Skip to main content

Keystone Native Trees Promote Biodiversity

By now, most gardeners understand the importance of native plants in performing our critical ecosystem services. These services are carbon sequestration, soil restoration, food web value, wildlife habitat, watershed value, pollinator habitat, and weather moderation. While the exotic plants we grow in our gardens may perform some of these functions, they do not contribute to the food web in any sustainable way. Native plants, adapted to our area, are truly the workhorses of biodiversity and ecosystem stability.

That said, not all native plants contribute at the same level. In fact, about 5% of plants support around 75% of insects. These are called KEYSTONE plants, because of their critical function and contribution to ecosystems.   And as insects are the food of most vertebrate species, we must support and increase their numbers as much as possible. We can have a positive and quite efficient effect in our yards by choosing and planting local keystone native plants.

Begin with trees, which are the food web powerhouses, both for pollinators (yes, the bees are in the trees!) and for insect bird food. Rogue Valley trees listed in this article will be linked to the Oregon Flora where you can read a description of each. If you have a small suburban yard, some of these trees may not be appropriate. Here are our top keystone trees:

Native Willows (Salix): In the western United States, willow trees host the highest number of moths and butterflies (312 species of Lepidoptera), which are the primary source of food for our songbird nestlings and fledglings. These are NOT the weeping willow planted in yards and parks, which comes from Asia. Oregon willows are widespread and varied.  Several occur in Jackson County. They prefer wet sites and should not be planted on small lots or near drain or sewer lines, as they will invade pipes. But if you have property with a creek, or low wet area, by all means get some established.

Native Cherry (Prunus):  Most of us are familiar with Prunus avium, the sweet cherry introduced from Europe that is now naturalized throughout much of the Willamette Valley and coastal mountains. Birds have carried these seeds to wild areas where they establish. Please plant one of our three native cherries, Bitter Cherry (Prunus emarginata), Klamath Plum (Prunus subcordata) and Chokecherry  (Prunus virginiana). All three are small trees which can be grown in smaller lots as specimen trees or added to a hedgerow along a fenceline to provide screening, cover, food and nesting sites for birds. Native cherries host 240 species of Lepidoptera.

Native Oaks (Quercus): Our local native oaks are Canyon Live Oak (Quercus chrysolepis), Garry or Oregon White Oak (Quercus garryana), California Black Oak (Quercus kelloggii), and a quite nice shrubby chaparral species, Huckleberry Oak (Quercus vacciniifolia). This last is not a huckleberry, but a true oak, with acorns and leaves that resemble Vaccinium. Hence the name. Western oaks host over 200 species of moth and butterflies and tasty caterpillars for baby birds.

There are many other keystone trees you could explore: birches, alders, aspen, poplars, Douglas Fir and maples. Choose trees that are appropriate to your soil and water conditions.

Some of these plants and many more are for sale in our JCMGA nursery, on the SOREC Extension campus, 569 Hanley Road, Central Point. The nursery is open for sales on Wednesdays from 10 am to noon, April through October, and by appointment. Contact Lynn at to schedule an appointment. We also have seasonal pop-up sales, so be on the lookout for those.

Garden for Life!