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The combined uncertainty of when and by how much greenhouse gas emissions will increase over time, the level of climatic response to those emissions, and potential for feedback systems make it difficult to predict the exact impacts of climate change. Despite this uncertainty, land managers can still take action to mitigate or adapt to climate change.
Natural areas in Pennsylvania are experiencing a myriad of issues related to increased carbon emissions into the atmosphere from the burning of fossil fuels. Impacts of human-caused climate change include higher temperatures, increased precipitation, a higher number of extreme storm events, more frequent droughts, less snowfall, and less ice on rivers and large bodies of water.
Climate change is often referred to as “the great multiplier,” as climate change impacts often exacerbate other natural and human-caused climatic and biological processes—including their effects on the distribution of plants and animals. Natural areas managers in the region will need to adapt their management approaches to cope with the direct and indirect impacts of human-caused climate change.
Numerous climate models analyzing varying emissions rates predict that Pennsylvania will get warmer and wetter with more severe weather events. Based on high and low emission scenarios modeled by the International Panel on Climate Change, average temperature could increase by approximately 2.5°F in the next decades and 2°-5.5°F by mid-century. By the end of the century, average temperature is predicted to increase 4°-8°F during winter months and 5.5°-11°F during the summer.
While the total annual precipitation amount is likely to increase, low precipitation in the summer is likely to increase the frequency of short-term summer droughts. Higher winter temperatures could cause a decrease in the percentage of total precipitation in the form of snow, leading to winter flooding and earlier peak flows for streams.
Native plant and animal species will likely experience a range of population trends due to climate change. As the climate changes and temperatures increase, habitat regions may shift north, possibly as much as 350-500 miles. The singularly rapid rate of change, long distances, and habitat fragmentation by intensive human land uses will affect species ability to migrate with or adapt to any changes. Species at the southern end of their range, highly dependent on specific habitats or hydrologic regimes, or closely tied to the phenology (life cycle) of other species are most vulnerable. Habitat generalists, species with a high tolerance for drought and flooding, and those with a wide range of food sources, are most likely to be climate-change winners. Some species such as oaks may experience an increase in suitable habitat in Pennsylvania, while many others, such as black cherry and numerous bird species will face shifting and decreasing habitat availability. Aquatic species are also at risk due to increasing water temperatures. Climate change is likely to impact species of small, isolated habitats the most, as other suitable habitat areas will not be available or connected, stranding species in habitat that may become increasingly inhospitable.
Species may also shift based on elevation or soil conditions. To reach colder microclimates, species may migrate higher topographically, putting species already near the topographic apex (highest point) of their region at risk of habitat loss. Species that colonize xeric (dry) or variable soils may expand their range while species that require hydric (wet) soils or high-water tables may face a contracting range as more prevalent droughts and higher temperatures dry soils and lower water tables.
Invasive plants and pests are likely to increase their ranges with higher temperatures. The factors that allow them to successfully compete with native plants will also help them adapt to climate change: prolific seeding and wide-ranging dispersal, ability to colonize disturbed and marginal areas, rapid growth, and the lack of co-evolved predators, parasites, and pathogens that would otherwise weaken their ability to adapt. Without long cold spells, these species will be less restricted in their ranges and be able to outcompete natives in more areas. Gaps produced by plant die-offs, which may become more prevalent with climate change, will open more growing space for introduced plants, especially in the canopy.
Climate change impacts also influence the amount of greenhouse gasses released into the atmosphere from natural areas. Greenhouse gases sequestered by soils and forests, including carbon dioxide, nitrous oxide, and methane, are released at higher levels as trees die off and as higher temperatures increase soil respiration. Decomposition rates, especially of organic material in wetlands, are expected to rise in a warmer, wetter climate, which will lead to faster releases of carbon after plant die-offs. Saturated soils, such as in wetland environments, hold more methane than drier soils. Droughts could cause more greenhouse gases to be released as saturated soils dry out. All of these create a feedback cycle where the impacts from climate change lead to additional greenhouse gases in the atmosphere, thereby worsening climate change impacts and causing further releases of greenhouse gases, and so on.
The combined uncertainty of when and by how much greenhouse gas emissions will increase over time, the level of climatic response to those emissions, and potential for feedback systems make it difficult to predict the exact impacts of climate change. Despite this uncertainty, land managers can still take action to mitigate or adapt to climate change. As such, natural areas stewardship plans should include recommendations for climate change adaptation and mitigation activities.
Pennsylvania state agencies have released plans that dive into how natural areas can help the region mitigate and adapt to climate change. The Department of Conservation and Natural Resources’ (DCNR) 2018 Climate Change Adaptation and Mitigation Plan lays out objectives to prepare for and mitigate the risks associated with climate change, focusing on higher temperatures and more extreme weather events, range shifts for wildlife and plant species, and invasive species threats. In 2021, Pennsylvania released a Climate Action Plan to reduce greenhouse gas emissions from 2005 levels by 26% by 2025 and 80% by 2050. Both the Pennsylvania Climate Action Plan and the DCNR Climate Change Adaptation and Mitigation Plan identify natural areas as a resource to help mitigate and adapt to climate change, including through:
Additionally, natural areas can provide low-carbon-emitting recreational opportunities (local hiking, birding, etc.) and relief from higher temperatures in more developed areas. Most importantly, the role of natural areas in climate change adaptation and mitigation first and foremost should be to support native species and ecological processes. This chapter is designed to help land managers determine which option or options are most appropriate for their properties.
Assessment activities are the first step in incorporating climate change impacts and actions into stewardship planning and natural areas management. Assessments are important to understand the current conditions, identify what species and habitats may be most vulnerable to climate change, evaluate physical changes like soil loss and changes to stream flow, and evaluate runoff and groundwater hydrology. Data from assessment and monitoring activities is important in identifying management strategies required to adapt to new conditions and essential to understand how to adapt management actions to meet management goals. Assessments form the basis of an adaptive management strategy.
Natural areas managers must first identify which plants and animals are most vulnerable to climate change impacts. This is a complex task. Species vary in their tolerance of, or adaptability to, change or to the expected climate conditions, resulting in a group of “climate winners” and another group of “climate losers.” We can make assumptions that species at the southern edges of their range may be most vulnerable to climate change as these areas are more likely to become too hot to support such species. Likewise, species found in isolated habitats, such as forest patches surrounded by development or agriculture, may lack the habitat connections needed to migrate.
There are tools available to help understand species vulnerability, such as NatureServe’s Climate Change Vulnerability Index, which is a spreadsheet-based tool that allows the user to record research findings in an organized format to synthesize anticipated threats to biodiversity or to particular species. The tool helps resource managers prioritize strategies for climate change adaptation by better understanding which species may naturally persist in an area, which ones may decrease in prevalence over time without intervention, and which species may move into an area. This information can then inform conservation priorities, goals, and actions. Another source of information is DCNR’s Climate Adaptation and Mitigation Plan which includes lists of common tree species native to the mid-Atlantic region and their projected vulnerability to climate change.
Management of natural areas in relation to climate change is often focused on actions to adapt to the new changing conditions brought about by human-caused climate change and minimize their impacts on the specific species and natural communities found there. These management actions are often organized into three categories resistance, resilience, and transformation, or “R-R-T.”
All of these approaches can help maintain some or all ecosystem services under new climatic conditions. Resistance and resilience options are usually sought for highly valued resources as these options focus on maintaining current ecosystems and functions.
There are some sites in our region where managers are attempting to resist the impacts of climate change. While not addressing the root causes of climate change, resistance measures work to eliminate, control, or slow their symptoms—the negative impacts of climate change—usually as a last-ditch effort for the highest priority species or sites. This approach includes strategies that address ecological stressors such as eliminating exotic plant competitors and pests and preventing wildfires. An example of this type of effort is the protection of old-growth hemlock forests of the Allegheny Plateau, where warmer winters have resulted in the expansion of the hemlock wooly adelgid, a pest that has decimated old-growth hemlock trees across the eastern United States. Within these stands, managers are working to slow the spread of the adelgid by treating large remaining stands of old-growth hemlock forests with insecticides. Resistance measures are often expensive and time-intensive, and by default temporary, and therefore should be carefully planned and implemented as resources are often a limiting factor.
Resilience actions are generally conservative options as these are actions to help ecosystems and populations adapt to new conditions regardless of future ecological states. Resilience options are focused on maintaining natural conditions as much as possible by managing and minimizing stressors, such as by reducing competition from invasive plant competitors, keeping ecosystems intact (not fragmented or developed), and fostering healthy, diverse ecosystems. By having healthy ecosystems, these natural areas will be less stressed overall and more likely to recover from the added stresses and disturbances associated with climate change. Protecting high quality, biologically diverse ecosystems from development is one of the most important components of a climate change resilience strategy. In forests with a diverse composition of native trees and adequate regeneration, resilience options may include accelerating or maintaining conditions favoring old-growth character by allowing a forest stand to age, selectively thinning immature even-aged stands, controlling invasive species, managing buffers to protect intact areas of interior forest, and protecting old trees. In forests with composition or regeneration issues, whether due to historical land uses, such as poor forest management, or current ecological stressors, such as overbrowsing by white-tailed deer, more active management is needed to speed the development of old-growth character, which improves resilience.
Transformation can be used for areas where there is a high likelihood that existing conditions will be very vulnerable to climate change or where converting to a different ecosystem or set of species will have added benefits for climate change mitigation. For instance, in a forest comprised predominantly of species projected to be vulnerable to climate change, a land manager may consider transitioning the forest to a different species composition by planting saplings in light gaps of species projected to be more resilient and creating light gaps by cutting some trees of less resilient species that are beginning to show signs of ill health. Another example is converting a meadow along a stream to a forest or shrubland to better address flooding issues. It could involve creating habitat for rare or threatened species in new areas and assisting with their migration, or simply allowing an area to transition to a new community without interference over time (although the latter approach risks transition to a community dominated by invasive species). However, a lack of confidence in future climate projections or the effectiveness of specific actions may lead to a reluctance to implement transformation activities. For transformation activities in particular, management goals should be carefully developed with the best available understanding of future site conditions and sites should be monitored to ensure goals are met.
This section gives examples of a few possible impacts, opportunities, and management strategies relating to climate change. Other resources may include a broader range of strategies and a more extensive explanation of impacts. The Northern Institute of Applied Climate Science is one such resource that has created extensive “menus” of possible climate change adaptation strategies.
Natural areas may be protected and managed to serve as refugia—areas of habitat projected to be resilient to climate change—for certain species of plants and animals displaced by the changing climate, particularly rare and important species. The Nature Conservancy (TNC) defines a resilient site as “an area of land where high microclimatic diversity and low levels of human modification provide species with connected, diverse climatic conditions they will need to persist and adapt to changing regional climates.” Put simply, these are areas where there are healthy ecosystems with a diversity of climate conditions (including cooler areas along streams or at higher elevations) that can support species despite climate change impacts. To identify specific properties that may possess a greater resilience to climate change impacts, TNC developed the online Resilient Land Mapping Tool, in which users can identify sites that exhibit a high degree of resilience to climate change impacts based on physical, biological, and landscape factors.
Identification of resilient areas may lead to certain strategies:
The Pennsylvania Natural Heritage Program’s (PNHP) climate change connectivity work and mapping (available through the DCNR PNHP website) takes a statewide view of the most critical connections that may allow species the best opportunities to move with changing temperatures and precipitation.
Pennsylvania is truly a keystone state in allowing passage, largely along the spine of the Appalachians, across the eastern part of the United States for many species. The map below shows areas that PNHP has identified as important for migration cores and connectors. These cores and connectors largely occur along ridges, waterways, and large swaths of connected natural areas. The second map shows how the tool can be used at a more local scale.
Protection and restoration or reclamation of critical areas that secure and enhance the natural habitats within the designated corridors will benefit species at state and regional levels in the face of climate change. Several conservation organizations in Pennsylvania and DCNR have adopted comprehensive land protection strategies that focus on connecting critical habitat.
Strategies:
One key part of managing natural areas in the face of climate change is to control other stressors such as invasive plants and deer. This will boost the overall health and native species diversity of the natural area, reducing stress and making it more likely that the community will be better able to withstand the impacts of climate change. Other strategies include directly restoring species and structural diversity and addressing erosion issues. This may not be a departure from current management practices, yet the added threat of climate change lends additional weight to the importance of these actions.
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While not traditionally a primary reason for protecting natural areas, their carbon sequestration (pulling carbon from the atmosphere) and carbon storage (retaining carbon within biomass, such as within roots, stems, branches, and soil organic matter) potential is an increasingly important benefit of natural areas conservation. Certain tools, like TNC’s Resilient Land Mapping Tool, incorporate evaluation of carbon sequestration and storage to guide land protection planning and stewardship of properties. TNC’s tool is a simple and elegant way to estimate a site’s carbon stock and sequestration rate using models of aboveground biomass, coarse woody debris, soil carbon, and other data. Tools like this are easy to use and provide important information for land protection and management.
Beyond land protection from future development, land managers can take actions in natural areas to improve carbon storage and sequestration. Forests sequester and store carbon at a high rate. Stands of different ages all contribute. Young forests have a high rate of carbon sequestration with a lower level of carbon storage, as the carbon has not had a chance to accumulate in the forest over time. Maturing and mature forests still sequester high amounts of carbon as older trees continue to grow and young trees fill in light gaps, sequestering carbon at the fast rate of young trees, and they have already accumulated more stored carbon than young forests. Old-growth forests have a large amount of stored carbon accumulated over many years, in living and dead wood and in soils. The rate of sequestration is slower as there are fewer individual trees overall and fewer younger trees. However, disturbance of old-growth forest, such as logging, can release large amounts of stored carbon. The best way to keep their high carbon reserves in storage is to maintain them as healthy old-growth.
Young, maturing, and mature forests can be managed to maintain and increase carbon sequestration and storage capacity. Mature trees, with their high level of carbon storage (and outsized role in ecosystem function), should be retained. Increasing forest resilience by promoting tree species diversity and planting species predicted to have high resilience will also increase carbon sequestration and storage capacity. Dead and downed trees should be retained as they continue to store carbon while slowly decomposing. Additionally, forests with dense structural layers sequester and store more carbon than forests with a low abundance of plants underneath the tree canopy.
Grasslands and meadows also store and sequester carbon at high rates. While herbaceous plants do not have the same volume of aboveground biomass and its associated carbon storage potential, their extensive, high-biomass root systems can sequester and store large amounts of carbon. Native plants, perennial warm-season grasses in particular, are more beneficial than turf grasses and introduced cool-season grasses for this reason. Native perennial warm-season grasses’ roots can reach 12 feet deep, in contrast to turf grasses’ and introduced cool-season grasses’ roots, which may only reach 2-6 inches deep.
Shrublands also contribute to carbon sequestration and storage through both aboveground and belowground biomass.
Strategies:
Forests
Grasslands and Meadows
Due to human-caused climate change, Pennsylvania's planting zones have shifted considerably since 1990. Between 1990 and today, Pennsylvania’s warmest counties, Philadelphia and Delaware, moved from zone 6b (average minimum temperature of -5° to 0°F) to 7b (5° to 10°F). Change was also observed in the coldest counties. McKean County moved from 4b (-25° to -20°F) to 5b (-15° to -10°F). Penn State Extension states that it would not be surprising for the zones shift again within the next 20 years in many places in Pennsylvania, as much as a half-zone.
This change will most noticeably impact gardeners, open space and parks managers in urban areas, and agricultural operations as crops, garden plants, and street trees become more heat- and water-stressed. Crops that formerly were impossible to grow in Pennsylvania may become more prevalent. Introduced species formerly invasive only farther south (e.g., kudzu) will become troublesome here.
This change will also affect managers of natural areas as plant communities shift to include species from southern regions and lose species that are already at the southern edge of their range. Land managers may see a changing palette of plant material available from nurseries. Restoration projects often take this shift in planting zones into account, but practitioners must also account for extreme climate events which can include flooding and droughts. Practitioners should plant a variety of native species to increase the probability that at least some species will survive. Practitioners should also plant a variety of forms of plant material in restoration projects—seeds, small individuals (plugs), and large individuals (container-grown or transplanted). This can help increase the likelihood that some of the new plantings will withstand extreme weather events. For instance, larger individuals may be less susceptible to drought while a seedling may succumb to low water availability.
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Increased precipitation and warmer temperatures due to climate change will almost certainly result in changes to Pennsylvania's wildfire frequency and severity. With more frequent and severe droughts, many ecosystems will become more prone to wildfire. Prescribed fire, a key method in the toolkit of natural areas managers, could be more difficult to implement due to climate change, especially with changes to the fire season, local weather, and moisture levels. At the same time, prescribed fire will become more important than ever as a means of wildfire prevention. With more favorable growing conditions and few low-intensity fires in our region, greater fuel loads are almost certain to lead to more catastrophic wildfires.
Wildfires, because of their higher severity compared with prescribed fires, can facilitate invasion of burned areas by introduced plant species. Managers will need to focus more resources and time into invasive species control at sites where wildfires have occurred.
Finally, smoke from large wildfires in western states, Canada, and even locally may lead to more periods of poor air quality, impacting recreational opportunities.
Strategies
Altered precipitation patterns and warmer temperatures due to climate change will result in changes to the frequency and severity of flooding of streams and rivers in Pennsylvania. Managers must consider the destructive forces of floodwaters when managing sites on floodplains. Changes in precipitation due to climate change compound other human-caused changes in flood risk, including increases in the amount of impervious surface in the watershed due to agriculture, construction, and development, and modifications to the floodplain itself. Combined, these modifications and the impacts of climate change will continue to increase the severity of flooding. Typically, managers would determine a site’s potential impacts from floodwaters if the site were situated within the “100-year floodplain,” as defined by the Federal Emergency Management Agency (FEMA). The boundaries of the 100-year floodplain are determined, using historical weather data, as the estimated likelihood of flooding during a 100-year storm, that is, one that has a 1% chance of occurring in any given year. However, the weather is changing every year due to human-caused climate change, so the relevant period of data collection is too short to serve as a basis for accurate predictions. One workaround is to base management decisions on the more extensive, 500-year floodplain.
The tidal portion of the Delaware River (the entire river downstream from Trenton) is likely to rise one to four feet in the next century due to the warming climate and associated sea level rise. Tidal flooding will increase along the lower Delaware, even on days without severe storms, and flooding will increase during storm events farther upstream on the Delaware and along all of the other rivers and large creeks in Pennsylvania. The lower Delaware River’s water is also expected to become more saline as the salt line migrates up the river. Invasive plants, such as common reed (phragmites) are often more tolerant of saltwater than native freshwater marsh species, meaning that that the populations of invasives will likely continue to expand along the Delaware Estuary as a result of climate change.
Changes to flood intensity on all of Pennsylvania’s rivers and creeks may change the species composition of floodplains, as the floodwaters rework alluvial material. This may lead to changes in plant composition as species shift because of tolerance to saturated soils.
Land managers can focus on adaptation and mitigation actions to deal with these impacts. Adaptation measures for increased flood frequency and intensity include constructing permanent infrastructure in a way that can accommodate these changes. Natural areas managers must account for more water when designing culverts and stream crossings, detention basins, retention ponds, and other types of water management and control structures. For example, detention basins adjacent to parking lots may need to be larger to accommodate increased stormwater runoff from more frequent and severe storms. Watershed modeling can help in designing the appropriate size of these structures.
Greater frequency of flooding will result in more time and effort being required to clear flood debris, restore eroded trails, and address downed and hazard trees. Such additional management needs and their subsequent costs should be factored into work plans and budgets. These impacts are likely to extend much more frequently into the 500-year floodplain.
In addition to reactive management after flooding, land managers can also be proactive. Natural areas can play a vital role in flood mitigation due to their general natural cover and lack of infrastructure. Proper management of headwater floodplains, including ecological restoration of floodplain wetlands and hydrogeomorphology (the connection between water, surface features, and geology) can reduce flood intensity downstream, reduce sediment transport, lower pollution, and provide critical habitat for wildlife and plant species. This can include planting riparian buffers where lacking and increasing the density of existing riparian buffers. Land managers can also address legacy sediments to support proper floodplain functionality (see EPA Region 3 Water Protection Division: Stream Restoration Project Shows Benefits of Removing Legacy Sediments).
Removing development in the floodplain improves river floodplain connectivity by creating longer stretches of natural areas along waterways. It reduces the amount of stormwater runoff from impervious surfaces and increases the infiltration capacity of vegetation cover in the areas most susceptible to flooding. This action has the added benefit of creating corridors for wildlife species movement along waterways.
Protecting, restoring, and maintaining or increasing connectivity between freshwater tidal marshes along the lower Delaware River will provide protection against storm surges and tidal flooding. The tidal marshes act as sponges, soaking up water and buffering inland areas from flooding. The more expansive and connected they are, the better tidal marshes can perform these functions.
For any site to provide effective flood mitigation, natural areas managers need to prioritize conservation and management activities that seek to protect and restore natural ecosystem function. This includes actions such as controlling invasive plants, controlling deer browsing, increasing the diversity and abundance of native plants, and minimizing impervious surfaces. (See respective chapters for more information). As an additional benefit, these actions improve the quality of the aquatic ecosystem and mitigate other human-caused stressors.
Strategies
Urban areas may face the brunt of climate change impacts, particularly as many urban areas were built around streams and rivers. Due to the high levels of development and impervious surfaces and relatively low amounts of natural vegetation cover, urban areas are subject to the heat island effect as an abundance of dark surfaces absorb more of the sun’s rays, reradiating them as heat and increasing air temperatures. Asphalt, concrete, automobile exhaust, and heat generated from cooling large buildings all contribute to the urban heat island effect. Impervious surfaces reduce precipitation infiltration, and instead result in high volumes of stormwater runoff. Increasing temperatures and rainfall from climate change will only worsen these effects.
Planting trees, creating green spaces, building green roofs, and adding native plants in urban areas will reduce the carbon dioxide that contributes to climate change. Tree canopies, parks, green roofs, and vegetated areas reduce the urban heat island effect and reduce the need for air conditioning and reduce urban stormwater runoff. Green stormwater infrastructure in particular can be used to capture stormwater and allow it to infiltrate the soil. Examples of green stormwater infrastructure include rain gardens, street bump-outs, and curb cuts. These actions not only reduce direct flooding impacts, they also avoid inundating wastewater treatment systems, which negatively impact the aquatic ecosystems of large rivers when they overflow with stormwater. Furthermore, planting additional native plants throughout urban areas can support pollinators, birds, and other wildlife. For more information on urban planting, see Native Plants and Their Care and Habitat Improvements for Wildlife.
While it may be difficult to prevent entirely in urban areas, development in floodplains should be minimized, and if possible, reversed to avoid putting, or continuing to put, people directly in the way of flooding.
Strategies
Natural areas are significant destinations for outdoor recreation. There are several ways in which climate change will impact recreation opportunities. What is more, certain types of recreation, like motorized boating which burns fossil fuels, can worsen climate change. Land managers can take actions to support recreation in the face of climate change challenges and mitigate the climate impacts of recreation.
Recreational infrastructure such as trails and culverts should be built to accommodate more frequent and greater volumes of stormwater runoff. This can involve increasing the size of culverts and installing green stormwater infrastructure along trails and other recreation-related structures. Land managers should avoid development other than green stormwater infrastructure in floodplains. To help counteract increased heat, trees can be planted to shade recreational facilities like parking lots and trails.
Land managers can also support recreational activities that are low-carbon-emitting such as hiking, birding, canoeing, kayaking, and mountain biking. As a co-benefit, these activities are more generally compatible with natural areas stewardship anyway than recreation activities that emit greenhouse gases. Climate change makes it ever more important for managers to be committed to monitoring impacts, regulating recreation activities, providing up-to-date information to users, ensuring public safety, and addressing impacts from improper uses or overuse as flooding, severe storms, and high temperatures increase.
Strategies
Land managers should monitor for changes to the environment due to climate change and subsequent impacts. Examples of possible monitoring variables include:
In addition to monitoring, land managers should be prepared to act rapidly to address impacts of climate change. Routine, frequent monitoring will help inform when such actions are necessary. Restoration plans should include planning for the uncertainty of extreme climate events and making funds available for adaptive and rapid responses to catastrophic events.
Strategies
If a link is broken, try searching on the keyword string preceding the link.
Pennsylvania Department of Environmental Protection: Climate Action Plan (dep.pa.gov/Citizens/climate/Pages/PA-Climate-Action-Plan.aspx, as of 2024)
Pennsylvania Department of Conservation and Natural Resources: Climate Change Adaptation and Mitigation Plan (dcnr.pa.gov/Conservation/ClimateChange/pages/default.aspx, as of 2024)
Adaptation Planning and Practices for Pennsylvania Forests (forestadaptation.org/learn/adaptation-planning-and-practices-pennsylvania-forests, as of 2024)
Pennsylvania Department of Conservation and Natural Resources: Climate Change Adaptation and Mitigation Plan in 2017 (elibrary.dcnr.pa.gov/PublicAccessProvider.ashx, as of 2024)
The Nature Conservancy: Resilient Land Mapping Tool (maps.tnc.org/resilientland, as of 2024)
NatureServe: Climate Change Vulnerability Index (http://natureserve.org/ccvi-species, as of 2024)
Pennsylvania Natural Heritage Program: Climate Change Connectivity (storymaps.arcgis.com/stories/1afdb4e7fba64c178bff31620cb6808c, as of 2024)
Open Space Institute: Meeting the Challenge of Climate Change—How Land Trusts, Policymakers, and Public Agencies Can Achieve Carbon Goals through Strategic Forest Protection (s3.us-east-1.amazonaws.com/osi-craft/OSI_LandProtectionCarbonGoals_v5.pdf, as of 2024)
Pennsylvania Natural Heritage Program: Priorities for Climate Change Connectivity in Pennsylvania (storymaps.arcgis.com/stories/1afdb4e7fba64c178bff31620cb6808c, as of 2024)
U.S. Department of Agriculture: Climate Change Resource Center (climatehubs.usda.gov/hubs/climate-change-resource-center, as of 2024)
Millar, C.I., N.L. Stephenson, and S.L. Stephens. 2007. Climate change and forests of the future: managing in the face of uncertainty. Ecological Applications 17:2145-2151. (scc.ca.gov/webmaster/ftp/pdf/climate_change/psw_2007_millar029.pdf, as of 2024)