The redwood family was once a dominant tree association in global forests before the cooling period known as the ice age occurred. Many of these trees became extinct during this prolonged period of climate change. These days, redwoods are found in the far-east and in a relatively small area along the Pacific Coast of the United States.
There are two species of this very primitive family of trees found in North America: the redwood tree and giant sequoia. Both of these trees grow to a very large size and have a long lifespan. Redwood trees are found in a small area along the Oregon and California coastline in an area called the “fog belt,” because moisture so often permeates the atmosphere. Redwoods are one of the fastest growing trees in nature, and mature examples can grow to a height of 250 to 300 feet. Redwood trees are very shade-tolerant, able to thrive below a closed canopy, and eventually developing to a dominant place in the overstory. The very thick bark makes redwood trees quite fire resistant; however, younger redwoods are easily damaged by fire. Despite this susceptibility, most redwood trees sprout vigorously when cut and are quick to grow back from stump sprouts following severe fires.
The giant sequoia does not grow as tall as the redwood or Douglas fir, but it greatly exceeds these trees in diameter. One of the largest individuals, the General Sherman tree, has a 30.7 foot diameter at 4.5’ above ground, and is 272 feet in height. Sequoia trees are found on the west slope of the Sierra Nevada Mountains, usually growing at elevations of 3,000 – 5,000 feet above sea level. This thick-barked tree is also very fire resistant. Sequoia produce a lot of tannins, making them very resistant to insects and disease, and their wood is extremely rot resistant. Sequoias are some of the oldest growing trees, with ages exceeding 4,000 years. Only the bristlecone pine is thought to be older.
The metasequoia tree is in the same family as redwoods and sequoias. Metasequoias were once one of the more dominant trees found across the globe, but their numbers declined until it was believed that this group of trees was extinct. However, in 1942, a grove of sequoia-like trees was found in China that resembled sequoia, but the tree had deciduous leaves that fell off during the fall. Following various discussions on how to classify this tree, in 1948 it was decided that a new genus and species was discovered— Metasequioa glyptostrobodies, or dawn redwood tree. There was only one species known to exist. The dawn redwood tree was deemed a living fossil, with most of its family members having long since vanished from the face of the earth, preserved only in fossil records. Although the dawn redwood has a fairly small native distribution in China, it has found much favor as an ornamental tree, and is widely planted. Dawn redwoods exhibit rapid growth, and can attain 150’ height at maturity. Dawn redwood have attractive red bark and a pyramidal crown that does not require much pruning to maintain this natural shape. Dawn redwood are also resistant to disease and most insects, Japanese beetles and red spider mites being the exception. This insect damage is mostly cosmetic, however. The dawn redwood does not tolerant alkaline soils. The fast growth and large size means that these trees should only be planted in open areas away from homes, roadways, and other structures. Dawn redwoods are normally seen growing in campuses, parks, and large estates.
The Maryland native bald cypress is another example of a deciduous conifer tree. There are two species of bald cypress worldwide, occurring in the southern part of the United States and Central America. Bald cypress normally grow in river bottoms and swampy areas throughout its range. Bald cypress is a fast growing tree that will grow to a height of about 120 feet at maturity. The base of the tree becomes very wide, with woody projections growing around the tree that are called “knees,” which are thought to help the tree with aeration, since it often grows in swampy conditions. The bald cypress is very wind firm, standing up to most hurricanes that batter coastal areas. The wood is also very rot resistant.
There are seven species of yew trees that grow throughout the world. Most yew trees are fairly small, resembling a shrub or small tree. The European and Japanese yew are often used for landscape plantings. The Pacific yew is distributed throughout the Rocky and Sierra Mountains in the west, where it is normally found as an understory tree. A cancer fighting drug called Taxol is derived from the bark of the Pacific yew.
Article by FCFCDB member
Nature Note for 12/23/2018