Climate Change and Cultural Landscapes: Adapt

Adapt to Changing Conditions

Resources that are maintained in good condition are better positioned to adapt to a changing climate. Anticipating and adapting to the effects of climate change is a standard part of preservation planning and decision-making. As the NPS adapts management practices to account for the impacts of climate change, goals of preservation remain focused on:

• preserving historic integrity,

• avoiding impairment,

• protecting cultural and natural resources,

• building resiliency in the landscape, and

• preparing for future conditions.

What actions and adjustments does the NPS take to maintain historic resources, preserve historic character, and protect the integrity of cultural landscapes against the impacts of climate change?

Compatible Alterations

When substitutions or alterations are made to a historic cultural landscape to accommodate changing conditions, changes should be compatible in character and preserve the historic integrity. Resource managers must often make compromises between historic accuracy and the realities of maintaining resources in ways that are feasible and appropriate.

Red pine trees form a dense screen around the pool terrace at Val-Kill in 1940.

NPS

At Eleanor Roosevelt National Historic Site, rows of native red pine trees (Pinus resinosa) were planted around 1930, lining both sides of Val-Kill Lane on the approach to Stone Cottage. The trees matured to form a dense screen around the pool terrace and gardens south of Stone Cottage. By the early 1960s, however, the lower canopy had thinned, losing the historic screening. This was likely due to lack of maintenance and pruning, poor drainage, increased shade, and vulnerability to red pine scale (Matsucoccus resinosae).

The red pine scale was most likely introduced in New York in 1939 and has been decimating red pine stands in low-elevation areas of the southeastern part of the state, where hot and humid summers are becoming more frequent. Rather than replace the stand with more red pines, which will likely be vulnerable to the same threats, a substitute pine species would replicate the historic character of the stand.

Meanwhile, a different pest has threatened trees at Rapidan Camp in Shenandoah National Park. The site was developed to be a rustic getaway for President Herbert Hoover and First Lady Lou Henry Hoover during their time in the White House (1929-1933), used for respite, recreation, and meetings. The site was densely wooded, providing comfortable shade in the summertime. This native vegetation was one of the defining characteristics of the site and a feature that the Hoovers were careful to preserve as they did their best to add the buildings of the camp around existing trees.

Hemlock trees created a shaded and secluded setting for Rapidan Camp (date unknown).

NPS

The hemlock woolly adelgid (Adelges tsugae; HWA) is an insect that was accidentally introduced into this country in the 1950s. In its native habitat of Japan, HWA populations are controlled by natural predators and the resistance of their host trees. Unfortunately, hemlock trees in the eastern United States don’t share these controls.

In Shenandoah National Park in Virginia, the insect has killed thousands of hemlocks, destroying valuable shaded riparian habitat along streams and springs and transforming the character of historic landscapes, including Rapidan Camp. Attempting to reintroduce the hemlocks would require extensive treatment with pesticides, and they would likely become infected by HWA. At the Rapidan Camp landscape, one option is to allow the native yellow poplar trees to grow into a canopy. While the character of the deciduous poplars would be different from the historic hemlock glen, it will quickly create a shady, closed canopy of single-age trees with minimal intervention. The shady conditions may shelter a future population of hemlock, once the threat of HWA has passed.

Adelgid infestations are easily recognizable by the appearance of what looks like tiny cotton balls” at the base of the hemlock needles.

NPS / Wheeler

Recent progress in pest management protocols offers alternatives to tree removal, as chemical and biological treatments have shown positive impacts on historic hemlock forests. The use of predator beetles (Laricobius nigrinus), a systemic insecticide called imidacloprid, and monitoring standards are helping to promote a balanced ecosystem and maintain historic character.

Natural Resources

Cultural landscapes often contain natural systems that are part of the historic character. Preservation treatment and management of historic landscapes take into account how to best protect these natural resources and systems, while also recognizing the threats they can carry.

At Mount Rainier National Park in Washington, innovative flood protection protects cultural resources while preserving the scenic views of a river alongside a road. Engineered log jams absorb the energy from glacial lake outburst floods, where a large volume of water is suddenly released as a result of a melting or shifting glacier or heavy precipitation. By imitating the function of naturally-occurring logjams, these constructed features protect historic roads from damage without detracting from the scenic quality and historic character of the landscape.

Open Transcript 

Transcript

Carbon River Project TRANSCRIPT Interview with Eric Walkinshaw, Project Manager & Civil Engineer, Mount Rainier National Park; and Kirt Hanson, Project Engineer & Geologist, Cardno Entrix

Walkinshaw: My name is Eric Walkinshaw. I’m the Project Manager Civil Engineer here at Mount Rainier National Park and we’re at the Carbon River Entrance Area; and we’re involved in a project of installing about five log-constructed flood protection structures. So it protects the entrance station to the park and some other facilities here in the park. We hired the consultant to come in and they did the design work for us for these structures last October of 2010 and now we actually have a contractor on board: Mike McClung & Co., Construction Company (Mike McClung Construction, Inc., Buckley, WA), and they’re constructing these structures for us; and Kirt’s here to kind of oversee that part of the project to make some adjustments if they’re needed on the structures.

Hanson: Yeah, I’m Kirt Hanson, Engineer and Geologist with Cardno Entrix. I’m excited to be part of what I think is a historic project. Engineered log jams have been around in ecologic and bank protection, flood protection systems for going on probably close to twenty years- more likely fifteen- and this is the first project where an engineered log jam has been installed inside of a National Park.

Walkinshaw: We, like I said, we’re constructing a total of about five of these structures, one of which is called an engineered log jam, which is a more beefier structure, and that’s on the leading edge just up upstream, about a hundred yards from us. It’s basically to calm the water, to have some habitat, but also in calming the water it drops out material that the river is carrying, mostly rock and silt. So by doing that it kind of builds up that area so when the river floods again it forces it over more to the center of the channel and away from our banks. So that’s the intent of that, but we had the advantage in this area of having a natural log jam, which is kind of what you see back behind us; there is another one further down where the contractor is currently working. So Entrix designed these linear structures as kind of fences on either side of those to kind of contain that. What they didn’t want to have happen- what we don’t want to have happen, is for those natural log jams to raise up and float and leave. Cause they’re in a good location that’s protecting our facilities but they needed the added help of putting in these structures to kind of encapsulate it so it doesn’t float away-

Hanson: -to reinforce the existing log jams.

Hanson: The first thing the contractor is taking care of is ground water, and McClung has done an absolute fantastic job of maintaining their de-watering systems. That involves an initial excavation to a depth below the bottom of the structure, typically these initial excavations extend 17-18 feet below the ground surface to create a sump. From that point, the ground water is pumped into a sedimentation system where fine sediments are dropped out before being returned to the river. The general, on this particular project, the general depth to the bottom of our excavation is about fifteen feet. That’s where these vertical piles that you can see right behind me, that’s the elevation that those are installed to: fifteen feet below the ground’s surface. This pile, here, is actually, it’s probably about five and a half feet tall from where I’m standing- this is actually over a twenty-five foot pile. So there’s about twenty feet of log buried beneath my feet right here. So following the installation of the vertical piles, there’s an angled log that extends- that log is about thirty-five feet long, extending back into the earth, also excavated to a depth of about fifteen feet below existing pre-construction ground surface. Following the installation of those, other horizontal members are added, racking material out front to help control scour, and also create fish habitat, is installed, and final site grading completed. This is an innovative design, designed to catch additional wooden debris coming down the channel, creating additional habitat, and providing additional stability to the existing park structure and park entrance.

Walkinshaw: Basically all of our rivers are a lot like this. We’re having problems in other areas as far as getting a lot of deposition, getting the river bed higher than our facilities, dealing with levees, dealing with- we’re going to be installing, especially on- hopefully on the the success of these, which I’m really confident that these are going- I mean they are pretty beefy structures, I think they’re going to do the trick- and so we’re going to use them a lot. This is just really the first, as Kirt mentioned, this is really the first location that we’ve done it in earnest, these many structures. So we’re really going to be watching this and seeing how it performs and I’m sure we’re going to use it in a lot of other locations.

Duration:

5 minutes, 33 seconds

Discover what it takes to install flood protection structures such as engineered log jams. In the future, these structures will help protect park facilities and roads from damage from flooding. RT: 05:33

At Vanderbilt Mansion National Historic Site, historic vegetation included highly invasive species like barberry and English ivy. Treatment recommendations for the landscape specified non-invasive substitutions to prevent these plants from spreading into nearby forests.

Endangered nēnē at ‘Āinahou Ranch in Hawai‘i Volcanoes National Park use the landscape for breeding during the winter, where they nest on the ground. The NPS schedules mowing and other maintenance activities so that they do not impact the nēnē.

The Hawaiian Goose, or nēnē, is found only in the state of Hawaii.

NPS / David Restivo

Building resiliency in the landscape helps it to better withstand adverse conditions. This might include selecting stronger materials, improving the health and vigor of the biotic systems, or replacing vulnerable vegetation with more resilient species. At Golden Gate National Recreation Area, drought-tolerant native plantings enhance the historic character and survive the dry summers.

Cycles of Maintenance, Repair, and Replacement

Routine and on-going maintenance, repair, and replacement are always a part of preservation, and this is particularly necessary as conditions change to due to climate change. For example, properly maintaining historic fruit trees improves their health, helping them withstand periods of drought and fend off diseases. The fruit and nut orchards at Eugene O'Neill National Historic Site require routine care and may need periodic replacement as they age.

By 1944, there were about 115 almond trees at what is now Eugene O'Neill National Historic Site. Today, there are about 83, and about 36 are historic. The NPS planted trees over the years to replace missing trees.

NPS

Relocating Resources

There are times when no amount of protection can ensure the survival of cultural resources. In the case of high-value resources, these may be relocated away from the threat.

When the Cape Hatteras Light Station was moved in 1999 due to shoreline erosion, other features of the light station cultural landscape were also relocated. This included moving other structures, retaining their 1870 alignment, and maintaining the spatial layout of the historic structures on the landscape.

While this is a notable example, it is not the only instance of cultural resources being relocated for protection, safety, or a changing environment.

Recording and Releasing Resources to Succession

Finally, some resources will not be able to be saved. The only practical recourse will be to record them and let them go, preserving their stories and lessons through cultural practices.

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These examples show how adaptation can be a reaction to changing conditions, or it can be a proactive response, involving planning and action to physically protect resources from the impacts of climate change.