The Union Democrat
Centuries-old sugar pine in Yosemite Valley comes down
Alandmark Sugar Pine tree in Yosemite Valley, the centuries-old namesake for Sugar Pine Bridge on the Merced River below Royal Arches and Half Dome, fell in October.
The old tree stood several yards downstream from the bridge on the north side of the river, and many photos of the old tree exist because of its photogenic location. Photos of the tree in recent decades showed it leaning toward the river and its massive roots structure exposed to erosion from the rise and fall of the snowmelt-fed, man-modified Merced River.
A 1991 diagram of Sugar Pine Bridge in Yosemite Valley notes the bridge used to be known as Kenneyville No. 2 Bridge. Kenneyville was the name of a small settlement with stables, near the base of Royal Arches, that was demolished in 1925 to make way for The Ahwahnee Hotel, which opened in 1927. The bridge itself dates to 1928.
The fallen Sugar Pine is estimated to be nearly 400 years old, predating Europeans, California statehood, and creation of the national park by more than two centuries. The tree was still alive when it fell, and it had green needles despite some dieback from the top, park staff said in comments a week ago on an online post. Scientists say Sugar Pines can live to be 400 to 500 years old.
Park custodians intend to leave the fallen tree in the river where it fell for the time-being. Whether they can leave it fully spanning the river, or they will need to pivot it to move it to one side of the river, remains to be determined based on risk to the bridge, an ongoing floodplain restoration project, and public safety, park staff said.
Asked how the fallen tree could impact the Sugar Pine Floodplain Restoration project on the south side of the bridge, park resource management and science
team members said that if the tree moves downstream and/or is broken up by the river, it would contribute to the park’s goal of improved river and riparian habitat and reconnection of the river with its floodplain, and it would not have a direct impact on the floodplain restoration project.
However, if the tree does not move naturally, it could cause water to back up under and behind Sugar Pine Bridge. That could force more water than anticipated into newly-excavated floodplain channels. Park engineers and other scientists are currently evaluating this and other possibilities, and any actions they may need to take.
When park staff first posted Nov. 6 about the fallen Sugar Pine at Sugar Pine Bridge, they said they lamented “the loss of such a beautiful, longlived tree.” To emphasize human connections to the old tree they posted photos of the tree that included longtime Yosemite ranger and naturalist Robert “Bob” Fry, who worked in Yosemite from the early 1960s to the early 2000s, as well as people on the Merced River next to the landmark Sugar Pine, downstream from Sugar Pine Bridge.
The Merced River Restoration Study, conducted by the National Park Service and the University of California, Santa Barbara, has been ongoing over the past decade. Its goals include evaluation of human impacts to the Merced River through Yosemite Valley; a restoration strategy; and guidelines and designs to implement restoration.
The river in the vicinity of Sugar Pine Bridge is over-widened, locally confined within its banks by riprap, and largely disconnected from its onceactive floodplain, according to hydrologists and other scientists.
The restoration study team was specifically asked to perform further hydrologic impact studies to try to more completely understand the effects of Sugar Pine Bridge on the river’s alluvial nature.
Because effects of any single structure on a river can only be understood in its broader watershed context, the scope of the restoration project extends to upstream boundaries of the Merced River watershed, with particular focus on three linear river miles between Happy Isles Bridge and Sentinel Bridge near Yosemite Village, according to park staff.
This stretch of the Merced River and its floodplain is among the most human-occupied and heavily-visited areas in the park, where a combination of manmade housing structures, commercial structures, office buildings, museums, campgrounds, roads, paved trails, unpaved trails, bridges, parking lots, a library, a post office, a courthouse, and a skating rink compete with unique natural resources.
For more information about the Merced River Restoration Study, visit www.nps.gov/yose/learn/ nature/ mer ced restorationstudy. ht mon line.
There are more than a dozen bridges in Yosemite Valley. Most of them span the Merced River and many of them were built in the 1920s or earlier.