Author Archives: Rose City Bluff Restoration

In 2023, Neil alerted us to the spread of the Japanese beetle (Popillia japonica), a threat in North America to hundreds of species of plants. The adult beetles damage plants by skeletonizing — consuming material between a leaf’s veins. Jeff has shared that the Rose City Golf Course has several traps for collecting the beetles, though none have been trapped recently. You may have seen the bright green traps around Portland. The Oregon Department of Agriculture (ODA) deployed something on the order of twenty to thirty thousand insect traps during the 2026 season including traps for the spongy moth, Japanese beetle, emerald ash borer, and other agricultural pests.

ODA was able to resume its statewide insect trapping program in 2026 pursuant to the restoration of funding by House Bill 5204. This ODA map of Insect Traps Placed in 2026 shows the location of traps all over Portland. ODA field staff, technicians, and entomologists place and check the traps by navigating to mapped public and private sites, servicing them at regular intervals during the summer, and logging data via mobile devices. Suspected positive catches of high-consequence pests (such as Japanese beetle or spongy moth) are immediately flagged and sent to ODA entomologists for laboratory confirmation.

ODA is especially concerned about the damage to Oregon’s agriculture. Although the Japanese beetle is best known as a pest of ornamental plants, turfgrass, grapes, roses, and fruit trees, it is not limited to non-native plants. Adults feed on many economically important crops, larvae damage turfgrass, and the beetles could also affect native ecosystems, especially oak savannas, and riparian forests. It is a highly generalist herbivore that feeds on hundreds of species of plants. Several Pacific Northwest native species could become hosts. For ecological restoration projects in Oregon, this is an important concern. The Japanese beetle could reduce the value of native plantings for insects, birds, and other wildlife. Though the Oregon white oak is not under widespread attack, oaks are among the beetles’ favorite hosts nationwide. Maples are common hosts, and bigleaf maple is known to be fed upon. Roses are among the beetles’ preferred plants, so there is concern for our wild Nootka. Other native plants that may have at least a moderate chance of appealing to the Japanese beetle include the red alder, serviceberry, ocean spray, Pacific ninebark, and snowberry. In 2023, Oregon officials confirmed the first Oregon white oak known to be infested, and about thirty Oregon white oaks in the Wilsonville area were subsequently confirmed with infestations.

One interesting point for urban restoration work is that the ODA trap network is risk-based rather than uniform. Trap density is much higher in urban areas like Portland because those areas receive the greatest volume of imported nursery stock, ornamental plants, cargo, and travelers — the primary pathways by which invasive insects arrive. Rural areas generally have much lower trap densities unless there has been a recent detection or they contain a specific high-risk site such as a port, campground, or nursery. This is why neighborhoods in the Portland metropolitan area have far more ODA traps per square mile than most of eastern Oregon. The number of Japanese beetles trapped in residential areas has steadily decreased since 2017. If eradication efforts remain successful, the ecological impact on native habitats can be minimized before populations become widespread. For restoration projects, it’s wise to monitor high-value native species such as Oregon white oak, wild roses, and serviceberry during the adult flight season (typically late June through August) and report suspected beetles. You can help by reporting invasive species to the Oregon Invasives Hotline.

We owe the idea for this post to Homegrown National Park and to Heather Holm in consultation with Desiree Narango, Ph.D. for developing the concept of soft landings. Soft landings are diverse native plantings under keystone trees (or any other regionally appropriate native tree). These plantings provide critical shelter and habitat for one or more life cycle stages of moths, butterflies, and beneficial insects. In addition to plants, soft landings also include leaf litter, duff, and plant debris.

One critical step in the life cycle of moths and butterflies is caterpillar dispersal and soft-landing spots make successful dispersal possible. Many caterpillars disperse almost immediately after emerging from the egg. Some species simply crawl to another leaf or nearby plant. Others use “ballooning” (also called silk dispersal), where they release a silk thread and are carried by the wind. Most land only a few meters away, although some can travel tens or even hundreds of meters under favorable conditions. Caterpillar dispersal is extremely risky. Caterpillars face high mortality from birds, predatory insects, spiders, ants, and failure to locate another suitable host. For many species, well over half of all larvae die before becoming adults.

Even though adult butterflies are adept at long-distance movement, the arrangement of vegetation around host plants can influence caterpillar survival, especially during short-distance dispersal and pupation. Native host plants should ideally not be planted as isolated specimens. Instead, restoration designs can improve habitat quality by planting clusters of host plants rather than single individuals, providing nearby native shrubs, grasses, and leaf litter for pupation, and creating a mosaic of vegetation that allows larvae and newly emerged adults to move through the landscape with lower risk.

A restoration site should enable insects to locate suitable habitat to maintain viable populations over time. The Society for Ecological Restoration emphasizes restoring ecological processes, not just species or vegetation. A restored plant community achieves its full ecological function when the insects and other animals that interact with it can also complete their life cycles.

The Oregon white oak is one of the most important native host plants in the Portland area. More than two hundred insect species have been documented using it in some part of its range, and well over one hundred occur in the Willamette Valley. While Douglas fir dominates much of western Oregon, Oregon white oak supports a disproportionately high diversity of insects because it has coevolved with many native herbivores over thousands of years. The Rose City Bluff has many soft landings under its oaks, big leaf maples, pines, and firs. There is one huge oak and many smaller ones that we hope will become major keystone host plants for our insects and birds.

By Luke Coleman, RCBR Volunteer

Hi! My name is Luke Coleman; I’m a rising senior at McDaniel High School and have spent a little bit of time volunteering with Rose City Bluff Restoration. I’m writing in this newsletter, though, because I was asked to share my experience working with Northwest Youth Corps. First, a quick rundown of what Northwest Youth Corps is. Northwest Youth Corps is a nonprofit that works with the forest service, among many other partners, to give conservation jobs to young people. Teens aged 15-18 work on crews of 4-10 people for 5 weeks at a time in various areas in the Northwest, completing conservation projects such as trail building, invasive species removal, and campground cleanup and getting paid for the work they do. I’ll talk specifically about what I did this year and why it was so important for me.

My crew and I backpacked into the Idaho Panhandle National Forest and helped remove brush and dig tread on the 17-mile Saint Joe River Trail (No. 48). Working a total of 185 hours lopping away huckleberries, thimbleberries, alders, conifers, and more that were growing into the trail as well as digging over a mile of tread to create a more flat and stable trail for people to walk on. A large part of the experience, as well, was being able to fully immerse myself in a natural environment. I saw moose and bears, learned to identify trees, flowers, and mushrooms, and ate wild berries. Camping every night under the stars completely removed from society as a whole (technology especially) really made me appreciate the life I was living so much more. I was able to, for once in my life, take a breath.

I can’t say it was ever easy, but I think the challenge was part of the fun, pushing myself beyond my limit, having to crush miles while doing 8-10 hours of work most days. On one day in particular, our crew leader’s step counter hit about 15 miles (I took an extra long nap that afternoon). Through the hardships faced, I learned to be more self-sufficient, able to cook my own meals and treat water and take care of myself; I learned to be more organized and, most importantly in my opinion, I learned to be more flexible and not be so scared of the unknown.

What I can say is that it was super rewarding. This work is important not only because a trail being usable means people can immerse themselves in nature, something that is often missing from our lives in a world filled with concrete and computers, but also because people being exposed to the wonders of the natural world means more people care about conservation. I think there was important emphasis placed on why we do the work we do. A lot of this I learned from the forest service employees that we got to work and talk with throughout the trip. It was really satisfying when groups of hikers passed by us on the trail and complimented our work and helped to encourage my passion for conservation work in general. I was taught valuable skills and knowledge that I hope I can bring to volunteering with Rose City Bluff Restoration. I think it’s really important for youth like me to be involved in conservation, because if we aren’t, in 50 years, who will take care of our public lands?

Thank you for letting me share my experience!

In our last post we mentioned that Douglas Tallamy and his Homegrown National Park are making the case for creating connected habitats. The Homegrown National Park movement emphasizes the necessity of ecological connectivity and wildlife corridors. Traditional nature preserves and national parks are too isolated and fragmented to independently preserve native biodiversity. One of the biggest discoveries in urban ecology is that many small habitat patches can function as one larger network when they’re close together.

Connectivity matters more than size. Modern urban restoration increasingly emphasizes connectivity rather than isolated habitat patches. Networks of connected habitat including residential yards, street plantings, parks, and natural areas often provide greater ecological benefits than the same total area of habitat scattered in disconnected patches. By improving movement, recolonization, and genetic exchange, connected habitat networks enhance biodiversity and increase the resilience of urban ecosystems.

Restoring public natural areas like the Bluff creates habitat anchors. If homeowners within a quarter- to half mile of the bluff also convert portions of their yards to native plantings, those private landscapes can function as stepping stones that improve connectivity for birds, pollinators, and other wildlife moving through the urban environment. The ecological impact of restoring the Bluff can be multiplied if nearby neighborhoods participate in residential habitat restoration. Coordinated efforts over the next 20 to 30 years could create a continuous network of hundreds of acres of connected native habitat, even though most of that habitat would exist in many small patches rather than in large parks. This distributed habitat model is increasingly recognized by urban ecologists as an effective way to improve biodiversity and ecosystem resilience in cities.

Rose City Bluff Restoration hopes to be an anchoring area in a potential wildlife corridor from Rose City Park to the Bird Alliance of Oregon’s new Wildlife Care Center and Nature Sanctuary to Rocky Butte. Many Portland yards have the potential to become a part of this ecological network. We encourage our area homeowners to make their yards stepping stones by adding even just a few Pacific Northwest natives to their yard.

Much of the above was sourced from ChatGPT so we asked it for citations. If you want to learn more about connectivity these are all good places to start:

Rudd, Vala & Schaefer (2002) – Restoration Ecology. This was one of the earliest papers to explicitly apply connectivity theory to urban restoration.

Zhang et al. (2012) – Ecological Engineering. This study developed restoration planning methods that prioritize connectivity rather than simply protecting the largest habitat patches.

Shanahan et al. (2011) – Biological Conservation. This study examined bird communities in urban revegetation projects.

Ossola et al. (2019) – Landscape Ecology (U.S. Forest Service). This research quantified the role of residential properties in Boston’s urban forest.

Sexton & Lawhorn (2025) – Urban Forestry & Urban Greening. A recent review of urban restoration summarized decades of research.

SER – The Society for Ecological Restoration – International Principles and Standards for the Practice of Ecological Restoration. SER has elevated the importance of connectivity in its guidance.

In a recent post we asked whether restoration projects like the Rose City Bluff should adjust plant selection in anticipation of climate change. This is a question for restoration ecology experts who consider policy for much larger restoration projects or even ecoregions. Now, Rose City Bluff Restoration is a relatively small-scale project. But Douglas Tallamy and his concept for a Homegrown National Park are making the case that when we all take part, we create the connected habitats that life depends on.

Seed provenancing in anticipation of climate change is one strategy ecologists consider. Per Wikipedia: “Seed provenancing is a seed-sourcing strategy that focuses on the geographic location of seed sources . . . The traditional approach to provenancing has been to source seed from within the restoration site (local provenancing), but the threats of climate change have sparked debate on whether the use of nonlocal provenances may be beneficial to the longevity of broadscale restoration efforts under specific circumstances.”

Also Wikipedia:  “Although it has been long-maintained that the use of local provenance is best since local seed will be best adapted to the conditions, arguments have been made to move away from the strict use of local provenance for populations that are expected to face rapidly changing environmental conditions in the face of climate change. This is because the use of local provenancing can establish a population that does not have sufficient adaptive genetic variation to cope with future environmental changes, thus compromising the longevity of broadscale restoration efforts. Additionally, the strict use of local provenance has the potential to encourage inbreeding and low genetic variation in a population, further threatening a population’s ability to persist long-term. With this, many new provenancing strategies have been proposed to supplement local provenances with nonlocal ones to maximize evolutionary potential to increase the long-term success of restored populations that are facing changing environmental conditions.”

My understanding is that Douglas Tallamy strongly advocates for using locally native plants sourced from your immediate latitude and eco-region rather than wide admixtures, despite climate change. Tallamy warns against the practice of “assisted migration” or sourcing plants from far south of your area to prepare for a warming climate. Because it’s variability that marks climate change, not a gradual benign warming. Local plants are adapted to historical weather patterns and seasonal shifts at that specific latitude. Bringing in non-local ecotypes can result in plants being killed by unseasonal freezes.

Portland’s youth continue to impress us at Rose City Bluff Restoration with their interest in ecology volunteering. When they come to us through the PP&R website for volunteers (volunteer.portland.gov), when we host a SOLVE event, or when Portland Public School groups visit, our age 13 to 18 volunteers show up, work hard, and are clearly interested in the RCBR brand of environmentalism through restoration.

Most of our area youth have already determined what their summer plans will be, but for future reference here are just a few of the volunteer or paying programs that we’ve learned about from students and parents:

Portland Parks & Recreation (PP&R) offers the Youth Conservation Crew (YCC) program. It provides paid summer work for teens to restore local natural areas, manage community gardens, maintain trails, and explore environmental careers. Crew members work from June 23 to August 7, 2026. Portland Parks & Recreation’s (PP&R) Youth Conservation Crew (YCC) is a paid summer employment program for Portland-area youth (ages 14–19). Teens work in local parks protecting natural areas, community gardens, and trails while exploring environmental careers.

Northwest Youth Corp. Northwest Youth Corps (NYC) provides opportunities for youth and young adults to learn, grow, and experience success through paid conservation service work that enhances public lands and strengthens communities across Oregon, Washington, and Idaho.

Portland Public Schools offer several ecology-oriented programs. For example, McDaniel High School’s Sustainable Agriculture Program is an Oregon State Career and Technical Education (CTE) Program. Students can receive six college credits for taking Intro to Sustainable Agriculture, and four college credits for taking Urban Farming. Through hands-on urban farming and practical gardening, the program offers agricultural and business skills training.

Bird Alliance of Oregon has environmental education programs that explore and connect with the natural world. Through programs for kids like camps, field trips, and mentorship programs, their educators help young people develop a relationship with the natural world, all while exploring wild places and learning about natural history.

We could go on, but we just want to encourage students and parents to think ecology when looking for volunteering, summer job, or future career opportunities. Thanks to all our youth who give us hope for the future!

We have wondered if the efforts of Rose City Bluff Restoration should or could be adjusted in anticipation of climate change. Do ecologists know enough yet to offer advice on what to plant now in anticipation of the climate of the future? Currently we’re focused on planting species that worked in the past (native plants that evolved for our environment), but that may not be the right thing to do in the future. Wouldn’t it be nice to know what native plants might have the best chance for survival in the coming decade(s) and beyond?

A small weed, the mouse-ear cress (Arabidopsis thaliana), has become an important plant for studying how varied species respond to climate change. Arabidopsis thaliana is native to Eurasia and Africa. It’s naturalized in many other countries, including the U.S. It’s commonly found along the shoulders of roads and in disturbed soils. A quick look at iNaturalist found two hundred observations in the Portland Metro area for mouse-ear cress since 2016. We don’t know if it’s been seen on the Bluff, but it was found just a few blocks north in our Roseway neighborhood.

Arabidopsis thaliana is the most widely used model organism in plant biology. Its small genome makes it ideal for experimental genetics. It was the first plant to have its genome sequenced and is a valuable tool for understanding the molecular biology of many plant traits, including flower development and light sensing.

A recent article by Robert Sanders (UC Berkeley), “Plant Evolution in Response to Climate Change,” summarizes a research study from a worldwide team lead by evolutionary ecologist and geneticist Moisés Expósito-Alonso: “For decades, ever since biologists recognized the potential environmental harms from climate change, they have worried that plants will not be able to evolve fast enough to adapt to a rapidly warming planet. But the pace of research to understand how species respond has been slow, typically based on single, stand-alone experiments by isolated research groups around the world.

“Moisés (Moi) Expósito-Alonso grew frustrated with that approach. Instead, he and his colleagues created a network of fellow scientists to plant simultaneous experiments in 30 different climate zones around Western Europe, the Mediterranean, the Middle East, and North America and allow them to evolve for five years, untended except for weeding. The goal of this unique experiment was to tease out how fast these plants — a genetically diverse mix of the common lab plant Arabidopsis thaliana, an annual within the mustard family — would evolve under different climate stresses, ranging from the snowy Alps to the heat of the Negev Desert.”

The study concluded that although rapid (as in just a few years) climate adaptation is possible, understanding which environmental, genetic, or species-specific conditions limit evolutionary survival capabilities will be critical for predicting biodiversity responses to climate change. Though practical applications for restoration work are not imminent, it is encouraging that the research has begun.

This spring we noticed a new patch of dozens of spurge (Euphorbia) on the Bluff along NE 72nd Drive. iNaturalist told us it was eggleaf or oblong spurge (Euphorbia oblongata) which is highly invasive. Once established it aggressively displaces native vegetation. It spreads rapidly via creeping roots and seed pods that shoot seeds up to six feet away. It also produces biochemicals that inhibit the growth of surrounding plants. Seeds can remain viable in the soil for up to 8 years. The plant’s milky white sap is toxic, a strong skin and eye irritant.

Eggleaf spurge is a Rank B plant on the Portland Nuisance Plant List. The site along NE 72nd Drive also contains a native plant community (Rubus ursinus and Toxicodendron diversilobum) so patches of invasive plants should be removed to prevent further degradation and allow the native species to re-colonize. There’s also the potential for introducing another appropriate native species.

We decided to contact (our first time) the Oregon Invasive Species Hotline. As their website explains, invasive species experts in Oregon face the daunting challenge of tracking hundreds of potential new invaders across millions of acres of farms, forests, and waterways. They need the help of Oregonians to be their eyes in the field. By using the Online Hotline to report suspected invasive species in your area you are contributing vital early detection information. The Online Hotline lets you connect with experts to get positive identifications and answers to your questions.

So last week we used the hotline to report our spurge. We heard from a Portland Bureau of Environmental Services employee and he paid a visit to the site the same day. Currently, BES doesn’t seem to have the resources, so we agreed to remove the eggleaf spurge ourselves. They were able to provide us with large bags and Rose City Golf Course maintenance allowed us to put the bags in their dumpster. We have sheet mulched the area with cardboard and a thick layer of wood chips.

We do recommend contacting the Oregon Invasive Species Hotline if you suspect a problem species. You may end up handling it yourself, but it’s still a good idea to make them aware of problems like ours.

In our last post we talked about Oregon white oaks and fire suppression. We got an extremely helpful response from longtime supporters of the Bluff, Lenny and Gisela. We’d like to share it with you because it gets across the point of last week’s post so much better than our mere recitation of facts:

“RCB folks,

My wife, Gisela, and I have enjoyed our walks along the Bluff for a bunch of years now and deeply appreciate all the work you have done. We have some land in Klickitat County near Goldendale, WA and suffered a wildfire a few years ago. A fine grove of grand old Oregon White Oaks was lost. See the photo attached. Here’s the story: we have a spring which not only led these Oaks to grow to immense size but also produced a lush understory of native Willow and Hawthorn. We removed some dead Hawthorn from one fine Oak, but it was very tough work sawing 4″ trunks by hand. But we got some fine firewood for our wood stove, but alas there was so much Willow and Hawthorn, especially dead, that when wildfire struck, they burn with such intensity that the big Oaks were simply cooked.

Keep up the good work!

Lenny & Gisela”

Thank you Lenny and Gisela! Storytelling is such an effective way to inspire and influence. Rose City Bluff Restoration has not set out to merely clear blackberries and other invasive plant species, or to only restore native plants to our neighborhood – we have a long-term goal to build a connected, sustainable community centered around nature, wildlife, and neighborhoods. Storytelling is essential to creating this community. With the return of the Bird’s Eye Café this Sunday, we invite all our neighbors to come out to volunteer or to tell stories. If you have a story you’d like to share, please tell us.

One area of the Bluff just about a city block long has fifteen relatively young Oregon white oaks (Quercus garryana). In 2018 the oaks were overtopped by Himalayan blackberry. Perhaps the most important step Rose City Bluff Restoration volunteers have taken in the past eight years is removing most of the old dry Himalayan blackberry brambles. As the Clackamas Soil and Water Conservation District notes, Himalayan blackberry forms dense, impenetrable thickets, with cane densities sometimes exceeding 100 per square yard. Thickets not only inhibit the growth of native plants, but they also create the type of fire hazard that can kill an Oregon white oak.
Oregon white oaks evolved to withstand the region’s dry summers, poor rocky soils, heat, and long summer droughts. It’s also fire-resistant; mature trees have thick bark and deep taproots. Though Oregon white oak is fire-resistant, it will succumb to the intense, continuous, fuel bed of burning blackberry thickets in dry conditions, especially when mixed with dead vegetation like grasses. The oaks will not, however, be bothered by the low intensity fire suppression once practiced by Indigenous peoples and now by land managers.

In Oregon, land managers are actively restoring oak ecosystems because they are considered more resilient under future climate conditions. These projects aim to reduce wildfire fuel, support pollinators and wildlife, and create landscapes better able to tolerate heat and drought. Historically, Indigenous burning maintained Oregon oak savannas and woodlands. Fire suppression allowed Douglas-fir and other conifers to invade many oak habitats. Climate adaptation efforts on large scales now often include prescribed burning and conifer removal.

Managing the blackberry on the Bluff and removing it completely when practical is an ongoing effort. For oak protection, the next step will be removing much of the invasive English hawthorn which is particularly abundant around our fifteen young oaks. Besides competing with the oaks for sometimes scarce water resources the hawthorns are potential fire fuel ladders. We look forward to the day our oaks aren’t threatened by thickets, invasive trees or damaging fires.