• Giant Sequoia Trees

    Sequoia & Kings Canyon

    National Parks California

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  • Sequoia and Kings Canyon National Parks Institute Stage 2 Fire Restrictions

    Effective July 28, 2014, the parks are in Stage 2 fire restrictions. See link below for more information. These restrictions will remain in place until further notice. More »

  • Road Construction Delays on Park Roads for 2014 Season

    Expect occasional 15-minute to 1-hour delays in Sequoia and Kings Canyon National Parks on weekdays only (times vary), including delays to/from the General Sherman Tree, Crystal Cave, and Grant Grove. More »

  • Vehicle Length Limits in Sequoia National Park (if Entering/Exiting Hwy 198)

    Planning to see the "Big Trees" in Sequoia National Park? If you enter/exit via Hwy. 198, and your vehicle is longer than 22 feet (combined length), please pay close attention to vehicle length advisories for your safety and the safety of others. More »

  • You May Have Trouble Calling Us

    We are experiencing technical problems receiving incoming phone calls. We apologize for the inconvenience. Please send us an email to SEKI_Interpretation@nps.gov or check the "More" link for trip-planning information. More »

Restoring Landforms and Soils

Excavator reworks the grade of a steep hill in Giant Forest

Restoration of natural landforms required the use of heavy equipment.

NPS photo

Landforms in Giant Forest had been altered by creating level pads for buildings and parking lots and by cutting into slopes to create a bench for roads. Road construction uses a "cut and fill" procedure where soil from the up- slope side of a road is cut, then pushed to the down-slope side as fill. To reestablish natural contours and drainage patterns, this road construction process was reversed: the fill material on the down-slope side of the road was excavated and placed against the cut slope. The original topsoil could usually be recognized at the bottom of the fill slope and was placed as the top layer of the finished surface.

In some cases there was not enough soil on site to restore the original topography. Because soils brought from other locations may have different physical and chemical properties, may not support growth of the same vegetative community, and may contain seeds of species or genotypes that don't belong in Giant Forest, the use of import fill was minimized. Import fill was used only where necessary to restore natural drainage patterns. In such cases, fill was used in deep layers only, reserving local soil for the surface layer.

 
Small front end loader decompacts soil.

A light tractor decompacts soil and mixes organic matter into the soil's top layer.

NPS photo by Athena Demetry

Soil properties were restored to approximate those of surrounding, undisturbed soils. The most severely altered soil properties were compaction, alteration of aggregate structures, and loss of organic matter. To decompact soils and convert platy and blocky aggregate structures to natural crumb or granular structures, moist soils were cultivated to a depth of 5 to 8 inches with small, agricultural-type equipment . Cultivation was conducted outside the drip lines of mature trees and was halted or made shallower if major roots were encountered. To restore organic matter in the topsoil, highly decomposed forest bark humus was added during cultivation in some locations. Contractors conducted soil tests to determine application depth of humus necessary to raise organic matter content to 7 to 10 percent by weight. Because a major influx of carbon in organic matter can cause soil microorganisms to proliferate and sequester the soil’s limited nitrogen for their own use, nitrogen fertilizer was added during cultivation if soil tests indicated that this was necessary.
 
Line of granite rocks form a small dam across a gulley to check the flow of water.

Rock check dams slow the flow of water and reduce its ability to erode the soil.

NPS photo by Athena Demetry

Loosened soils were protected with wood chip mulch, soil retention blanket, or native litter and duff, which was salvaged prior to demolition if present or was collected from surrounding areas for restoration of linear features such as roads and trails.

During human occupancy of Giant Forest, erosion gullies had developed where roads, trails, and parking lots concentrated runoff from rain storms or snow melt. In most sites, the removal of the hardened asphalt surface and restoration of the landform was sufficient to correct the erosion problem. In sites where the erosion gully would continue to receive concentrated drainage, rock check dams were installed to slow the flow of water and reduce its ability to erode the soil.

All landform and soil restoration work described in this section was accomplished by contractors.

Did You Know?

Fairy lantern wildflowers.

The unusual diversity of climates and ecosystems in Sequoia and Kings Canyon National Parks led to its designation as an International Biosphere Reserve. There are 580 reserves in 114 countries that hold this honor world-wide.