Project Area
The eastern hemlock-northern hardwood community type is the most vulnerable community type at Mohonk Preserve due to widespread decline and mortality due to hemlock woolly adelgid. Hemlock-northern hardwood forests are typically found on the property's ravines and lower slopes. The community is dominated by eastern hemlock and is associated with eastern white pine, sugar maple, red maple, yellow birch, black birch, and black cherry. The density of the canopy cover limits the ground layer. Shrubs and herbaceous plants are generally found in low densities.
Management Goals
Four main goals for this project include:
(1) Reduce the loss of bird habitat associated with eastern hemlock decline to minimize negative impacts on avian species and support recreational birding.
(2) Mitigate the long-term hydrologic impacts of hemlock decline.
(3) Assure future vegetation communities provide valuable recreational experience for users.
(4) Assure that HWA impacted stands continue to provide valuable ecosystem services and support desirable species as hemlock becomes less dominant.
Climate Change Impacts
Both the Mid-Atlantic Forest Ecosystem Vulnerability Assessment and the Climate Change Tree Atlas use projections of potential emission scenarios to model future climate change.
The future average temperature is likely to increase somewhere between 1 and 8 degrees Fahrenheit (depending on emissions levels) by the end of the century, with potentially even greater temperature increases in summer and fall.
The intensity and frequency of large precipitation events is likely to continue to increase.
Total summer precipitation is likely to remain unchanged, but the time between rain events may become longer, resulting in decreased moisture availability, especially late in the (warmer) growing season.
The Shawangunk Ridge will likely experience an increased frequency and intensity of disturbances including forest fires, extreme precipitation, and wind disturbances.
The occurrence and damage associated with pests and pathogens also may increase. Increased temperatures have already allowed for a greater prevalence of hemlock woolly adelgid and range expansion of southern pine beetle.
Northern Hardwood species such as American beech, eastern hemlock, and eastern white pine are likely to decline.
Challenges and Opportunities
Climate change will present challenges and opportunities for accomplishing the management objectives of this project, including:
Challenges
Continued fire suppression is likely to shift species composition and structure, for example transitioning pitch pine communities to more oak-dominated forests.
Wind disturbances following Hurricane Irene and Superstorm Sandy have already led to tree mortality and excess woody debris. Future disturbances may accelerate a shift to intermediate-shade tolerant species like white oak, flowering dogwood, and hickory
The stressors of climate change (drought, temperature, etc.), combined with the harmful effects associated with forests pests and pathogens, will play an increased role in tree mortality, reduced tree vigor, and shifts in vegetation community composition
Dominant species such as eastern hemlock and American beech, as well as the ash genre, have already declined as a result of pests and pathogens; milder winters may exacerbate resulting declines in structural complexity and regeneration potential.
Increased herbivory associated with reduced snowpack may also decrease regeneration potential.
Increasing frequency of high-intensity disturbances may result in more single-aged stands.
Extreme precipitation events may increase erosion in riparian areas, threatening vegetation establishment and survival.
Prescribed fire opportunities may decrease with reductions in air quality and soil moisture.
Avian species may respond to climate change in unique ways, making habitat-focused management more difficult.
Milder winters and longer growing seasons may shift plant phenology and increase the competitive advantage of nonnative invasive species.
Recreational opportunities and visitor perceptions will be impacted by disturbances (e.g., trail erosion, fallen trees) and aesthetic changes to the forest.
Opportunities
With abundant moisture, carbon dioxide fertilization may offset the effect of higher temperature on plant water loss, better supporting mature forests.
Increasing frequency of low-intensity disturbances may promote a diversity of age classes and increased structural complexity (e.g., woody debris).
Understory microclimates may be buffered from immediate exposure to climate change impacts, promoting understory density in the short term.
Higher elevations, such as the ridge, may serve as important refugium for some avian species.
Tangible impacts of climate change on forests can become the subject of visitor education and outreach, increasing understanding and support for forest management
Adaptation Actions
Project participants used the Adaptation Workbook to develop several adaptation actions for this project, including:
Area/Topic
Approach
Tactics
Hemlock-Northern Hardwoods
1.1 Reduce impacts to soils and nutrient cycling.
1.2. Maintain or restore hydrology.
1.3. Maintain or restore riparian areas.
1.2. Maintain or restore hydrology.
1.3. Maintain or restore riparian areas.
Explore management strategies that prioritize the protection and facilitation of native vegetation in riparian zones.
Utilize spatial analysis tools to identify areas of hemlock-northern hardwood communities that can successfully support chestnut oak community types.
1.4. Reduce competition for moisture, nutrients, and light.
2.2. Prevent the introduction and establishment of invasive plant species and remove existing invasive species.
2.3. Manage herbivory to promote regeneration of desired species.
2.2. Prevent the introduction and establishment of invasive plant species and remove existing invasive species.
2.3. Manage herbivory to promote regeneration of desired species.
Implement an early detection and rapid response program for invasive species including forests pests and pathogens.
Optimize deer management activities to promote successful regeneration.
Identify and monitor areas of no-management.
1.5. Restore or maintain fire in fire-adapted ecosystems.
2.1. Maintain or improve the ability of forests to resist pests and pathogens.
2.2. Prevent the introduction and establishment of invasive plant species and remove existing invasive species.
3.1. Alter forest structure or composition to reduce risk or severity of wildfire.
5.2. Maintain and restore diversity of native species.
2.1. Maintain or improve the ability of forests to resist pests and pathogens.
2.2. Prevent the introduction and establishment of invasive plant species and remove existing invasive species.
3.1. Alter forest structure or composition to reduce risk or severity of wildfire.
5.2. Maintain and restore diversity of native species.
Explore the reimplementation of prescribed fire as a management tool.
8.1. Use seeds, germplasm, and other genetic material from across a greater geographic range.
8.2. Favor existing genotypes that are better adapted to future conditions.
8.2. Favor existing genotypes that are better adapted to future conditions.
Explore the potential for genetic material management and conservation.