Riparian Restoration

Ecological restoration is probably the best kind of work landowners can do to improve the value of their property and provide benefit for the whole Island.  Of all the kinds of restoration, arguably the most important is restoration of riparian zones.

A riparian zone is the vegetated area on either side of streams, including seasonal streams.  A healthy zone consists of plants, animals, and insects living alongside the water course.

The environmental benefits of these zones are enormous.  They keep temperatures cool in the stream, a critical feature if you want to encourage fish to spend time there.  They drop organic litter into the water, providing food to fish and insects as well as replenishing stream soil.  They slow down or halt bank erosion, which, if uncontrolled, can silt up a stream and smother plants at its mouth.

Sad to say, most Island riparian areas aren’t healthy.  For more than a century, many have been stripped away so that the streams they accompany can be “controlled” through channeling or “improved” as property features.  Agricultural/yard chemicals and animal waste now easily enter some streams because there’s little to no riparian buffer to stop them. Stream banks have collapsed along stretches of the Island’s larger creeks due to field runoff that normally would be slowed down if a riparian buffer were still intact.

So you can see the importance of riparian restoration if your property has a stream.  Here are a few basic guidelines for doing the work.

First, be sure the proposed planting area on either side of the creek is wide enough.  Even an area as narrow as twice the width of the creek on either side can be effective.

Plant the area in vertical layers.  Begin with trees that will grow to be an overstory, shading the creek.  Douglas-fir will give fast growth for this purpose.  Bigleaf maple grow fast too and do fine streamside.  Red alder have the bonus of dying relatively quickly (in tree years) and falling across the creek to slow the water’s flow and create cooling pools.

Next, plant trees that will tolerate shade to produce an understory.  Western red cedar and grand fir are good picks here.  Native willows are an obvious waterside choice.

Then install a shrub layer consisting of woody-stemmed perennials like osoberry, snowberry, and Douglas spiraea.

Lastly, fill in with a groundcover.  Here, too, commonly available species, like sword ferns and sedges, can fill the bill.

There’s really no need, in your restoration, to plant the water’s edge right away.  You can add semi-aquatic plants there once you’ve stabilized the bank, created some shade, and gotten a little ecosystem effect from the bigger stuff mentioned above.