers should be attached to map sheets. Be careful that inventory records are organized by date and should be consulted in chronological order.

Herbaceous species : Noxious or native

One of the most important issue for pesticide application units is to be sure to treat target noxious species and distinguish them from native species used as food, medicine or for ceremonies and that should remain safe. Some of them unfortunately just look like noxious plants during some seasons. For that reason it is recommended that application units just follow orders and stick to established mapping process.

In this report some less frequent species that should be treated before spreading and while they are still manageable are listed. Other species that should be discussed are also mentioned, as well as non-noxious species that treatments must avoid.

Integrated vegetation management

Here are some guidelines expressed in the report. First, it is essential that the entire area become involved in the management program to be created. Otherwise noxious species from untreated areas would keep spreading to already treated ares, all the work done for nothing. Second, chemical treatment on is own is insufficient. Noxious plants are often more competitive than native ones and therefore after chemical treatment reseeding with native species is essential. Third, from chemical comparisons Transline herbicide seems to be more appropriate than Tordon 22k. Indeed, more non-noxious species survive the treatment which means less reseeding needed, less endangered feeling from observers and residents thanks to the “green effect” of remaining plants, less erosion, less loss for people harvesting native species and less need to retreat the area next season. Furthermore, even if Transline seems more expensive, it is more diluted which make his cost per hectare comparable to the one of Tordon 22k. For all these reasons, they recommend in this report to replace Tordon 22k by Transline which appear more economical and efficient, except for Hound’s Tongue or Dalmatian Toadflax, two species on which it does not work.

Community Involvement : feedback

This report present three feedbacks from different communities. First, the aboriginal community reject chemical treatments and prefer bio-release though those efforts seem to be less efficient. Unfortunately due to political matters the only option is to offer them information about Transline rather than proposing a solution. Second, people harvesting native species want a change of information presented on warning signs. They would like information more useable and understandable for them such as the date after when the area would be risk-free. Third, visitors of UREP (Use, Recreation and Enjoyment of the Public) would like warning signs colors to be less offensive to allow them to enjoy better the natural beauty of Lillooet area.

  • Source Ministry of Forests, Lillooet District. August 2001. Final Report : Survey and Inventory Noxious Weed Program 2001 ( Bridge Seton Watershed). Prepared by DJ Sylviculture. Available at : [Accessed 03/2021].