Yosemite National Park Plans Restoration Of Mariposa Grove

Yosemite National Park officials have settled on a plan for restoring the Mariposa Grove of Giant Sequoias.

Pine cones the size of bread loaves. Trees that climb 20 stories into the sky. These are some of the wonders of the Mariposa Grove of Giant Sequoias at Yosemite National Park.

And under a plan developed by Yosemite staff, these and other natural aspects of the sequoia grove located not far from the park's South Entrance will be better taken care of in the years to come.

The Mariposa Grove, along with Yosemite Valley, was included in the Yosemite Grant that was signed into law on June 30, 1864. This marked the first time the federal government set aside land for protection and is considered to be the genesis of the national park idea. The Mariposa Grove contains approximately 500 mature giant sequoia trees that are among the oldest, rarest, and largest living organisms in the world.

The main objectives of the restoration plan, which is estimated to cost about $21 million according to the final environmental impact statement, include restoring degraded habitat and natural processes in the grove. This includes restoring prime giant sequoia habitat and associated wetlands that currently are being impacted by the parking lot and roads in the lower grove area.

Under the plan, tram tours of the grove will end, most visitor parking at the grove will be removed and replaced with parking near the South Entrance, where free shuttles will carry visitors to the grove. A limited number of parking spaces could be provided in the lower Grove area as well as at the picnic area adjacent to Mariposa Grove Road for when the shuttle is not in operation.

Under the plan, the abandoned historic Washburn Wagon Road alignment to the Grove would be cleared of vegetation and rehabilitated as a pedestrian path from South Entrance parking lot to the Mariposa Grove Road picnic area. Where the Washburn Wagon Road ends in the vicinity of the existing picnic area, a new trail would be constructed for the remaining distance to the lower portion of the Grove, including a pedestrian bridge across Rattlesnake Creek. An accessible trail would be constructed through the lower Grove area, and an accessible overlook to the Grizzly Giant would be provided.

Restoration and improvements to the Mariposa Grove specifically include:

* Restoring giant sequoia and associated wetland habitat

* Constructing a transit hub at the South Entrance which will allow for the relocation of the current parking area away from the grove

* Adding shuttle service between the South Entrance and the Lower Grove area during peak use periods

* Building accessible trails through the grove to allow for improved access without impacting the sequoia trees and other sensitive areas.

* Restoring natural hydrology and reducing noise by eliminating commercial tram service through the grove.

* Establishing a new pedestrian trail between South Entrance and the lower grove area, and several new accessible trails within the grove.

Following a 30-day no action period, the National Park Service (NPS) will document a final decision in a Record of Decision (ROD), which will be published in the Federal Register.

Statement by Neal Desai, Director of Field Operations for the Pacific Region, National Parks Conservation Association

“The National Parks Conservation Association (NPCA) supports Yosemite National Park’s preferred alternative, released today in the final environmental Restoration of the Mariposa Grove of Giant Sequoias plan. The preferred alternative strikes a sound balance between keeping the park’s beloved giant sequoias accessible to the more than one million people who visit the grove each year, while restoring and protecting these precious natural wonders for the long-term," said Neal Desai, director of field operations for the National Parks Conservation Association in its Pacific region. "The proposed actions will inspire stewardship of our country’s special places for the benefit of ours and future generations.

“This overdue plan provides resilience to the big trees by restoring wetland habitat and natural hydrology that sustains the grove for the long term. With its plan to replace the outdated tram system with new trail systems and transit services, Yosemite National Park is taking positive steps to prevent further degradation of the massive, ancient giant sequoia trees while diminishing noise in an area where natural quiet is a cherished gift. NPCA also applauds plans to improve accessibility through road access and a new trail that complies with ADA regulations.”

Traveler footnote: Those huge pine cones are from sugar pines that grow in the grove, not Giant sequoias.


So if you are physically limited or have small children, I guess you will have to go somewhere else to see the great Sequoias. What is the problem with keeping a shuttle that goes through the grove itself? Is there any evidence that the shuttle has caused any damage to the trees? If it is an emissions problem, there are ways to abate that with electric or natural gas powered vehicles. If noise is the only issue, there must be a solution with electric vehicles. If not, we need to remember that a limited amount of noise is an aesthetic issue, not an eco issue. Hydrology? Could not a paved road be replaced with a gravel road for the trams?

The needs of those physically limited by lung or heart disease, limited mobility, and those with small children should also be weighed against those who would demand more quiet. Surely with the added trails there would be places people could walk to be out of range of the sound of a tram.

Don't come back here later and complain about the lack of public support in the budget for the NPS if you are going to turn places like Yosemite into a place where only the younger and healthy can see up close at least a meaningful sampling of the sites such as the Sequoias. What's next? Getting rid of the shuttles and campsites in the valley and dropping visitors off at the Eisenhower Tunnel entrance view so as to reduce the noise?

Drs. Richard J. Hartesveldt, Thomas Harvey, and H. Shellhammer, and R. Stecker


Dr. Hartesveldt also found that road contruction altered the near surface hydrology within the ancient Sequoias Groves, adversely affecting their health; this research was first ignored by Western Region Managers & Scientists despite the death of some Sequoias.

More historical evidence that the NPS Culture has been difficult to change positively concerning relevant new research findings with management implications.

By Richard Hartesveldt, et. al. Visit: http://www.nps.gov/history/history/online_books/science/hartesveldt/chap6.htm

Investigations revealed that soils were severely compacted in areas of heavy human foot traffic. Depending upon the weight of the body and the size of the foot, the latter's force in walking represents a pressure of 5-20 psi of ground surface. In areas where auto traffic had been permitted for years, the compaction was severe and the old roadways traveled by stagecoaches and wagons with narrow- and steel-rimmed wheels were still so densely packed after more than 35 years of abandonment that few woody plants had become established. But these narrow bands of compacted soil covered relatively small percentages of the larger sequoias' rooting areas.
In some regions with no pathways to channel visitors, the soils compacted by human traffic constituted as much as an acre of land. Around such popular trees as the Grizzly iant, compaction greatly reduced water infiltration and the soil's capacity to absorb excessive surface flow. Such accumulated surface water created drainage channelways which then became gullies of erosion as volume and velocity of flow increased. In several places erosion had exposed the roots of sequoias to a depth of a foot and more, threatening the trees' future stability. Likewise, accumulations of water on impervious pavement had created similar channels to the side, some of them 3 and 4 ft deep. Yet to this date, no giant sequoia is known to have fallen as a result of this channeling.

Compacted soils were definitely shown to restrict penetration by roots, an effect that Meinecke believed very important. However, field studies of sequoia growth patterns revealed no sequoias tending toward death as a result, but rather an increased average annual growth rate of almost all sequoias growing in such soils. The soil profile of areas subject to extensive foot traffic showed a soil moisture regime almost universally more favorable than that in untrampled soils. Compaction to a degree restrictive to root penetration generally did not extend much below 6 inches in depth. The compacted layer seemed to form a protective cap which helped maintain the moisture level deeper down. Another important factor was the reduced competition for soil moisture by smaller plant species. The abrasion resulting from human trampling had largely eliminated these plants and consequently reduced most species' reproduction. Considering the relatively small volume of soil sufficiently compacted to be restrictive within a sequoia's rooting zone, very possibly the improved soil moisture at greater depths more than offsets the losses within the compacted zone. Whether affected trees adjust their feeder roots to greater depths, as has been suggested, is yet to be determined. Most significant is the fact that no record exists of a giant sequoia having succumbed due to compacted soil.
Changes in the chemical relationships of soils because of severe trampling fail to show any significance in statistical comparisons. The total organic content of the uppermost—or A1soil-horizon—has changed but little even in those areas where trampling has virtually eliminated the leaf litter layer. Reduction of basic soil nutrients was also light. The increased soil moisture at depths less than about 5 inches would undoubtedly have proven significant had a statistical comparison been made. Although these changes were of no consequence to the larger sequoia trees, they did have a profound effect upon the smaller herbaceous plants and seedlings of both trees and shrubs. Surface soils were powdery dry by late summer and, in these circumstances, sequoias do not seem to produce seedlings at all.
Two other great concerns were the effects of road-building activities, namely, road ballast and pavement placed over sequoia roots, and the cutting of roots from the side of large specimens to accommodate road cuts. Deep cuts made close to a trunk, on occasion, eliminated as much as 35% of the entire root system.
Pavement which covers rather large portions of a tree's entire root system produces growth increases exceeding those mentioned earlier in compacted soils. Not only does impervious pavement eliminate plant competition, but surface evaporative losses are also reduced to a minimum leaving the "relict" sequoia a greater supply of soil moisture that enables growth to continue beyond the normal growing season. In effect, then, the growing season for such trees extends late into the fall and, in some cases, until freezing weather commences in December. One such specimen, the Sentinel Tree, situated between the Generals Highway and the Giant Forest Village parking lot, has about 75% of its root system covered with pavement, causing great concern until increment borings showed the tree growing nearly 50% faster than before the addition of pavement. Vigor of growth, however, may not be the final criterion of man's influence on such trees. The effects have been measured over a small percentage of the tree's total life, and these changes may eventually prove harmful.
Where roadway construction has cut away roots, annual increment to the trunk has declined significantly immediately after severance because of reduced delivery of soil moisture and nutrients to the crown's photosynthetic factory. Root removal would seem to reduce proportionately the crown foliage, just as large burn scars do, yet the trees so affected still have healthy crowns. And, curiously enough, the growth patterns developed during the years since the roots' removal show a gradually increasing growth rate even though the total rooting area has not seemed to increase. This may be due to proliferating feeder roots in the reduced root zone, or to greater lateral translocation of photosynthate in the trunk. Here again, no sequoia has apparently fallen or otherwise died because of either of these disturbances by man. However, considering the regulations governing the management of sequoias, this should not be regarded as license to treat them in such a manner.
The most profound change since the advent of western civilization had hitherto not been suspected, although Joha Muir's observations on the relationships of fire could well have permitted him to recognize it. The change resulted from man's benevolent regard for the great sequoias and his abhorrence of wildfires. His successful program of fire prevention and suppression was more than admirable; yet he had failed to recognize the disadvantage he had prescribed for the sequoia and other early-stage plants whose reproductive success was diminishing in competition with shade-tolerant species. The virtual elimination of sequoia reproduction remains not too serious a problem for species survival. A tree whose life span is 2000-3000 years or more can maintain the species by reproducing under favorable conditions after several centuries of failure. But the circumstances man has created have possibly a more profound effect than he knows, and consequently the studies we have described were undertaken to better understand the relationships of fire to the giant sequoia. Despite considerable knowledge at this time, we can undoubtedly learn much more. Our final section will discuss further these relationships.