A Faculty of Trees
One in three trees are at risk for extinction.
University Arboretums and Botanical Gardens are a vital defense against diversity and species loss.
Santa Catalina Ironwood Lyonothamnus floribundus ssp. floribundus, Tree ID 91630, Planted 1984 1 of 1 with ramets Discovered in 1874 on just one Channel Island 26 miles off the coast of California, the Catalina ironwoods survive mostly in clonal groves - each tree in a stump spread is genetically identical. Just 110 plants are thought to exist. Seeds from these trees have proven mostly non-viable with only one sapling recorded before 1990. The removal of feral goats has helped increase their chances. A few new saplings have been observed. So if they can reach maturity and they can produce viable seed and this increases the genetic diversity and they don’t cross breed with their fern leafed island cousins- the Santa Cruz Ironwood and they can tolerate climate change, then maybe….
Guadalupe Island Cypress Cupressus guadalupensis, Tree ID 91359, Planted 1976 1 of 11 Almost driven to extinction by feral goats left as food sources by whalers and fur traders in the 1800s, fewer than 200 of this island cypress tree remain in the wild on Isla Guadalupe, a lone volcanic island, 130 miles off the coast of Baja California. The island and surrounding seas were declared a biosphere reserve 2005, the feral goats removed, giving the species the ability to regenerate itself. Its other threat, the diminishing occurrence of fog it relies on for water, continues to jeopardize its future.
Harvested Cork Oak Quercus suber, Tree ID 91345, Planted 1941 2 of 532 The first plant structure drawn by viewing through an early microscope was from the bark of a cork oak. Robert Hooke the 17th century inventor discovered the structure and coined it a “cell” and the word was born. If that isn’t amazing enough the Cork Oak tree can stop desertification, and have its precious protective skin removed over and over again and still thrive. The oldest cork oak in the world, planted in 1783, has been harvested 21 times. Humans have used its bark for at least 5000 years (likely longer). Cork made ancient sandals and wine stoppers, but also insulation, flooring, fishing buoys and today NASA spaceship and electric car components. Cork Oaks were planted at UC Davis when WWII caused a worldwide cork shortage.
UnHarvested Cork Oak Quercus suber, Tree ID 91401, Planted 1941 1 of 532 The first plant structure drawn by viewing through an early microscope was from the bark of a cork oak. Robert Hooke the 17th century inventor discovered the structure and coined it a “cell” and the word was born. If that isn’t amazing enough the Cork Oak tree can stop desertification, and have its precious protective skin removed over and over again and still thrive. The oldest cork oak in the world, planted in 1783, has been harvested 21 times. Humans have used its bark for at least 5000 years (likely longer). Cork made ancient sandals and wine stoppers, but also insulation, flooring, fishing buoys and today NASA spaceship and electric car components. Cork Oaks were planted at UC Davis when WWII caused a worldwide cork shortage.
Torey Pine Pinus torreyana, Tree ID 91837, Planted 1941 1 of 12 Torrey pines live on nothing, they take root and make life on nutrient poor sandstone bluffs battered by wind and eroded by the relentless waves of the Pacific. If you look inside at their tree rings you will see their windward side growth circles are flattened and oblongated from the sheer force of the wind. They harvest the sea air and irrigate themselves - dropping condensed water from long slender needles to below - a much needed source of water during dry months. They survive despite. They are the rarest pine tree in North America, found only in Torrey Pines State Reserve and 26 miles out to sea on Santa Rosa Island.
Santa Cruz Ironwood Lyonothamnus floribundus ssp. aspleniifolius, Tree ID 91293, Planted 1995 1 of 16 Discovered by California’s first forester William S. Lyon in 1884. The fossil record shows ironwoods were widespread in California six million years ago. Space and cool wet weather; the things they needed to survive were lost on California’s mainland when the climate warmed. And the ironwoods went extinct, surviving out to sea on just four Channel Islands. Cousin to the Santa Catalina Ironwood, this tree has been reintroduced to the mainland through nurseries. Its beautiful fern like fronds and white flowers thrive in coastal gardens.
Santa Cruz Ironwood Lyonothamnus floribundus ssp. aspleniifolius, Tree ID 91340, Planted 1995 1 of 16 Discovered by California’s first forester William S. Lyon in 1884. The fossil record shows ironwoods were widespread in California six million years ago. Space and cool wet weather; the things they needed to survive were lost on California’s mainland when the climate warmed. And the ironwoods went extinct, surviving out to sea on just four Channel Islands. Cousin to the Santa Catalina Ironwood, this tree has been reintroduced to the mainland through nurseries. Its beautiful fern like fronds and white flowers thrive in coastal gardens.
Valley Oak Quercus lobata, Tree ID 91247, Wild Origin c 1625 1 of 3350 Oaks are one of the only species of trees that survive better outside a forest. This huge valley oak began growing in the West when the Mayflower was just landing in the East (c1620). It could live another 100 years. But the species is already struggling in a climate that is 4-5 degrees hotter than it evolved in. Valley oaks are classified as a California foundational species, fundamental to the structure and support of other species. A further projected 4-5 degree increase will endanger it and all the species this tree supports.
Coast Redwood Sequoia sempervirens, Tree IDs 5782, 5783 & 5785, unknown planting 3 of 1246 The California state tree, the symbol of Northern California, is known worldwide and was the most planted tree on UC Davis’ campus. The redwoods here are stressed and suffering from limb drop and top dieback in the increased heat and diminishing fog due to climate change. Some fear that there will be no suitable climate for coast redwoods south of San Francisco by 2070 - a staggering possible loss.
Dawn Redwood Metasequoia glyptostroboides, Tree ID 90453, planted 1986 1 of 15 Believed to have originated 100 million years ago where eastern Russia is now, the Dawn Redwood spread across the Bering land bridge to North America, lived and then went extinct about 20 million years ago. Or so it was thought, until a Chinese forester found an enormous dawn redwood (waterfir) in Sichuan province in 1941. Its name, already given to its ancestor fossils, means akin to Sequoia - the Metasequoia. After WWII its seeds were quickly collected and spread to arboretums and gardens around the world, saving the “Fossil Tree”.
Northern California Black Walnut Juglans hindsii, Tree ID 90589, Planted 1934 and Stump Sprout 1 and 1 stump sprout of 32 Northern California walnuts are the mother of all walnut trees, literally. The rootstock that supports the growth of walnut trees world wide was created when Luther Burbank crossed a mother California black walnut tree with an father English (Persian) walnut tree on his Sonoma Farm in 1894. The original species in the wild was believed to be seriously endangered by cross breeding. In 2018, a UC Davis genetics study found it to be more hardy in that area. With only 4 or 5 known wild pre-European settlement communities of trees left in Northern California though, it continues to be endangered by climate change and habitat loss.
Valley Oak with Oak Apples Quercus lobata, Tree ID 29813, Wild Origin unknown 1 of 3350 Oak apples are formed when a wasp lays its eggs into developing leaf tissues. Chemicals injected into the tree by the insect larvae trigger the tree to form globes around the growing larvae protecting the oak but also feeding the insects. Then they dry out, fall off, and the metamorphosed insects fly out. Photographed in winter without leaves I mistakenly thought they were walnuts (it is in a walnut grove). I loved the image and now I love its story.
California Buckeye, Aesculus Californica, Tree ID 91610, Planted 1957
A Faculty of Trees
A handmade artist book covered with a beeswaxed walnut veneer
17.5x13 in, 12 black and white tree portraits
on 30 feet of accordion-ed cotton rag with accompanying text