Climate Change Specialist Report final

Transcription

1 United States Department of Agriculture Forest Service Rocky Mountain Region Climate Change Specialist Report final La Garita Hills Restoration Submitted by: Trey Schillie R2 Climate Change Coordinator GHG emissions updated by Jason Remshardt 2/2017

2 La Garita Hills Restoration Project Climate Change Report Introduction Evidence of human-caused climate change continues to grow, and is widely accepted throughout the scientific community. The fifth Intergovernmental Panel on Climate Change (IPCC) assessment recognizes both human and non-human contributions to climate change. Anthropogenic influences contributions have likely made substantial contributions to observed warming since the 1950s (Climate Change 2014 Synthesis Report Summary for Policymakers, p. 5; IPCC). As stated: Human influence on the climate system is clear, and recent anthropogenic emissions of greenhouse gases are the highest in history. Recent climate changes have had widespread impacts on human and natural systems (p. 2; IPCC). Carbon Dioxide (CO2), the most common greenhouse gas (GHG) accounts for approximately 76% of annual global emissions that are attributable to human activity. CO2 comes from a variety of anthropogenic and natural sources. Elevated concentrations of GHGs are largely attributable to human activities, such as fossil fuel combustion and land-use change. The following analysis includes both qualitative and quantitative discussion that is commensurate with Council on Environmental Quality Climate Change and NEPA guidance (CEQ, p. 9; 2014), as well as Climate Change Consideration in Project Level NEPA Analysis (USFS, 2009). Existing Condition Temperature Trends and Greenhouse Gases Temperature and precipitation patterns continue to be impacted by climate change. Impacts are variable throughout the world, and the United States. In the lower 48 United States, 7 of the 10 warmest years have all occurred since 1998 (White House Climate Change Action Plan; NOAA source). The 10 warmest years globally, have all occurred since There is a close correlation between temperature rise and atmospheric concentrations of greenhouse gases.

3 Figure 1 Data from NOAA National Climatic Data Center and the Mauna Loa Observatory, from U.S. Forest Service Climate Change Resource Center. Climate researches use historical temperature and precipitation data, as well as models to predict trends into the future. Projection models vary based on many assumptions, including future concentrations of greenhouse gases (GHGs) in the atmosphere. Current concentrations of CO2 are approximately 400 ppm (Global Climate Change, Vital Signs of the Planet; NASA); pre-industrial era (late 1700s) concentrations were approximately 280 ppm. As concentrations of GHGs increase, temperature is expected to also increase. Vegetation management activities associated with the action alternatives for this project will initially add to atmospheric concentrations. However, as trees re-establish and stands mature, carbon sequestration will reduce atmospheric concentrations of GHGs. Both processes are described qualitatively throughout this section. While the carbon cycle is considered here, the purpose of this project is more relevant to climate change adaptation, creating healthier stands more resilient to climate change impacts. Climate Change Impacts Climate change effects vary greatly depending on location and impact. For example, sea-level rise is a more direct threat to low-lying countries in the South Pacific, than to National Forests in Colorado. However, warmer temperatures and the proliferation of destructive insects are important management concerns to National Forests in Colorado. Colorado Climate Change Vulnerability Study (Colorado Energy Office, 2015) summarized observed and predicted impacts specific to Colorado including, but not limited to:

4 Increased average annual temperatures by 2 degrees Fahrenheit over the past 30 years, projecting an additional increase of 2.5 to 5.5 degrees by mid-century; Peak runoff has shifted 1-4 weeks earlier over the past 30 years; projecting an additional 1-3 weeks earlier are expected by mid-century; and Observed and projected more frequent drought conditions The report continues by assessing vulnerability in key sectors, including agriculture, transportation, outdoor recreation and tourism, and public health. Forest health and resiliency are important considerations on the Rio Grande National Forests and forested stands have become increasingly susceptible to insects and disease, exacerbated by climate change impacts. Smoke from wildfires affects public health; watershed conditions impact tourism and drinking water; and precipitation and snowpack affect water availability for downstream agriculture. Climate change, forest management, and human health and economy are all interrelated. The U.S. Forest Service and other land management agencies are developing and implementing strategies to adapt to climate change. Land managers often respond to drought, floods, fire, and destructive insects; many climate change adaptation tactics are responses to these events. The proposed activities, described in detail in chapter 1 and the Silviculture, Forest Products, and Biodiversity Reports, promote forest health; and timber harvesting reduces hazardous fuels, reducing the risk of wildfire. Adapting to Climate Change The La Garita Hills (LGH) project is largely in response to impacts, either caused, or worsened by climate change. The proposed activities are consistent with the Climate Project Screening Tool: An Aid for Climate Change Adaptation (Morelli, et. al, 2012) as described in appendix 1 of that publication. Some of the forest types analyzed under LGH have been severely affected by insects or disease. While these insects are native to these forests, many have expanded to epidemic levels, as noted in the vegetation report of this analysis. Sudden Aspen Decline (SAD), for example, is likely attributable to drought conditions and higher summer temperatures. Droughts and temperature fluctuations are natural events, but are well-documented as being exacerbated by climate change. The purpose and need of this project details objectives that promote forest health, diversity and resilience to insects, disease, and other stressors. It also recognizes that approximately 25% of spruce-fir or spruce-mixed acres have already been heavily impacted and identifies is a need to salvage trees for timber production where there is still economic value. Both commercial timber sales and non-commercial treatments facilitate thinning, reforestation (both planting and natural regeneration), and increasing stand vigor, and better position individual trees to be

5 less susceptible to insects, disease, and drought all worsened by climate change - in the future. Another aspect of the project focuses on reducing fuels in the WUI to increase defensible space for fire suppression efforts. These are also climate change adaptation techniques. The Forests chapter from Climate Change Impacts in the United States (US Global Change Research Program, 2014, p. 178) describes both the increased risks of wildfire due to climate change, as well as the effectiveness of forest management to reduce wildfire risks to communities and watersheds. The purpose and need also calls for relocating specific sections of roads to reduce impacts to watersheds, lessons the stressors on streams, rivers, and riparian areas. Reducing stressors to watersheds facilitates landscape resilience and is also considered an adaptation strategy for climate change. Carbon Sequestration and Greenhouse Gases Forest carbon sequestration has recently been estimated for the Rio Grande National Forest and this information has been incorporated into this analysis (US Forest Service 2015) on a baseline and cumulative analysis level. The Rio Grande National Forest carbon assessment is based on forest inventory and analysis (FIA) data and uses a baseline, which does not completely reflect changes due to the current extent of spruce beetle mortality. At the national scales, uncertainty of carbon flux is between percent. Therefore, at the forestlevel, the uncertainty can be much higher. Although uncertainty is high, ongoing research is focused on reducing these uncertainties over time. As time goes on, better carbon estimates for the Forest will be developed. Uncertainty around the carbon estimates should not prevent local managers from using this as a baseline and engaging the public around this non-market benefit of sequestered carbon. Carbon uptake by forests in the United States, offsets about 13 percent of our national CO2 emissions each year, including the approximately 75 teragrams (1 teragram equals one million metric tons) of carbon stored in the Forest (figure 3). Carbon stored in U.S. forests is projected to peak between 2020 and 2040 and then decline through 2060, although the Rio Grande National Forest, and other western forests, may emit greater amounts of carbon dioxide if wildfire and insect disturbances increase as expected, due to climate change and other stressors. Growth rates may increase in high-elevation forests during years with earlier spring snowmelt, abnormally warm annual temperatures, and longer growing seasons. These results suggest that projected changes in regional climate will likely result in increased productivity and carbon

6 stocks of high-elevation forest, otherwise this project will likely have little effect on the overall carbon sequestration changes for the Forest overall. Figure 3. Forest Carbon summary within Rio Grande National Forest and other regional forests from the 2015 Rio Grande National Forest Carbon Assessment. Alternative 1 (No Action) Climate change is part of the environmental baseline and will continue to happen in the absence of this project. Under the no action alternative, forest health conditions would continue to deteriorate, limiting the adaptive capacity of these forest types. Carbon dioxide would gradually be released through decomposition and decay of dead and dying trees. Without management, stands will likely be at higher risk to wildfire. In the case of wildfire, stands would burn causing an immediate release of stored carbon. As stands re-establish post-wildfire, carbon sequestration would increase as trees grow. Some intense wildfires result in damaged soil conditions that severely limit reforestation. While highly speculative, the potential for carbon sequestration would be very limited.

7 Direct, Indirect, and Cumulative Effects There would be no direct effects of GHG emissions associated with the no action alternative. However, indirect effects would continue to occur as stands emit CO2 and sequester carbon through the succession and stand development. Emissions from fire are speculative, but are also worth mentioning as a possible indirect effect. Both emissions and sequestration have a cumulative effect on atmospheric concentrations of GHGs. Effects Common to Alternatives 2, 3, and 4 Forest management activities for LGH are intended to increase resiliency over the long term. Although there will be short term increase in GHG emissions, as summarized below, these will be buffered by longer term carbon sequestration. Increased stand resiliency correlates with an ability to better withstand climate change impacts and sequester carbon. Timber harvesting, slash piling and burning, and reforestation all change the amount of carbon sequestered in forest vegetation and soil. Timber harvests result in reduced carbon in forests as biomass is removed. This reduction may come from either living biomass carbon pool, or standing dead carbon pool. Some of the carbon will continue to be stored in wood products (Nunery and Keeton, 2010), or may be used as a source of energy that could range from wood pellets, to firewood. Both forms have the potential to offset energy from traditional fossil fuels. Many of the lower elevation stands analyzed for treatment under LGH are at risk for uncharacteristically large or intense wildfires that could release large amounts of CO2. In 2008 wildfire on 931,000 hectares resulted in approximately 143 million metric tons (mmt) of CO2, as compared to prescribed fire on 783,000 hectares that resulted in about 20 mmt (Heath, et. al, Managed Forest Carbon Estimates for the US Greenhouse Gas Inventory, 2010). This large discrepancy is not surprising because prescribed fires including pile burning and the prescribed broadcast burns are controlled and usually result in lower emissions on a per area basis. Emissions from harvesting activities considered under the action alternatives are qualitatively considered in the context from potential emissions from uncontrolled wildfire and quantitatively considered by estimating GHG emissions by alternative (see table 1). Alternative 2 (Proposed Action) The proposed action analyzes treatment up to 56,390 acres of commercial harvest and 64,725 acres of non-commercial treatments. Both commercial and non-commercial treatments will result in the initial loss of stored carbon through vegetation loss, soil disturbance, and

8 emissions associated with equipment and machinery. However, as stands re-establish and grow, both as a result of thinning or planting, carbon will be sequestered as part of the typical terrestrial carbon cycle. These stands could burn and trees will still die, or decompose and release carbon in the future. The capacity to adapt to stressors associated with climate change is central to the purpose and need for this project. This can be accomplished through commercial and non-commercial activities. Adaptation would be maximized under this alternative. While this decision does not compel action on 121,115 acres, it allows management that will facilitate resiliency and increase stand vigor, while still allowing commercial harvest of trees with economic value. Watershed health would also be improved with the relocation of up to 10 miles of roads. Direct, Indirect, and Cumulative Effects Greenhouse gas emissions, including CO2, would occur directly from tree cutting, soil disturbance, and machinery associated with mechanical treatments and harvest operations including needed road work. These direct emissions would be greater than Alternatives 3 and 4. Indirectly, more carbon would be retained in wood products or biomass, than under alternatives with few acres for commercial operations. Wood products would continue sequestering carbon for the life of the product and biomass could displace emissions from other fuel sources. All GHG emissions would cumulatively add to atmospheric concentrations. However, as trees re-establish and thinned stands continue to grow, carbon would be sequestered, reducing atmospheric concentrations. Alternative 3 The alternative analyzes treatment up to 18,155 acres of commercial harvest and 70,275 acres of non-commercial treatments. Both commercial and non-commercial treatments would result in the initial loss of stored carbon through vegetation loss, soil disturbance, and emissions associated with equipment and machinery. Landing areas impacted under this alternative would be less than half (740 acres) than under Alternative 2 (2,260 acres), resulting in less disturbance and emissions from landing sites. Fewer commercial harvest acres would also result in few emissions from machinery, skid trails, and other activities associated with a commercial timber harvest operation. While this decision does not compel action on 88,430 acres, it allows forest management that will facilitate resiliency and increase stand vigor, while still allowing commercial harvest of trees with economic value.

9 Direct, Indirect, and Cumulative Effects Greenhouse gas emissions, including CO2, would occur directly from tree cutting, soil disturbance, and machinery associated with mechanical treatments and harvesting, although less than Alternative 2. Indirectly, more carbon would be retained in wood products or biomass, than under alternatives with few acres for commercial operations, but probably less than Alternative 2, which maximizes the commercial aspects of harvesting. Wood products would continue sequestering carbon for the life of the product and biomass could displace emissions from other fuel sources. All GHG emissions would cumulatively add to atmospheric concentrations. However, as trees re-establish and thinned stands continue to grow, carbon would be sequestered, reducing atmospheric concentrations. Alternative 4 Alternative 4 analyzes up to 37,795 acres of commercial treatments and 45,060 acres of noncommercial treatments. Both commercial and non-commercial treatments will result in the initial loss of stored carbon through vegetation loss, soil disturbance, and emissions associated with equipment and machinery. The emissions are commensurate with the number of acres that will be treated and the methods of treatment, heavy equipment vs. hand equipment. Landing areas impacted would be approximately 1,515 acres; therefore, disturbance and associated GHG emissions from landing sites would be roughly in between Alternatives 2 and 3. While this decision does not compel activities on all 82,855 acres, it allows forest management that will facilitate resiliency and increase stand vigor, while still allowing commercial harvest of trees with economic value. Direct, Indirect, and Cumulative Effects Greenhouse gas emissions, including CO2, would occur directly from tree cutting, soil disturbance, and machinery associated with mechanical treatments and harvesting, although less than Alternative 2, but more than Alternative 3. Indirectly, more carbon would be retained in wood products or biomass, than under alternatives with few acres for commercial operations, but probably less than Alternative 2, which maximizes the commercial aspects of harvesting. Wood products would continue sequestering carbon for the life of the product and biomass could displace emissions from other fuel sources. All GHG emissions would cumulatively add to atmospheric concentrations. However, as trees re-establish and thinned stands continue to grow, carbon would be sequestered, reducing atmospheric concentrations.

10 Comparison of alternatives for GHG emissions Site specific GHG emission factors and fuel consumption was estimated using values from several sources within the San Luis Valley, and within and outside Colorado (Dubinsky and Karunanithi 2016; TSS Consultants, 2001; USDA-Forest Service 2005) and incorporated into the Forest Service CarbonPlus Calculator (USDA-Forest Service 2016). Of the action alternatives, alternative 2 represents the highest estimate of total GHG emissions (84,412 CO2e Metric Tons), relative to the increased acres proposed for treatment over the life of the project. The amount of GHG for the no action alternative (3,983 CO2e Metric Tons) represents ongoing road maintenance and some level of harvest for firewood collections. Table 1. Summary of gallons of fuel used and metric tons of GHG emissions by alternative. Alt1 Alt2 Alt3 Alt4 Road maintenance open maintain roads closed maintain roads re-opened roads 0 208,800 96, ,800 Forest management Commercial (salvage/thinning) 0 5,277,543 1,744,987 3,537,236 non-commercial thinning/wui/burn 346,800 1,592,551 1,750,351 1,063,094 meadow encroachment reduced 0 250, , ,002.2 riparian encroachment reduced 0 22, , , Total gallons of fuel used 346,920 7,352,977 3,866,924 5,025,849 Total GHG CO2e Metric Tons (Mg) emissions 3, , , ,696.75