Urban Forest Renewal in Waskesiu: FAST FACTS
The Waskesiu Community Council (Council) and Prince Albert National Park (PANP) are working together to ensure the continued health and ongoing renewal of Waskesiu’s iconic white spruce forest.
The changing forest
Trees live so long compared to people that we start to believe that the forest has always been and will always be the same as we see it now.
Today’s white spruce forest gradually replaced a deciduous mixed forest over several decades. Now the forest is renewing itself again, as many of the mature white spruce trees in town are approaching the end of their lives.
Many of the dominant trees have heart rot and are weakened by root exposure and insect damage which make them hazardous and susceptible to being knocked down in strong winds. Human activities have added to these stresses as well.
The Waskesiu Vegetation Management Plan
Nearly every spruce tree in the core area of Waskesiu was planted. Unless we continue to manage our forest, which includes planting trees, Waskesiu’s spruce forest will gradually be lost, like the aspen and birch forest it replaced.
Building on the Waskesiu Community Plan, the Waskesiu Vegetation Management Strategy was developed in 2003. Recognizing the value of the white spruce forest to the community, the Waskesiu Vegetation Management Plan uses a co-operative, consultative approach to forest management.
PANP monitors spruce health and reports to Council, recommending management options annually.
Maintaining a mature white spruce tree canopy is a key goal of all parties.
2012 Spruce Health Management Actions
In 2011, PANP and the Council agreed on actions for 2012 which included:
Reduce spruce budworm:
- Twice in the spring of 2012 and 2013, 310 ha of the core town site will be sprayed aerially with Foray 76B to reduce spruce budworm defoliation and improve spruce tree health.
- Foray 76B is made up of Bacillus thuringiensis subspecies kurstaki, Btk, and is a bacterium found naturally in soils. For approximately 30 years it has been used successfully world-wide as a biological pest control agent to combat a variety of forestry and agricultural insect pests.
Btk only becomes toxic in the alkaline gut of specific butterfly and moth larvae (caterpillar stage). It is not specific to spruce budworm and targets any feeding caterpillars. It does not affect adult moths and butterflies, other insects, bees, fish, birds or mammals.
- There are no groundwater infiltration concerns as Btk does not percolate through the soil beyond 25 cm.
As resources permit, plant trees:
- A random planting of 30 trees that are 3 m (10 feet) high;
- Arbour Day planting and fencing of a mix of deciduous and conifer trees 1-2 m (3-5 ft) high; and planting of jack pine and deciduous seedlings in the nursery at the old compound site next to the 275 spruce seedlings planted in August 2011.
- Monitor, assess and remove any trees on park lands found to be hazardous. Residents are responsible for removing hazardous trees on their leaseholds. PANP carries out a hazardous tree assessment on leaseholds upon request.
- Monitor spruce health in fall 2012. Results will be reported to Council in October 2012 and will be publicly available.
- PANP will continue to work with Council to develop and carry out plans that will ensure the continuation and renewal of Waskesiu’s beautiful white spruce forest.
Q & A - Spruce Budworm and Spraying Foray 76B
What is spruce budworm?
Spruce budworm is a naturally occurring insect in Prince Albert National Park that experiences cyclical population surges. The budworm caterpillars emerge from their winter silk tents underneath the bark of white spruce trees in May and June. They eat the favoured new growth buds on the ends of tree branches and, as foliage is consumed, they rappel by silk threads to lower branches and continue to feast.
Why is spruce budworm an issue in Waskesiu?
Although spruce budworm populations have dropped to insignificant levels in the majority of Prince Albert National Park without any intervention, the native insects are currently experiencing a cyclical increase in the town site of Waskesiu. If left to natural processes, several high-use areas with dense stands of mature white spruce trees in Waskesiu will be affected by moderate to severe defoliation. These trees are nearing the end of their natural lives and are weakened by age and human development. Defoliation could accelerate the mortality of approximately 30% of those trees. Aesthetically, many visitors and seasonal residents find the sight of budworm caterpillars disturbing.
What is the history of this issue?
The Waskesiu Community Council and Parks Canada sprayed Btk twice each spring over 310 ha of the town site for spruce budworm during a province-wide outbreak in 2003, 2004 and 2005. The pesticide Foray 48B, a lesser concentrated form than Foray 76B which is commonly used now, reduced spruce budworm numbers but it did not eliminate them. It simply interrupted the outbreak.
Annual monitoring of spruce trees in Prince Albert National Park showed that budworm populations began to return within a couple years of the last spray program, reaching a high level and causing severe defoliation in localized areas again by 2010.
What is the current situation?
Mature white spruce trees are a Waskesiu heritage symbol that many visitors and seasonal residents have a strong connection to. This is also an aesthetic issue. As the dominant tree species, white spruce are very prominent in the town site making the defoliation highly visible.
Parks Canada presented its annual white spruce tree monitoring report to the Waskesiu Community Council in October 2011. Parks Canada informed Council about the state of white spruce trees in the town site, predicted budworm activity in 2012 and offered five options for recourse. Parks Canada recommended a reforestation and hazardous tree removal program.
Council deliberated and in December 2011, recommended to Parks Canada a pesticide spray program in addition to reforestation activities. Parks Canada conditionally accepted Council’s recommendation pending an environmental assessment and a 2/3 financial contribution from the community for the spray contract.
What is the role of the Waskesiu Community Council?
Parks Canada and the Waskesiu Community Council have a memorandum of understanding that recognizes the elected Council’s role as advisors to Parks Canada.
From the MOU:
“The Minister's statutory discretion under the Canada National Parks Act shall not be fettered by this memorandum of understanding. It is acknowledged that the Minister delegates authority on his/her behalf. However, it is agreed that the Superintendent will generally accept and act upon the decisions and advice of the Council in relation to matters of local concern to the community.”
What is being proposed?
The Waskesiu Community Council and Parks Canada are proposing an aerial application of Foray 76B, a stronger concentration than the previously used Foray 48B, which contains the active ingredient Btk (Bacillus thuringensis, subspecies kurstaki), over 310 hectares of the town site of Waskesiu Lake in Prince Albert National Park. A cost-shared approach has been agreed upon by both parties.
Foray 76B will be applied twice in late May or early June in 2012 and again in 2013. Annual health monitoring of the trees and reporting to Council will continue. The area to be sprayed comprises less than 1% of the total area of Prince Albert National Park.
Will spraying save the old white spruce trees?
Spraying Foray 76B may prolong the lifespan of the trees and will maintain their aesthetic appeal. There are many factors affecting their health in Waskesiu including age, the removal of trees for development, heart rot, wind, lack of forest diversity that enables the spread of disease and insect infestations. The area being sprayed is much too small to keep budworm from moving back in. The goal is to keep the trees in a healthy and aesthetically pleasing state while giving the community time to continue planting the next generation of trees. It is not to extend the trees’ lives forever; however, the imminent and simultaneous death of many trees in the community should be avoided through spraying.
Are town site trees more susceptible to spruce budworm than the same trees elsewhere in the park?
Based on data gathered since the last spray program in 2005, the town site trees had a reprieve from defoliation for about two to three years before budworm resurged. The open developed area and thick tree clumps consisting of only mature white spruce are easily susceptible to continued re-infestations. Spruce trees living in a continuous canopy of mixedwood forest have a higher diversity of tree species and different environmental conditions than in the town site that may help these forests rejuvenate quicker after an outbreak occurs.
What is the Waskesiu Urban Reforestation Plan?
The community is working together to plant a mixed forest of younger trees that more closely reflect the natural surroundings and which will ultimately create a stronger town site forest which will be more resistant to spruce budworm and other diseases or insect outbreaks.
Parks Canada has also started its own mixed species tree nurseries that will one day provide all the trees to be transplanted around the town site as needed.
What is the National Park Policy on spraying for spruce budworm in a national park?
From the “Guiding Principles and Operational Policies”
"Provided that park ecosystems will not be impaired, the manipulation of naturally occurring processes such as fire, insects and disease may take place when no reasonable alternative exists and when monitoring has demonstrated, that without limited intervention:
i. there will be serious adverse effects on neighbouring lands; or
ii. major park facilities, public health or safety will be threatened; or
iii. the objectives of a park management plan prescribing how certain natural features or cultural resources are to be maintained cannot be achieved.”
"Where manipulation is necessary it will be based on scientific research, use techniques that duplicate natural processes as closely as possible, and be carefully monitored.”
Why was Btk selected to control spruce budworm?
Btk is the industry standard pesticide used to control spruce budworm. It is approved by Health Canada for use in forestry, crop and residential situations and has low ecological impact. Other areas of Saskatchewan use Btk, such as Candle Lake, and it is used world-wide with success. Btk is a naturally occurring element found in soil.
There are other pesticides that would control spruce budworm but they are not as selective and would therefore kill other species, nor are they created from naturally occurring bacterium the way that Btk is.
What is Btk and how does it work?
Bacillus thuringensis sub-species kurstaki, known as Btk, is a bacterium found naturally in soils. The spray compound is sticky so that it adheres to foliage where the caterpillars (larvae) will consume it. When consumed it causes the spruce budworm to cease feeding and die within two to four days.
Bt is one of the few pesticides acceptable to organic growers around the globe because it is a naturally occurring biological organism rather than a synthetic chemical. For this spray program, Btk under the commercial name of Foray 76B will be used. Btk is approved for usage by Health Canada.
Are there human or mammal health concerns?
Btk is not considered harmful to people or mammals and is approved for use around the globe including Canada.
Btk compounds are made with either a potato or wheat base and may cause irritation to the airways of some people. Similar precautions should be taken as when avoiding pollen and other airborne allergens or when air quality advisories are issued.
For Bt toxins to be activated, they need an alkaline environment such as exists in certain insects’ digestive systems. Btk does not affect animals with acidic stomach environments such as birds, fish, and mammals.
No significant health risks are associated with any of the chemicals found in Btk. Under typical circumstances, the inert ingredients in Btk formulations will not harm humans or animals. Inert ingredients include stickers and binders that allow the spray to remain on vegetation after it is applied. There have been no reported ill effects of ingesting Btk.
“Btk is a registered, restricted pesticide that can only be used according to the manufacturer’s directions and with a licence by a technician with proper training. It is not required that people stay indoors during spraying, but if sprayed with Btk on the body, it is advised to wash clothing and shower to avoid any potential skin irritation.”
Questions and Answers about BTK and Health
What are the other chemicals used in Btk?
A variety of other substances may be found in the mixture, including food products that also provide nutrition for bacteria, such as potato starch, glucose or sucrose, proteins from corn or soy, and water. Additional ingredients might be sodium hydroxide, potassium phosphate, and a thickening agent found in cream cheese and ice cream. Other inert ingredients might be used but always in much smaller quantities than those mentioned above.
Are petroleum products used as carriers?
What are the ecological impacts of Btk?
The pesticide that lands on foliage begins to degrade through exposure to sunlight and microorganisms.
Btk does not infiltrate ground water as Btk does not percolate deeper than 25 cm.
Btk should not be sprayed on bodies of water as its effect on water insects is still unknown.
What is the effect on other insects?
Other moth and butterfly species that are in the larval or caterpillar stage when spraying occurs are also susceptible to Btk toxins but adult moths and butterflies are not harmed by it. Populations begin to return within one to two years of spraying.
It has been found in several studies that applications of Btk to the soil surface can reduce the populations of nematodes (roundworms) in egg, larvae, and adult stages, and several beetle species. The extent of mortality and how these species may or may not respond when Btk is applied in the Waskesiu area is unknown.
Bees, mosquitoes, other organisms such as slugs and earthworms are not in danger.
What about species that feed on insects?
While species that feed upon insects (songbirds that eat caterpillars) may be affected by the drop in food source, they are not affected by ingesting Btk.
No substantial evidence exists to conclude that Btk is toxic or harmful to amphibian or bird eggs.
What about species that rely on moths and butterflies for pollination?
There are no rare native plant species in the Waskesiu core town site and there are no native plants that rely on just one moth or butterfly for pollination.
Since the area being sprayed is small, adult species of moths and butterflies will be able to move in from other areas of the park to pollinate plants.
What happens to aquatic species if Btk drifts into Waskesiu Lake or the beaver ponds?
Btk is not toxic to fish, amphibians or water plants, or birds and animals that eat water species.
There is no substantial evidence to conclude that Btk is toxic or harmful to water insects; however, the product label should be followed and spraying directly onto water is to be avoided. Weather conditions will be assessed so that spraying occurs during optimal periods to avoid any direct spraying of or drift of the pesticide into bodies of water.