Arbutus

Arbutus
(Arbutus menziesii)
Written by Moralea Milne and Jim McPherson

RANGE

The Arbutus (known as madrone in the U.S.) is one of the most unique trees of Canada’s west coast. It is found from Mexico to southern Vancouver Island. In British Columbia it is found within about 8 kilometres of the shorelines of the Straits of Juan de Fuca and Georgia. It is usually found on exposed rocky bluffs overlooking the ocean, but the tree will grow well on deeper soils as well.
Arbutus have been found as far north as Quadra Island and Discovery Passage and on the west coast of Vancouver Island at the head of Nootka Sound.

HABITAT AND LIFE HISTORY

The Arbutus needs little in the way of tender loving care. The tree is found on very dry, excessively drained sites, such as exposed rock and rocky soils. It loves the sun and has adapted to survive the prolonged summer dry spells of southern Vancouver Island. The arbutus is a very useful for erosion control on disturbed sites.
Rufous Hummingbirds and bees are both attracted to the flowers. The berries are food for waxwings, robins, thrushes, band-tailed pigeons, and woodpeckers. Secondary cavity nesters such as tree swallows use the natural cavities created by broken branches for nest sites.
Arbutus may be associated with other species such as Garry Oak, Douglas-fir, oceanspray, salal or Oregon-grape.
The rare mushroom, Tubaria punicea (Christmas naucoria) only grow from the hollowed and rotting centres of ancient arbutus trees. These dark red mushrooms of late fall and early winter have been found on arbutus trees in Metchosin.

DESCRIPTION

Arbutus is the only native broadleaf evergreen tree in Canada – it does not lose its leaves in winter. The largest member of the heath family (Ericaceae), the arbutus is also related to rhododendrons, blueberries, kinnikinnick, manzanita, heather and salal.

The Arbutus will grow up to 30 metres tall. It often has a crooked or leaning trunk that divides into a number of crooked branches. It can survive the harshest west coast storms in the winter withstanding high winds and pounding ocean waves. The main stems of arbutus are rigid and seldom break under the strain of vicious winter storms. But a thick accumulation of heavy wet snow may weigh so heavily on branches that one or more branches might snap off

According to British Columbia’s Big Tree Registry, the largest Arbutus in British Columbia is located on Thetis Island. The circumference at breast height of this specimen is 6.64m. The tree is 35.54m tall and has a crown spread of 25m.

Metchosin's largest arbutus is located at Witty's Beach. This specimen has a circumference of 4.24m, is 28.04m tall and has a crown spread of 21.03m.

Leaves: New growth leaves are coarse, shiny green and almost waxy to the feel. The leaves are oval to egg-shaped. Since the arbutus is an evergreen, the tree sheds older leaves all the time. Older leaves turn yellow to brown before falling off. Arbutus leaves do not decompose easily. When used as a mulch, arbutus leaves should be ground up to speed up decomposition.

Flowers: Whitish-yellow Arbutus flowers are presented in large drooping clusters. Flowers are fragrant.

Fruits: Berries, globe-shaped, orange to red, about 1 cm across; surface finely granular.

Bark: One of the most striking features of this tree, the bark is what makes the Arbutus impossible to confuse with anything else. The tree has a very smooth reddish bark which curls up and eventually falls off, revealing a fresh new greenish layer beneath.

REPRODUCTION

Arbutus are best raised from seed. They are very hard to transplant from the wild because their root systems are very sensitive. Root rot can quickly set in when arbutus roots are disturbed. Arbutus are adapted to fires and their crown will resprout after a fire, giving them a competitive edge over conifers.

PROPAGATION

If you want to try your hand at growing an arbutus from seed, here’s what to do;
• Collect seeds from October to December.
• Macerate and float off the pulp. Dried seeds or berries can be stored at room temperature for one to two years and at 1-4ºC for longer periods. Air dry at 16-20ºC and rehydrate to separate seeds.
• Moist stratify at .5-4ºC for 30-90 days or stratify naturally outdoors over winter.
• Use a sand/peat medium and transplant to individual containers when large enough to handle.
• Arbutus grow quickly and should be transplanted to their final locations as quickly as possible.
• Water deeply and occasionally the first year. After that the trees are quite drought tolerant. Protect from deer with a wire cage until well established.

THREATS

In BC, the arbutus is fighting a losing battle with development and urbanization. Arbutus grow in just those areas that so many people find desirable and want to build their homes and businesses.

Disease is another ongoing concern with arbutus trees. Arbutus decline is probably the result of a cumulative host of factors, including stress from environmental conditions (drought, soil disturbance and pollution) and pathogens. The possibly introduced canker fungus, Nattrassia mangiferae, is thought to be the major pathogenic agent, with other opportunistic pathogens such as Fusicoccum aesculi and Armillaria attacking stressed trees. It has been postulated that the elimination of fire as a disturbance factor has allowed these pathogens to proliferate.

CULTURAL USES

Since the arbutus tree tends to be twisted and crooked, the tree has not been cut for timber. The wood, however, is hard and beautifully grained and has a rich look to it that makes arbutus wood very suitable for woodworking and carving.
Craftspeople and artists display and sell arbutus items at various galleries and studios on Vancouver Island including the Metchosin – East Sooke “Stinking Fish Studio Tour” and in Vancouver and the Lower Mainland. For further information, see http://www.stinkingfishstudiotour.com/
In Plants of Coastal British Columbia, Jim Pojar and Andy MacKinnon tell us that the arbutus is very important to Aboriginal people. The Saanich used arbutus bark and leaves for medicinal purposes. Straits Salish legend has it that the arbutus provided an anchor against the great flood. Another legend informs us that if the arbutus were to disappear, the Earth would fly apart.

FURTHER INFORMATION AND REFERENCES

We acknowledge and credit the following sources which were used to compile this brief description of the Arbutus. We encourage the reader to go to the references below for further information on Arbutus.

http://www.for.gov.bc.ca/hfd/library/documents/treebook/arbutus.htm
http://linnet.geog.ubc.ca/Atlas/Atlas.aspx?sciname=Arbutus%20menziesii
http://www.britishcolumbia.com/wildlife/?id=28
http://www.fs.fed.us/database/feis/plants/tree/arbmen/all.html
http://www.flickr.com/photos/ngawangchodron/193752251/in/set-72157594209753222/
http://www.bceh.com/arbutus_trees.htm
http://coastbotanicalgarden.org/articles/arbutus.htm
http://www.goert.ca/propagation_guidelines/

And the following publications:

Elliott, M. et al, 2002. Role of Fungal Disease in Pacific Madrone. NWest Science Vol 76, No 4
Fenger et al, 2006. Wildlife and Trees in British Columbia. Lone Pine Publishing.
Klinka, K. et al, 1995. Indicator Plants of Coastal British Columbia. UBC Press.
Pojar and MacKinnon, 1994. Plants of Coastal British Columbia. Lone Pine
Publishing.