This image is of a 100+ foot tall Ponderosa Pine in Leidig Meadow in Yosemite Valley, across from Camp 4.
Rock climbers' legend says that Muir climbed this tree in 1869 during a lightning storm. However, it is extremely doubtful that Muir would climb a tree during a lightning storm, despite the risks he often took in mountain climbing. He was a risk-taker, but not stupid.
It is likely that this doubtful legend is confusing the true story of Muir climbing a Douglas Fir in 1874, far from Yosemite, up in the Yuba River country, during a wind storm, not a lightning storm.
Andy Skinner took this beautiful photo of the tree, Moonbeams Lance through the "John Muir Tree," in January 6, 2006.