By Zan Tomko
Welcome to the Cupressaceae family reunion! I’ll introduce you to the family, and then show you around the Arboretum. The big Cupressaceae family tree goes back about 240 million years to the Jurassic period. Over that period, plant life went from mosses, liverworts, ferns and ginkgoes to vascular plants that could move away from wet or swampy areas. These early gymnosperms were cone-bearing plants, which begins the journey that brings us to the modern day at the University of Minnesota Landscape Arboretum.
They don’t look alike now, but arborvitae, or northern white cedar, and juniper, or eastern red cedar, evolved from the Cupressaceae family. Neither tree is a true cedar, making life difficult for horticulturists! During the geologic Jurassic period, the continents were all closer together, but like some families, they drifted apart.
During that time, Cupressaceae began its evolution through natural selection and continental drift. Gradually, arborvitae grew to favor forests with more moisture while the juniper became a pioneer species, adapting to many soil types and preferring dry spaces, like prairie.
Junipers are a pioneer species, the first to arrive in an undeveloped area, but also highly volatile during a prairie fire. Its shredded bark can be gathered and used as a fire starter. The lateral branches are stronger than the main axis of the trunk and can cause breaking or bending under stress. Its needles start out soft and grow into sharp awl-like needles deterring herbivores or other pests while creating protected nesting habitat for small birds.
Wood from eastern red cedar is resistant to rot and used to make fragrant cedar lumber that may have a moth-repellent quality. Naturally weather-resistant, cedar poles and cedar sticks were used by Native Americans as wayfinders on trails.
There are many mature eastern red cedars in the Arboretum’s natural areas, and there are more juniper varieties in the shrub collections and the Japanese and Chinese Gardens.
The northern white cedar or arborvitae, revered in Ojibwe culture, is one of the four sacred plants along with sweetgrass, sage and tobacco. In Latin, arborvitae means “tree of life.” It is high in vitamin C and is used for its medicinal qualities as well as in traditional ceremonies. Like the juniper, the wood is resistant to moisture.
A trait that is shared by the trees in the Cupressaceae family is that they contain terpenes. Terpenes are chemical compounds produced by these conifers as a defense mechanism against herbivores and threatening elements in the environment such as fungi. You may recognize the names (and fragrances) of terpenes such as pinene, camphor, menthol or limonene.
Scientific studies show that the smell of a pine forest has a restorative effect on humans through aromatherapy. These compounds are antioxidants and anti-inflammatory. Vicks VapoRub® is a contemporary medical aid that contains such ingredients and has a direct effect on the respiratory system. Native Americans in this region developed extensive knowledge and practice of using the compounds from plants including arborvitae and juniper.
Between the two different Cupressaceae family members, there may be over a hundred individuals to search out at the Arboretum.
Indoors, gray reindeer lichen (Cladonia rangiferina) has been dyed bright green for an accent on the table decoration at the Eatery at the Arboretum. The natural specimen on the right in the photo above is from Cedar Creek Reserve in East Bethel, Minnesota. In the Nordic areas of the world, this reindeer “moss” lichen is used as a supplementary food for reindeer and humans. People in Iceland even make soup or bread with the lichens.
Zan Tomko is an artist, horticulturist and a Minnesota Master Naturalist. More information about the program is available at www.minnesotamasternaturalist.org.