Chapter 2: Climate, Disturbance, and Vulnerability To

2 Vegetation Change in the Northwest Forest Plan Area 3 4 Matthew J. Reilly1, Thomas A. Spies2, Jeremy Littell3, Ramona Butz4, and John Kim5 5 6 7 Introduction 8 Climate change is expected to alter the structure and function of forested ecosystems in the

9 United States (Vose et al. 2012). Increases in atmospheric concentrations of CO2 and 10 corresponding increases in temperature and fire activity over the next century are expected to 11 have profound effects on biodiversity and the delivery of ecosystem services within the 12 Northwest Forest Plan (NWFP) area. The effects of climate change on ecological processes may 13 occur through a variety of mechanisms at a range of spatial scales and levels of biological 14 organization from the physiological responses of individuals to the composition and structure of 15 stands and landscapes (Peterson et al. 2014). The ecological interactions and diversity of 16 biophysical settings in the region are complex. Understanding and incorporating how climate 17 change projections and potential effects vary within the region (e.g., Deser et al. 2012) will be 18 essential in mitigating effects and developing strategies for adaptation and mitigation. 19 20 21 22 23 24 1 Matthew Reilly is a Postdoctoral Scholar, Oregon State University, College of Forestry, Corvallis, 25 Oregon; 2 Thomas Spies is a is a Senior Scientist, United States Forest Service, Pacific Northwest Research 26 Station, Corvallis, Oregon; 3 Jeremy Littell is a Research Scientist, U.S. Geological Survey, Alaska Climate Science 27 Center, Anchorage, Alaska; 4 Ramona Butz is an Ecologist, U.S. Forest Service, Region 5, Eureka, California; 5 John 28 Kim is a Biological Scientist, U.S. Forest Service, Pacific Northwest Research Station, Corvallis, Oregon;

1 2 Figure 1—Geographic distribution of potential vegetation zones (Simpson 2013) and ecoregions 3 in the Northwest Forest Plan area. Map credit: Ray Davis. 4

Peer Review Draft 10/19/16 “THIS INFORMATION IS DISTRIBUTED SOLELY FOR THE PURPOSE OF PRE-DISSEMINATION PEER REVIEW UNDER APPLICABLE INFORMATION QUALITY GUIDELINES. IT HAS NOT BEEN FORMALLY DISSEMINATED BY [THE AGENCY]. IT DOES NOT REPRESENT AND SHOULD NOT BE CONSTRUED TO REPRESENT ANY AGENCY DETERMINATION OR POLICY.” 1 The broad range of environmental and climatic gradients is reflected in the distribution of 2 several potential vegetation zones across the region (figs. 2 and 3) (Simpson 2013, available 3 from www.ecoshare.info/category/gis-data-vegzones). Vegetation zones have a unique species 4 pool with similar but internally variable biophysical conditions and historical disturbance 5 regimes that vary geographically (Winthers et al. 2005). Potential vegetation zones represent 6 climax vegetation types that would eventually develop in the absence of disturbance, therefore 7 existing or current vegetation varies often within zones depending on seral stage and time since 8 disturbance. For example, the most abundant vegetation zone in the NWFP area, western 9 hemlock (Tsuga occidentalis), is currently dominated primarily by Douglas-fir (Psuedostuga 10 menziesii). Vegetation zones provide an ecological framework for discussing climate and 11 vegetation change across broad geographic extents. They have common pathways of structural 12 development that differ in complexity and reflect regional gradients in productivity as well as 13 historical and contemporary disturbance regimes (Reilly and Spies 2015). 14 Major vegetation zones (fig. 4) generally correspond to those presented by Franklin and 15 Dyrness (1973) and were initially broken into moist and dry forests in the NWFP. This 16 characterization is overly simplistic as annual precipitation in any given zone varies 17 geographically. Moist vegetation zones make up approximately 60 percent of the region, and are 18 primarily located in the coastal areas and west of the Cascade Crest. These include Sitka spruce 19 (Picea sitchensis) and redwood (Sequoia sempervirens), tanoak (Lithocarpus densiflorus), 20 western hemlock, Pacific silver fir (Abies amabilis), and mountain hemlock (Tsuga 21 mertensiana). Dry forest vegetation zones are located east of the Cascade Crest and also 22 comprise a large portion of inland areas in southwestern Oregon and northwestern California. 23 They include western juniper (Juniperus occidentalis), ponderosa pine (Pinus ponderosa), 24 Douglas-fir, grand fir (Abies grandis) and white fir (Abies concolor), and subalpine forests 25 dominated by subalpine fir (Abies lasiocarpa), Engelmann spruce (Picea engelmanii), and 26 whitebark pine (Pinus albicaulis). More information on geographic variability and current 27 vegetation in Oregon and Washington is available at: www.ecoshare.info/publications. Appendix 28 1 provides crosswalk between the Simpson vegetation zones (2013) and existing vegetation in 29 northern California based on Regional Dominance 1 in the Region 5 CALVEG 30 database: http://www.fs.usda.gov/detail/r5/landmanagement/resourcemanagement/?cid=stelprdb 31 5347192.

1 2 Figure 2—Maps of major environmental and climatic gradients across the Northwest Forest Plan 3 area including a) elevation, b) annual precipitation, and c) annual temperature. Temperature and 4 precipitation are derived from 800-meter monthly PRISM (Parameter-elevation Regressions on 5 Independent Slopes Model) grids averaged over 30 years (1971-2000) and were obtained from 6 the Landscape Ecology, Modeling, Mapping and Analysis group at Oregon State University.

1 2 Figure 3—Maps of gradients in summer climate across the Northwest Forest Plan area including 3 a) summer temperature, b) summer precipitation, c) summer moisture stress, and d) summer fog. 4 Temperature and precipitation are derived from 800-meter monthly PRISM (Parameter-elevation 5 Regressions on Independent Slopes Model) grids averaged over 30 years (1971-2000) and were 6 obtained from the Landscape Ecology, Modeling, Mapping and Analysis group at Oregon State 7 University. Summer moisture stress was calculated by dividing summer temperature by summer 8 precipitation. Summer fog is proxy based on the optimal path length from coastline and is 9 modified by terrain blockage (Daly et al. 2008). 10 11 12 13 14 15 16

9 Guiding Questions 10 1. What are the historical and contemporary trends in climate change, and how do they vary 11 around the region? 12 2. What are the major tools for projecting climate change? What are the associated 13 uncertainties and limitations? What changes do they project, and how do they vary across 14 the region? 15 3. What are the mechanisms of vegetation change associated with climate change? What are 16 the major tools for projecting vegetation response to climate change, and what are the 17 associated uncertainties and limitations? 18 4. What are the implications of recent and projected climate trends on vegetation change? 19 5. Which ecosystems and species are most vulnerable to climate change? 20 6. What are the key adaptation strategies that could mitigate these vulnerabilities? 21 Key Findings

22 Historical Climate Change in the Northwest Forest Plan Area 23 The climate and vegetation of the Northwest Forest Plan area have gone through continuous 24 change over the past 12,000 years during the Holocene. During this time complex interactions 25 between climate and fire drove vegetation change at millennial scales (Whitlock 1992, Bartlein 26 et al. 1998, Whitlock et al. 2008, Marlon et al. 2009). Both temperature and precipitation varied 27 considerably and recent climate and species assemblages have developed only within the past 28 2,000 to 2,500 years (Whitlock 1992, Briles et al. 2005). Since then, climate has fluctuated at 29 centennial scales with the warmest temperatures occurring during the Medieval Warm Period 30 (900-1250 AD) and the coldest during the Little Ice Age (1450-1850 AD) (Steinman et al. 2012).

Peer Review Draft 10/19/16 “THIS INFORMATION IS DISTRIBUTED SOLELY FOR THE PURPOSE OF PRE-DISSEMINATION PEER REVIEW UNDER APPLICABLE INFORMATION QUALITY GUIDELINES. IT HAS NOT BEEN FORMALLY DISSEMINATED BY [THE AGENCY]. IT DOES NOT REPRESENT AND SHOULD NOT BE CONSTRUED TO REPRESENT ANY AGENCY DETERMINATION OR POLICY.” 1 Regional fluctuations in temperature and precipitation have also occurred on annual and 2 decadal scales in response to surface temperatures in the Pacific Ocean, and have become more 3 apparent over the past 1,000 years (Nelson et al. 2011). Sea surface temperatures in the 4 equatorial Pacific Ocean associated with the El Niño Southern Oscillation (ENSO) result in 5 periodic (2 to 7 years) anomalies that affect regional temperature and precipitation with warmer 6 and drier than average winter and spring conditions during El Niño years (McCabe and Dettinger 7 1999). During years in the opposite phase, called La Niña, weather conditions are generally 8 wetter and cooler, leading to deeper than average snowpack (Gershunov et al. 1999). The Pacific 9 Decadal Oscillation (PDO) is defined by fluctuations in surface temperature in the Pacific Ocean 10 and has longer characteristic periodicity of 20 to 30 years (Mantua et al. 1997), although there is 11 evidence that the Pacific Decadal Oscillation is not consistent over time at these frequencies 12 (McAfee 2014) and has exhibited variable regime transitions in the pre-instrumental period 13 (Gedalof and Smith 2001). The relationship is weaker in northern California where ENSO and 14 PDO controls on climate are weaker and less predictable (Wise 2010). 15 16 20th Century Climate Change in the Northwest Forest Plan Area 17 Increases in temperature and precipitation across the region during the 20th century have 18 exceeded global averages and vary across the region as well as among seasons (Mote 2003, 19 Abatzoglou et al. 2104a). Attributing the relative importance of human influence and longer-term 20 climatic variation to observed trends is difficult. There is evidence supporting both human 21 influence (Abatzoglou et al. 2014a, Abatzoglou et al. 2014b) and temperature increases 22 associated with atmospheric variability (Johnstone and Mantua 2014a, Johnstone and Mantua 23 2014b). Average annual temperature in western Oregon and Washington increased by 1.6 °F 24 (0.91 °C) during the 20th century with the greatest increase of 3.3 °F (1.83 °C) occurring during 25 the winter (Mote 2003). Likewise, precipitation during the same period also increased by 13 26 percent with the greatest increase of 37-percent occurring during spring (Mote 2003). 27 California has also experienced accelerated warming since 1970 (Cordero et al. 2011) 28 and recently experienced the hottest and driest period (2012 to 2014) in recorded history (Mann 29 and Gleick 2015). This same period also includes the lowest precipitation (Diffenbaugh et al. 30 2015) in recorded history and potentially the last 1200 years (Griffin and Anchukaitis 2014). In 31 northwestern California mean temperature increased 0.3 °F (0.18 °C) and minimum temperature

Peer Review Draft 10/19/16 “THIS INFORMATION IS DISTRIBUTED SOLELY FOR THE PURPOSE OF PRE-DISSEMINATION PEER REVIEW UNDER APPLICABLE INFORMATION QUALITY GUIDELINES. IT HAS NOT BEEN FORMALLY DISSEMINATED BY [THE AGENCY]. IT DOES NOT REPRESENT AND SHOULD NOT BE CONSTRUED TO REPRESENT ANY AGENCY DETERMINATION OR POLICY.” 1 increased 0.9 °F (0.47 °C) with maximum temperature decreasing by 0.4 °F (0.24 °C) during the 2 20th century (Rapacciuolo et al. 2014). Twentieth century trends in precipitation varied in 3 northern California with evidence of increases (Killam et al. 2014) as well as slight decreases in 4 some areas (Rapacciuolo et al. 2014). Climate trends across the region are similar to those 5 reported from studies across the western United States. These studies found increases in spring 6 (March to May) temperature of approximately 1.8 °F (1 °C) from 1950 to 1998 (Cayan et al. 7 2001) and declines in snowpack from 1950 to 1997 (Mote et al. 2005). Fog frequency along the 8 coast of northern California also declined by 33-percent during the 20th century (Johnstone and 9 Dawson 2010). 10 11 Projected Future Climate Change in the Northwest Forest Plan Area 12 Atmosphere-ocean general circulation models (GCM) are the primary tools for projecting future 13 climate scenarios (e.g., IPCC 2013). GCMs incorporate interactions among the components of 14 the climate system including atmosphere, land, ice, and ocean to simulate past and future climate 15 based on different scenarios of increasing greenhouse gas concentrations in the atmosphere. Due 16 to differences in model construction and sensitivity to forcing, GCM projections using the same 17 initial conditions and emissions scenario vary (Lynn et al. 2009), as do projections from the same 18 GCM due to internal variability (Deser et al. 2014). The use of ensemble projections 19 (combinations of projections from multiple GCMs) is commonly used to capture the range and 20 patterns of variability among projections, and ensemble means appear to provide the best 21 estimates of observed climate (Pierce et al. 2009, Rupp et al. 2013). 22 The range of projections in an ensemble also provides a measure of the amount of 23 uncertainty which increases as projections are made further into the future (Tebaldi and Knutti 24 2007). Uncertainty in climate change projections can be attributed to three main factors: (1) 25 climate change-scenario uncertainty, (2) model-response uncertainty, and (3) natural variability 26 in climate (Hawkins and Sutton 2009). For a given climate change scenario, uncertainty in the 27 warming estimates arises from differences in GCM construction and parameterization. Natural 28 climate variability presents the greatest uncertainty in the near- to mid-term for projecting 29 climate change for the first half of the 21st century (Hawkins and Sutton 2009) and poses a major 30 challenge for analyzing and communicating internal climate change within a region (Deser et al. 31 2012).

Peer Review Draft 10/19/16 “THIS INFORMATION IS DISTRIBUTED SOLELY FOR THE PURPOSE OF PRE-DISSEMINATION PEER REVIEW UNDER APPLICABLE INFORMATION QUALITY GUIDELINES. IT HAS NOT BEEN FORMALLY DISSEMINATED BY [THE AGENCY]. IT DOES NOT REPRESENT AND SHOULD NOT BE CONSTRUED TO REPRESENT ANY AGENCY DETERMINATION OR POLICY.” 1 For its fifth assessment (AR5), the Intergovernmental Panel on Climate Change relied on 2 a set of future greenhouse gas concentration scenarios as a set of representative pathways. Each 3 pathway describes potential future trends in human population growth, economic and 4 technological development, energy systems, and social beliefs and values that result in varying 5 levels of emissions, and therefore climate warming (van Vuuren et al. 2011). Climate change 6 scenarios (e.g., RCP2.6, RCP8.5) are considered to be plausible and do not have probability 7 distributions associated with them (Collins et al. 2013). Although current rates of greenhouse gas 8 concentrations are near the higher end of these plausible scenarios, there is currently insufficient 9 information to rule out any scenario (Manning et al. 2010, van Vuuren et al. 2010). All scenarios 10 project increases in global mean temperatures, but there is a large range among the scenarios. 11 Under the RCP2.6 scenario, which represents strong mitigation action, the global mean 12 temperature is projected to increase by 2.9 °F ± 0.7 °F (1.6 °C ± 0.4 °C) by the end of the 13 century, while under RCP8.5, the no-mitigation, high-growth scenario, the warming is projected 14 to be 7.7 °F ± 1.3 °F (4.3 °C ± 0.7 °C) (Collins et al. 2013). 15 Analysis of GCM projections for Oregon and Washington (Mote et al. 2014) and 16 northern California (Cayan et al. 2008, Garfin et al. 2014) depict a possible future with 17 significant warming by the end of the 21st century. In Oregon and Washington, simulation results 18 project 4.3 °F (2.4 °C) and 5.8 °F (3.2 °C) increases in annual average temperature by the 19 middle of the century (2041 to 2070) under RCP4.5 and RCP8.5 scenarios, respectively (Dalton 20 et al. 2013). By the end of the century (2070 to 2099), the degree of warming is projected to be 21 5.9 °F (3.3 °C) to 17.5 °F (9.7 °C), depending on the scenario (Mote et al. 2014). Comparable 22 degrees of warming are projected to occur across the four seasons (Dalton et al. 2013). Projected 23 changes in precipitation are more uncertain, with some models projecting a 10-percent decrease 24 in annual precipitation by 2070 to 2099 and others projecting as much as an 18-percent increase 25 in precipitation (Mote et al. 2014). Models generally project wetter winters and drier summers 26 (Dalton et al. 2013). Under RCP8.5, most of Oregon and Washington are projected to depart 27 from their historical climate regime by 2050 when the mean annual temperature of a given 28 location will exceed the 20th century range of variability (Kerns et al. 2016). No-analog 29 temperature and precipitation conditions are projected across much of the western Cascades 30 compared with those occurring in the recent past (Saxon et al. 2005).

Peer Review Draft 10/19/16 “THIS INFORMATION IS DISTRIBUTED SOLELY FOR THE PURPOSE OF PRE-DISSEMINATION PEER REVIEW UNDER APPLICABLE INFORMATION QUALITY GUIDELINES. IT HAS NOT BEEN FORMALLY DISSEMINATED BY [THE AGENCY]. IT DOES NOT REPRESENT AND SHOULD NOT BE CONSTRUED TO REPRESENT ANY AGENCY DETERMINATION OR POLICY.” 1 In northern California, analyses of climate change projections are available for an older 2 version of climate change scenarios: the B1 and A2 scenarios, which are most closely analogous 3 to RCP4.5 and RCP8.5, respectively. Under the sustainability-oriented B1 scenario, annual 4 temperature is projected to increase by 2.7 °F (1.5 °C) by 2100, and under the high growth A2 5 scenario, the increase is projected to be 8.1 °F (4.5 °C) (Cayan et al. 2008). Simulations depict 6 drier futures under the B1 and A2 scenarios, with annual total precipitation decreasing by 18 7 percent in the more extreme A2 scenario (Cayan et al. 2008). Increases in temperature are 8 projected for all season across northern California, with the greatest increases occurring during 9 the summer months (Cayan et al. 2008). Projected decreases in summer precipitation range from 10 4 to 68-percent while projected change during winter months range from a 9-percent decrease to 11 a 4-percent increase. More recent projections of increases in winter precipitation using the 12 RCP8.5 scenario show a high degree of agreement (Neelin et al. 2013). Interannual variability is 13 expected to increase with the occurrence of greater wet and dry extremes during the wet season 14 (Berg and Hall 2015). Most of California is projected to depart from its 20th century climate by 15 the year 2040 (Kerns et al. 2016). As with the western Cascades, the projected future climate for 16 the Klamath Mountains represents conditions of temperature and precipitation with no analog in 17 the recent past (Saxon et al. 2005). Temperature is projected to depart the 20th century range of 18 variability between 2046 and 2065 under the A2 scenario (Klausmeyer et al. 2011). 19 20 Implications of Observed Climate Trends for Vegetation Change 21 Changes in temperature and precipitation will most likely affect vegetation by altering the 22 availability of water in the soil through changes in the amount and timing of precipitation. 23 Cumulatively, these will be expressed ecologically through deficits in water balance. This deficit 24 is defined as the difference between potential evaporation and actual evapotranspiration 25 (Stephenson 1998). Ecologically, water-balance deficit equates to the difference between the 26 atmospheric demand for water from vegetation and the amount of water that is actually available 27 to use. Projections for changes in water-balance deficit vary among models (Littell et al. 2016) 28 and across the region (fig. 5). The eastern Cascades, Klamath Mountains, and southern portion of 29 the western Cascades in Oregon are likely to become drier (i.e., have the greatest increases in 30 water-balance deficit). The least amount of change is projected in the northern portions of the

3 4 Figure 5—Projected changes in summer (June, July, August, and September) water balance 5 deficit across the Northwest Forest Plan area for 2030-2059 from a composite of the ten best 6 GCM scenarios (CMIP3/AR4) following Littell et al. (2016). Higher water balance deficit

Peer Review Draft 10/19/16 “THIS INFORMATION IS DISTRIBUTED SOLELY FOR THE PURPOSE OF PRE-DISSEMINATION PEER REVIEW UNDER APPLICABLE INFORMATION QUALITY GUIDELINES. IT HAS NOT BEEN FORMALLY DISSEMINATED BY [THE AGENCY]. IT DOES NOT REPRESENT AND SHOULD NOT BE CONSTRUED TO REPRESENT ANY AGENCY DETERMINATION OR POLICY.” 1 (browns) means decreased water available for plant uptake. Change is compared to water- 2 balance deficit from 1916 to 2006. 3 4 Decreases in the proportion of precipitation falling as snow (Klos et al. 2014), the amount 5 of water contained in spring snowpack (snow water equivalent) (Hamlet et al. 2005), and 6 increased evapotranspiration from longer growing seasons has increased water deficits since the 7 1970s (Abatzoglou et al. 2014a). The effects of increases in winter temperature are expected to 8 drive decreases in snowpack and earlier snowmelt which will alter stream flow timing (Stewart 9 et al. 2004, Stewart et al. 2005, Hamlet et al. 2005, Jung and Chang 2011). Remote-sensing 10 studies suggest most vegetation zones have already experienced stress associated with drought 11 and high temperatures during the early 21st century (Asner et al. 2015, Mildrexler et al. 2016). 12 Given projected changes in temperature, the cumulative effects of these trends will result in a 13 further reduction in the availability of soil water during the growing season (Elsner et al. 2010). 14 While trends in average temperature and precipitation provide some context for 15 vegetation change in the future, individual events may also be drivers of future dynamics 16 (Jentsch et al. 2007). Climate extremes (e.g., acute drought) related to changes in the variability 17 of temperature and precipitation may have disproportionate effects on vegetation and result in 18 rapid vegetation change (e.g., Allen and Breshears 1998). Increased frequency and intensity of 19 heat waves and extreme temperatures are predicted across North America by the end of the 21st 20 century (Meehl and Tebaldi 2004). Prolonged heatwaves (Bell et al. 2004) as well as dry daytime 21 and humid nighttime heatwaves are projected in northern California (Gurshunov and Guirguis 22 2012). Models project increases in the number of both dry days and very heavy precipitation 23 days during the wet season in northern California (October to March) (Berg and Hall 2015). 24 Increases in peak flow magnitudes also suggest greater potential for flooding in portions of 25 inland northern California (Das et al. 2013) where floods could be more frequent and severe 26 (Dettinger 2011). Heavy precipitation events from warming and shifts in seasonal precipitation 27 patterns may also increase flooding in Oregon and Washington (Tohver et al. 2014) and the 28 northern California Coast Range (Kim 2005). 29 Considering the coarse resolution of climate projections, it is important to recognize the 30 potential for landscape scale variability in future climate change. Differences in vegetation 31 structure and topography can drive fine-scale variation in temperature extremes, with differences

15 The effects of climate change and increased levels of atmospheric CO2 on vegetation dynamics 16 may occur through a variety of mechanisms at a range of spatial scales and levels of biological 17 organization, from the physiological responses of individuals to the composition and structure of 18 stand and landscapes (Peterson et al. 2014). The direct effects of climate change and increasing

19 CO2 on vegetation are likely to be expressed through changes in growth, reproduction, and 20 mortality. The indirect effects of climate change will be expressed through increases in the 21 frequency and extent of disturbances, particularly fire and insects. These are predicted to be a 22 greater driver of ecological change than direct effects (Littell et al. 2010). The relative 23 importance of these drivers, however, is likely to vary across the region among species, seral 24 stages, and physiographic provinces. Species are expected to respond individualistically to future 25 changes in climate as they have in the past (e.g., Whitlock 1992). 26 The response of tree growth to climate change varies substantially as limiting factors 27 (e.g., water, growing season length) may vary among species and across the range of individual 28 species (Peterson and Peterson 2001, Littell et al. 2010). Growth in Douglas-fir is predicted to 29 decrease where it is currently water limited (Restaino et al. 2016), but may increase in areas 30 where it is limited by the length of the growing season or lower than optimal temperature (Littell 31 et al. 2008, Littell et al. 2010). In species of higher elevation forests where growth is limited by

6 species (e.g., ponderosa pine) may further vary depending on the potential for CO2 to enhance

7 growth by increasing water-use efficiency (Soule and Knapp 2006). Increased levels of CO2 8 have the potential to accelerate maturation and increase seed production (LaDeau and Clark 9 2001, LaDeau and Clark 2006), but little information is available within the region on the effects 10 of climate change on reproduction. 11 The ability of a species to track changes in climate (e.g., earlier warming and drying) 12 with shifts in phenology will be an important factor in determining responses to projected 13 climate change. A major concern in the NWFP area associated with warmer winters and earlier 14 springs is the requirement for many species (e.g., Douglas-fir, western hemlock, Pinus spp, Abies 15 spp.) to experience chilling required for budburst (Harrington and Gould 2015). Douglas-fir may 16 experience earlier budburst in some portions of its range due to warming, but reduced chilling 17 may cause later budburst in the southern portion of its range (Harrington and Gould 2015). 18 Earlier growth in northern and higher elevation portions of the range Douglas-fir may lead to 19 earlier growth initiation, but reduced chilling in the southern and lower elevation portions of its 20 range are likely to lead to delayed growth initiation (Ford et al. 2016). 21 Biotic interactions are also likely to affect dynamics related to climate change in complex 22 ways, but are currently poorly understood with the exception of several recent studies from 23 higher elevation wet forests in Washington. The negative effect of competition on growth is 24 likely to be greater for saplings than for adults and climate change may have less effect on lower 25 elevation closed-canopy forests (Ettinger and HillesRis Lambers 2013). Individual growth is 26 likely to increase most in lower density stands as trees may show little response to climate at 27 higher density (Ford et al. In Press). There is little known regarding the effects of climate change 28 on positive effects of species interactions (e.g., facilitation) though they can be important in 29 stressful environments (Callaway et al. 2002) and are thought to play a role in early stand 30 development in dry and cold vegetation zones in the NWFP area (Reilly and Spies 2015). 31

Peer Review Draft 10/19/16 “THIS INFORMATION IS DISTRIBUTED SOLELY FOR THE PURPOSE OF PRE-DISSEMINATION PEER REVIEW UNDER APPLICABLE INFORMATION QUALITY GUIDELINES. IT HAS NOT BEEN FORMALLY DISSEMINATED BY [THE AGENCY]. IT DOES NOT REPRESENT AND SHOULD NOT BE CONSTRUED TO REPRESENT ANY AGENCY DETERMINATION OR POLICY.” 1 Tree mortality— 2 Tree mortality from higher temperatures and drought stress may increase in the 21st century, with 3 many effects already manifest at the end of the 20th century. Mortality rates in old-growth forests 4 of the region have increased since the mid-1970s (van Mantgem et al. 2009). A regional study on 5 mortality rates on Forest Service lands in Oregon and Washington corroborated the occurrence 6 of high mortality rates in old-growth forests from the mid-1990s to mid-2000s during region- 7 wide drought (Reilly and Spies 2016). However, Acker et al. (2015) found that mortality rates in 8 old-growth forests on National Park Service lands in western Washington were lower than those 9 in both van Mantgem et al. (2009) and Reilly and Spies (2016) from 2008 to 2013. This could be 10 due to geographic variation not represented in van Mantgem et al. (2009) and Reilly and Spies 11 (2016), but may also be indicative of decreasing stress related mortality which appears to have 12 peaked in the mid-2000s (Cohen et al. 2016) during the warmest decade the region has 13 experience in the past 100 years (Abatzoglou et al. 2014a). Greater increases in mortality in 14 younger stands have been documented in other regions and suggest that younger stands may be 15 more vulnerable to changes in climate (Luo and Chen 2013). However, Reilly and Spies (2016) 16 found that mortality rates in early and mid-seral stages from the mid-1990s to mid-2000s were 17 lower than the few existing ecological studies of mortality in younger forests of the region (Lutz 18 and Halpern 2006, Larson et al. 2016). With the exception of old-growth forests where increased 19 mortality led to cumulative losses in basal area and density (van Mantgem et al. 2009), there is 20 currently poor understanding of the effects of recent mortality on stand structure and 21 composition. 22 23 Fire and area burned— 24 The indirect effects of climate change expressed through increases in the frequency and extent of 25 disturbances, particularly fire and insects, are predicted to be an increasing driver of ecological 26 change in the future (Littell et al. 2010). Increases in the frequency and extent of fire since the 27 mid-1980s have been attributed to longer fire seasons associated with earlier snowmelt and 28 warmer spring and summer temperatures (Westerling et al. 2006) as well as drought (Littell et al. 29 2009). The effects of recent fires have been extremely variable across the region, with most 30 occurring in the Klamath, the Eastern Cascades, and the western Cascades of Oregon (fig. 6). 31 The annual area burned has increased in most vegetation zones since the mid-1980s, but most

1 2 Figure 6—Cumulative patterns of fire severity from 1985 to 2010 in the Northwest Forest Plan 3 area. Figure following Reilly et al. In Review. 4 5 A number of studies project increases in area burned in the region during the 21st century, 6 but projections vary considerably across the NWFP area. Stavros et al. (2014) found that the 7 probability of very large fires will increase based on climate projections for Oregon and 8 Washington, but increases are minor in northern California. McKenzie et al. (2004) used 9 statistical models and found that an increase in temperature of 2 °C will increase fire extent by

Peer Review Draft 10/19/16 “THIS INFORMATION IS DISTRIBUTED SOLELY FOR THE PURPOSE OF PRE-DISSEMINATION PEER REVIEW UNDER APPLICABLE INFORMATION QUALITY GUIDELINES. IT HAS NOT BEEN FORMALLY DISSEMINATED BY [THE AGENCY]. IT DOES NOT REPRESENT AND SHOULD NOT BE CONSTRUED TO REPRESENT ANY AGENCY DETERMINATION OR POLICY.” 1 1.4 to 5 times for many western states, including Oregon, Washington, and California. Using a 2 similar statistical approach, Littell et al. (2010) found that area burned is likely to increase from 2 3 to 3 times across Washington by the end of the 2040s. They also found that area burned in the 4 western Cascades of Washington is expected to increase by more than eight times, but on 5 average will still affect only a small extent (9,100 acres) of the ecoregion by the 2080s. Turner et 6 al. (2015) project increase in area burned from 3 to 9 times in a portion of the central western 7 Cascades of Oregon. Krawchuck et al. (2009) also predict increases in fire probability in the 8 western Cascades. Barr et al. (2010) project increase in annual fire extent of 11-22% in the 9 Klamath Basin by 2100. 10 There are few statistical predictions for wetter maritime forests because of the lack of 11 recent area burned (Littell et al. 2010). Liu et al. (2012) projected increases in fire potential 12 associated with warming and drought, but depict substantial ecoregional variability from 2014 to 13 2070. Fried et al. (2004) suggest a decrease of 8 percent in area burned by contained fires along 14 the north coast of California, and Krawchuck et al. (2009) also project a decrease in area burned 15 in coastal forests over the 21st century. Liu et al. (2012), however, predict an increase in fire 16 potential from 2.5 to 5 times due to changes in fire weather in coastal forests. Westerling et al. 17 (2011) project 300 percent increases in area burned in coastal and interior northwestern 18 California. Rogers et al. (2011) used a mechanistic vegetation model (MC1) that integrates fire 19 and suppression efforts, and found increases in area burned in Oregon and Washington from 76 20 to 310 percent by 2070 to 2099. 21 22 Insects and pathogens— 23 Future climate change is expected to exacerbate the effects of insects and pathogens in forests 24 (Dale et al. 2001, Bentz et al. 2010, Kolb et al. In Press). Several native and invasive insects and 25 diseases exist in the Northwest Forest Plan area (see Shaw et al. 2009 for more information on 26 identification and management). Biotic disturbances (e.g., insects and pathogens) elevate 27 mortality above background rates, associated competition and stand development, but rarely 28 reach the mortality levels that occur in fire (Reilly and Spies 2016). Even if insects and 29 pathogens do not result in immediate tree mortality, the resulting decline in tree growth and vigor 30 (Hansen and Goheen 2000, Marias et al. 2014) may initiate the long process of mortality 31 (Manion 1981) and predispose trees to stem breakage (Larson and Franklin 2010). Insects are of

Peer Review Draft 10/19/16 “THIS INFORMATION IS DISTRIBUTED SOLELY FOR THE PURPOSE OF PRE-DISSEMINATION PEER REVIEW UNDER APPLICABLE INFORMATION QUALITY GUIDELINES. IT HAS NOT BEEN FORMALLY DISSEMINATED BY [THE AGENCY]. IT DOES NOT REPRESENT AND SHOULD NOT BE CONSTRUED TO REPRESENT ANY AGENCY DETERMINATION OR POLICY.” 1 concern in the drier portions of the Klamath Mountains and have affected dry forests in the 2 eastern and northern Cascades in recent decades (Meigs et al. 2015, Hicke et al. 2016), but are 3 less prevalent in wet forests west of the Cascades where pathogens play a more prominent role 4 (Reilly and Spies 2016). Despite concern that insect outbreaks may exacerbate fire effects, there 5 is a growing body of literature within the region and across the Western United States indicating 6 that the two disturbances are not positively linked (Hart et al. 2015, Meigs et al. 2015), and that 7 pre-fire insect activity does not make fires more severe (Simard et al. 2011, Harvey et al. 2013, 8 Agne et al. 2016, Meigs et al. 2016, Reilly and Spies 2016). 9 The role of insects and pathogens is likely to increase as trees become more stressed, but 10 effects are uncertain (Chmura et al. 2011) and differ among species. Swiss needle cast 11 (Phaeocryptopus gaeumannii) is a disease specific to Douglas-fir. Ritokova et al. (2016) found 12 that the area affected by Swiss needle cast more than tripled between 1996 and 2015 with growth 13 reductions of 23 percent in the Oregon Coast Range. Swiss needle cast is predicted to increase in 14 the Oregon Coast Range in response to warmer and wetter conditions in the future (Stone et al. 15 2008). Douglas-fir is also susceptible to Douglas-fir beetle (Dendroctonus psuedotsugae), 16 especially after blowdown from wind events (Powers et al. 1999). White pine blister rust 17 (Cronartium ribicola) and mountain pine beetles (Dendroctonus ponderosae) are threats to 18 whitebark pine (Pinus albicaulis) (Goheen et al. 2002, Ward et al. 2006) as well as both western 19 white pine (Pinus monitcola) and sugar pine (Pinus lambertiana) (Goheen and Goheen 2014). 20 Decline of Pacific madrone (Arbutus menziesii) related to multiple fungal diseases has been 21 reported in over the past 30 years with larger older trees experiencing the most mortality (Elliott 22 et al. 2002). Balsam woolly adelgid (Adelges piceae) has affected subalpine fir and especially 23 grand fir at lower elevations west of the Cascades (Mitchell and Buffam 2001). 24 Invasive pathogens may be of particular concern especially in southwestern Oregon and 25 northwestern California. Sudden oak death (Phytophthora ramorum) has the potential to spread 26 through air, water, and infected plant material (Rizzo and Garbelloto 2003) and may affect 27 tanoak, various species of oak (e.g., California black oak), other hardwood species [e.g., 28 madrone (Arbutus menziessii), bigleaf maple (Acer macrophyllum)], and several species of 29 shrubs (e.g., Rhododendron spp.). The area affected by sudden oak death is predicted to increase 30 tenfold by the 2030s under the projected milder and wetter conditions (Meentemeyer et al. 2011). 31 Sudden oak death has also been linked with increased fire severity effects on soils in

Peer Review Draft 10/19/16 “THIS INFORMATION IS DISTRIBUTED SOLELY FOR THE PURPOSE OF PRE-DISSEMINATION PEER REVIEW UNDER APPLICABLE INFORMATION QUALITY GUIDELINES. IT HAS NOT BEEN FORMALLY DISSEMINATED BY [THE AGENCY]. IT DOES NOT REPRESENT AND SHOULD NOT BE CONSTRUED TO REPRESENT ANY AGENCY DETERMINATION OR POLICY.” 1 northwestern California (Metz et al. 2011). Port Orford cedar (Chamaecyaparis lawsoniana) is 2 susceptible to a lethal, nonnative root pathogen (Phytophthora lateralis) that may be spread over 3 long distances via organic matter carried on boots, vehicles, and animal hooves (Hansen et al. 4 2000, Jules et al. 2002). Recent work suggests that despite rapid initial spread and colonization 5 of Phytophthora lateralis, the rate of spread has slowed greatly since 2000 (Jules et al. 2014). 6 7 Cumulative Effects on Species’ Distributions and Range Shifts— 8 The cumulative effects of changes in mortality, growth, and recruitment will ultimately be 9 manifest in shifts in species’ distributions and ranges. Range expansion occurs through migration 10 and colonization at the upper limits or “leading edge” of a species’ distribution and is controlled 11 through by fecundity and dispersal (Thuller et al. 2008). Thus, more vagile species producing 12 more seeds with a greater ability to disperse further may have greater potential to track climate 13 change than those with poor dispersal ability. Range contraction will occur through local 14 extinction at the lower limits or “trailing edge” of a species range and is related to the ability of a 15 species’ to persist. Individuals at the trailing edge may thus play an important role as refugia for 16 genetic diversity (Hampe and Petit 2005). Although local extinction may occur throughout the 17 range of species, small, isolated populations at the trailing edge may be particularly vulnerable as 18 the climate changes rapidly (Davis and Shaw 2001). 19 It is likely that species that are more adapted to cold environments will be more sensitive 20 to climate change at their lower limits (i.e. elevation/latitude), while expansion of species 21 adapted to warmer conditions is expected at upper range limits (i.e. high elevation/latitude) 22 (HillesRisLambers et al. 2015). Warmer temperatures are likely to lead to range expansion at the 23 leading edge for some species at tree line, but not necessarily for species in closed canopy forests 24 at lower elevations (Ettinger et al. 2011, Ettinger and HilleRisLambers 2013). However, 25 expansion at upper range limits may be limited by dispersal and low abundance of adult trees 26 that produce seed (Kroiss and HilleRisLambers 2015). Warmer temperatures may increase 27 germination and survival of seedlings, as well as increase sapling growth rates (Ettinger et al. 28 2011, Ettinger and HilleRisLambers 2013, HillesRisLambers et al. 2015), but many tree species 29 are long-lived and may exhibit lagged responses in terms of range shifts (Kroiss and 30 HillesRisLambers 2015).

Peer Review Draft 10/19/16 “THIS INFORMATION IS DISTRIBUTED SOLELY FOR THE PURPOSE OF PRE-DISSEMINATION PEER REVIEW UNDER APPLICABLE INFORMATION QUALITY GUIDELINES. IT HAS NOT BEEN FORMALLY DISSEMINATED BY [THE AGENCY]. IT DOES NOT REPRESENT AND SHOULD NOT BE CONSTRUED TO REPRESENT ANY AGENCY DETERMINATION OR POLICY.” 1 A common approach to detecting range shifts is comparing current distributions of 2 mature trees and seedlings. Juveniles (and seedlings specifically) with limited root systems and 3 smaller reserves of carbon are more vulnerable to mortality from drought and temperature 4 extremes (Jackson et al. 2009). Monleon and Lintz (2015) found evidence of tree range shifts in 5 California, Oregon, and Washington where the range of seedlings was 0.22 °F (0.12 °C) colder 6 than that of adult trees, and seedlings had higher mean elevation and latitude than mature trees 7 for most species. Results also suggested that overall, distributions of individual species 8 remained relatively stable, but most species may become more abundant towards the colder edge 9 of their range and distributions changed the least at the warm end. Some of the more common 10 tree species with seedlings found at significantly higher temperatures included western red cedar 11 (Thuja plicata), silver fir, western hemlock, grand fir, and mountain hemlock. 12 Thus far, individual tree species have shown differential responses to recent warming and 13 it is likely that not all tree species will respond the same to projected future changes in climate 14 (Davis and Shaw 2001). Lintz et al. (2016) examined recent changes in basal area and density of 15 twenty-two tree species on unburned Forest Service lands in Oregon and Washington. Several 16 species had stable populations including noble fir (Abies procera), western red cedar, western 17 hemlock, ponderosa pine, and Douglas-fir. These findings are consistent with HilleRisLambers 18 et al. (2015) who suggest that compositional change in the near term will be slow in higher 19 elevation wet forests of the region. The greatest levels of mortality in Lintz et al. (2016) occurred 20 in western white pine, whitebark pine, Pacific madrone, subalpine fir, lodgepole pine (Pinus 21 contorta), grand fir, Engelmann spruce (Picea engelmanii), and western yew (Taxus brevifolia). 22 23 Vegetation Models and Potential Future Change 24 Several types of simulation models have been used to predict vegetation responses to potential 25 future climate scenarios, each with unique assumptions, strengths, and weaknesses (see Peterson 26 et al. 2014 for a more in-depth review). Models simplify the complexity of processes by making 27 assumptions that are ideally based on empirical measurements. However, because empirical data 28 are often only available for a few species at a few geographic locations, models are most often 29 are based on applications of theory. As a result, the best use of models may be for understanding 30 variability in the magnitude of effects as opposed to predicting specific outcomes (Jackson et al. 31 2009, Littell et al. 2011).

Peer Review Draft 10/19/16 “THIS INFORMATION IS DISTRIBUTED SOLELY FOR THE PURPOSE OF PRE-DISSEMINATION PEER REVIEW UNDER APPLICABLE INFORMATION QUALITY GUIDELINES. IT HAS NOT BEEN FORMALLY DISSEMINATED BY [THE AGENCY]. IT DOES NOT REPRESENT AND SHOULD NOT BE CONSTRUED TO REPRESENT ANY AGENCY DETERMINATION OR POLICY.” 1 Some of the most common models used to project the effects of climate change can be 2 generally characterized as species distribution models, dynamic global vegetation models 3 (DGVM), and biogeochemical models. Species distribution models are statistical models based 4 on empirical observations of the relationship between a species occurrence and the underlying 5 environment or bioclimatic envelope. DGVMs are a type of process model that predict 6 ecosystem processes along with the distribution of specific biomes or plant function groups. 7 Biogeochemical models are also process models but focus more specifically on carbon, water, 8 and nutrient cycles and have primarily been used to investigate the effects of climate change on 9 productivity and carbon storage. Results from several modeling studies suggest the potential for 10 a wide range of responses to future climate scenarios among species and across the region, which 11 are synthesized and discussed in depth by Peterson et al. (2014) (see Chapter 8). 12 Some studies project persistence of cool, maritime forests in western Oregon and 13 Washington (Rogers et al. 2011, Shafer et al. 2015, Turner et al. 2015), but most species in 14 lower-elevation, moist vegetation zones are predicted to have less suitable climatic conditions 15 than currently by the mid-21st century. The greatest changes are projected for the south and 16 western part of the region with less change in the north and in the western Cascades (Hargrove 17 and Hoffman 2005, Rehfeldt et al. 2006, Crookston et al. 2010, McKenney et al. 2007, 18 McKenney et al. 2011). Turner et al. (2015) found that the dominant vegetation type in a portion 19 of the central western Cascades of Oregon remained forest by 2100, but projected a transition 20 from evergreen needleleaf forest to a mixture of broadleaf and needleaf growth forms. Latta et al. 21 (2010) suggest annual growth increases of 2 to 7-percent west of the Cascades depending on 22 scenario, while DGVM results vary with some projecting moderate to extreme decreases (Rogers 23 et al. 2011), and others projecting little to slight decreases in growth (Coops and Waring 2011a). 24 Shafer et al. (2015) suggest that growth may decrease in the southwestern part of the region, but 25 overall there is little model agreement on future dynamics in low-elevation moist forests. 26 Multiple species distribution models project that high-elevation vegetation zones will 27 experience the greatest change within the region with moderate to total reductions in suitable 28 climate by the end of the 21st century (Hargrove and Hoffman 2005, Rehfeldt et al. 2006, 29 Crookston et al. 2010, McKenney et al. 2007, McKenney et al. 2011, Halofsky et al. 2013, 30 Scahfer et al. 2015, Mathys et al. 2016). Several model projections agree and suggest that 31 suitable climate for subalpine fir will only be available in the northern Cascades (Rogers et al.

Peer Review Draft 10/19/16 “THIS INFORMATION IS DISTRIBUTED SOLELY FOR THE PURPOSE OF PRE-DISSEMINATION PEER REVIEW UNDER APPLICABLE INFORMATION QUALITY GUIDELINES. IT HAS NOT BEEN FORMALLY DISSEMINATED BY [THE AGENCY]. IT DOES NOT REPRESENT AND SHOULD NOT BE CONSTRUED TO REPRESENT ANY AGENCY DETERMINATION OR POLICY.” 1 2011, Coops and Waring 2011a), but Coops and Waring (2011a) project an increase in climate 2 suitability for mountain hemlock in Oregon. Multiple studies predict large decreases in the 3 distribution of lodgepole pine by the 2100s (Coops and Waring 2011b, Mathys et al. 2016). In 4 general, there is more model agreement for subalpine forests than for other vegetation types, and 5 most suggest that suitable climate will likely be reduced except in the northern Cascades. 6 Model projections for vegetation change in dry coniferous forests in the southern and 7 eastern parts of the region show little agreement. Species distribution models suggest decreases 8 in suitable climate for ponderosa pine, while some DGVMs project increases or only slight 9 changes in temperate coniferous forests (Coops et al. 2005, Rogers et al. 2011, Halofsky et al. 10 2013) and others project decreases (Coops and Waring 2011a). Halofsky et al. (2014) suggest 11 that while the area of dry mixed-conifer is expected to increase from 21 to 26-percent by 2100, 12 the area of moist mixed conifer is expected to decrease 36 to 60-percent. Shafer et al. (2015) 13 project expansion of woodland vegetation during the 21st century. Due to the lack of agreement 14 on vegetation change among model projections, caution should be used when interpreting these 15 results (Peterson et al. 2014). 16 In northern California, the projected changes of most scenarios include losses of 17 evergreen conifer forests and increases in mixed evergreen forest primarily due to increased fire 18 activity (Lenihan et al. 2008). Mathys et al. (2016) project that Douglas-fir will be stressed in 19 across almost all of northern California. Increases are projected in the hardwood component, 20 shrublands, and grasslands, particularly throughout the eastern and drier areas. Barr et al. (2010) 21 project that the upper Klamath River basin will support primarily grassland in place of sagebrush 22 and juniper by 2100. In the lower basin (California), conditions suitable for hardwood forests 23 (oaks, tanoak, madrone, etc.) are projected to expand while those suitable for conifer-dominated 24 forests are projected to contract. Results from Kueppers et al. (2005) primarily suggest expansion 25 and persistence of current populations of valley oak (Quercus lobata). Expansion and persistence 26 of blue oak (Quercus douglasii) is projected in the northern part of its range, but projections 27 primarily suggest range contraction towards the southern portion of northern California. 28 29 Other Vulnerabilities 30 Invasions of exotic species have the potential to alter vegetation dynamics, soil properties 31 (Caldwell 2006, Slesak et al. 2016), and disturbance regimes (Brooks et al. 2004). Most invasive

Peer Review Draft 10/19/16 “THIS INFORMATION IS DISTRIBUTED SOLELY FOR THE PURPOSE OF PRE-DISSEMINATION PEER REVIEW UNDER APPLICABLE INFORMATION QUALITY GUIDELINES. IT HAS NOT BEEN FORMALLY DISSEMINATED BY [THE AGENCY]. IT DOES NOT REPRESENT AND SHOULD NOT BE CONSTRUED TO REPRESENT ANY AGENCY DETERMINATION OR POLICY.” 1 plant species were initially introduced for horticultural uses, erosion control, or in contaminated 2 crop seed (Reichard and White 2001). Gray (2008) used a systematic inventory of forest health 3 monitoring plots and found that over 50 percent of plots in almost all ecoregion in the NWFP 4 area had non-native species present. Most common invasive plants are associated with 5 management (e.g. cleacuts, thinning), though there is potential for spread of some shade tolerant 6 shrubs in undisturbed forests (Gray 2005). There is also evidence from the region that roads 7 facilitate the spread of invasive plants (Parendes and Jones 2000, Rubenstein and Dechaine 8 2015). Little information is available on trends in the abundance of invasive plants, but 9 increasing temperatures may favor exotic species, especially grasses in California (Sandel and 10 Dangremond 2012). Warm, dry sites with increased topographic exposure may be particularly 11 vulnerable to exotic species following high-severity wildfire (Dodson and Root 2015). Gray et 12 al. (2011) provide a field guide and prioritized list of invasive plants along range maps that 13 covers the entire Northwest Forest Plan area. More information on management of invasive 14 species is also available in Harrington and Reichard (2007). 15 Narrowly distributed species (e.g., rare and threatened, endemics) that specialize in 16 uncommon or sparsely distributed habitat (e.g., serpentine soils, montane meadows) are expected 17 to have difficulty responding to changing climatic conditions. Damschen et al. (2010) found 18 decreases in the richness and cover of endemics on serpentine soils in southwest Oregon that 19 were consistent with a warming climate from the 1950s to early 2000s. Harrison et al. (2010) 20 found changes in forest herb communities that were also consistent a drier climate including 21 lower cover of species with northern affinities and greater compositional similarity to 22 communities on southerly aspects. Loarie et al. (2008) projected that two-thirds of California’s 23 native flora will experience more than an 80-percent reduction in range size by 2100. If warming 24 climatic trends are accompanied by drying during the growing season, mesic topographic 25 microclimates are likely to become increasingly important microrefugia (Dobrowski 2011, Olson 26 et al. 2012, van Mantgem and Sarr 2015). Montane wetlands may be especially at risk to 27 reductions in water levels, shorter hydroperiods, and increased drying (Lee et al. 2015). 28 29 Adaptation to and Mitigation of Key Vulnerabilities 30 Adaptation and mitigation are two options when planning for the effects of climate change 31 (Millar et al. 2007). Adaptation options include management actions at stand and landscape

Peer Review Draft 10/19/16 “THIS INFORMATION IS DISTRIBUTED SOLELY FOR THE PURPOSE OF PRE-DISSEMINATION PEER REVIEW UNDER APPLICABLE INFORMATION QUALITY GUIDELINES. IT HAS NOT BEEN FORMALLY DISSEMINATED BY [THE AGENCY]. IT DOES NOT REPRESENT AND SHOULD NOT BE CONSTRUED TO REPRESENT ANY AGENCY DETERMINATION OR POLICY.” 1 scales to reduce vulnerabilities. Halofsky and Peterson (2016) provide a recent synthesis and 2 review of adaptation options that we summarize in Table 1. The scientific basis of these 3 proposed actions is primarily based on well-established theory and we are not aware of any 4 empirical studies in this NWFP area that document how well these actions might address climate 5 change concerns. Strategies are thought to be similar across physiographic provinces, thus there 6 may be a limited number of available options. They provide a summary of an extensive list of 7 vulnerabilities and corresponding strategies and tactics that were identified and developed 8 through a series of science-management partnerships across the Northwestern United States 9 (available online: http://adaptationpartners.org/library.php). 10 11 Adaptation— 12 Manipulation of stand and landscape structure is assumed to increase resistance and 13 resilience to future vulnerabilities associated with drought and disturbance (e.g., fire, insects) 14 (Spies et al. 2010, Hessburg et al 2015). Thinning to reduce stand density is an adaptation option 15 to increase resilience to moisture stress, fire, and insects. Findings from other regions support the 16 use of thinning as an option to increase soil water availability, reduce growing season moisture 17 stress, and improve vigor in older trees (McDowell et al. 2003, McDowell et al. 2006), but the 18 NWFP area is lacking studies on this topic. Prescribed fire has also been found to increase 19 resistance to drought in dry forests of other regions (van Mantgem et al. 2016). Thinning has 20 effectively been used and reduced fire severity in dry forests of the region (Prichard et al. 2010), 21 and other regions in the western United States (Wimberly et al. 2009). A general principle for 22 thinning to reduce fire severity includes maintaining older trees of fire-tolerant species, reducing 23 understory density, and increasing height to live crowns (Agee and Skinner 2005). Landscape- 24 scale treatments that restore heterogeneity in places where historical fire regimes were 25 interrupted have been proposed as a way to reduce vulnerability to high-severity fire and 26 extensive pathogen and insect outbreaks (Hessburg et al. 2015). Increasing landscape 27 heterogeneity is thought to impede the spread of contagious disturbances (e.g., fire, insects), but 28 empirical evidence supporting this is currently lacking. 29 30 31

Peer Review Draft 10/19/16 “THIS INFORMATION IS DISTRIBUTED SOLELY FOR THE PURPOSE OF PRE-DISSEMINATION PEER REVIEW UNDER APPLICABLE INFORMATION QUALITY GUIDELINES. IT HAS NOT BEEN FORMALLY DISSEMINATED BY [THE AGENCY]. IT DOES NOT REPRESENT AND SHOULD NOT BE CONSTRUED TO REPRESENT ANY AGENCY DETERMINATION OR POLICY.” - Maintain connectivity for natural spp. migration Exotic Species Increase control - Early detection/ rapid response / frequent efforts inventory - Interagency coordination 1 2 Assisted migration of genotypes and species that are adapted to future climate scenarios 3 may improve resilience of species that may not be able to migrate, but this is controversial and 4 poorly understood (Marris 2009). Coastal Douglas-fir populations in particular have been 5 identified to being genetically “maladapted” to future climates in Oregon and Washington (St. 6 Clair and Howe 2007). Bansal et al. (2015) found that populations of Douglas-fir from cooler 7 climates had greater resistance to drought, contrary to expectations. Populations from areas with 8 relatively cool winters and dry summers are more tolerant to drought and cold and may be the 9 best adapted to future climate conditions (Bansal et al 2016). There is little information available 10 from other species from the region, though a study from Arizona found that ponderosa pine 11 seedlings that originated from low elevation, drier sites survived the longest during drought 12 (Kolb et al. In Press). 13 An alternative to assisted migration involves increasing connectivity by establishing 14 corridors, or facilitating the flow of organisms through the matrix of unsuitable habitat (Krosby 15 et al. 2010, Nunez et al. 2013). However, even increasing connectivity may be insufficient for 16 those species that are unable to migrate as rapidly as the climate changes (Dobrowski et al. 17 2013). Planning and monitoring are also essential for adaptation and can help identify refugia, 18 coordinate planning across jurisdictions and ownerships, and revise management goals and 19 objectives to be consistent with the uncertainty that accompanies climate change (Spies et al. 20 2010). 21 Mitigation— 22 Mitigation includes efforts to increase carbon sequestration in forest ecosystems and provide new 23 energy efficient products and technologies for society. Forests in the NWFP area have great 24 potential to store large amounts of carbon in both live and dead biomass (Smithwick et al. 2002). 25 Total carbon stores vary among ecoregions (fig. 7) as a result of productivity and disturbance 26 (Law et al. 2004). Recent findings suggest that forests on USFS lands in Oregon and Washington

Peer Review Draft 10/19/16 “THIS INFORMATION IS DISTRIBUTED SOLELY FOR THE PURPOSE OF PRE-DISSEMINATION PEER REVIEW UNDER APPLICABLE INFORMATION QUALITY GUIDELINES. IT HAS NOT BEEN FORMALLY DISSEMINATED BY [THE AGENCY]. IT DOES NOT REPRESENT AND SHOULD NOT BE CONSTRUED TO REPRESENT ANY AGENCY DETERMINATION OR POLICY.” 1 currently store approximately 63% of their potential maximum carbon (Gray et al. 2016). At 2 current rates, harvest and disturbance have little overall impact on carbon sequestration on 3 federal lands in Oregon and Washington as a whole, but this differs at smaller scales among 4 geographic areas (Gray and Whittier 2014) and projections suggest future decreases in carbon 5 stores from climate driven increases in fire activity (Raymond and McKenzie 2012). In forests 6 west of the Cascades where fire is less frequent, decreasing harvesting, increasing rotation age, 7 and maintaining and increasing the extent of late-successional and old-growth forests are 8 strategies to increase carbon storage toward theoretical maximum limits (Hudiberg et al. 2009). 9 Maintaining and increasing the area of dense old-growth forests with high biomass also has the 10 potential to mitigate microclimatic changes in temperature in mountainous environments (Frey et 11 al. 2016). 12 Carbon stores in the drier eastern and southwestern part of the region are more unstable 13 and less predictable due to higher fire frequency. Some studies suggest that thinning and fuel 14 reduction can mitigate carbon loss from fire. Fuel reduction may reduce losses of carbon at stand 15 levels compared to high-severity wildfire burning in stands with high fuel loads (Finkral and 16 Evans 2008, Hurteau et al. 2008, Hurteau and North 2009, North et al. 2009, Stephens et al. 17 2009, Hurteau et al. 2011, North and Hurteau 2011, Hurteau et al. 2016). However, other studies 18 indicate that this result does not hold at landscape scales. At landscape scales where the 19 likelihood of treated areas burning is low, slight differences in losses due to combustion in fire 20 compared with losses from fuel reduction are unlikely to make fuel reduction a viable mitigation 21 strategy (Mitchell et al. 2009, Ager et al. 2010, Campbell et al. 2012, Kline et al., In Press). As 22 the amount of fire on the landscape increases, the difference in carbon sequestration between 23 untreated and treated landscapes declines and the likelihood that thinning will pay off in respect 24 to the overall carbon balance increases (Loudermilk et al. 2014).

1 2 Figure 7. Total forest carbon density in the Northwest Forest Plan area (2000-2009). Map 3 following Wilson et al. (2013).

2 Limitations 3 Despite the accumulating science, considerable uncertainty in region-scale projections of climate 4 and corresponding vegetation change remains and presents significant challenges to forest 5 management (Millar et al. 2007). Many of these are mentioned throughout the chapter but we 6 identify several specific information gaps here. 7 1. Future role of climate extremes and weather events.

8 2. Clarification of the effects of future changes in CO2, temperature, and water deficit 9 on growth and mortality and how these effects vary geographically within and among 10 species and seral stages. 11 3. Effects of recent mortality on composition and structural development across seral 12 stages. 13 4. Role of drought on current and future patterns of fire severity. 14 5. Effects of climate change on demographic processes related to migration (e.g., 15 fecundity, dispersal). 16 6. Limited understanding of the role of biotic interactions. 17 7. Uncertainty surrounding changes in dry coniferous forests. 18 8. Effects of thinning on resilience to drought. 19 9. Effects of increased landscape heterogeneity on future fire and insect severity. 20 10. Phenotypic responses of individual species to drought and warmer winter 21 temperatures. 22 11. Geographic distribution of climate refugia. 23 12. Multiscale assessment of fuel treatment effects on carbon mitigation under increasing 24 fire activity. 25 Conclusions and Management Considerations 26 Despite the uncertainty associated with projections of future climate and vegetation change 27 around the region, several key vulnerabilities have emerged. Most models agree and project that 28 the region will experience warmer, drier summers and potentially warmer and wetter winters. 29 Conditions are projected to exceed the 20th century range of variability around the 2050s, 30 particularly in northern California and the southern Cascades of Oregon. Potential impacts in

Peer Review Draft 10/19/16 “THIS INFORMATION IS DISTRIBUTED SOLELY FOR THE PURPOSE OF PRE-DISSEMINATION PEER REVIEW UNDER APPLICABLE INFORMATION QUALITY GUIDELINES. IT HAS NOT BEEN FORMALLY DISSEMINATED BY [THE AGENCY]. IT DOES NOT REPRESENT AND SHOULD NOT BE CONSTRUED TO REPRESENT ANY AGENCY DETERMINATION OR POLICY.” 1 lower-elevation, wet forests include decreased growth and productivity, particularly where 2 species are already water limited. The greatest vulnerability to impacts of climate change are in 3 higher-elevation forests. These are likely to experience large decreases in area and may 4 potentially be limited to refugia in the northern Cascades (Mote et al. 2014). Although there is a 5 great deal of uncertainty in dry forests, most models consistently agree on an increased role of 6 fire in the 21st century, which is likely to include increased area burned and larger patches of 7 high severity. 8 Recent scientific findings suggest several important management considerations for 9 mitigation and adaptation in the face of ongoing climate change across the Northwest Forest Plan 10 area. 11 1. Projections for climate and vegetation change represent a range of outcomes that can 12 be used estimate the potential magnitude of effects across the region, but they do not 13 predict specific outcomes. It is important to consider the potential variability among 14 ecoregions and even among landscapes and topographic settings within an ecoregion 15 when planning management activities. 16 2. Considering a variety of approaches may be helpful when managing in the face of 17 uncertainty. “Bet hedging” strategies and multiple courses of action may help to 18 minimize risk. 19 3. Maintaining dense late-successional forests may help mitigate effects of climate and 20 have the potential to buffer change at finer scales in wet vegetation zones where fires 21 are infrequent. In addition to storing large amounts of carbon, late successional 22 forests may also provide refugia for species that depend on cooler, mesic habitats. 23 4. Landscape-scale treatments with thinning, prescribed fire, and managed wildfire may 24 promote heterogeneity where historical fire regimes were interrupted during the 20th 25 century and may also reduce vulnerability to high-severity fire and extensive 26 pathogen and insect outbreaks. Topography can provide a physical template to 27 consider when designing and implementing landscape-scale treatments. 28 5. Maintaining and increasing connectivity may facilitate migration of species 29 experiencing unsuitable climatic conditions. In situations where species climatic 30 envelopes are changing more rapidly pace than species are migrating, assisted 31 migration can promote genetic and phenotypic diversity and may help maintain forest

Peer Review Draft 10/19/16 “THIS INFORMATION IS DISTRIBUTED SOLELY FOR THE PURPOSE OF PRE-DISSEMINATION PEER REVIEW UNDER APPLICABLE INFORMATION QUALITY GUIDELINES. IT HAS NOT BEEN FORMALLY DISSEMINATED BY [THE AGENCY]. IT DOES NOT REPRESENT AND SHOULD NOT BE CONSTRUED TO REPRESENT ANY AGENCY DETERMINATION OR POLICY.” 1 cover, although the net benefits of this practice are uncertain and controversial in the 2 scientific literature 3 6. Monitoring of populations is essential to inform management decisions and help 4 prioritize objectives. Most species are expected to respond individually to projected 5 changes in climate and disturbance. Understanding the responses of individual 6 species and how they vary across its range can assist in developing strategies to 7 promote species persistence and prioritize management efforts. 8 9 Literature Cited 10 Abatzoglou, J.T.; Rupp, D.E.; Mote, P.W. 2014a. Seasonal climate variability and change in the 11 Pacific Northwest of the United States. Journal of Climate 27: 2125-2142. 12 Abatzoglou, J.T.; Rupp, D.E.; Mote, P.W. 2014b. Questionable evidence of natural warming of 13 the Northwestern United States. Proceedings of the National Academy of Sciences 111: 14 E5605-E5606. 15 Acker, S.A.; Boetsch, J.R.; Bivin, M.; Whiteaker, L.; Cole, C.; Phillipi, T. 2015. Recent tree 16 mortality and recruitment in mature and old-growth forests in western Washington. Forest 17 Ecology and Management. 336: 109-118. 18 Agee, J.K. 1993. Fire ecology of Pacific Northwest forests. Washington, DC: Island Press. 493p. 19 Agee, J.K., Skinner, C.N., 2005. Basic principles of forest fuel reduction treatments. Forest 20 Ecology and Management 211:83-96. 21 Ager, A.A., Finney, M.A., McMahan, A., Cathcart, J., 2010. Measuring the effect of fuel 22 treatments on forest carbon using landscape risk analysis. Natural Hazards and Earth System 23 Sciences 10, 2515e2526. 24 Agne, M.C., T. Woolley, and S. Fitzgerald. 2016. Fire severity and cumulative disturbance 25 effects in the post-mountain pine beetle lodgepole pine forests of the Pole Creek Fire. 26 Forest Ecology and Management 366: 73-86. 27 Allen, C.D. and D. D Breshears. 1998. Drought-induced shift of forest-woodland ecotone: Rapid 28 landscape response to climate variation. Proceedings of the National Academy of Sciences 29 95: 14839-14842.

Peer Review Draft 10/19/16 “THIS INFORMATION IS DISTRIBUTED SOLELY FOR THE PURPOSE OF PRE-DISSEMINATION PEER REVIEW UNDER APPLICABLE INFORMATION QUALITY GUIDELINES. IT HAS NOT BEEN FORMALLY DISSEMINATED BY [THE AGENCY]. IT DOES NOT REPRESENT AND SHOULD NOT BE CONSTRUED TO REPRESENT ANY AGENCY DETERMINATION OR POLICY.” 1 Asner, G.P.; P.G. Brodrick; C.B. Anderson; N. Vaughn; D.E. Knapp; R.E. Martin. Progressive 2 forest canopy water loss during the 2012-2015 California drought. Proceedings of the 3 National Academy of Sciences 113:E249-E255, doi: 10.1073/pnas.1523397113 4 Bansal, S.; C.A. Harrington; P.J. Gould; J. Bradley St. Clair. 2015. Climate-related genetic 5 variation in drought-resistance of Douglas-fir (Pseudotsuga menziesii). Global Change 6 Biology 21: 947–958. 7 Bansal, S.; C.A. Harrington; J.B. St. Clair. 2016. Tolerance to multiple climate stressors: a case 8 study of Douglas-fir drought and cold hardiness. Ecology and Evolution 6: 2074-2083. 9 Barr, B.R., M.E. Koopman, C.D. Williams, S.J. Vynne, R. Hamilton, and B. Doppelt. 2010. 10 Preparing for Climate Change in the Klamath Basin. National Center for Conservation 11 Science & Policy and the Climate Leadership Initiative. 12 Bartlein, P.K., K. Anderson, P. Anderson, M. Edwards, C. Mock, R. Thompson. R. Webb, and 13 C. Whitlock. 1998. Paleo-climate simulations for North America over the past 21,000 years: 14 features of the simulated climate and comparisons with paleoenvironmental data. 15 Quarternary Science Reviews 17: 549-585. 16 Bell, J.L.; L.C. Sloan; M.A. Snyder. 2004. Regional changes in extreme climatic events: a future 17 climate scenario. Journal of Climate 17: 81-87. 18 Bentz, B.J., J. Regniere, C.J. Fettig, E.M. Hansen, J.L. Hayes, J.A. Hicke, R.G. Kelsey, J.F. 19 Negron, and S.J. Seybold. 2010. Climate change and bark beetles of the western United 20 States and Canada: Direct and indirect effects. Bioscience 60: 602-613. 21 Berg, N.; Hall, A. 2015. Increased interannual precipitation extremes over California under 22 climate change. 28: 6234-6334. 23 Briles, C.E.; C. Whitlock; P.J. Bartlein. 2005. Postglacial vegetation, fire, and climate history of 24 the Siskiyou Mountains, Oregon, USA. Quarternary Research. 64: 44-56. 25 Brooks, M.L., C.M. D’Antonio, D.M. Richardson, J.B. Grace, J.E. Keeley, J.M. DiTomaso, R.J. 26 Hobbs, M. Pellant, and D. Pyke. 2004. Effects of invasive alien plants on fire regimes. 27 Bioscience 54: 677-688. 28 Caldwell, B.A. 2006. Effects of invasive Scotch broom on soil properties in a Pacific coastal 29 prairie soil. Applied Soil Ecology 32:149-152.

Peer Review Draft 10/19/16 “THIS INFORMATION IS DISTRIBUTED SOLELY FOR THE PURPOSE OF PRE-DISSEMINATION PEER REVIEW UNDER APPLICABLE INFORMATION QUALITY GUIDELINES. IT HAS NOT BEEN FORMALLY DISSEMINATED BY [THE AGENCY]. IT DOES NOT REPRESENT AND SHOULD NOT BE CONSTRUED TO REPRESENT ANY AGENCY DETERMINATION OR POLICY.” 1 Callaway, R.M.; R.W. Brooker; P. Choler; Z. Kikvidze; C.J. Lortie; R. Michalet; L. Paolini; F.I. 2 Pugnaire; B. Newingham; E.T. Aschehoug; C. Armas; D. Kikodze; B.J. Cook. 2002. Positive 3 interactions among alpine plants increase with stress. Nature 417: 844-848. 4 Campell, J.L.; M.E. Harmon; S.R Mitchell. 2012. Can fuel-reduction treatments really increase 5 forest carbon storage in the western United States by reducing future fire emissions? 6 Frontiers in Ecology and the Environment 10: 83–90. 7 Cayan, D.R.; S. Kammerdiener; M.D. Dettinger; J.M. Caprio; and D.H. Peterson, 2001: Changes 8 in the onset of spring in the western United States. Bulletin of the American Meteorological 9 Society. 82: 399-415. 10 Cayan, D.R.; Maurer, E.P.; Dettinger, M.D.; Tyree, M.; Hayhoe, K. 2008. Climate change 11 scenarios for the California region. Climatic Change 87(Supplement 1): S21-S42. 12 Chen, J.; Franklin, J.F.; Spies, T.A. 1993. Contrasting microclimates among clearcut, edge, and 13 interior old-growth Douglas-fir forest. Agricultural and Forest Meteorology 63: 219-237. 14 Chmura, D.J.; Anderson, P.D.; Howe, G.T. [et al.]. 2011. Forest responses to climate change in 15 the northwestern United States: ecophysiological foundations for adaptive management. 16 Forest Ecology and Management. 261: 1121–1142. 17 Cohen, W.B., Z. Yang, S.V. Stehman, T.A. Shroeder, D.M. Bell, J.G. Masek, C. Huang, and 18 G.W. Meigs. 2016. Forest disturbance across the conterminous United States from 19 1985-2012: the emerging dominance of forest decline. Forest Ecology and Management 20 360: 242-252. 21 Collins, M., R. Knutti, J. Arblaster, J.-L. Dufresne, T. Fichefet, P. Friedlingstein, X. Gao, W.J. 22 Gutowski, T. Johns, G. Krinner, M. Shongwe, C. Tebaldi, A.J. Weaver and M. Wehner, 23 2013: Long-term Climate Change: Projections, Commitments and Irreversibility. In: Climate 24 Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth 25 Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. 26 Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. 27 Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, 28 NY, USA. 29 Coops, N.C.; Waring, R.H.; Law, B.E. 2005. Assessing the past and future distribution and 30 productivity of ponderosa pine in the Pacific Northwest using a process model, 3-PG. 31 Ecological Modelling. 183: 107–124.

Peer Review Draft 10/19/16 “THIS INFORMATION IS DISTRIBUTED SOLELY FOR THE PURPOSE OF PRE-DISSEMINATION PEER REVIEW UNDER APPLICABLE INFORMATION QUALITY GUIDELINES. IT HAS NOT BEEN FORMALLY DISSEMINATED BY [THE AGENCY]. IT DOES NOT REPRESENT AND SHOULD NOT BE CONSTRUED TO REPRESENT ANY AGENCY DETERMINATION OR POLICY.” 1 Coops, N.C.; Waring, R.H. 2011a. Estimating the vulnerability of fifteen tree species under 2 changing climate in Northwest North America. Ecological Modelling. 222: 2119–2129. 3 Coops, N.C.; Waring, R.H. 2011b. A process-based approach to estimate lodgepole pine (Pinus 4 contorta Dougl.) distribution in the Pacific Northwest under climate change. Climatic 5 Change. 105: 313–328. 6 Cordero, E. C., W. Kessomkiat, J. Abatzoglou, and S. A. Mauget. 2011. The identification of 7 distinct patterns in California temperature trends. Climatic Change 108:357-382. 8 Crookston, N.L.; Rehfeldt, G.E.; Dixon, G.E.; Weiskittel, A.R. 2010. Addressing climate change 9 in the forest vegetation simulator to assess impacts on landscape forest dynamics. Forest 10 Ecology and Management. 260: 1198–1211. 11 Dale, V.H., L.A. Joyce, S. McNulty, R.P. Neilson, M.P. Ayres, M.D. Flannigan, P.L. Hanson, 12 L.C. Irland, A.E. Lugo, C.J. Peterson, D. Simberloff, F.J. Swanson, B.J. Stocks, and B.M. 13 Wotton. 2001. Climate change and forest disturbances. Bioscience 51: 723-734. 14 Dalton, M., P.W. Mote, and A.K. Snover, eds., 2013: Climate Change in the Northwest: 15 Implications for Our Landscapes, Waters, and Communities. 224 pp. Island Press. 16 Daly, C.; M. Halbleib; J.I. Smith; W.P. Gibson; M.K. Doggett; G.H Taylor; J. Curtis; P.P 17 Pasteris. 2008. Physiologically sensitive mapping of climatological temperature and 18 precipitation across the conterminous United States. International Journal of Climatology 28: 19 2031-2064. 20 Daly, C.; D.R. Conklin; M.H. Unsworth. 2010. Local atmospheric decoupling in complex 21 topography alters climate change impacts. International Journal of Climatology 30: 1857- 22 1864. 23 Damschen, E.I., S. Harrison, and J.B. Grace. 2010. Climate change effects on an endemic-rich 24 edaphic flora: resurveying Robert H. Whittaker’s Siskiyou sites (Oregon, USA). Ecology 91: 25 3609-3619. 26 Das, T.; Maurer, E.P.; Pierce, D.W.; Dettinger, M.D.; Cayan, D.R. 2013. Increases in flood 27 magnitudes under warming climate. Journal of Hydrology 501: 101-110. 28 Davis, M.B.; Shaw, R.G. 2001. Ranges shifts and adaptive responses to quaternary climate 29 change. Science 292: 673-679.

Peer Review Draft 10/19/16 “THIS INFORMATION IS DISTRIBUTED SOLELY FOR THE PURPOSE OF PRE-DISSEMINATION PEER REVIEW UNDER APPLICABLE INFORMATION QUALITY GUIDELINES. IT HAS NOT BEEN FORMALLY DISSEMINATED BY [THE AGENCY]. IT DOES NOT REPRESENT AND SHOULD NOT BE CONSTRUED TO REPRESENT ANY AGENCY DETERMINATION OR POLICY.” 1 DeFrenne, P.; F. Rodriguez-Snachez; D.A. Coomes; [et al.]. 2013. Microclimate moderates plant 2 responses to macroclimate warming. Proceedings of the National Academy of Sciences 110: 3 18561-18565. 4 Deser, C.; Knutti, R.; Solomon, S.; Phillips, A.S. 2012. Communication of the role of natural 5 variability in future North American climate. Nature Climate Change 2: 775-779. 6 Deser, C., A. S. Phillips, M. A. Alexander, and B. V. Smoliak, 2014: Projecting North American 7 Climate over the next 50 years: Uncertainty due to internal variability. Journal of Climate 8 27: 2271-2296. 9 Dettinger, M. 2011. Climate change, atmospheric rivers, and floods in California – a multimodel 10 analysis of storm frequency and magnitude changes. Journal of the American Water 11 Resources Association 47: 514-523. 12 Diffenbaugh, N. S., D. L. Swain, and D. Touma. 2015. Anthropogenic warming has increased 13 drought risk in California. Proceedings of the National Academy of Sciences 112:3931-3936. 14 Dobrowski, S.Z. 2011. A climatic basis for microrefugia the influence of terrain on climate. 15 Global Change Biology 17: 1022-1035. 16 Dobrowski, S.Z.; J. Abatzoglou; A.K. Swanson; J.A. Greenberg; A.R. Mynsberge; Z. A. Holden; 17 M.K. Schwartz. The climate change velocity of the contiguous United States during the 20th 18 century. Global Change Biology 19: 241-251. 19 Dodson, E.K. & H.T. Root. 2014. Native and exotic plant cover vary inversely along a climate 20 gradient 11 years following stand-replacing wildfire in a dry coniferous forest, Oregon, USA. 21 Global Change Biology 21: 666-675. 22 Elliott, M.; Edmonds, R.L.; Mayer, S. 2002. Role of fungal diseases in decline of Pacific 23 madrone. Northwest Science 76: 293-303. 24 Elsner, M.M.; Co, L.; Voisin, N.; Deems, J.S.; Hamlet, A.F.; Vano, J.A.; Mickelson, K.E.B.; 25 Lee, S.-Y.; Lettenmaier, D.P. 2010. Implications of 21st century climate change for the 26 hydrology of Washington State. Climatic Change. 102: 225–260. 27 Ettinger A.K.; K.R. Ford; J. HilleRisLambers. 2011. Climate determines upper, but not lower, 28 altitudinal range limits of Pacific Northwest conifers. Ecology 92: 1323-1331. doi: 29 10.1890/10-1639.1 30 Ettinger, A.K.; J. HilleRisLambers. 2013. Climate isn’t everything: competitive interactions and 31 variation by life stage will also effect range shifts in a warming world. American Journal

Peer Review Draft 10/19/16 “THIS INFORMATION IS DISTRIBUTED SOLELY FOR THE PURPOSE OF PRE-DISSEMINATION PEER REVIEW UNDER APPLICABLE INFORMATION QUALITY GUIDELINES. IT HAS NOT BEEN FORMALLY DISSEMINATED BY [THE AGENCY]. IT DOES NOT REPRESENT AND SHOULD NOT BE CONSTRUED TO REPRESENT ANY AGENCY DETERMINATION OR POLICY.” 1 of Botany 100: 1344-1355. 2 Finkral, A.J.; Evans, A.M. The effects of a thinning treatment on carbon stocks in a northern 3 Arizona ponderosa pine forest. Forest Ecology and Management 255: 2743-2750. 4 Ford, K.R.; A.K. Ettinger; J.D. Lundquist; M.S. Raleigh; J. HilleRisLambers. 2013. Spatial 5 heterogeneity in ecologically important climate variables and fine scales in a high-snow 6 mountain landscape. 2013. PLoS ONE 8:e65008. doi:10.1371/journal.pone.0065008 7 Ford, K.R.; C.A. Harrington; S. Bansal; P.J. Gould; B. St. Clair. 2016. Will changes in 8 phenology track climate change? A study of growth initiation timing in coast Douglas-fir. 9 Global Change Biology doi:10.1111/gcb.13328 10 Ford, K.R.; I.K. Breckheimer; J.F. Franklin; J.A. Freund; S.J. Kroiss; A.J. Larson; E.J. Theobald; 11 J. HilleRisLambers. In Press. Competition alters tree growth responses to climate at 12 individual and stand scales. Canadian Journal of Forest Research. 13 Franklin, J.F. and C.T. Dyrness. 1973. Natural Vegetation of Oregon and Washington. Oregon 14 State University Press, Corvallis, Oregon, USA. 15 Frey, S.J.K., A.S. Hadley, S.L. Johnson, M. Schulze, J.A. Jones; M.G. Betts. 2016. Spatial 16 models reveal the microclimatic buffering capacity of old-growth forests. Science Advances 17 2: E1501392. 18 Fried, J.S; Torn, M.S.; Mills, E. 2004. The impact of climate change on wildfire severity: a 19 regional forecast for northern California. Climatic Change. 64:169-191. 20 Garfin, G.; Franco, G.; Blanco, H.; Comrie, A.; Gonzalez, P.; Piechota, T.; Smyth, R.; Waskom, 21 R. 2014. Chapter 20: Southwest. Climate Change Impacts in the United States: The Third 22 National Climate Assessment, J. M. Melillo, Terese (T.C.) Richmond, and G. W. Yohe, Eds., 23 U.S. Global Change Research Program, 462-486. doi:10.7930/J08G8HMN. 24 Gedalof , Z.; Smith DJ. 2001. Interdecadal climate variability and regime-scale shifts in Pacific 25 North America. Geophysical Research Letters. 28:1515–1518. 26 Gershunov, A.; Barnett, T.P.; Cayan, D.R. 1999. North Pacific interdecadal oscillation seen as 27 actor in ENSO-related North American climate anomalies. EOS, Transactions, American 28 Geophysical Union 80: 25-30. 29 Gershunov, A.; Guirguis, K. 2012. California heat waves in the present and future. Geophysical 30 Research Letters 39: L18710, doi:10.1029/2012GL052979. 31 Goheen, Ellen Michaels; Goheen, Donald J.; Marshall, Katy; Danchok, Robert S.; Petrick, John

Peer Review Draft 10/19/16 “THIS INFORMATION IS DISTRIBUTED SOLELY FOR THE PURPOSE OF PRE-DISSEMINATION PEER REVIEW UNDER APPLICABLE INFORMATION QUALITY GUIDELINES. IT HAS NOT BEEN FORMALLY DISSEMINATED BY [THE AGENCY]. IT DOES NOT REPRESENT AND SHOULD NOT BE CONSTRUED TO REPRESENT ANY AGENCY DETERMINATION OR POLICY.” 1 A.; White, Diane E. 2002. The status of whitebark pine along the Pacific Crest National 2 Scenic Trail on the Umpqua National Forest. Gen. Tech. Rep. PNW-GTR-530. Portland, OR: 3 U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 21 p. 4 Goheen, E.M.; E.A. Willhite. 2006. Field guide to the common diseases and insect pests of 5 Oregon and Washington conifers. USDA Forest Service, Pacific Northwest Region. R6- 6 NR-FID-PR-01-06. Portland, Oregon. 7 Goheen, E.M.; Goheen, D.J. 2014. Status of sugar and western white pines on federal forest 8 lands in southwest Oregon. Inventory query and natural stand survey results. USDA Forest 9 Service, Pacific Northwest Region, Report No. SWWOFIDSC-14-01, 71 pp. 10 Gray, A.N. 2005. Eight nonnative plants in western Oregon forests: associations with 11 environment and management. Environmental Monitoring and Assessment. 100: 109-127. 12 Gray, A.N. 2008. Monitoring and assessment of regional impacts from nonnative invasive plants 13 in forests of the Pacific Coast, United States. In: Kohli, R.K.; Jose, S.; Singh, H.P.; Batish, 14 D.R. Invasive Plants and Forest Ecosystems. Boca Raton, FL: CRC Press: 217-235. 15 Gray, A.N.; K. Barndt; S.H. Reichard. 2011. Nonnative invasive plants of Pacific coast forests: a 16 field guide for identification. Gen. Tech. Rep. PNW-GTR-817. Portland, OR: U.S. 17 Department of Agriculture, Forest Service, Pacific Northwest Research Station. 91 p. 18 Gray, A. N.; T.R.Whittier. 2014. Carbon stocks and changes on Pacific Northwest national 19 forests and the role of disturbance, management, and growth. Forest Ecology and 20 Management 328:167–178. 21 Gray, A.N.; Whittier, T. R.; Harmon, M.E. 2016. Carbon stocks and accumulation rates in 22 Pacific Northwest forests: role of stand age, plant community, and 23 productivity. Ecosphere 7:e01224. 10.1002/ecs2.1224 24 Griffin, D., and K. J. Anchukaitis. 2014. How unusual is the 2012–2014 California drought? 25 Geophysical Research Letters 41:9017-9023. 26 Halofsky, J.E.; M.A. Hemstrom; D.R. Conklin; J.S. Halofsky; B. Kerns; D. Bachelet. 2013. 27 Assessing potential climate change effects on vegetation using a linked model approach. 28 Ecological Modelling 266: 131-143. 29 Halofsky, J.S.; J.E. Halofsky; T. Burcsu; M.A. Hemstrom. 2014. Dry forest resilience varies 30 under simulated climate-management scenarios in a central Oregon, USA landscape. 31 Ecological Applications 24: 1908-1925.

Peer Review Draft 10/19/16 “THIS INFORMATION IS DISTRIBUTED SOLELY FOR THE PURPOSE OF PRE-DISSEMINATION PEER REVIEW UNDER APPLICABLE INFORMATION QUALITY GUIDELINES. IT HAS NOT BEEN FORMALLY DISSEMINATED BY [THE AGENCY]. IT DOES NOT REPRESENT AND SHOULD NOT BE CONSTRUED TO REPRESENT ANY AGENCY DETERMINATION OR POLICY.” 1 Halofsky, J.E.; D.L. Peterson. 2016. Climate change vulnerabilities and adaptation options for 2 forest vegetation management in the Northwestern USA. Atmosphere 7: 3 Hamlet, A.F.; Mote, P.W.; Clark, M.P.; Lettenmeir, D.P. 2005. Effects of temperature and 4 precipitation variability on snowpack trends in the western United States. Journal of Climate 5 18: 4545-4561. 6 Hampe, A.; Petit, R.J. 2005. Conserving biodiversity under climate change: the rear edge 7 matters. Ecology Letters 8: 461-467. 8 Hansen, E.M. and E.M. Goheen. 2000. Phellinus weirii and other native root pathogens as 9 determinants of forest structure and process in western North America. Annual Review of 10 Phytopathology 38: 515-539. 11 Hansen, E. M., E.M. Goheen, E. S. Jules, and B. Ullian. 2000. Managing Port Orford cedar and 12 the introduced pathogen, Phytophthora lateralis. Plant Disease 84:4–10. 13 Hargrove, W.W.; Hoffman, F.M. 2005. The potential of multivariate quantitative methods for 14 delineation and visualization of ecoregions. Environmental Management. 34: S39–S60. 15 Harrington, C.A.; P.J. Gould. 2016. Tradeoffs between chilling and forcing in satisfying 16 dormancy requirements for Pacific Northwest tree species. Frontiers in Plant Science 6: 1-12. 17 Harrington, T.B.; S.H. Reichard. 2007. Meeting the challenge: invasive plants in Pacific 18 Northwest ecosystems. Gen. Tech. Rep. PNW-GTR-694. Portland, OR: U.S. Department of 19 Agriculture, Forest Service, Pacific Northwest Research Station. 166 p. 20 Harrison, S.; E.I. Damschen; J.B. Grace. 2010. Ecological contingency in the effects of climatic 21 warming on forest herb communities. Proceedings of the National Academy of Science 107: 22 19362-19367. 23 Hart, S.J., T. Schoennagel, T.T. Veblen, and T.B. Chapman. 2015. Area burned in the western 24 nited States is unaffected by recent pine beetle outbreaks. Proceedings of the National 25 Academy of Sciences 112: 4375-4380. 26 Harvey, B.J., D.C. Donato, W.H. Romme, and M.G. Turner. 2013. Influence of recent bark 27 beetle outbreak on fire severity and postfire tree regeneration in montane Douglas-fir forests. 28 Ecology 94: 2475-2486. 29 Hawkins, E.; Sutton, R. 2009. The potential to narrow uncertainty in regional climate 30 predictions. Bulletin of the American Meteorological Society. 90: 1085-1107.

Peer Review Draft 10/19/16 “THIS INFORMATION IS DISTRIBUTED SOLELY FOR THE PURPOSE OF PRE-DISSEMINATION PEER REVIEW UNDER APPLICABLE INFORMATION QUALITY GUIDELINES. IT HAS NOT BEEN FORMALLY DISSEMINATED BY [THE AGENCY]. IT DOES NOT REPRESENT AND SHOULD NOT BE CONSTRUED TO REPRESENT ANY AGENCY DETERMINATION OR POLICY.” 1 Hessburg, P.F.; D.J. Churchill; A.J. Larson; R.D. Haugo; C. Miller; T.A. Spies; M.P. North; 2 N.A. Povak; R.T. Belote; P.H. Singleton; W.L. Gaines; R.E. Keane; G.H. Aplet; S.L. 3 Stephens; P. Morgan; P.A. Bisson; B.E. Rieman; R.B. Salter; G.H. Reeves. 2015. Restoring 4 fire-prone Inland Pacific landscapes: seven core principles. Landscape Ecology 30: 1805- 5 1835. 6 Hicke, J.A., A.J.H. Meddens, and C.A. Kolden. 2016. Recent tree mortality in the western 7 United States from bark beetles and forest fires. Journal of Forestry 16: 141-153. 8 HilleRisLambers, J.; L.D.L. Anderegg; I. Breckheimer; K.M. Burns; A.K. Ettinger; J.F. 9 Franklin; J.A. Freund; K.R. Ford; S.J. Krolss. 2015. Implications of climate change for 10 turnover in forest composition. Northwest Science 89: 201-218. 11 Hudiberg, T; B. Law; D.P. Turner; J. Campbell; D. Donato; M. Duane. 2009. Carbon dynamics 12 of Oregon and Northern California forests and potential land-based carbon storage. 13 Ecological Applications 19: 163-180. 14 Hurteau, M.D., G.W. Koch, and B.A. Hungate. 2008. Carbon protection and fire risk 15 reduction: toward a full accounting of forest carbon offsets. Frontiers in Ecology 16 and the Environment 6:493-498. 17 Hurteau, M.D.; M. North. 2009. Fuel treatments effects on tree-based forest carbon storage and 18 emissions under modeled wildfire scenarios. Frontiers in Ecology and the Environment 7: 19 409-414. 20 Hurteau, M.D., M.T. Stoddard, and P.Z. Fule. 2011. The carbon costs of mitigating high-severity 21 wildfire in southwestern ponderosa pine. Global Change Biology 17:1516-1521. 22 Hurteau, M.D., S. Liang*, K.L. Martin*, M.P. North, G.W. Koch, B.A. Hungate. 2016. 23 Restoring forest structure and process stabilizes forest carbon in wildfire-prone southwestern 24 ponderosa pine forests. Ecological Applications 26:382-391. 25 Intergovernmental Panel on Climate Change [IPCC]. 2013. Climate Change 2013: The Physical 26 Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the 27 Intergovernmental Panel on Climate Change. Stocker, T.F., D. Qin, G.-K. Plattner, M. 28 Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.). 29 Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1535 30 pp.

Peer Review Draft 10/19/16 “THIS INFORMATION IS DISTRIBUTED SOLELY FOR THE PURPOSE OF PRE-DISSEMINATION PEER REVIEW UNDER APPLICABLE INFORMATION QUALITY GUIDELINES. IT HAS NOT BEEN FORMALLY DISSEMINATED BY [THE AGENCY]. IT DOES NOT REPRESENT AND SHOULD NOT BE CONSTRUED TO REPRESENT ANY AGENCY DETERMINATION OR POLICY.” 1 Jackson, S.T.; Betancourt, J.L.; Booth, R.K.; Gray, S.T. 2009. Ecology and the ratchet of events: 2 climate variability, niche dimensions, and species distributions. Proceedings of the National 3 Academy of Sciences of the United States of America. 106: 19685–19692. 4 Jentsch, A.; Kreyling, J.; Beierkuhnlein, C. 2007. A new generation of climate change 5 experiments: events, not trends. Frontiers in Ecology and Evolution. 5: 315-324. 6 Johnstone, J.A.; Dawson, T.E. 2010. Climatic context and ecological implications of summer fog 7 decline in the coast redwood region. Proceedings of the National Academy of Sciences 4533- 8 4538. 9 Johnstone, J.A.; Mantua, N.J. 2014a. Atmospheric controls on northeast Pacific temperature 10 variability and change, 1900-2012. Proceedings of the National Academy of Sciences 111: 11 14360-14365. 12 Johnstone, J.A.; Mantua, N.J. 2014b. Reply to Abatzoglou et al.: Atmospheric controls on 13 northwest United States air temperatures, 1948-2012. Proceedings of the National Academy 14 of Sciences 111: E5607-E5608. 15 Jules, E. S., Kauffman, M. J., Ritts, W. D. and Carroll, A. L. 2002. Spread of an invasive 16 pathogen over a variable landscape: a nonnative root rot on Port Orford cedar. Ecology. 83: 17 3167–3181. 18 Jules, E.S.; Steenbock, C.M.; Carroll, A.L. 2014. Update on the 35-year expansion of the 19 invasive root pathogen, Phytophthora lateralis, across a landscape of Port Orford cedar 20 (Chamaecyparis lawsoniana). Forest Pathology doi: 10.1111/efp.12158 21 Jung, I.; H. Chang. 2011. Assessment of future runoff trends under multiple climate change 22 scenarios in the Willamette River Basin, Oregon, USA. Hydrological Processes 25: 258-277. 23 Kerns, B.K., J.B. Kim, J.D. Kline, and M.A. Day. 2016. U.S. exposure to multiple landscape 24 stressors and climate change. Regional Environmental Change (in press). 25 Killam, D.; Bui, A.; LaDochy, S.; Ramirez, P.; Willis, J.; Patzert, W. 2014. California getting 26 wetter to the north, drier to the south: natural variability or climate change? Climate. 2: 168- 27 180.

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Peer Review Draft 10/19/16 “THIS INFORMATION IS DISTRIBUTED SOLELY FOR THE PURPOSE OF PRE-DISSEMINATION PEER REVIEW UNDER APPLICABLE INFORMATION QUALITY GUIDELINES. IT HAS NOT BEEN FORMALLY DISSEMINATED BY [THE AGENCY]. IT DOES NOT REPRESENT AND SHOULD NOT BE CONSTRUED TO REPRESENT ANY AGENCY DETERMINATION OR POLICY.” 1 McKenzie, D.; Gedalof, Z.; Peterson, D.L.; Mote, P. 2004. Climatic change, wildfire, and 2 conservation. Conservation Biology. 18: 890–902. 3 Meehl, G.A.; Tebaldi, C. 2004. More intense, more frequent, and longer lasting heat waves in the 4 21st century. Science. 305: 994–997. 5 Meentemeyer, R. K., N. J. Cunniffe, A. R. Cook, J. A. N. Filipe, R. D. Hunter, D. M. Rizzo, and 6 C. A. Gilligan. 2011. Epidemiological modeling of invasion in heterogeneous landscapes: 7 spread of sudden oak death in California (1990–2030). Ecosphere 2(2):art17. 8 doi:10.1890/ES10-00192.1 9 Meigs, G.W., R.E. Kennedy, A.N. Gray, and M.J. Gregory. 2015. Spatiotemporal dynamics of 10 recent mountain pine beetle and western spruce budworm out breaks across the Pacific 11 Northwest. Forest Ecology and Management 339: 71-86. 12 Meigs, G.W.; Zald, H.S.J.; Campbell, J.L.; Keeton, W.S.; Kennedy, R.E. 2016. Do insect 13 outbreak reduce the severity of subsequent forest fires? Environmental Research Letters. 14 doi:10.1088/1748-9326/11/4/045008 15 Metz, M.R.; Frangioso, K.; Meentemeyer, R.K.; Rizzo, D.M. 2011. Interacting disturbances: 16 wildfire severity affected by stage of forest disease invasion. Ecological Applications 21: 17 313-320. 18 Mildrexler, D.; Yang, Z.; Cohen, W.; Bell, D. 2016. A forest vulnerability index based on 19 drought and high temperatures. Remote Sensing of Environment 173: 314-325. 20 Millar, C.I.; Stephenson, N.L.; Stephens, S.L. 2007. Climate change and forests of the future: 21 managing in the face of uncertainty. Ecological Applications 17: 2145-2151. 22 Miller, J.D., C.N. Skinner, H.D. Safford, E.E. Knapp, and C.M. Ramirez. 2012. Trends and 23 causes of severity, size, and number of fires in northwestern California. Ecological 24 Applications 22: 184-203. 25 Mitchell, R.G.; Buffam, P.E. 2001. Patterns of long-term Balsam woolly adelgid infestations and 26 effects in Oregon and Washington. Western Journal of Applied Forestry 16: 121-126. 27 Mitchell, S. R., M. E. Harmon, and K. E. B. O’Connell. 2009. Forest fuel reduction alters fire 28 severity and long-term carbon storage in three Pacific Northwest ecosystems. Ecological 29 Applications 19:643–655. 30 Monleon, V.J., H.E. Lintz. 2015. Evidence of tree species range shifts in a complex landscape. 31 PLoS ONE 10: e0118069. doi:10.1371/journal.pone.0118069

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Peer Review Draft 10/19/16 “THIS INFORMATION IS DISTRIBUTED SOLELY FOR THE PURPOSE OF PRE-DISSEMINATION PEER REVIEW UNDER APPLICABLE INFORMATION QUALITY GUIDELINES. IT HAS NOT BEEN FORMALLY DISSEMINATED BY [THE AGENCY]. IT DOES NOT REPRESENT AND SHOULD NOT BE CONSTRUED TO REPRESENT ANY AGENCY DETERMINATION OR POLICY.” 1 Peterson, D.W.; Peterson, D.L. 2001. Mountain hemlock growth responds to climatic variability 2 at annual and decadal time scales. Ecology. 82: 3330–3345. 3 Peterson, D.W.; Peterson, D.L.; G.J. Ettl. 2002. Growth responses of subalpine fir to climatic 4 variability in the Pacific Northwest. Canadian Journal of Forest Research. 32: 1503-1517. 5 Peterson, D.L.; Kerns, B.K.; Dodson, E.K. eds. 2014. Climate change effects on vegetation in the 6 Pacific Northwest: A review and synthesis of the scientific literature and simulation model 7 projections. Gen. Tech. Rep. PNW-GTR-900. Portland, OR: U.S. Department of Agriculture, 8 Forest Service, Pacific Northwest Research Station. 183 p. 9 Pierce, D.W.; Barnett, T.P.; Santer, B.D.; Gleckler, P.J. 2009. Selecting global climate models 10 for regional climate change studies. Proceedings of the National Academy of Science. 106: 11 8441-8446. 12 Powers, J.S.; Sollins, P.; Harmon, M.E.; Jones, J.A. 1999. Plant-pest interactions in time and 13 space: A Douglas-fir bark beetle outbreak as a case study. Landscape Ecology 14: 105-120. 14 Prichard, S.J.; Peterson, D.L.; Jacobson, K. 2010. Fuel treatments reduce the severity of wildfire 15 effects in dry, mixed conifer forest, Washington, USA. Canadian Journal of Forest Research 16 40: 1615-1626. 17 Rapacciuolo, G.; Maher, S.P.; Schneider, A.C.; Hammond, T.T.; Jabis, M.D.; Walsh, R.E.; 18 Iknayan, K.J.; Walden, G.K.; Oldfather, M.F.; Ackerly, D.D.; Beissinger, S.R. 2014. 19 Beyond a warming fingerprint: individualistic biogeographic responses to heterogeneous 20 climate change in California. Global Change Biology 20: 2841-2855. 21 Raymond, C.L. and D. McKenzie. 2012. Carbon dynamics of forests in Washington, USA: 21st 22 century projections based on climate driven changes in fire regimes. Ecological Applications 23 22: 1589-1611. 24 Rehfeldt, G.E.; Crookston, N.L.; Warwell, M.V.; Evans, J.S. 2006. Empirical analyses of plant- 25 climate relationships for the western United States. International Journal of Plant Sciences. 26 167: 1123–1150. 27 Reichard, S.H.; P.S. White. 2001. Horticulture as a pathway of invasive plant introductions in the 28 United States. Bioscience 51: 103-113. 29 Reilly, M.J., Spies, T.A., 2015. Regional variation in stand structure and development in forests 30 of Oregon, Washington, and inland Northern California. Ecosphere 6: 192. doi./10.1890/ 31 ES14-00469.1

Peer Review Draft 10/19/16 “THIS INFORMATION IS DISTRIBUTED SOLELY FOR THE PURPOSE OF PRE-DISSEMINATION PEER REVIEW UNDER APPLICABLE INFORMATION QUALITY GUIDELINES. IT HAS NOT BEEN FORMALLY DISSEMINATED BY [THE AGENCY]. IT DOES NOT REPRESENT AND SHOULD NOT BE CONSTRUED TO REPRESENT ANY AGENCY DETERMINATION OR POLICY.” 1 Reilly, M.J. and T.A. Spies. 2016. Disturbance, tree mortality, and implications for 2 contemporary regional forest change in the Pacific Northwest. Forest Ecology and 3 Management 374: 102-110. 4 Reilly, M.J.; C.J. Dunn; G.W. Meigs; T.A. Spies; R.E. Kennedy; J.D. Bailey; K. Briggs. 5 Contemporary patterns of fire extent and burn severity in forests of the Pacific Northwest 6 (1985-2010. In Review. 7 Restaino, C.M., D.L. Peterson, and J. Littell. 2016. Increased water deficit decreases Douglas-fir 8 growth throughout western US forests. Proceedings of the National Academy of Sciences 9 doi: 10.1073/pnas.1602384113 10 Ritokova, G., D.C. Shaw, G. Filip, A. Kanaskie, J. Browning, and D. Norlander. 2016. Swiss 11 needle cats in western Oregon Douglas-fir plantations: 20-year monitoring results. Forests 12 7:155 doi: 10.3390/f7080155 13 Rizzo, D.M.; Garbelotto, M. 2003. Sudden oak death: endangering California and Oregon forest 14 ecosystems. Frontiers in Ecology and the Environment 1: 197-204. 15 Rogers, B.M.; Neilson, R.P.; Drapek, R.; Lenihan, J.M.; Wells, J.R.; Bachelet, D.; Law, B.E. 16 2011. Impacts of climate change on fire regimes and carbon stocks of the U.S. Pacific 17 Northwest. Journal of Geophysical Research. 116: G03037. doi:10.1029/2011JG001695. 18 Rubenstien, S.M.; J.M. Dechaine. 2015. Native-nonnative seed dispersal and establishment along 19 an interstate highway. Northwest Science 89: 324-335. 20 Rupp, D.E., Abatzoglou, J.T., Hegewisch, K.C. and Mote, P.W., 2013. Evaluation of CMIP5 21 20th century climate simulations for the Pacific Northwest USA. Journal of Geophysical 22 Research: Atmospheres, 118(19). 23 Ryan, M.G., M.E. Harmon, R.A. Birdsey et al. 2010. A synthesis of the science on forests and 24 carbon for U.S. Forests. Issues in Ecology. The Ecological Society of America. 13:1-16. 25 Sandel, B. and E.M. Dangremond. 2012. Climate change and the invasion of California by 26 grasses. Global Change Biology 18: 277-289. 27 Saxon, E.; Baker, B.; Hargrove, W.; Hoffman, F.; Zganjar, C. 2005. Mapping environments at 28 risk under different climate change scenarios. Ecology Letters. 8: 53-60. 29 Shafer, S.L.; P.J. Bartlein; E.M. Gray; R.T. Pelltier. 2015. Projected future vegetation changes 30 for the Northwest United States and southwest Canada at a fine spatial resolution using a

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Western Hemlock Douglas-fir (40.3%), White Fir (18.5%), Jeffrey Pine (15.5%), Tanoak (Madrone) (9%), Black Oak (3.9%), Ultra Mafic Mixed Conifer (3.7%), California Bay (2.9%), Red Fir (2.4%) Tanoak Douglas-fir (40.3%), Tanoak (Madrone) (11.3%), Oregon White Oak (6.2%), California Bay (5%) Shasta Red Fir Red Fir (33.2%), White Fir (10.1%), Jeffrey Pine (10.1%), Barren (10%), Mixed Conifer – Fir (8.1%), Alpine Grasses and Forbs (5.1%), Pinemat Manzanita (5%), Subalpine Conifers (4.9%), Upper Montane Mixed Chaparral (2.9%), Perennial Grasses and Forbs (2.1%) Port Orford Cedar Douglas-fir (46.6%), Ultramafic Mixed Conifer (24.8%), Douglas- fir – White Fir (7.9%), Tanoak (Madrone) (2.9%), Douglas-fir – Ponderosa Pine (2.9%), Mixed Conifer – Pine (2.2%), Oregon White Oak (2%)