National Pride

The land in Yellowstone is fragile and complex. Management policies differ, as do vegetation techniques from those used within the boundaries of the National Park Service (NPS) in Yellowstone. In Yellowstone National Park vegetation techniques are used which promote natural processes to include salvaging of existing topsoil, collection of indigenous native seeds, and minimal disturbance to resources and hydrology. Design elements reflect the historic character of the park roads.

The park’s Grand Loop Road is historically significant and is on the National Register. One of the elements of significance is historic road character which must be retained as roads are changed. Aging park roads are in need of restoration and reconstruction to repair poorly built road bases and to widen the surface to accommodate increasing sizes of vehicles. The multi-mile road program will cost $280 million and require 30 years to complete. Several segments of road involving 10-30 miles of road are under construction each season. It takes seven years to plan and build a segment of road. Park Landscape Architects are involved in the process from planning through construction.

Disturbance is minimized on all park projects as a strategy to reduce the impacts of construction and the cost of mitigation.

Revegetation Principles Used at Yellowstone National Park

A bridge crossing Nez Perce Creek on the Fountain Freight Road was upgraded using simulated stone. The concrete patterning was developed from the historic Nez Perce Creek bridge and adapted for use on the smaller bridge as a cost-saving.

• Where possible, only one side of a road that is being widened will be disturbed, leaving older growth and undisturbed vegetation on one side of the new road. This also allows the historic alignment to be preserved.

• Landscape Architects assist in the placement of construction limits so that the cuts are curvilinear following drainages and natural features as opposed to straight, harsh lines.

Simulated stone walls made of concrete are also used. Paul Nasvik of Milestones, Inc. has worked with the park to produce carefully crafted walls that resemble historic walls.

• Large, specimen trees are saved where possible.

• Curves and views are retained on park roads.

• A detailed specification package is included in the construction documents.

Stone masonry detailing retains historic road character along park roads. This exhibit is near Nez Perce Creek.

• Interdisciplinary teams of Yellowstone Park staff work with Federal Highways staff during design and construction to

assure that the intent is carried through the entire project. Training continues with the construction crews, as wildlife management and vegetation conservation are discussed. Before any clearing occurs on park projects, the construction crew is advised of park topsoil handling requirements (which are also included in the specifications for the work. Topsoil management is critical to protecting park vegetation resources. The park climate is harsh and precipitation occurs in the form of snow for six to nine months each year. Decay and organic material formation in soils is very slow in this region. (It is like trying to grow things in a refrigerator/freezer.) Soils are also very low in nitrogen (which is required for the digestion of wood fibers by ungulates.) Still, park vegetation is evolutionarily adapted to the climate. So many species inhabit each space. The goal of restoration is to preserve the critical ecology of the project area to enable the species to regrow. This must all be done in an economic manner.

• Careful removal of topsoil, defined in Yellowstone as the upper most layer of organic material, including woody material 3" in diameter or under 3’ in height, is performed by equipment such as excavators.

Park roads thread through fragile resources. Beryl Springs is one of the hottest thermal features in the park.

• The topsoil is windrowed in a line at the top of a cut and at the bottom of a fill. This keeps the topsoil clean, unmixed and in the same general location from which it originated. Topsoil stored in a pile creates gases, which kill mycorrhizae and seed causing the soil to be voided of growth potential. Topsoil which is mixed with lower layers of material or topsoil from another area is also diluted and does not contain the same seed materials. Using existing topsoil serves the best function of providing the park with genetically indigenous, economic material. It came from the site and if returned will provide the best possible mixture of seed for the site. Wetland topsoils are handled similarly but even more carefully.

• Topsoil must be replaced as soon as possible in wetlands and must be replaced before winter in all other locations. Because existing topsoil is so carefully handled, additional seed is only required to augment, not replace this effort.

Topsoil being replaced on a soil slope with an excavator. Woody materials are included in the park topsoil material. These provide shade and shelter for windblown seed.

• Seeding is done in the park using hand-collected, indigenous natives, which are cleaned and then sown, on the site. Yellowstone has an Interagency Agreement with the Natural Resource Conservation Service, Bridger Plant Center to provide expertise in seed cleaning, storage and any plant propagation requirements. Seeding is expensive and could potentially alter the genetics of an area, so it is minimized.

• No additional fertilizer is used on park projects because of the resulting effects on vegetation. Fertilized vegetation (particularly nitrogen) attracts ungulates and causes the vegetation to grow in unnatural patterns in the park.

Yellowstone Park’s Landscape Architects work to restore balance in form and function in each construction project. The result is a compliment between park resources and historic roads.

• After the topsoil is replaced, dead trees from the area are placed on the slope to create an area for plant colonization and erosion control. A small amount of collected seed is used on the uphill side of the slope.

• Each area is then lightly mulched with a partially decomposed, inert, shredded bark mulch; a combination of Douglas fir and cedar which holds moisture and catches windblown seed. The moisture retention of the mulch is important because the park soils contain obsidian sand, which is a dark glass. Dark, hot sand dries out very quickly and moisture percolates through the fine grains rapidly. Emerging seedlings can desiccate quickly without the moisture and cover provided by the mulch. Mulch products are very important but controversial in Yellowstone. The Douglas fir/cedar combination has been used successfully for 16 years. It is the most economic, environmentally desirable product for use in this specific area. Other products have not tested well and are not used. Hydromulching is not used because of the tacifier and the contents of the mulch. Excelsior products of any sort, including rolls, attract ungulates because they contain aspen, which has a high nitrogen content. Jute mesh or other mat type materials of any form are not used in the park because of the conflict with wildlife and soils. Hoofed animals get caught in the products as do birds and snakes. Because of the concentrations of herds, none of the products is desirable for use in this area. The park has clay in some of the soils and fibrous products such as jute or burlap harden and become impermeable to growing plants.

Stone masonry walls are used where visitors touch surfaces in designed viewing areas. This newly built wall at Steamboat Geyser Overlook utilizes stone from a rock cut nearby.

Exotic plants are controlled mechanically and chemically before and after construction to reduce their effect. All imported material such as gravel comes from a certified weed free source or is heated to kill any seed that might be brought into the park. Earth moving equipment is steamed cleaned and inspected before it is brought into the park to reduce possible contamination.

Each slope is designed to follow the historic road edges; the rock faces are carefully sculpted and shaped. Soil slopes are also shaped and stabilized. The form of the slopes and cliffs are important aspects of the vistas in the park. Blasting is done to avoid mechanical faces so that slopes look natural. Pockets are created on the rock faces for topsoil and plants. Hydrology is preserved so that seeps will restore naturally.

Just as rock slopes are part of the historic context of the road, so are the details which contribute to the character. Parking areas are carefully designed to include stone masonry where visitors contact surfaces or where the road crosses water. Where fills must be stabilized or visitors drive but do not stop, simulated stone masonry is used to reduce costs. Secondary bridges are simulated rock while primary bridges on the Grand Loop Road are stone masonry. Stone masonry headwalls are used to face each culvert opening. Masonry waterways and flumes are also found on park road projects.

A rock cut on East Entrance before construction occurs.

Even construction signing in the park takes on park character (and economics.) Since the projects have a life of 30 years, signs are designed to utilize the same post with a variety of changeable sign faces. They follow the aesthetics of the park sign standards.

A large staff of Landscape Architects attends to the details of the park road projects. They work with engineers and other staff experts to provide visitors with roads which reflect park values and experiences. Since most visitors spend the majority of their time along road corridors during their visits, road edges may be the largest component of their experience.

Eleanor Williams Clark, is the Chief Landscape Architect for Yellowstone National Park. Clark spent her under graduate years influenced by the Olmsted landscape that comprises the grounds of Smith College, later she received a M.L.A. from the University of Colorado. Clark first worked at the NPS Denver Service Center before moving to Yellowstone sixteen years ago. She heads a Branch of Landscape Architecture which includes ten Landscape Architects, plant technicians, sign makers, and laborers. The Branch is involved in the multi-million road restoration, cultural landscapes and design for park developed areas. Clark is licensed in Wyoming.