Friday, October 30, 2020

Battle of the Blowers vs Bloviators

It's that time of year to start the leaf blower battles. The autumn leaves are down, trails are covered and the debate rages as to what is better--"clean" or "natural."

I say there is no universal right or wrong approach, but generally I favor groomed trails. 

In fact, for the most part I don't think leaf removal adversely affects trails and more likely may confer benefits to trail users.

Before you load your aspersions and invectives in a flaming bag to hurl at me, let's lay out some facts or at least some informed opinions that I'll use to make my case.

One of the biggest arguments against leaf removal is that this increases trail erosion, but does it? Here's why I think this may be a false assumption or at least an idea that needs to be taken with a grain of salt.

1.) Not all trails are the same and there are WIDE variations in soil, grade/slope, and volume-of-use that all affect erosion.

2.) Based on these wide variations, a single example of good or bad outcomes from leaf cover removal can not be used to make broad recommendations one way or another.

3.) Poorly designed trails will battle erosion regardless of presence or absence of leaf cover, and the MAJORITY of the trails we use are legacy trails that were in place long before good trail building practices were a prime concern. 

In regard to soil types (this may sound like a medieval organization), you should review the Twelve Orders of Soil Taxonomy on the USDA web site and you can then read the 600+ page Illustrated Guide to Soil Taxonomy. The different types of soil handle water, drainage, and erosion differently.

In one small area of trails near my house (approx 88 acres), there are at least 9 distinct soil types all with different traits and characteristics:

  • 31A--Walpole Sandy Loam, 0-3% percent slopes
  • 31B--Walpole Sandy Loam, 3-8% percent slopes
  • 43A--Scarboro Mucky Fine Sandy Loam, 0-3% percent slopes
  • 52A--Freetown Muck, 0-1% slopes
  • 242C--Hinckley Loamy Sand, 8-15% slopes
  • 242E--Hinckley Loamy Sand, 25-55% slopes, very rocky
  • 254B--Merrimac Fine Sandy Loam, 3-8% slopes
  • 254C--Merrimac Fine Sandy Loam, 8-15% slopes
  • 600--Gravel Pits

Based on that soil type information, one could *start* to calculate what's called the "Universal Soil Loss Equation" using the Soil Erodibility Factor.

But, before a conclusion could be made, in addition to soil type and slope, the length of the slope and tree cover/vegetation also play important roles.

All of these factors come into play, so leaf removal on a steep sandy trail will have very different effects than leaf removal on flat loam or muck.

Simply put, dirt is not dirt. 

Next, leaf cover will actually keep trails wetter longer. Most people think of wood chips/bark when they think of mulch, but technically, mulch is any ground cover--from leaves, to wood chips to plastic sheeting. Mulch is great in the garden to prevent weeds from growing or to keep plantings moist, but that latter property will prevent evaporation and keep trails wetter longer. I believe that uncovered trails will dry faster.

So, what about leaving the leaves on the trail and letting them break down naturally? Yes, I'm 100% in support of this, but another huge factor in this equation is the volume-of-use  in a particular trail. Natural leaf decomposition can take up to a year or more but on a well used trail system, this will be accelerated by the mechanical effects of tires, feet, hooves or paws. For popular trails, the leaf removal might be a moot point, but for lesser utilized trails, I think leaf removal is an important component to regular maintenance, just like trimming back overgrowth. So again, a one-size-fits-all approach doesn't make sense.   

And one last point as it pertains to erosion, if you've ever been out to the trails immediately after a big storm, you've seen first hand the damage that strong wind and rains can do. Heavy rain will move compacted soil, rocks, and gravel--will a cover of leaves prevent that? Poorly drained trails can have lingering puddles--will leaves prevent those? This goes back to my point that trail design plays a more important role in erosion than anything that's done after the trail is built.

Don't just take my word for it, according to New Hampshire's Department of Resources and Economic Development Division of Parks & Recreation Bureau of Trails:

Here in the Northeast, we have inherited a legacy of poor trail layout. Many of our trails went from point A to point B with no consideration for steepness of terrain. Many trails, especially OHRV or snowmobile trails, have evolved over time on old woods roads or skid trails that were never designed for the type of use they get today. The result is inappropriate water management and erosion which is a trails arch enemy.

Now, I get it that gas-powered leaf blowers are loud, no argument there. In true wilderness areas, many power tools are not allowed, but I'd say that most of the places we ride are in the suburbs. Ambient noise from traffic can often be heard, along with other contributors to noise pollution--nearby construction, planes flying overheard, even rowdy trail users. I'm not saying I *want* to add to noise pollution, but a once-a-year brisk walk through with a leaf blower would have minimal impact as an operator should be able to cover about 2-3 miles in an hour. The duration of the noise should be minimal in any one area. This, is vastly different from the duration of noise encountered from landscapers who often have a team of workers in a yard or series of yards with mowers, trimmers, and leaf blowers, often in a neighborhood for hours. And, if the noise is your primary argument against leaf blowers, how do you feel about the 13.5HP Briggs & Stratton gas motor on the Snowdog trail groomers? But, I digress...

Does a leaf blower disrupt the natural habitat? Yes, but you know what else does? A trail. Just by having a trail, the area is changed--flora and fauna must adapt to the trail, and if the decision has been made already to have a trail, then that's already happened. Anything and everything about that trail will affect the habitat, whether that's 6 riders on a group ride or one person doing maintenance.

So, overall, I'd say that in many situations leaf removal is not bad, but why do I think it's good?

First, I think it makes trail use easier, especially for less experienced users. A common argument against virtually any trail modifications is, "if you want groomed trails, go to a rail trail." I think this is a ridiculous statement, as if there are only two trail types, technical gnar and flat & smooth. Unless a trail system is a dedicated mountain bike area, trails really need to be accessible to *most* users. Not everyone has, nor should have, a $6000 full suspension bike with a dropper post and 150mm of travel. There are plenty of hardtails out there, and plenty of 26" hardtails at that. And, believe it or not, there are hikers and runners that use trails too. Everyone can benefit from a clear path to follow and everyone can benefit from reducing the risk of falling from hitting hidden roots and rocks covered by wet leaves. I see people on some of my local trails with strollers, so why not make their outdoor experience safer?

Keeping the trail distinct and obvious also keeps people ON the trail and will cut down on people cutting corners, or otherwise widening the trail.

Another, less thought-of benefit to keeping trails clean is that this lowers the risk of transmitting tick-borne illnesses. Ticks LOVE leaf litter, so by removing their habitat, you'll be less likely to end up with Lyme Disease or Anaplasmosis or Ehrlichiosis or Babesiosis or Powassan virus or Borrelia miyamotoi or, well, you get the point.

If you look up this topic on the interwebs, you'll find plenty of supporting information for both opinions--remove the leaves or leave them. I've found that in situations like this the real answer is somewhere in the middle, and unless a true scientific study could be done, there will never be a final determination. In scientific studies, all variables need to be accounted for, so even if you were to try a small "research" study in your own back yard, one year's drought might confound the results from another year's unusually strong series of storms. Climate change is here, and it's effects on the environment are going to be more profound than clearing some leaves from a ribbon of dirt.

A conscientious and "light touch" approach to trail clearing can have little to no adverse effects and many potential benefits.

Besides (tongue firmly in cheek), this is what our president wants:

"I said, you gotta clean your floors, you gotta clean your forests — there are many, many years of leaves and broken trees," said Donald J. Trump, impeached President of the United States, who also questioned the use of injecting disinfectant or shining bright lights into humans to combat the coronavirus.


No comments: