Climate Change and Cultural Landscapes: Mitigation

The NPS responds to the impacts of changing climate while also aiming to reduce the impact of our own operations. Mitigation includes actions to quantify and reduce our carbon footprint by improving efficiency, minimizing waste, reusing material, and conserving ecosystems that store carbon.

Building resiliency in the landscape can help resist against the effects of climate change and reduce the demand to consume further resources. Landscapes with healthy, balanced systems can be more self-sustaining and require less maintenance. Improving soil health, increasing organic matter and natural nutrients, encouraging healthy root systems, and maintaining vigorous, disease-free plants and trees are ways to build resilient landscape systems.

After trees were planted in the historic orchard area, staff and volunteers added mulch to support tree health.

NPS

Landscape maintenance can contribute significantly to a park’s energy consumption and waste generation, so it can also be an essential opportunity for improving sustainability in park operations. Cultural landscape managers can reduce the impact of landscape care by using environmentally responsible practices in landscape maintenance, intentionally targeting the level of maintenance required in the landscape, and building healthier, more self-supporting systems in historic landscapes.

Landscape planners incorporate potential environmental impacts and their mitigation in treatment recommendations, considering both routine maintenance and long-term management.

Historic Character

Maintaining turf grass is a major landscape maintenance activity across the National Park System, and it can result in a significant use of greenhouse gas, water, fertilizer, and herbicide. Solutions to reduce mowing can help parks move toward a lower carbon footprint. For example, a Cultural Landscape Report (CLR) might recommend a mowing plan that reduces the area or frequency of mowing to best represent a significant time period. CLRs help define character objectives and establish a goal for the appearance of a landscape based on a historic period, past and present uses, and change over time.

The south lawn of Glenmont at Thomas Edison National Historical Park was historically a meadow, speckled with daisies, black-eyes Susans, buttercups, and wildflowers. Once a grazing area for cows and horses and cut for hay, the area has been maintained as mowed turf grass in recent years. The CLR treatment plan recommends converting a portion of the lawn to meadow by increasing the variety of species and reducing the frequency of mowing.

The south (lower) meadow area of Glenmont was used as a grazing area, where cows helped to maintain the vegetation (no date).

NPS / Thomas Edison NHP Archives

Converting specific areas of turf into meadow would result in a substantial reduction in the area that is regularly mowed. This reduction in mowing can have a striking impact, both in terms of reduced energy consumption and enhanced historic character.

Focused Management Areas

Focusing management on specific areas can also reduce the overall amount of maintenance resources that are used in the overall landscape.

At ‘Āinahou Ranch in Hawai'i Volcanoes National Park, the garden around the craftsman house has a highly ornamental, residential character. Horticulturist Herbert Shipman developed the property from 1941 to 1971 as an aesthetic showcase of his botanical collections from around the world, incorporating the natural lava features and patterns of native trees and outcroppings. Today, landscape maintenance at the site is primarily focused in the area around the house. Areas associated with historic views or circulation receive periodic mowing to keep grass moderately low, while other parts of the landscape are only mowed when necessary.

A similar strategy was used at Fort Baker, part of Golden Gate National Recreation Area, where a portion of turf areas in the parade ground were converted to meadow to reduce the park’s mowing.

Reducing Resources through Substitutions

Substituting non-historic species or varieties that are better adapted to current conditions can reduce the use of resources. Substitution commonly occurs when there is an opportunity to supplement existing vegetation, reintroduce vegetation that has been lost, or replace of non-historic vegetation. This can help reduce the need for water, pesticides, and other maintenance activities like pruning or mowing.

At Vanderbilt Mansion National Historic Site in New York, the plant palette for the formal garden is compatible with historic conditions, and it also gives park staff and volunteers flexibility to accommodate plant availability and maintenance needs. A Cultural Landscape Report provides guidance on character, size, color, texture, and arrangement of the annuals, perennials, vines, and roses in the garden beds.

Lower Perennial Garden at Vanderbilt Mansion National Historic Site.

NPS

The formal gardens, a defining feature of the designed landscape, were originally laid out in 1875 and later altered by the Vanderbilts in the early 1930s. They represent the work of several notable landscape architects and horticulturalists and are characteristic of Gilded Age estates.

Irrigation ditches bring water from Rainbow Creek to Buckner Orchard in North Cascades National Park. Construction on the system began in 1911, and the family obtained water rights in 1912. This method of irrigation continues to be used to water the historic orchard.

NPS

Historic Landscape Practices

Sometimes historic landscape practices are revived or modified to meet current needs while reducing resource use.

This can enhance historic character through land use, encourage sustainable practices, and provide an opportunity for interpretation.

Water-wise irrigation practices can supply water to historic vegetation while minimizing the overall consumption of water. These methods include the use of drip irrigation, solar pumps and controllers, irrigating at night, and irrigating only when needed.

Other Landscape Practices: Mulch, Equipment, Weeding, Composting

• Using mulch reduces water consumption by reducing evaporation. The choice of mulch should consider function as well as historic character. For example, mulch used at Manzanar National Historic Site needed to be larger particles of chipped wood to withstand the frequent high winds.

• Purchasing or retrofitting equipment to run on alternative fuels, such as propane gas, biofuels, and electricity, can reduce emissions.

• Chemical applications of herbicides, pesticides, and fertilizers can threaten both natural and cultural resources. In addition to the petroleum used to manufacture and transport them and the pollution from storm runoff, these chemicals can damage historic materials.

• Alternative methods for weed management and removal can be effective without requiring the use of chemicals.

• Composting waste and applying it in the landscape returns nutrients to the soil, reduces the use of chemical fertilizers and other treatments, reduces exported waste, and sequesters carbon on site. Nutritional mulch composed of composted materials reduces water loss and returns nutrients to the soil.

Shredded bark mulch extends to the dripline around trees in the historic orchard at Manzanar National Historic Site. In this dry, windy environment, the mulch reduces evaporation and stays in place, helping reduce watering.

NPS

Thoughtfully-maintained historic landscapes are better equipped to endure the challenges of time and change.

By taking a holistic approach to cultural landscape management, landscapes are healthier and can be more resilient to the impacts of a changing environment. Vital, balanced systems are better able to withstand threats like pests, diseases, drought, invasive vegetation, and high winds.