While we were in Yosemite National Park, Laura took us to Mariposa Grove, where there are several hundred mature Giant Sequoias. Two of its trees are among the 25 largest Giant Sequoias in the world.
Giant Sequoias are not the oldest, tallest or fattest trees in the world, although they come close on all three counts. However, their claim to fame is that in total volume the Giant Sequoias are the largest living things known to humans. (Americans seem to like having biggest things.)
Sequoiadendron giganteum is the sole living species in the genus Sequoiadendron, and one of three species of coniferous trees known as redwoods. The tree occurs naturally only in a total of 68 groves on the western slopes of the Sierra Nevada Mountains of California.
The giant sequoias are having difficulty reproducing in their original habitat due to the seeds only being able to grow successfully in mineral soils in full sunlight, free from competing vegetation. Frequent fires, caused naturally by lightning strikes, maintained these conditions. Following European settlement, these fires were not allowed to run their natural course, and now few of the remaining groves have sufficient young trees to maintain the present density of mature giant sequoias for the future. Today, controlled burns are carried out to remove competing vegetation, and the young trees are beginning to grow again.
Wood from mature giant sequoias is highly resistant to decay, but due to being fibrous and brittle, it is generally unsuitable for construction. From the 1880s through the 1920s logging took place in many groves in spite of marginal commercial returns. Due to their weight and brittleness trees would often shatter when they hit the ground, wasting much of the wood.
Giant Sequoias have been successfully grown in other parts of USA, as well as Europe, Australia, New Zealand and Chile – obviously in places where there is lots of room. They very rarely reproduce in cultivation.
Like pets, many of these magnificent trees have been given cutesy nicknames. The Fallen Monarch is one of the first trees to be seen as you enter the grove. The top picture is mine, and the one below is a famous 1899 photograph of F Troop US Cavalry officers on their horses up on top. I was amazed to see how little the tree had changed in over a century.
Tannic acid in the wood suppresses the initial growth of fungi and bacteria, essentially arresting decay. Only when rain and melting snow have leached the tannin from the wood can decay begin. Biologists suspect that this tree had been down several hundred years before the Cavalry photograph was taken.
Unlike the US Cavalry, we weren’t allowed to climb on the Fallen Monarch.
A slice has been carved out of this fallen tree to let visitors into the park.
I think that this is the Three Graces, minus the Bachelor, out of The Bachelor and Three Graces. This is a group of four trees, three of them growing very close together, with a fourth a little more distant. Their roots are so intertwined that if one of them were to fall, it would probably bring the others along with it.
The entire root system of a mature Giant Sequoia is less than two metres deep, but can extend up to four acres in area. Visitors were urged to stay on designated paths to avoid damaging the delicate root systems, so close to the surface.
The Grizzly Giant, estimated to be over 2,700 years old, is the oldest tree in Yosemite National Park, and possibly the oldest on the planet. Its base circumference is 30 metres, and it’s 64 metres tall.
US Cavalry at the Grizzly Giant, 1902.
Photo: C. C: Pierce. (No, I didn’t take this photo.)
As can be clearly seen in this picture, the Grizzly Giant leans slightly, approximately 17 degrees out of plumb. It is able to remain standing because of compensation with root development and additional growth. These giants are often targets of lightning; the Grizzly Giant was once hit six times in a single storm.
This photo was taken in 1903 (Joseph N. LeConte) of a group of dignitaries at the base of the Grizzly Giant. One of the dignitaries is President Theodore Roosevelt (but I don’t know which one.)
Laura and a bit of the Grizzly Giant. My opinion is that she is better looking than President Roosevelt, whichever one he is.
Jan and even less of the Grizzly Giant.
Pat and Laura (and several other people) at the California Tunnel Tree. This was cut in 1895 to allow coaches to pass through it (and as a marketing scheme to attract visitors to the grove.) Thankfully, no such act of vandalism would be permitted today.
Laura in the California Tunnel Tree.
Laura with some little Christmas trees which might be very big trees in a few hundred years time.
Pat and a tree which is big already.
We saw one deer in Mariposa Grove, quite a distance away.
Pat and Laura study the map, dwarfed by the trees.
The tree on the right is the Clothespin Tree. Countless fires throughout this tree’s life nearly severed its trunk, creating a space in it large enough for a pick-up truck to drive through.
The Faithful Couple: This is a rare case in which two trees grew so closely together that their trunks have become fused together at the base.
This picture is a close up of the section where the two trees join together.
This is the Faithful Couple, looking up to the top.
This is the base of the Faithful Couple, showing how the two trees have fused together.
We were lucky to see these striking Snow Flowers (Sarcodes sanguinea). They looked almost artificial, poking up out of the brown leaf litter, with no green leaves of their own.
Sarcodes sanguinea, is a parasitic plant that obtains food and water from mycorrhyzal fungi that attach to roots of trees. Mycorrhizal fungi are themselves symbiotic parasites that help plants fix nitrogen from the atmosphere in exchange for nutrients from plant roots.
It was called the snow flower or snow plant because it was thought to come up through the snow, but it actually comes up after the snow melts or has mostly melted. It grows in conifer forests of California, and portions of western Nevada and northern Baja California.
Thank you Laura, for an amazing day.
Portrait of Dora Maar (1937) 
