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Home / Author Archives for Charlotte Trowbridge

Charlotte Trowbridge

Why Wood is Good for Streams

July 21, 2023

When you imagine a healthy stream – whether it’s one that runs through an urban neighborhood or weaves through a natural area – does that picture include large pieces of wood scattered across the water? While streams naturally contain obstacles like fallen trees, boulders, and log jams, studies show that people often perceive wood in waterways negatively. They may view it as a safety hazard, a barrier to recreation, or simply a messy aesthetic. But, as it turns out, this “mess” is all part of nature’s plan to create a healthy ecosystem.

Trees naturally fall across and into streams, providing important habitat for aquatic species and stabilizing stream channels.

Trees that grow along streams tend to fall into the water over time. This happens due to natural causes like wind, death, beaver activity, or shifting of the banks that once held roots in place. In areas with lots of human activity, these trees are often removed from waterways to allow for recreation or navigation, or to protect infrastructure. But removing fallen trees also removes an important component of the stream ecosystem.

In recent decades, scientists have learned a lot about how wood in streams benefits the aquatic ecosystem. In fact, the benefits are so apparent that many restoration projects now include adding wood back to the stream to mimic natural conditions.

Still, many well-intentioned people remove wood from streams thinking that they are reducing barriers for fish, facilitating water flow, or improving the beauty of the stream. Understanding the role large wood plays in streams can help us reshape our view of what’s beautiful and notice the many benefits that some woody clutter provides.

What counts as “large wood” when we’re talking about streams?

In the field of stream ecology, large wood is anything that is at least four inches wide and six feet long. This includes whole trees that have toppled across the stream, log segments that have traveled downstream, large branches that have fallen from streamside trees, and clumps of roots. It may appear as a single fallen tree or pile up into a larger log jam. Depending on the type of wood, it can remain in the water for decades!

Large logs lay across a stream.
In an effort to improve part of Clear Creek, a stream in western Washington County, the Tualatin River Watershed Council placed large pieces of wood to create a log jam. The log jam slows water down, decreasing erosion of the streambanks and creating important areas of refuge for aquatic species. Photo: Tualatin River Watershed Council.

Wood in streams improves wildlife habitat.

Fish are some of the biggest beneficiaries of large wood in streams. While some people perceive logs and woody material as barriers to fish movement, they’re important for creating the habitat conditions that fish thrive in. Wood slows water down, making it easier for migrating fish to move upstream. As water backs up behind logs, it creates pools of varying depths and temperatures where fish can rest, hide from predators, or take refuge when water levels are low. The wood also provides shade, helping to keep the water cool.

Fish aren’t the only ones who benefit – reptiles and birds can use exposed parts of logs for basking and perching. Larger animals use the downed trees as pathways for crossing streams and rivers. A wildlife camera set up by Oregon State University researchers captured a wide variety of critters, including cougars, bobcats, and deer, making use of a downed tree to cross a stream.

Aquatic food webs are more robust in areas with large wood.

Wood in streams plays an important role in the food chain. It captures organic matter like leaves and provides a surface for algae to grow on. Aquatic insects and macroinvertebrates, including mayflies, caddisflies, and crayfish, feed on the algae and plant material. In turn, they are eaten by larger organisms, like fish and amphibians.

The more complex a food web is, the better able the habitat is to support a wide variety of species. Increased biodiversity helps ensure that the ecosystem, and species within it, are more resilient to disturbances.

Logs and root clumps help stabilize stream channels.

Wood also helps maintain the healthy structure of a stream channel. It slows water down, which reduces erosion of the stream’s banks. While erosion and movement of streambanks is a natural process, the stability of the stream can be disrupted if it happens too quickly. When wood is removed from a stream channel, water moves through the channel faster, causing soil to slough off the streambanks at a higher rate. Slower moving water also allows sediment, like sand and gravel, to settle to the bottom of the stream. A healthy stream channel has a variety of sediment types, each providing distinct benefits to aquatic species. 

Embracing the “messy” side of nature benefits wildlife habitat.

Large wood in streams isn’t the only case in which nature’s “mess” has positive impacts. Mimicking what we see in nature is an effective way to improve the conditions of our surroundings, whether in a natural area or in backyards and community spaces. Similarly, by leaving fallen leaves on the ground as shelter and food for insects or allowing dead trees to stay standing as homes for birds, we can provide wildlife with the resources they need to thrive.

So, next time you find yourself looking at a stream, see what evidence you can find of woody debris and think about all the wonderful ways it is contributing to a vibrant stream ecosystem!


We’re Seeking Community Members to Join Our Budget Committee

January 11, 2023

Tualatin Soil and Water Conservation District is a local unit of government that helps Washington County communities care for the land and water. We are a non-regulatory organization that collaborates with residents to conserve our shared natural resources for current and future generations. Learn more about who we are and what we do.

We are seeking two community members to join the Budget Committee which is responsible for reviewing Tualatin SWCD’s proposed budget for the upcoming fiscal year beginning July 1st, 2023.

What is the Budget Committee?

The Budget Committee is composed of 14 community members. Seven members are Tualatin SWCD elected Board of Directors, and seven are citizen members appointed by Tualatin SWCD. Currently, two citizen member positions are vacant. Service on the Budget Committee is voluntary. Oregon Budget Law prohibits the District from offering a stipend or other form of financial compensation for service.

What does the Budget Committee do?

The committee will meet a minimum of two times during the months of April and May. The first Budget Committee meeting is tentatively scheduled for the end of April or beginning of May. The second meeting will be held two weeks after the first meeting. There is the potential for a third meeting in May or June. The meetings are held virtually in the evening. The date and times will be finalized in March 2023.

The purpose of the committee meetings is to review Tualatin SWCD’s proposed budget for the coming fiscal year beginning July 1st. The Committee has the authority to make suggestions and changes to fulfill Tualatin SWCD’s mission before it adopts a recommended budget.

Who can join the Budget Committee?

Appointed citizen Budget Committee members must meet the following requirements:

  • Reside in and are registered to vote within Washington County, OR.
  • Willing to serve a three-year term beginning in 2023.
  • Demonstrate an interest in Tualatin SWCD’s conservation work and the planning and budgeting process that supports this work.
  • Demonstrate a commitment to working on a team

An employee or anyone directly benefiting financially from Tualatin SWCD is not eligible to serve as an appointed citizen on the Budget Committee.

We value and seek the perspectives of those with diversity in age, ability, gender identity or expression, marital status, national origin, race, religion, sex, sexual orientation, and/or veteran status.

How to apply:

If you are interested in serving on our Budget Committee, please complete the Citizen Budget Committee Member Interest Form below.

You may also download the form and mail it to: Tualatin Soil and Water Conservation District, 7175 NE EvergreenEvergreen Plants that maintain their leaves all year long. Parkway, Suite 400, Hillsboro, OR  97124

Forms submitted by February 1, 2023, will be reviewed first. Following the deadline, forms will be accepted and reviewed on a rolling basis, as needed.


Join Tualatin SWCD’s Board of Directors – Elections in November 2022

July 21, 2022

Do you love your community and want to help keep it healthy and thriving? Do you have ideas on how public funding could be used to better serve Washington County residents? If so, Tualatin SWCD’s Board of Directors could be the place for you to share your thoughts and expertise!

On November 8, 2022, Washington County will hold a general election that includes Board of Director positions for Tualatin Soil and Water Conservation District.

Seven elected members make up our board. Five of these members are “zone” directors — this means they represent a specific part of the county. The other two members are “at-large” directors who represent the entire county. All positions serve a four-year term.

Four director positions will be open for election in November 2022, with terms beginning January 1, 2023:

  • Zone 3 – representing Forest Grove, Manning, Buxton, and the northwest portion of the county.
    Zone 4 – representing southern Hillsboro, Cornelius, and the south-central portion of the county.
  • Zone 5 – representing northern Hillsboro, North Plains, Banks, and the northeast portion of the county.
  • At-Large 2 – representing the entire county.
Map of Washington County’s five director zones.

Click here to view a PDF version of the zone map.

What does a board member do?

Board members help guide Tualatin SWCD by working with district leadership to establish policy and strategies. Specific duties include ensuring fiscal responsibility, adopting the budget, attending board and committee meetings, representing Tualatin SWCD at local and regional events, and helping set the strategic direction for the organization. Read more about our current Board of Directors here.

A diversity of lived experiences, identities, and skill sets among board members helps us provide Washington County communities with responsive and accessible services. While conservation is core to our mission, Tualatin SWCD is strengthened when board members bring expertise in a variety of fields, such as community organizing, outreach, education, financial and business management, human resources, public service, agriculture, environmental sciences, and more.

Am I eligible to run for a director position?

Eligibility requirements for board director positions are fully described in the Candidate Packet for SWCD Director Elections, provided by Oregon Department of Agriculture:

  • 2022 Candidate Packet for SWCD Director Elections
  • Paquete para candidatos para las elecciones de Directores del SWCD 2022

The Tualatin SWCD office can help you determine if you are eligible for an at-large position or a zone position.

Help guide Tualatin SWCD as an elected director.

Interested community members who meet the eligibility requirements must file the requisite forms between July 21 and August 30, 2022.

Each candidate must file a “Declaration of Candidacy” and a “Petition for Nomination Signature Sheet” with the Oregon Department of Agriculture, Natural Resources Division. The filing deadline is 5:00 p.m. on August 30, 2022. Election forms and information can be found at the Oregon Department of Agriculture’s SWCD Elections page.  

Questions?

Contact Judy Marsh with any questions about Board of Director elections: 503-334-2288 | judy.marsh@tualatinswcd.org.

Masters of Disguise: Mimicry in Nature

April 22, 2022

They say imitation is a form of flattery but, for some, it’s a means of survival. All throughout the animal and plant world, we find organisms pretending to be something they’re not. Some take on the looks of other organisms or objects to scare off or hide from predators. Others are known to imitate different species to lure in prey. This is known as mimicry. This complex tactic is widely used by amphibians, snakes, insects, and spiny plants.

Defensive mimicry is used to protect against predators.

Predators tend to avoid eating prey that they’ve had unpleasant experiences with. So, it can be beneficial to put on a disguise that makes a predator confuse you with another species they are actively avoiding.

Some fly species exhibit Batesian mimicry by imitating the appearance of bees.

With Batesian mimicry, a creature displays warning signals or characteristics of a more dangerous or distasteful species in the hopes that potential predators will pass them by. For example, some types of hover flies (including drone flies) mimic the appearance and movement of bees. Because they cannot sting, these flies rely on masquerading as an insect that can sting to keep safe from predators.

Moths appear to be the experts in Batesian mimicry. There are moth species that mimic the appearance of owls, wasps, dead leaves, and more. Hummingbird moths, which are found all throughout the U.S., not only mimic the body shape of a hummingbird, but also move like one and can produce a similar humming sound.

Mullerian mimicry occurs when two or more species share similar anti-predator characteristics and co-mimic each other. Both species benefit because predators learn to avoid them all. A primary example of this type of mimicry appears in the monarch butterfly and the viceroy butterfly. Monarch butterflies are common in the western United States and their range overlaps with that of the viceroy butterfly. The two species have very similar markings, with only subtle differences on the wings. At first, scientists thought the viceroy butterfly exhibited Batesian mimicry by imitating the monarch butterfly, which is toxic to animals that eat it. Once scientists learned the viceroy is also distasteful to predators, it became Mullerian mimicry because both butterflies benefit from having a similar appearance.

Aggressive mimicry is a tactic to lure in prey.

Not all mimicry is defensive. Sometimes a disguise is used to appear harmless to potential prey. This tactic extends beyond typical camouflage to take on the look of a harmless creature or object. Biologists have referred to this strategy as being “a wolf in sheep’s clothing.”

The zone-tailed hawk, a raptor found in the southwestern U.S., displays aggressive mimicry tactics. It looks and flies like the harmless turkey vulture. The hawk benefits from appearing like a non-threatening species since its prey assume they don’t need to be on high alert when it is nearby.

Aggressive mimicry isn’t limited to physical appearance. Some animals, like the margay (a wild cat), display vocal mimicry, imitating the sound of the prey they are hunting in order to draw it closer to them.


Adaptation is key to survival.

Mimicry is just one form of the incredible adaptations that plants and animals have to navigate the world. Over time, organisms are able to change their body parts, body markings, and behaviors to evade danger and obtain the resources they need. Sometimes the best strategy for staying safe is to play dress up!


Want to bring more wildlife to your yard or community?

Check out our tips for creating wildlife habitat.

Tualatin SWCD Awards Over $500,000 in Conservation Grants in 2021

July 11, 2021

Protecting natural resources is a team effort. Tualatin SWCD strives to support the conservation efforts of other organizations and community groups in Washington County by providing funding and technical support to get projects rolling.

In early 2021, we were proud to offer two grant programs aimed at supporting conservation education, community agriculture, on-the-ground habitat restoration, and conservation research projects. Through our Conservation Education Grant and our Tualatin River Environmental Enhancement Grant, we awarded a total of $502,806.00 to eight applicants. This year’s grantees included non-profit organizations, a school, a local unit of government, and local businesses.

Meet our recent grantees and learn about their conservation projects!

  • Confluence Project was awarded a grant to support their Confluence Outdoors program, providing K-12 students with outdoor education field trips to natural areas. Through visits to Quamash Prairie Natural Area, Jackson Bottom Wetlands Preserve, and other local natural areas, students of Native American heritage will connect with the Indigenous ecological knowledge passed down through generations in this region.
  • Tualatin Riverkeepers will use grant dollars to provide educational activities and signage at their Cook Park River Rentals station. Summer boaters will be able to learn about local wildlife, water quality, and soil health while exploring the Tualatin River by canoe, kayak, or stand-up paddleboard.
  • Westview High School students will hone their science skills with new microbiology lab equipment funded through a Conservation Education grant. After collecting water samples from nearby Rock Creek, students will use the lab equipment to identify microscopic organisms in the water, test for the presence of toxic organisms, and complete water quality investigations.  
  • Adelante Mujeres will provide regenerative agriculture courses, mentoring, and place-based community gardening to engage Latinx families in agriculture and conservation. This grant will help build the infrastructure for Juniper Community Garden, a 0.75-acre garden for farmworker families and residents of Bienestar affordable housing properties. These programs aim to provide educational opportunities that will advance cultural, economic, and health equity for the Latinx community in Washington County and have a positive impact on the land and climate.
  • Ash Creek Forest Management will carry out habitat restoration activities at the Tualatin River National Wildlife Refuge. This 90-acre natural area supports diverse populations of birds, mammals, amphibians, reptiles, and fish. The grant will fund restoration of wetland and oak woodland areas, including invasive species management, planting of native species, and creation of habitat features.  
  • Tualatin Hills Park & Recreation Department will be bringing a portion of Hall Creek back to life by removing the stream from an underground pipe and letting it flow through Raleigh Park. Restoration of the stream will include installing natural structures to slow erosion, planting thousands of native species along the stream banks, and removing invasive weeds.
  • Tualatin River Watershed Council will add large woody debris and boulders to Clear Creek (a tributaryTributary A river or stream flowing into a larger body of water. of Gales Creek) to improve habitat for fish and wildlife, including steelhead, Coho, chinook, cutthroat trout, and Pacific lamprey. Placing wood in the stream will create pools, helping to keep water cool for fish. Adding boulders to the stream allows pebbles and other coarse sediment to accumulate, providing habitat for macroinvertebrates.
  • WEST Consultants will use grant funding to study how mosses and mycelia can be used in rainwater facilities to improve water quality while also providing pollinator habitat. This research project will include development of two demonstration sites in Washington County.

Interested in applying for a grant from Tualatin SWCD? Find details and guidelines on our Grants & Funding page.  

What Can Frogs and Salamanders Tell Us About Water Quality?

April 14, 2021

At the tail end of winter, as temperatures creep upward, frogs and salamanders make their yearly trip from terrestrialTerrestrial Growing or living on land, as opposed to air or water. habitats (forests and meadows) back to aquatic habitats (ponds, wetlands, and streams). After toughing out cold winters by hibernating in the ground or nestling into cozy cracks in logs, the critters find their way back to wet habitats to reproduce.

Frogs, toads, salamanders, and newts are amphibians.

The Pacific treefrog is common in Oregon.

Amphibians live on both land and in water. In fact, the word amphibian comes from the root words “amphi,” meaning both and “bios” meaning life. Typically, amphibians hatch from eggs laid in or near water and they begin life as aquatic larvae. The larvae then go through metamorphosis, with their physical features changing to help them become land-dwelling creatures.

Amphibians help us understand ecosystem health.

Amphibians are “indicator” species. They are sensitive to changes in the environment, so their presence or absence in a habitat can provide clues about ecosystem health. Keeping an eye on amphibian populations can reveal information about water quality, plant health, and changes in climate.

What makes amphibians so sensitive to environmental change?

  • They are ectotherms. Their body temperature is directly regulated by their environment.  If the water temperature in their habitat changes, it can affect their activity and health.
  • They breathe through their skin. Amphibians breathe with either gills or lungs (depending on their life stage), but they also take in oxygen through the pores in their skin! PollutantsPollutants A substance that has negative effects on the environment. in the water can pass through their skin and cause health problems.
  • They have complex growth processes. Metamorphosis is triggered by a combination of biological and environmental factors. If conditions become unsuitable, an amphibian’s physical development can be harmed.
The rough-skinned newt lives in forested areas throughout western Oregon. Photo: Jeremy Scroggins, Flickr.

Amphibian populations are declining worldwide.

Pollution, habitat loss, climate change, and invasive species are causing harm to amphibian species around the world. Amphibians are both predators and prey, so any decline in their populations can have dramatic impacts on the rest of the food web.

We can support amphibians by: 

  • Protecting their existing habitat. Amphibians need both land and water, plus safe ways to travel between both habitats.
  • Preventing water pollution. Amphibians need clean aquatic habitats to reproduce and grow. Chemicals, trash, and excessive amounts of sediment pollute waterways.
  • Watching for invasive species. Non-native species, like the American bullfrog (Lithobates catesbeianus), can hurt amphibian populations by eating too many of them or outcompeting them for limited resources. Invasive plants can also reduce amphibian’s access to food and shelter. Browse our Weed & Pest Directory to learn how to identify and report invasive species.
  • Participating in amphibian monitoring programs. Each winter, local organizations provide opportunities for volunteers to put on waders and help search for frog and salamander eggs! Get in touch with the Wetlands Conservancy or Metro to find out how you can join.

Our habitat conservation projects help protect amphibians.

Tualatin SWCD Conservation Specialist, Bethany, examines an egg mass recently laid in a pond.

Tualatin SWCD works closely with Washington County residents to improve streams, wetlands, and forests. Planting trees and shrubs along streambanks helps keep water cool and protects amphibians from predators. Leaves and branches from these plants deliver food and shelter when they fall into the water. Protecting forest habitats ensures that these animals have safe places to live in the winter.

We keep an eye out for amphibians while visiting project sites. The best way to determine if frogs and salamanders are present is by looking for their eggs. Clumps of eggs create masses in ponds and wetlands during breeding season, typically from late winter to early summer. Tracking their presence from year to year helps us understand changes in the ecosystem.

Want to learn more about the frogs and salamanders living in Oregon?

There are twelve native species of frogs and toads in Oregon. We tend to look for the Northern red-legged frog and Pacific treefrog, as well as the Northwestern salamander and long-toed salamander, and the rough-skinned newt.

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