Nature Watch: A Leg Up

About the author: Steve Ellis is a naturalist and Land Trust member who enjoys sharing his love of the natural world. His blog series, “Nature Watch,” will appear each month in “Habitchat,” chronicling native plants and wildlife you can expect to see during that particular time of year. We thank Steve for sharing his passion, illustrating the importance of island conservation.

Overview

The wealth of groundcover crowded beneath the trees in Whidbey and Camano Islands’ forests makes it nearly impossible for a seed to settle into a spot of open soil. The cover of ferns, salal, moss and other growth prohibits the start of new plants. A seed needs a leg up.

Potential sites for establishment of new plants can be found on fallen trees. Seeds drop into tiny fissures in the decaying bark and wood of a downed tree. A nurse log is born.

There are several advantages to sprouting in a fallen log. Moisture levels are maintained in rotting wood even during summer dry periods that parch surrounding soil. Many more pathogens are present in soil than are found in nurse logs. Trees, shrubs and herbs get a healthier start in decaying wood.

Tree seedlings have access to essential nutrients in rotting logs. They also hook up with helpful fungal partners that boost their growth rate and help inoculate them from certain diseases. When a tree falls, it opens the forest canopy so light and moisture can penetrate.

Nurse logs are perfectly positioned to capture these essentials.

While not all flora species find nurse logs inhabitable, many plants important to wildlife and forest health do. Salal, huckleberries, gooseberry and others find nurse logs to be genial hosts.

Among trees, western hemlocks do best at sprouting and growing from nurse logs. Sitka spruce, western redcedar and grand firs also can utilize fallen trees, but Douglas-firs cannot, as they need to take root in non-organic soil.

Not all nurse logs are equal. Douglas-firs outlast spruce and hemlock; the latter two rot away fairly quickly. Red alders and grand fir also waste away soon after falling, making them less valuable as fallen logs Western redcedar with its resistance to decay is the champion of nurse log longevity.

A large fallen tree impacts wildlife in various ways. Squirrels use them as a dining table to eat conifer seeds. Birds stop to rest and preen and thus end up inadvertently planting huckleberries and other shrubs. Small birds cache seeds in downed logs. Logs can impede the travel of deer that can’t leap over or crawl underneath. For squirrels and chipmunks, however, a fallen tree is an elevated superhighway that allows them to scamper along the log’s length at top speed.

You may come across a row of large hemlocks growing in a straight line, a result of their growing in a long-since decayed log. Eventually they too will take their places as a leg up in the forest. A tree falls but the forest continues.

Coastal Black Gooseberry by Martha Ellis.

Flora:  Coastal Black Gooseberry  (Ribes divaricatum)

The genus for gooseberry, Ribes, means “acid-tasting,” it’s definitely not a taste that I’ve acquired!

This shrub grows to six feet tall. The bark on the canes is dark gray to brown. Its leaves are maple-shaped and have three lobes edged with teeth. Large thorns grow near the leaves and blossoms.  Blooming for this formidable shrub begins in May. The flowers hang down in small clusters. Blossoms have long outer petals of a reddish color and the inner petals are whitish. Long stamens protrude beyond the petals.

Gooseberries are pollinated by Rufous Hummingbirds, miner bees, and echo blue butterflies. Berries that are black in color follow pollination.

Cedar Waxwings, American Robins, Black-headed Grosbeaks and Western Tanagers eat the ripe berries. Also taking the fruit are deer mice and Townsend’s chipmunks.

Deer occasionally browse the foliage, but the aroma exuded by the leaves is off-putting to many herbivores. An exception are several moth species that use gooseberry as a host plant.

Coastal black gooseberries can grow in full sun or partial shade. They thrive in moist soils and can be found on nurse logs. They can be grown from seeds or cuttings. A hedge or thicket of gooseberry provides good cover for wildlife.

Townsend’s chipmunk by Martha Ellis.

Fauna:  Townsend’s Chipmunk (Tamias townsendii)

This is the sprightly elf of our forests and thickets.

Townsend’s chipmunks are darker than other chipmunks, with stripes that are less distinct. The body is 5 ½ to 6 ½ inches in length and the tail adds another 4 to 6 inches. It’s the smallest member of the squirrel family on our islands. This chipmunk always holds its tail upwards when traveling, unlike the Douglas squirrel, its larger local cousin.

Preferring dense cover, Townsend’s chipmunks sometimes wander into the open. They can be found amidst scattered bushes or even among driftwood on the beach.

While not truly colonial, this species tolerates others of its kind. They are too busy foraging to get into squabbles as do Douglas squirrels. We’ve watched multiples gathering food from the same source without any signs of aggression.

The diet of Towsend’s chipmunks is quite varied. They eat seeds of conifers, bigleaf maples and alders. I’ve even seen them carefully eating the tiny seeds of oceanspray. Much fruit is on the menu as well. Elderberry, serviceberry, gooseberry and bitter cherry are all forage for them. They also take fungi, plant bulbs and large insects, especially beetles.

Hawks and owls are natural predators of chipmunks, but cats, cars and habitat loss are the main suppressors of their population.

Townsend’s chipmunks excavate dens under the base of trees or beneath large rocks. They cache food in their dens, carrying morsels in their cheek pouches. Stored food is valuable for maintaining their lives underground during the winter. Some local chipmunks truly hibernate, while others go into torpor, a less dormant state. Burrows are occupied starting in late November, with emergence in March.

Females give birth to two to seven kits in May. The young disperse in August.

Many Land Trust properties host chipmunks. By walking slowly, you should be able to see one of Camano and Whidbey’s most engaging creatures.

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