• Start-up
  • Planning
  • Action
  • Evaluation
The Canadian Forest Service of Natural Resources Canada is participating in a North American - wide study called the Adaptive Silviculture for Climate Change (ASCC) Network. The goals of this project are to test different silvicultural approaches to climate change and forest health adaptation that will also serve as useful examples across the U.S. and Canada.

Project Area

Resilience treatment aims to create multi-aged, well-stocked structure. Photo Credit: Jeff Fera, Canadian Wood Fibre Center
The Petawawa Research Forest (PRF), 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 establish 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 will be situated in stands with dominant and co-dominant components of white and red pine, and mid-canopy components of aspen, white birch, red maple, balsam fir, and white spruce. In these stands, the understory is 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 will represent level to upper slope positions.

Management Goals

Managers and scientists planning the PRF ASCC site. Photo Credit: Courtney Peterson, Colorado State University.

A team of natural resource specialists from the Canadian Forest Service, regional managers, and scientists came together for a three-day workshop in July 2019 to develop the study design for the ASCC project site. The team developed a set of Desired Future Condition statements, Objectives, and Tactics for each major climate adaptation trajectory (resistance, resilience, transition). These three trajectories are briefly summarized below:

 

 

No Action:

Since climate change impacts all forests globally, we cannot maintain a true “control.” With this in mind, we consider an approach in which forests are allowed to respond to climate change in the absence of direct silvicultural intervention as an appropriate baseline for many questions. Mature stands representing the Desired Future Condition (DFC) will be maintained and monitored for the duration of the study. These stands will serve as a benchmark of natural succession in the absence of management. 

"Business as Usual" Control:

Under a no-change scenario, the DFC at maturity (100 years) for white pine forests in the region is:

  • Regenerate a well-stocked, productive, pine-dominated stand (white pine and other drought-tolerant species common to the site)
  • Maintain or increase production of high quality sawlogs and other forest products
  • Manage for wildlife habitat and mitigation of pests through partial harvesting and planned retention of the original overstory species

Resistance:

  • Regenerate a well-stocked, productive, pine-dominated stand (white pine and other drought-tolerant species common to the site)
  • Maintain or increase production of high-quality sawlogs and other forest products 
  • Manage for wildlife habitat and mitigation of pest through partial harvesting and planned retention of the original overstory species 
  • Establish white pine adapted to future climate conditions

Resilience:

  • Create a well-stocked, multi-aged structure (promote species composition of white pine > red oak > aspen > red pine > other species)
  • Maintain/increase productivity and quality of wood products, and diversify wood products, including pine sawlogs 
  • Promote low susceptibility to disturbances, including drought, wildfire, wind, ice storms, insects, and diseases 
  • Enhance species diversity particularly among dominant species (including functional diversity, structural diversity, and genetic diversity)
  • Establish trees adapted to future climate conditions
  • Increase resilience to low intensity wildfires and reduce susceptibility to stand-replacing wildfires 
  • Manage for wildlife habitat and mitigation of pest by utilizing expanding gaps to create a multi-aged stand with a gradient of light conditions

Transition:

  • Provide quality wood products 
  • Promote a diverse species mix that is adapted to drought, wildfire, wind, ice storms, insects, and diseases, and adapted to future climate conditions 
  • Maintain wildlife habitat through structural retention and an increase in mast species 

Climate Change Impacts

Key projected climate change impacts that the project team considered for the Petawawa Research Forest include:
Increasing summer moisture stress due to drought and the increased potential for wildfire concerns
More irregular seed production necessitating a reduced reliance on natural regeneration
Increased frequency of snow and ice storms leading to crown damage and snow loading on seedlings
Warmer winter temperatures and increased evapotranspiration
Rain on snow events leading to rapid snow melt and fluctuating water tables

Challenges and Opportunities

Climate change will present challenges and opportunities for accomplishing the management objectives of this project, including:

Challenges

Important forest types to the PRF, including white pine, red pine, oak, and hardwood forest units will be exposed to increased drought stress, which could slow growth of established trees and increase mortality in regeneration
Changes in seasonality and shorter, milder winters could lead to challenges with the timing of vegetation management and harvest
Infrastructure on the PRF could be taxed by large storm events and heavy rains
Changes in precipitation patterns and increased drought could increase stress and lead to increases in losses from forest insects, diseases, and wildfire

Opportunities

Warmer temperatures and longer growing seasons could potentially increase tree productivity and enhance timber production
White pine, the most dominant and economically important tree species at the PRF, is generally expected to fare well under future climate conditions
Some tree species currently found on-site are expected to have increased habitat suitability, including red oak, which may create opportunities to diversify forest composition and forest product offerings

Adaptation Actions

The ASCC project was designed to explicitly test three different adaptation options: resistance, resilience, and transition. A detailed silvicultural prescription was designed for each adaptation option, which was replicated several times across the study site. Detailed silvicultural prescriptions can be found in the Adaptation Workbook. The study site also includes several no-action "control" stands for comparison. Some of the adaptation tactics employed in this project include:

Area/Topic
Approach
Tactics
"Business as Usual" Control
Two-cut shelterwood: seed cut 12-14 m2/ha (52-60 ft2/acre) basal area; final cut when height of white pine regeneration is 6 meters (20 ft) and contains 600 stems/ha (243 stems/acre) of desirable species
Mechanical site preparation (MSIP) following harvest for slash management and seedbed creation
Chemical site preparation (CHSIP) 1 year after MSIP for understory vegetation management
In autumn following CHSIP, plant 1125 seedlings/ha (455 seedlings/acre) of white pine from local seed zones, and 125 seedlings/ha (50 seedlings/acre) of red pine from local sources
Allow for natural regeneration of white pine, red pine, red oak, and spruce
Tending as needed to ensure survival and growth of target species
Final rotation in 80-100 years
Resistance
Two-cut shelterwood: Seed cut, 12-14 m2/ha residual (129-151 ft2/acre) basal area. Final cut when height of white pine regeneration is 6 meters, 600 stems/ha (243 stems/ acre) of desirable species; approx. 20 years
Mechanical site preparation (MSIP) following harvest for slash management and seedbed creation
Chemical site preparation (CHSIP) 1 year after MSIP for understory vegetation management
In autumn following CHSIP, plant 1250 seedlings/ha (500 seedlings/acre): 250 local white pine; 300 white pine optimized for 2011-2040 climate; 350 white pine optimized for 2041-2070 climate; 350 white pine optimized for 2071-2100 climate
Allow for natural regeneration of white pine, red pine, red oak, and spruce
Tending as needed to ensure survival and growth of target species
Final rotation in 80-100 years
Resilience
Irregular shelterwood with expanding gaps: Clearcut gaps 30 m diameter (707 m2 ; 0.2 acre); additional 10 m feathered edge thinned like shelterwood seed cut (1257 m2 ; 0.3 acre); gaps + edges (0.2 ha; 0.5 acre) allocated to cover 20-25% of the stand area
Gap expansion every 15-20 years; subsequent plantings allow adjustment of species and seed zones to reflect changing climatic conditions
CHSIP 1 year after harvest for understory vegetation management
In autumn following CHSIP, plant 1400 seedlings/ha (570 seedlings/acre)
420 white pine optimized for 2011-2040 climate; 420 white pine optimized for 2041-2070 climate; 210 red oak optimized for 2011-2040 climate; 210 red oak optimized for 2041-2070 climate; 140 white oak optimized for 2011-2040 climate
Allow for natural regeneration of pines and oaks
Tending as needed to ensure survival and growth of target species
Each expansion allows adjustments of species and seed zones to reflect changing climatic conditions and knowledge
Transition
Clearcut with seed trees; retain 16-35 stems/ha of dispersed large white and/or red pine to retain structure and provide a limited seed source for natural regeneration
MSIP following harvest for slash management and seedbed creation
CHSIP 1 year after MSIP for understory vegetation management
In autumn following CHSIP, plant 1760 seedlings/ha (710 seedlings/acre)
165 local red pine; 165 red pine optimized for 2041-2070 climate; 600 pitch pine optimized for 2011-2040 climate; 500 red oak optimized for 2041-2070 climate; 330 white oak optimized for 2011-2040 climate
Tending as needed to ensure survival and growth of desired species
Species mix will be conducive to commercial thinning or irregular shelterwood management after 60-80 years

Monitoring

Monitoring is an essential component of the ASCC study. Research partners from several institutions are working together to investigate the effectiveness of different silvicultural treatments aimed at creating adaptive ecosystems. Some of the monitoring items include:
Regeneration of planted seedlings
Residual tree survival and growth
Vegetation diversity
Microclimate conditions
Hydrology and catchment data
Coarse woody debris
Carbon and nutrient pools

Next Steps

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 will create harvested and unharvested forest conditions. Therefore, a paired- plot approach is to be employed where 7 plots will be established in gaps and 7 will be 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 BAM and 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 is scheduled for summer 2022. Chemical site preparation will be scheduled for summer 2023. Seedlings will be grown at a commercial nursery in the spring and summer of 2023. Tree planting is scheduled for September 2023. Wildlife usage monitoring was conducted in June 2021, sampling will be repeated 1 year, and 3- or 5-years post-harvest.

Keywords

Forest threats
Genetic diversity
Management plan
Oak
Planting
Regeneration
Research
Wildlife habitat

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