Trail Science 103: Tread Maintenance

Tread is the part of a trail that is actually walked on. Usually, and especially in the mountains, tread is constructed by cutting away varying amounts of the slope. The upslope must be cut into to form a flat area, which is the tread. Different ratios are used to measure the cut into the upslope, often depending on the soil type. A rocky upslope can have a steeper cut (backslope) into the slope because a harder material can hold together better than a loamier soil.

Other than water, two enemies of tread are slough and berms. On hillside trails, slough is soil, rock, and debris that has moved downhill, narrowing the tread. If slough is not removed from the tread, a trail will tend to "creep" downhill. Sloughing can be caused by hikers walking closer to the upslope side of the trail than the downslope or by too steep of a backslope.

Where as slough builds up on the inside of trails, berms build up on the outside. Berms will keep water from sheeting across a trail, keeping water on the trail. When the water can’t sheet, it flows down the length of the trail, carries away soil and, and as a result, builds up an even bigger berm.

Next: Stream Crossings

Trail Science 102: Keeping water off the tread

“The whole point of trail work is to get dirt where you want it and to keep it there. Water is the most powerful stuff in your world. Gravity is water's partner in crime. Their mission is to take your precious dirt to the ocean. The whole point of trail work is to keep your trail out of water's grip.” – Trail Construction and Maintenance Notebook

Trail with water (Photo credit: Wikipedia)

So, water is the great nemesis of trail development and preservation. Two ways to keep water off a trail are frequent grade reversals and outsloping the entire tread.

Water flows down a hill in sheets, referred to as sheet flow. To keep these sheets crossing the tread of a trail without puddling or running down the length of the trail, frequent grade reversals are needed. This simply means that a will designed trail should have its ups and downs. According to the forest service, a trail should have frequent grade reversals that extend for 10-15 feet.

An outsloped tread is one that is lower on the downhill side of the trail than it is on the inside or bankside. Outsloping lets water sheet across the trail naturally. A trail’s tread should be outsloped at least 5 percent, but not so much that it is awkward to walk on. Maintaining a trail’s outslope is key to keeping water from puddling.

Next: Tread

Trail Science 101: Trail Design

In a previous post a few days ago I said I would be writing a series of posts on “Trail Science.” This is the first installment following my introduction into what I like to call Trail Science.

According to the U.S. Forest Service’s Trail Construction and Maintenance Notebook, “There is a real art to trail layout.” It goes on to say that it takes a lot of experience to acquire an eye for proper trail building.

A particular trail’s specifications depend on several things, including what recreational activities will be performed on the trail, the amount of use and the characteristics of the trail’s particular landscape.



Typical hiking trail path in the redwood parks.  (Photo credit: Kid Cowboy)

The steepness of a hill or mountain gives a trail its difficulty quotient. The steeper the hillside, the more excavation will be needed to cut in a stable backslope. The trail’s grade on a steep hill also has a direct bearing on how much design, construction, and maintenance work will be needed to establish solid tread and keep it solid.

It is a general rule in trail building that a high-use trail should be built with a 5-10 degree grade. I can guarantee that no one told the builders of the trail up Mount Defiance, located on the Oregon side of the Columbia Gorge, of this rule. When 20 degrees or more, a trail becomes very difficult to maintain, let alone hike.

A trail should also be “aesthetically functional,” meaning it takes advantage of an area’s characteristics, making it appear as though it just appeared. It fits the setting.

A basic rule in trail design is the he half rule. It says that the trail grade should be no more than half the sideslope grade of the hill it is on. For example, if a hill has a 6-percent sideslope, the trail grade should be no more than 3 percent.

There are many other rules and specifications in the science (or art) of trail building. Those are more appropriate for upper level work, not the 100 series I will present to you in the coming days.

Next: Water - a trail's nemesis

Another hiker rescued in Phoenix, the U.S. leader in hiker rescues

The 65-year-old woman was carried down Echo Canyon Mountain in Phoenix Monday by paramedics after she suffered from what one of the hiker's friends described as a "panic attack," according to an azfamily.com report. The same friend of the hiker said the woman got concerned as she was walking up the mountain toward the steel guard rails used as support.

Larry Nunez with the Phoenix Fire Department said more hikers are rescued in Phoenix than anywhere else in the country. The attractive weather and trails play a major role in the large number of service calls.

So far this year there were 232 mountain rescue calls for help, including Monday's call. That number is up from 167 in 2011.

"People often don't pay attention to the trail markers or the rating system," Nunez said.

How the views have changed in Glacier National Park

Believe what you might about global warming and its causes. Here are some great historic and newer pictures of Glacier National Park.

http://www.dailymail.co.uk/sciencetech/article-2239189/The-Glacier-National-Park-soon-change-global-warming.html

Grizzly sow attacks hikers in British Columbia

November 26, 2012 - Two hikers were attacked by a grizzly bear in Southeast British Columbia on Sunday, according to CTV News.  

The man and woman had been walking in Cherry Creek, near Kimberley, B.C., when they came across a grizzly bear feeding on a deer it had killed. “The hikers got within 15 feet, unknowingly, and it startled the grizzly bear,” Sgt. Joe Caravetta, of the East Kootenay Conservation Officer Service, said Monday.

The grizzly bear attacked the female hiker first, then turned on the male hiker, only to return to the female and continue its attack. The woman is in her late 50s and the man is 80.

Sustaining bite injuries to the head, arms and legs, the pair were rushed to a local hospital and then flown to a Calgary hospital where they remain in stable condition.

After assessing the evidence, conservation officers classified the incident as defensive in nature. The bear was believed to have two cubs with it. “The bear was just defending its food,” Caravetta said, adding that had the grizzly been acting in a predatory fashion, conservation officers would be pursuing the animals to destroy them.

The man and woman are local to the area where the attack occurred, and regularly hike there.

“Trail science” is the base under which hikers experience the wilds

Hikers on the Steiregg hiking trail, above the town of Grindelwald, Switzerland. This is one of many spectacular and well-maintained hiking trails in the Swiss Alps. (Photo credit: Wikipedia)

Hikers who walk a myriad of trails know a good trail from a bad one. Detecting a bad trail is as simple as feeling it – in your feet, ankles, knees and hips, as leg muscles and joints adjust to poor trail conditions. Few things are worse on a hike than walking on a trail two feet wide and shaped like a half-pipe.

For the simple reason “if you’re gonna do it then do it right,” entire books and papers have been written about what I call “trail science.” It is the construction of good trails that will need minimal maintenance, maintenance that will correct a situation so it doesn’t happen again or for a decent length of time, and reconstruction of trails that were ill-conceived in the first place.

Because so many guides regarding “trail science” exist, I will use the U.S. Forest Service’s The Trail Construction and Maintenance Notebook for a series of posts in the coming days. Trail science is like any other science: it can get bogged down in the finer points a lot of people don’t much care about. The Forest Service’s manual also contains such information. It will be my job to make “trail science” interesting for hikers, something they can use to enjoy the hiking experience even more.  

Oregon wolf packs are mingling, setting up a rendezvous between OR-2 and OR-4

November 23, 2012 - Oregon Department of Fish and Wildlife researchers have discovered for the first time that wolves from two different wolf packs have bred.

Wolves Baiting a Bison (Photo credit: Wikipedia)

Sate wolf coordinator Russ Morgan said, "This is the first time we've been able to genetically show it. This is a confirmation of the necessary genetic interchange among packs, and that is a good thing."

Morgan said while the discovery of a wolf born into one pack successfully reproducing in another is not groundbreaking, it does show that packs are dynamic and change over time.

There are now six packs in eight different areas of the state, with wolves in some areas not in a big enough group to yet be considered a wolf pack.

Wenaha River (Photo credit: Pig Monkey)

The discovery was made by analyzing scat from the Wenaha pack’s pups. Each time a wolf is caught and collared by the state agency, a genetic sample is taken, Morgan said. The department confirmed with a genetic sample that OR-12 is the progeny of OR-2 of the Wenaha pack and OR-4 of the Imnaha pack.

Lightning strike evidence of Mother Nature's power

A recent lightning strike and its deadly outcome at a NASCAR race in Pennsylvania reminded me of the time I witnessed the remnants of a lightning strike near Timothy Lake in the Oregon Cascades. It was yet another reminder of how awesomely powerful Mother Nature can be.

Rajneesh recollections: Visits to Rajneeshpuram and a strange encounter



Osho Rajneesh Drive-by in Rajneeshpuram

The other night I was watching a show on the Rajneeshees, a group of folks that infiltrated northern Central Oregon in search of communal living and oneness with their spiritual leader, Bhagwan Shree Rajneesh, later known more simply as Osho. Anyone living in Oregon at the time, in the early 1980s, remembers him and his band of followers who wore various shades of red and a necklace bearing Bhagwan's picture.

Black Wolf Meadows elicit old story and trigger imagination

 A wolf nurses her pups outside their den

Wolves are making a lot of news lately. From wolf hunting in the upper Midwest to the expansion of the habitat, including into Oregon, wolves are a hot topic.. The latest news of wolves jarred loose the memory of a hike taken several years back into the area of High Rock atop the Clackamas River drainage.

Oregon's explosive past seen along the PCT south of McKenzie Pass

From left: Belknap Crater, Mt. Washington, Three Finger Jack and Mt. Jefferson

If a person wants to see evidence of recent volcanic activity, and by “recent” I mean within the past few thousand years, there is no place better than the Central Oregon Cascades. In this area, perhaps the best place to view this activity is along the McKenzie Pass. Here, a string of craters that once spewed immense flows of lava and spit cinder high into the air stretches for miles.

Landfill at Fish Lake shocks, angers

Calvin "The Wonder Dog" at Lower Lake

From the edge of the Olallie Lake Scenic Area, hikers can begin near the end of road 120 on a trail leading to a string of lakes within the scenic area. Unfortunately, negative human elements and nature can clash, which was the case when I hiked the path, known as the Fish Lake Trail. This hike is only 2.8 miles long, but filled with great scenery, especially if you enjoy lakeside views of the surroundings.

A few things to know about rattlesnakes that the Lone Ranger and Tonto didn’t

Modified tail scales form a rattle on a Western Diamondback Rattlesnake Crotalus atrox. (Photo credit: Wikipedia)

In a post from a few days ago, I wrote about a trip a friend and I took to eastern Oregon near the Idaho border in search of rattlesnakes. We were told the location of a rattlesnake den in which we caught several of the snakes. Over the years, I’ve had several encounters with rattlesnakes while either hiking or camping in Oregon, but really knew little about them. Even after keeping a live rattlesnake in an aquarium for a few years in my living room, feeding it mice on occasion, I still knew little about them. So I did some research on rattlesnakes, which might help folks understand them a little better.

Rattlesnake den provides a day of adventure

An old drawing of rattlesnake

It wasn't much of a hike, walking across a small portion of eastern Oregon, looking for "a large boulder" at which point we were told to "take a right." We had no idea whose property we were on, and knowing we were trespassing, watched carefully for anyone who might have a rifle aimed at us.