Steve Colombo

This report on climate change in Ontario provides:
• a synthesis of the current climate change impacts being seen in Ontario;
• a series of maps showing potential future climate across the province in the event international efforts to curb greenhouse gases are not successful at avoiding buildup of atmospheric CO2 concentrations to 450 ppm, resulting in a 4°C increase in global temperature;
• current and projected CO2 emission in Ontario and other Canadian jurisdictions, set against a theoretical cap on emissions that would limit global temperature change to 2°C; and,
• examples of opportunities for emissions reductions in Ontario, in particular in the forest and transportation sectors.
Climate change maps are used to show where the relative hazard produced by climate change might be highest across the province, by combining changes in temperature and precipitation into a single numerical hazard index.

Bud initiation and subsequent bud development are key steps in the nursery production of first-year temperate spruce seedlings for reforestation. An understanding of the bud initiation and development processes and monitoring methods are of vital importance to both tree seedling nursery workers and foresters. A review of bud morphology and the bud development process is given for spruce seedlings. The equipment required and techniques used in the determination of bud initiation, and estimation of the number of needle primordia are presented. When properly applied, the examination of spruce buds forms a cornerstone for successful nursery management using extended greenhouse culture.

Shoot tips collected from black spruce seedlings that were either starting to initiate terminal buds or were already developing terminal buds were stored under warm (20'C) or cool (6"C) conditions. After 14 days of storage the proportion of shoot tips in which terminal buds had initiated increased regardless of storage treatment. Needle primordia initiation continued in developing buds at a rate only slightly lower than that of intact seedlings when stored at room temperature. Buds placed into cool storage also continued to initiate needle primordia but at a rate less than that of buds stored under warm conditions.

The vulnerability of the forest vegetation of Ontario’s northern Clay Belt region to climate change was assessed using forest tree species composition and forest productivity as indicators. Changes in species composition were examined using the modelled bioclimatic niche of 15 tree species under current and future climate projected for three periods (2011-2040, 2041-2070, 2071-2100) using four general circulation models and two emissions scenarios (A2, B1). Using climate projections from an ensemble model for these same scenarios and periods as inputs to climate-based site index and genecological models, changes in height growth were examined for several major tree species of the region as a measure of effects of climate on forest productivity. Major northward geographic shifts in species bioclimatic niche were projected, resulting in suitable climatic habitat decreasing for boreal forest species of the region, and becoming more favourable for species currently associated with more southern, i.e., Great Lakes-St. Lawrence, areas. In general, results from the site index and genecological models suggest that where soil moisture availability remains relatively unchanged, initial warming over the next few decades will improve the growth of several boreal species. Collectively, these results suggest that assisted migration of seed sources and other climate change adaptation strategies directed specifically at maintaining productivity within the Clay Belt may not be necessary until mid-century.

The changes in global climate that have been projected for this century have major implications for the composition, structure, and function of ecosystems in Ontario. In this report, we present four approaches that summarize projected changes in climate across Ontario’s ecosystems at two scales: for  ecoregions and for selected natural heritage areas. First, the current climatic regime or “climate envelope” for each ecoregion is summarized and mapped for three future time  periods (2011-2040, 2041-2070, 2071-2100); this shows where current ecoregion climatic conditions are projected to move as the century progresses. Second, climate summaries are provided for each ecoregion for the current and three future time periods to show how climate is projected to change within the currently defined ecoregion boundaries. Similarly, current and future climate summaries are provided for 29 selected natural heritage areas. Finally, to introduce the concept of climate-related movement of flora and fauna, current and future climate envelopes are generated for 12 Ontario tree species that have a range of climate and site type preferences. The extent to which these species’ climate habitats are represented across Ontario’s network of natural heritage areas is shown for current and future climate. Our findings suggest that changes are in store for Ontario, with ecoregion climate envelopes projected to shift northward, becoming increasingly smaller and more scattered, and in some cases even disappearing, as the century progresses. These changes are driven by a northward shift in temperature combined with relatively stable precipitation patterns. Clearly Ontario’s natural heritage areas will also be affected by these changes. For example, the annual mean temperature in Polar Bear Provincial
Park is projected to increase from -4.5oC to nearly +2oC and the number of growing season degree days will more than double by the end of this century; this climatic shift would in principle make the park’s climate suitable for the growth of sugar maple. This type of assessment is an important first step in projecting the effects of future climate on Ontario’s ecoregions and natural heritage areas, and helps establish a basis for discussing and developing management strategies and policies to ensure the ecoregion framework remains relevant to land use planning in a rapidly changing climate. Together, these analyses provide novel perspectives on some of the challenges that resource managers are likely to face during the 21st century.

Assisted migration of tree species populations, or seed sources, is one of few adaptive strategies available to mitigate the projected effects of climate change on the structure, productivity, and distribution of forest ecosystems. In this report, we present the goals and objectives of a study intiated in 2008 to assess the potential of assisted migration as an adaptation strategy to manage for climate change in Ontario. In support of this study, we conducted a literature search on assisted migration and genetic variation in climatic response of forest tree species, through which we identified several hundred related scientific and technical publications. Citations and keywords for publications of greatest significance to using assisted migration as a climate change adaptation strategy are presented in the accompanying bibliography.

Carbon stocks in managed forests of Ontario, Canada, and in harvested wood products originated from these forests were estimated for 2010–2100. Simulations included four future forest harvesting scenarios based on historical harvesting levels (low, average, high, and maximum available) and a no-harvest scenario. In four harvesting scenarios, forest carbon stocks in Ontario’s managed forest were estimated to range from 6202 to 6227 Mt C (millions of tons of carbon) in 2010, and from 6121 to  6428 Mt C by 2100. Inclusion of carbon stored in harvested wood products in use and in landfills changed the projected range in 2100 to 6710–6742 Mt C. For the no-harvest scenario, forest carbon stocks were projected to change from 6246 Mt C in 2010 to 6680 Mt C in 2100. Spatial variation in projected forest carbon stocks was strongly related to changes in forest age (r = 0.603), but had weak correlation with harvesting rates. For all managed forests in Ontario combined, projected carbon stocks in combined forest and harvested wood products converged to within 2% difference by 2100. The results suggest that harvesting in the boreal forest, if applied within limits of sustainable forest management, will eventually have a relatively small effect on long-term combined forest and wood products carbon stocks. However, there was a large time lag to approach carbon equality,  with more than 90 years with a net reduction in stored carbon in harvested forests plus wood products compared to nonharvested boreal forest which also has low rates of natural disturbance. The eventual near equivalency of carbon stocks in nonharvested forest and forest that is harvested and protected from natural disturbance. reflects both the accumulation of carbon in harvested wood products and the relatively young age at which boreal forest stands undergo natural succession in the absence of disturbance.

"The potential of forest-based bioenergy to reduce greenhouse gas (GHG) emissions when displacing fossil-based energy must be balanced with forest carbon implications related to biomass harvest. We integrate life cycle assessment (LCA) and forest carbon analysis to assess total GHG emissions of forest bioenergy over time. Application of the method to case studies of wood pellet and ethanol production from forest biomass reveals a substantial reduction in forest carbon due to bioenergy production. For all cases, harvest-related forest carbon reductions and associated GHG emissions initially exceed avoided fossil fuel-related emissions, temporarily increasing overall emissions. In the long term, electricity generation from pellets reduces overall emissions relative to coal, although forest carbon losses delay net GHG mitigation by 16−38 years, depending on biomass source (harvest residues/standing trees). Ethanol produced from standing trees increases overall emissions throughout 100 years of continuous production: ethanol from residues achieves reductions after a 74 year delay. Forest carbon more significantly affects bioenergy emissions when biomass is sourced from standing trees compared to residues and when less GHG-intensive fuels are displaced. In all cases, forest carbon dynamics are significant. Although study results are not generalizable to all forests, we suggest the integrated LCA/forest carbon approach be undertaken for bioenergy studies."

Forest harvest for bioenergy is not immediately carbon neutral, since combustion of forest biomass adds CO2 to the atmosphere, which is not replaced by regrowth for many decades. Selecting the best mitigation option among forest utilization scenarios requires an assessment of all carbon stocks and GHG emissions over time for each option. Trade-offs between forest carbon stocks and bioenergy are significant. Understanding these trade-offs will become increasingly important under proposed cap and trade regulations where equal value is given to mitigating GHG emissions by reducing fossil fuel use and increasing ecosystem carbon stocks. Maximizing emissions reductions for forest bioenergy requires selection of a reference forest state that takes into account the most likely fate of the forest had there been no bioenergy project. Broader sustainability issues (e.g., ecological sustainability, economics), of which climate change mitigation is only one, must be balanced in guiding decisions about harvest of forests.

"A series of related growth chamber and greenhouse experiment were conducted to investigate the physiological responses of black spruce (Picea mariana (Mill.) B.S.P) and jack pine (Pinus banksian Lamb.) seedlings to high temperature. The ability to withstand high temperatures and physiological adaptation to heat are important attributes affectingt forest regeneration. Experiments addressed two key areas: i. factors affecting heat tolerance and ii. the effects of heat shock (elevated non-lethal temperatures), a treatment known to increase heat tolerance, on subsequent heat avoidance. Nearly all treatments or factors tested signiticantly affectetd the ability of seedling to tolerate high temperatures. Heat tolerance was higher with low rates of fertilization, high light intensity, heat shock temperatures, treatment with the stress-protectant chemicals Ambiol and uniconazole, in the afternoon compared to morning, and certain black spruce clones and families. Heat shock protein synthesis is frequently associated with greater heat tolerance. Greater concentrations of heat shock proteins were found in the afternoon compared to the morning, and in a black spruce clone displaying high heat tolerance compared to a less heat tolerant clone. Physiologically, black spruce and jack pine seedlings responded to heat shock by decreased needle water vapour conductance and reduced cell elasticity (increased bulk modulus of elasticity, e, determined by pressure-volume analysis). Decreased needle conductance predisposes plants to higher temperatures through reduced transpirational cooling. Decreased cell elasticity causes rapid turgor loss with a relatively small decrease in water content; reduced turgor causes stomatal closure, preserving moisture at the expensoef transpirational cooling. Since stomata will open at very high temperatures, reduced water loss following heat shock suggests that a primary role of heat conditioning is the retention of water at the expense of slightly higher temperatures; this preserves water for transpirational cooling if very high temperatures are eventually reached. These adaptations are explained by abscisic acid mediation of the effects of heat shock. Evidence derived from these experiments and the literature are integrated in a process-based physiological model."

"Minimum break-even and carbon-neutral periods resulting from displacing coal with wood pellets for energy generation at the Atikokan Generating Station (GS) were estimated using forest resource inventory for four forest management units (FMU) in northwestern Ontario. The break-even period was defined as the time since harvest at which the combined greenhouse gas (GHG) benefit of displacing coal with wood pellets and the amount of carbon in the regenerating forest equalled the amount of carbon in the forest had it not been harvested for wood pellets. The carbon-neutral period was defined as the time since harvest at which the amount of carbon in the regenerating forest equalled the amount of carbon in the forest had it not been harvested for wood pellets. Theoretically achievable minimum break-even and carbon-neutral periods were estimated as equal to 18 and 28 years after harvest, respectively. However, for the current forest age structure in the selected FMUs, production of wood pellets required for operation of the Atikokan GS would result in a minimum break-even period of 32 years after harvest. These results must be treated as optimistic since we assumed that all forest was available for harvest for wood pellet production, applied the “best” post-harvest silvicultural regime, and may have underestimated merchantable volume and total carbon stocks in older stands."

"The Boreal Campaign initiated by environmental non-governmental organizations has resulted in a number of public statements about detrimental effects of harvesting on boreal forest carbon stocks. These statements are examined in the context of Ontario’s boreal forest. A review of scientific literature and the results of the authors’ original work on forest carbon demonstrate that these statements are based on either incomplete or inaccurate use of published scientific information. We conclude that forest management in Ontario, as governed by the Crown Forest Sustainability Act, increases total boreal forest carbon stock over the long term and that these conclusions are likely applicable to other jurisdictions where boreal forests are managed sustainably."

Temperature data from 10 weather stations across Canada were used to model the effects of climate warming on the timing of bud burst and the risk of frost damage to white spruce (Picea glauca (Moench) Voss).  There was evidence of increasingly earlier dates of bud break over the course of this century at half of the stations examined (Amos and Brome, Québec, Cochrane, Ontario, Fort Vermilion, Alberta, and Woodstock, New Brunswick), with the period 1981-1988 having the earliest predicted dates of bud burst (earliest degree day accumulation).  Risk of frost damage at most stations in the 1980’s was usually greater than in earlier periods.  Weather data modelled for climate warming of 5oC predicts that bud burst will occur two to four weeks sooner than was the case during 1961-1980 at all stations, but that this will generally be accompanied by decreased risk of frost after bud burst.  However, while the expected trend is one of reduced frost risk in the future, as the climate gradually warms frost risk is expected to fluctuate upward or downward depending on interactions between provenance and local climate.

"Staff in Ontario's Ministry of Natural Resources were surveyed in 2005 to gauge their perceptions of risk from climate change to forest ecosystems and forest-based communities in Ontario. Participation in the survey was voluntary and anonymous.
More than 80% of respondents agreed that human activities are a major cause of climate change. Most survey participants believed that climate change will significantly change forest ecosystems and affect the communities that depend on them and that prompt action is required to address these impacts."

Boreal forest carbon (C) storage and sequestration is a critical element for global C management and is largely disturbance driven. The disturbance regime can be natural or anthropogenic with varying intensity and frequency that differ temporally and spatially the boreal forest. The objective of this review was to synthesize the literature on C dynamics of North American boreal forests after most common disturbances, stand replacing wildfire and clearcut logging. Forest ecosystem C is stored in four major pools: live biomass, dead biomass, organic soil horizons, and mineral soil. Carbon cycling among these pools is inter-related and largely determined by disturbance type and time since disturbance. Following a stand replacing disturbance, (1) live biomass increases rapidly leading to the maximal biomass stage, then stabilizes or slightly declines at old-growth or gap dynamics stage at which late-successional tree species dominate the stand; (2) dead woody material carbon generally follows a U-shaped pattern during succession; (3) forest floor carbon increases throughout stand development; and (4) mineral soil carbon appears to be more or less stable throughout stand development. Wildfire and harvesting differ in many ways, fire being more of a chemical and harvesting a mechanical disturbance. Fire consumes forest floor and small live vegetation and foliage, whereas logging removes large stems. Overall, the effects of the two disturbances on C dynamics in boreal forest are poorly understood. There is also a scarcity of literature dealing with C dynamics of plant coarse and fine roots, understory vegetation, small-sized and buried dead material, forest floor, and mineral soil.

The Thin Green Line symposium was attended by nearly 200 professionals, mainly from across Canada and the United States but also included participants from Europe and Asia. The symposium continued Ontario’s long and rich tradition in reforestation. Forest regeneration is a cornerstone of managing forests sustainably. Prompt and efficient regeneration gives society the benefits of wood products, as well as the economic wealth that obtaining and processing wood creates. Good reforestation habits provide more wood from less land and increased timber productivity means that demand for wood products can be met with less impact on non-wood uses of the forest.
This document is a compendium of invited and volunteer papers and posters presented at the symposium. (Where papers were not submitted, abstracts are provided.) Papers by invited speakers are first, followed by volunteer presentations organized by symposium themes as follows: status of reforestation and afforestation around the world, nursery methods to produce target seedlings, planting and planting site treatments to optimize regeneration, and enhancing timber production and non-timber values through stand establishment. Papers are printed as received and content is the responsibility of the authors.