Coniferous Trees Highlighted in January Tours

January 6th, 2016 by Catherine Nelson, Adult Tours Program Assistant

When the Olmsted Brothers first came to the Seattle area in the early 1900s, they were impressed by the size, abundance and beauty of our native conifers. Thirty years later when they designed the collection placement for the Washington Park Arboretum, they made a point of not removing our native trees, but placing the arboretum collection within a matrix of these native conifers. Eighty years later our park abounds with these tall stately beauties.

Many of the first conifers – or (mostly) evergreen trees – acquired in the collection were placed on Foster Island at the north end of the park; this site, while picturesque, turned out to be not so good for the needs of the trees themselves. Now much of our conifer collection resides in the Pinetum, which meets the needs of these plants as it is a site with better sun exposure and soil drainage. The rest of the collection is placed throughout the arboretum in areas suited to the needs of each species.

cupressusguadaloupensisCurrently the UW Botanic Gardens conifer collection includes 41 genera of conifers, comprising 216 species (not including subspecies or varieties) and approximately 2,974 individual plants. Our Sunday Free Weekend Walks in January will focus on this extensive conifer collection. With close to three thousand plants in the collection we cannot see all of them in the 90 minutes allotted, but our guides will show and talk about many of these amazing trees as well as what makes them unique in the plant world.

CguadaloupensisOne of the conifers in our collection that I have come to admire is the Cupressus guadaloupensis var. guadaloupensis, common name Guadaloupe Cypress. We acquired three of these trees in 1989 and two are still living; these plants highlight the conservation value of our collection.

Our Guadaloupe Cypress are not very big and sit unassumingly next to a path in the Pinetum. This tree caught my eye because if its exfoliating bark, which I had never seen on a conifer before, so of course I had to do some research on this tree. I’m glad I did, because it is an interesting story.

These conifers are endemic to Guadaloupe Island in the Pacific Ocean west of the California/Mexico border. Guadaloupe is a desert island and most of its moisture is received through ocean fogs rather than rain. The Guadaloupe Cypress has been cultivated since the 1800s but is rarely used in collections as it will not set seed outside its native habitat and is not necessarily resistant to cold temperatures. In the last century the tree became critically endangered in its native habitat due to a population of feral goats on the island.

A quote from The Gymnosperm Database at Conifers.org:

“For many years the species was severely limited by the grazing of goats, which reduced its population to about 3300 individuals on about 160 ha, with negligible regeneration. However, in 2005, under the leadership of Dr. Alfonso Aguirre Muñoz, the Grupo de Ecología y Conservación de Islas, A.C. succeeded in completely eradicating the goats from this large island and the trees and vegetation are now recovering. This is an uncommon bit of good news in the generally depressing landscape of rare conifer conservation.” Good news indeed.

Planting a Tree? Consider a Conifer!

August 13th, 2013 by UWBG Arborist, Chris Watson
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Black Pine (Pinus nigra)

Washington is known as the “Evergreen State” thanks to our vast conifer forests.  However, large conifers often get overlooked when selecting trees for urban areas.  Conifers such as pine, spruce or fir provide many year round benefits to the urban home or garden. 

The evergreen canopy offers cover for birds and other wildlife.  When planted strategically, conifers can reduce energy costs by shading homes in the summer and blocking wind in the winter.  The expansive root systems of conifers can help to stabilize slopes and reduce erosion.  The canopy of evergreen needles can filter air pollutants and reduce stormwater runoff.  Also, because of their unique form, large conifers will store more carbon and create more oxygen over a smaller area than trees with broad canopies.  Because conifers maximize these benefits all year, these large trees can be an excellent and sustainable choice if  your site has the appropriate space.  In addition to these ecosystem services, conifers often become beloved neighborhood icons as they mature.  

If you have room in your yard for planting a large conifer and live in Seattle, there are free trees available through Seattle reLeaf’s Trees for Neighborhoods Program.  Learn more and apply for your tree here: http://www.seattle.gov/trees/treesforneighborhoods.htm.

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Oriental Spruce (Picea orientalis)