The Petawawa Research Forest (PRF) is proud to be part of the Adaptive Silviculture for Climate Change (ASCC) Network as well as its first international site. The PRF is located in Chalk River, Ontario, Canada, is a 10,000 hectare (24,711 acre) research forest. Operated by Natural Resources Canada, Canadian Forest Service, the PRF aims to be a living laboratory for innovative forest research as well as a hub for forest knowledge transfer. The PRF was established in 1918, and has since continued to build upon a rich history of data and observations to help researchers develop solutions for the challenges facing the forests of today.
The PRF is located within the Great Lakes – St. Lawrence forest region that features white pine, red pine, red oak, yellow birch, sugar maple, and red maple as common dominant species. Soils are typically sandy loams, and the topography ranges from flat to rolling.
The ASCC research site at the PRF was established in stands with dominant and co-dominant components of white and red pine, and mid-canopy components of red oak, aspen, white birch, red maple, balsam fir, and white spruce. In these stands, the understory was predominantly hazel and ferns, with a limited herbaceous layer. Soils are well-drained sandy loams that vary in depths between shallow and deep. Reflecting the topographical heterogeneity of the region, study sites represent level to upper slope positions.
Key projected climate change impacts that the project team considered for the Petawawa Research Forest include:
Climate change will present challenges and opportunities for accomplishing the management objectives of the Petawawa Research Forest, including:
A team of natural resource specialists from the Canadian Forest Service, regional managers, and scientists participated in a three-day workshop in July 2019 to develop the ASCC treatments for the site. Within the region, white pine forests are typically managed under the uniform shelterwood system that includes 2-3 partial harvests (seed cut, first removal, final removal) designed to support regeneration establishment by providing a seed source and regulating understory light conditions. Once the white pine regeneration has surpassed a height of 6 meters (20 ft), the threat of weevil damage is minimized and the remaining overstory is harvested leaving a single-age stand to grow to maturity. The number of harvests depend on the health, composition and basal area of the pre-harvest stand. For example, stands with lower pine components often have only the seed cut and a final removal.
The team developed a set of management objectives, desired future conditions, and silvicultural tactics for each of the ASCC Network adaptation options (Resistance, Resilience, and Transition). The ASCC project at the PRF has 5 treatments: Control (business as usual), Resistance, Resilience, Transition, and un-treated reference conditions (no action). In each scenario No Action, the existing forest is harvested and renewal activities initiated. To learn more about the Resistance, Resilience, and Transition treatments, check out the links below:
Monitoring is an essential component of the ASCC study. We collaborate with research partners from many institutions to investigate the effectiveness of the different silvicultural treatments aimed at creating adaptive ecosystems. Some of the monitoring items include:
The study site is a large investment into research infrastructure that is expected to support and attract additional short- and long-term investigations as well as collaborations with internal and external partners.
Seven measurement plots were selected and established in each replicate of all but the Resilience treatment. The irregular shelterwood strategy used in the Resilience treatment creates harvested and unharvested forest conditions. Therefore, a paired-plot approach was employed where 7 plots were established in gaps and 7 were established in the matrix. In total, 207 ha has been allocated for the ASCC trial including 33 ha in Controls. The mean treatment unit size is 10.6 ha. There have been 168 measurement plots established across the range of Mean Basal Area (BAM) and Topographic Wetness Index (TWI) conditions.
Plots were located and established in fall 2020. Pre-treatment data collection, assessments and tree marking were completed in summer 2021. Harvesting operations commenced in November 2021 and were completed in February 2022. Mechanical site preparation was completed during summer 2022 and chemical site preparation was completed in summer 2023. Seedlings were grown at a commercial nursery in the spring and summer of 2023. Tree planting was completed in August and September 2023 by the research team inside the measurement plots and by a contractor outside of the plots. Wildlife usage monitoring has been conducted annually since June 2021.
Operational challenges have required some modifications to plans and also remedial actions.
The white oak seedling crop had poor greenhouse survival so seedlings were concentrated to the Transition measurement plots. A second source of white oak acorns were purchased in fall 2023 and directly sown into the Resilience gaps and the non-plot areas of Transition.
The 2023 chemical site preparation had inconsistent results and remedial tending was undertaken in 2024 to reduce the large amounts of vigorous woody competitors that persisted in many areas. Measurement plots in the Resilience gaps and Transition were brushsawed in summer 2024. The Resistance and BAU plots were re-treated with backpack sprayer applied herbicide in September 2024. Remedial brushsaw and backpack spray work was also conducted outside the plots in some blocks.
Post-treatment monitoring commenced in 2024 with a survey of planted seedlings and the residual overstory. The issues with the Chemical site preparation (CHSIP) forced a deferral of the remaining post-treatment assessments (e.g. understory, coarse woody, canopy photos) to 2025.
Seedling monitoring will proceed annually for 3-5 years. Other assessments will be scheduled at 5 year intervals.Mean
The ASCC PRF project background and experimental design are described in an open access professional paper published in the Forestry Chronicle:
Thiffault, N., J. Fera, M.K. Hoepting, T. Jones. 2024. Adaptive silviculture for climate change in the Great Lakes-St. Lawrence Forest Region of Canada: Background and design of a long-term experiment. The Forestry Chronicle 100(2): 155-164. https://doi.org/10.5558/tfc2024-016
The Petawawa Research Forest ASCC study is led by Natural Resources Canada: Dr. Trevor Jones (Research Scientist), Dr. Nelson Thiffault (Research Scientist), Jeff Fera (Forest Research Officer), Michael Hoepting (Silviculture Research Forester), and Tim Barsanti (Forest Technologist) . Additional collaborators include Dr. Lisa Venier (Natural Resources Canada) and Dr. Junior Tremblay (Environment and Climate Change Canada), who are conducting songbird and wildlife usage monitoring with autonomous recording units (ARUs) and camera traps. A three-day workshop to initiate planning of the PRF ASCC site was hosted by The Canadian Institute of Forestry, FPInnovations, and Friends of the Petawawa Research Forest, July 16-18, 2019 in Pembroke, ON. Staff from these organizations as well as researchers and practitioners from the following organizations were part of the team that developed the trial treatments at the workshop and may have long-term involvement in the trial.
Government and Academia:
Forest Industry:
Research Scientist
Natural Resources Canada,
Canadian Wood Fibre Centre
1219 Queen Street East
Sault Ste. Marie, Ontario, P6A 2E5
Phone: 705-541-5610
trevor.jones3@nrcan-rncan.gc.ca
Research Scientist
Natural Resources Canada,
Canadian Wood Fibre Centre
1055 du P.E.P.S.,
Sainte-Foy, Québec, QC, G1V 4C7
Phone: 418-454-1976
nelson.thiffault@nrcan-rncan.gc.ca
Forest Research Officer
Natural Resources Canada,
Canadian Wood Fibre Centre
1219 Queen Street East
Sault Ste. Marie, Ontario, P6A 2E5
Phone: 705-541-5616
jeff.fera@nrcan-rncan.gc.ca
Silviculture Research Forester
Natural Resources Canada,
Canadian Wood Fibre Centre
1219 Queen Street East
Sault Ste. Marie, Ontario, P6A 2E5
Phone: 705-541-5687
michael.hoepting@nrcan-rncan.gc.ca
Forest Research Technologist
Natural Resources Canada,
Canadian Wood Fibre Centre
1219 Queen Street East
Sault Ste. Marie, Ontario, P6A 2E5
Phone: 705-541-5687
tim.barsanti@nrcan-rncan.gc.ca