To Protect Natural Areas, Follow the Leash Laws

leash laws portland oregon ignored

Leash laws in Portland Oregon (they are valid)

Outdoor adventure with a dog is a blast. I understand. It’s difficult to learn something that brings so much joy can have a down side. However, if you care about clean water, wildlife habitat, and protecting Oregon’s natural areas for future generations, one important thing you can do is to follow the leash laws while hiking in natural areas. And in some of Oregon’s more fragile habitats, please follow the posted rules and leave your pets at home.

I’ve found on most trails within a few hundred miles of Portland, Oregon, it’s more common to see dogs off leash despite the posted rules. Dogs show up off leash in areas where they are not even allowed in the first place (Metro parks, nature preserves, etc.) We politely ask people about why they weren’t using a leash. And hear the following:

leash laws in portland oregon natural areas

  • That rule is for other dogs; my dog is friendly.
  • I have a leash here (just in case).
  • We pick up after our dog.
  • We just love watching our dog run and have a great time.
  • It’s for protection. Our dog scares away the bears / mountain lions.
  • This is a service dog. (Note: whether or not service dogs are permitted on a property depends on the landowner (private, public) as well as the property’s location (degree of remoteness, species of concern, etc.).
  • Those are just silly rules made by grumpy, dog-hating people.

In Lisa Johnson’s book, A Bark in the Park: The 45 Best Places to Hike with Your Dog in the Portland, Oregon, Region, she writes:

“Leash laws are like speed limits – everyone seems to have a

private interpretation of their validity.”

My goal is to spread the word that these rules are valid. 

One acquaintance of mine (a very lovely nurse who cares deeply about the environment) had posted on Facebook photos of her and her off-leash dog at Cascade Head (owned by The Nature Conservancy). She complained about the nasty  volunteer who yelled at her for having her dog running around freely. She admitted she’d seen the “no dogs allowed” signs and stated, “that’s why I was carrying the leash. Just in case.” She insisted the volunteer should not have been angry with her because she’s a good person and her dog is sweet. She is a good person. And her dog is sweet. That’s not the point. 

I’m still not sure why she felt she had the right to enter private land and:
  • threaten wildlife
  • trample rare plant populations
  • disturb rare butterflies
  • impact scientific research projects.

How can a vegan, who doesn’t eat meat because it’s cruel to animals, think it’s not cruel to let her dog run free on the home turf of endangered plants and animals? Are she and her dog really that *special*? 

What’s so bad?

(1) Dogs severely stress and may even kill wildlife.

METRO's why no dogs explanation

Dogs are not allowed in Metro parks and natural areas.

To a bird, squirrel, or other critter living in the woods, a dog is a predator. Even if the dog only chases for a bit, the prey has expended a lot of adrenaline and energy to save its life.

    • While being chased, and then recovering, the animal isn’t hunting, foraging, resting, traveling, or taking care of young.
    • The stress of a chase itself can cause death.
    • Pregnant wildlife and newborn animals do not have the reserves to repeatedly expend in running away from your dog.
    • Ground nesting wildlife is particularly at risk. Disturbed birds may be prevented from nesting, or if they already have a nest, they may fly away from it and neglect their eggs or chicks in the process. The chicks may die from exposure, lack of food, or predation.
    • Sometimes, dogs are successful in their chase. I’ve actually seen a fast dag chase, catch, and then kill a bird in the woods.

(2) Dogs trample and dig vegetation.

Your off-leash dog sees a squirrel or mouse and runs off the trail after it, leaving behind scattered wildlife, dog scent and a not-so subtle trail of trampled vegetation. On most trails within day-hike distance of Portland, it’s not long before another dog comes by. Perhaps he too picks up the scent and runs off into the sword ferns. The trail becomes more trampled.

Evidence of dog trampling is best seen at switchbacks. Dogs running off-leash often miss the turn – I’m not sure if they don’t see it or have too much momentum to make the about-face. The result is they keep running straight for a few yards before returning to the trail.

It’s even worse around creeks and streams. Gabriel Park, Woods Memorial Park, and other parks have to fence areas to keep dogs out. It’s obvious where the dogs can gain access to these delicate habitats.

(3) Poison oak is no fun.

Dogs don’t react to the allergenic oil urushiol of poison oak. But they can carry the oil on their fur back to you.

I’ve noticed that many of the hikers on Dog Mountain have dogs. I’ve also noticed that there is an abundance of poison oak along that trail — so much that if you’re not paying attention you’ll bump into it. I’m guessing that most dogs on that trail have come into contact with poison oak. Allowing your urushiol-contaminated dog to run up to strangers is pretty rude in my opinion. I know people who will be miserable for weeks after even a mild encounter with the plant.

(4) Even leashed dogs stress wildlife.

A controlled study in Australia demonstrated that dog walking caused a 41% reduction in the numbers of bird individuals detected and a 35% reduction in species richness. While humans walking alone also disturbed wildlife, it was less than 1/2 of the disturbance of humans with dogs. Another study in the pine forests and grasslands near Boulder Colorado demonstrated wildlife responds more strongly (gets more stressed out and leaves an area) to hikers with a dog on a leash than hikers without a dog. Imagine what a free roaming dog will do.

(5) Dogs can carry diseases.

Dogs can apparently transmit a number of pathogens to wildlife, many of which are transmitted through feces left on the trail. For example, wolf pups in Glacier National Park died due to a parvovirus that was contracted from dogs. Dogs also can spread ticks, tapeworms and fleas.

(6) Dog pooh is pollution.

It is a simple fact that most people do not clean up after their dogs. I’ve heard the following reasons:

  • It’ll decompose.
  • It’s natural.
  • It’s a big area.

None of those are correct. Your pet eats and digests a whole host of processed foods rich in nitrogen, other nutrients, preservatives, fillers, dyes and other chemicals that are foreign to that ecosystem.

Patrick Murphy, a plant ecologist in Colorado discusses how this extra-nutrient materials encourages the grown of non-native (often weedy) plants.

Warrior Rock, Sauvie Island

Warrior rock, at the northern end of Sauvie Island, is a basalt outcropping of Grande Ronde Columbia River lava. Just to the left of this photo is Oregon’s smallest still functioning lighthouse.

Dog feces are also directly linked to water quality issues. Sometimes, quite obviously so. The bacteria and nutrients from this dog dropping will run directly into the Columbia River. In municipalities across the globe, there is scientific evidence based on DNA markers that dog feces are present in our waterways. This fecal matter can harbor very large numbers of microbes, including antibiotic resistant strains of E. coli and parasites. If enough dog waste accumulates in a waterway, it can affect human health by transmitting diseases such as salmonellosis, giardiasis, and cryptosporidiosis. 

(7) Predator pee scares off animals.

While I’ve seen research demonstrating how urine from specific predator species scare off prey I’ve not found research about pet dogs’ pee having the same effect. It’s completely plausible, however. And something to think about. Scent marking is truly important to mammalian species, and I’ve been friends with some really cool dogs that need to mark nearly every tree on the trail.

(8)  News:  not everyone loves your dog.

Dog owners love their dog and often seem to assume everyone else will, too. But loose dogs compromise the trail experience for many people, even fellow dog walkers.

Recently, Dixon and I were at the top of Silverstar Mountain in WA when an oblivious family allowed their dog to sniff everyone’s lunch. It was clear that hikers, including other dog owners were perturbed. No one said anything, though, so that’s our fault.

I hike frequently alone and I’ve been scared by a dog bounding up the trail toward me. I have to assume that the dog is friendly, but without seeing the owner, there’s always the thought it may not be so. A smallish person (I’m not that big) or kid can be knocked over by a large dog and on the wrong section of trail that could be serious. Also, I’m frequently carrying expensive camera gear and do not appreciate your dog knocking me, nor my tripod, over.

Please obey posted rules.

Here’s a quick look at the various regulations for nearby adventures.

Portland Parks

Has specific off-leash areas, but otherwise, dogs must be on a leash. Dogs are not allowed at:  Tanner Springs Park, Whitaker Ponds Nature Park, Foster Floodplain Natural Area and the amphitheater at Mt Tabor Park. The citation for violating the leash and/or scoop law is $150. You can call Portland Park Rangers at (503) 823-1637
Outside of parks, Multnomah County Animal Control (503) 988-7387

Portland Metro Parks

Metro does not dogs or other pets in parks. Seeing-eye dogs or other service animals are permitted. At Graham Oaks Nature Park in Wilsonville, dogs are permitted on-leash on the Ice Age Tonquin Trail because it is a regional trail.

Oregon State Parks

Has specific off-leash areas, but otherwise, dogs must be on a leash. Some park areas prohibit dogs – for example, some of the trails in Silver Falls State Park.

USFWS, National Wildlife Refuges

Pets must be leashed. “Dogs and cats running at large on a national wildlife refuge and observed by an authorized official in the act of killing, injuring, harassing or molesting humans or wildlife may be disposed of in the interest of public safety and protection of the wildlife.” 50 C.F.R. § 28.43

USFS – Wilderness, Developed Campgrounds, Picnic Areas and Day Use Areas

In most, dogs are required to be on a leash. Most other areas within the National Forests do not require your dog to be on a leash, but they should be under your control at all times. The fine for dogs off leash is $200.

Mt. St. Helens National Monument

Pets are permitted only in designated pet areas and must be on a leash. Pets are prohibited at all recreation sites and trails within the Monument’s restricted area.

The Nature Conservancy

Dogs are prohibited from Conservancy lands except at a few remote preserves where they are expressly allowed provided they are kept on a leash at all times. None of these lands are within a day’s drive of Oregon. This prohibition includes service and companion dogs.



Banks, P., & Bryant, J. (2007). Four-legged Friend Or Foe? Dog Walking Displaces Native Birds From Natural Areas. Biology Letters, 611-613.

Johnson, L., & Chesworth, A. (2005). A bark in the park: The 45 best places to hike with your dog in the Portland, Oregon region. Montchanin, DE: Cruden Bay Books.

Miller, S.G., Knight, R.L. & Miller, C.K. (2001). Wildlife responses to pedestrians and dogs. Wildlife Society Bulletin, 29:124-132.

Murphy, Patrick. (2001). Retrieved April 8, 2015, from

Schueler, T. (1995). Microbes in Urban Watersheds: Concentrations, Sources & Pathways in Watershed Protection Techniques 3 (1). Edited by Thomas R. Schueler and Heather K. Holland.554-565.

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