JeffOYB

The new issue of CX mag came out with a nice analysis of the Austin disaster.

A master arborist contributed his thoughts on test events, jewel parks and trees.

It seems like his upshot was that courses need to stay a certain scientific distance away from trees to avoid compaction and harm to roots. It's a formula relating to tree diameter. Big trees seem to need 20-40 ft, depending. OK, I see that. But...

Hard-used trails everywhere around the world go really close to trees for, like, centuries sometimes (old trails) without hurting them. So? Obviously some trees can adapt. Sensitive roots must adapt into a new direction in such locations: obviously the same amount of roots never try to grow into rock that is next to a tree. Trees adapt.

I have also long wondered about sustainability of CX courses and practice areas.

Is there a "bible" out there of course design?

I note he said "in the state." ...How do designers work in Europe? Do they kill the trees in their heritage jewel courses? I hope not.

In the end I suspect that "stay away from trees" isn't the best expert answer. But that's what the expert said, so there ya go.

What I'm thinking is that he mostly means is: In areas where there isn't already a long established trail! That makes sense. The risk maybe comes more from something new that's being done to a tree, that it's not used to.

fietsbob

European courses are in publicly financed sports parks.

JeffOYB

So?

Does racing near trees kill them? Weaken them?

fietsbob

I Suggest asking at the USFS district office.. a question for someone with a degree in the subject.

what species of trees?

Or USDA your department of Agriculture extension office. .. Since you are a Taxpayer they are your employees.



If in doubt build a planked walkway over them , thats what is done in National Parks and Monuments

where there are many visitor feet, and the redwoods, for example, have their upper roots exposed ..

Bandera

Live Oak trees, like the ones on my property and in Zilker Park, grow slowly to impressive size with extensive root systems some of which are just sub-surface.
Damage the roots and you can kill a tree which takes a century or more to mature and can live to be appreciated by your great-great-great grandchildren.
A qualified arborist can advise on where to avoid any vehicular traffic of any kind and even route pedestrians away from sensitive areas.

I raced 'cross "back when", ecologically sensitive areas should be strictly off limits for any cycling: Go play somewhere else.
Build a 'cross course through and around all of the "Mountain Cedar" we have, kill as much as you can, it's a nasty invasive pest.

-Bandera

msu2001la

Trees adapt to their surroundings, which is why you see lots of old growth trees doing just fine next to sidewalks/trails that have been there for years.

Having said that, if you compact the root zone of a tree that has been growing in an uncompacted area for a long time, it will have a negative effect on the tree health. We see this all the time in the case of new construction around old trees, and it's why most park districts will erect tons of tree protection fencing around trees during construction, to prevent contractors from driving under the canopies and compacting the root zones.

So, your assumption that the risk comes from something new that's being done to the tree is 100% correct. Having said that, I'm not sure how much compaction would really occur from an occasional weekend cyclocross race. Unless it's super muddy, it doesn't seem like it would be enough to really affect most trees.

jfmckenna

Like all things in life... It depends.

Black wallnut 

I wonder about the health of the urban trees that are in New Orleans. 12 feet of water over a trees roots for more than a week is far more pressure than a bunch of bicycles over the course of a weekend. Trees have made it through floods since time began. "a degree in the subject" does not equate to them having the correct answer.

Bandera

A flood in NO a decade ago has nothing to do with the health of Live Oak trees in South Central TX.

Those of us whose families have been on this land w/ Live Oaks in the Hill Country since before TX was a Republic don't need a "degree in the subject" to know that "a bunch of bicyclists" racing 'cross is not acceptable on our ancient Live Oak's extended sub-surface root systems in the wet conditions (or ever) this spring.

Go play somewhere else on your bicycle like Ellensburg,WA where the environment and the tree species are so little affected apparently. Ours are not.

-Bandera

Black wallnut 

Where were you and those who think like you when the plans were made and permits drawn for the race last winter? How about doing an honest search of the health of the trees in New Orleans that were under water, a bunch of it in fact for several weeks. The same or nearly the same species of tree as were in the park in Austin. The point of the flood in New Orleans does have something to do with the health of the trees in the Texas hill country if it proves that you and the knee jerk 23rd hour environmentalists are wrong about the impact bicycles would have had on tree roots.

Your people agreed to host an event and didn't make good on a contract. At the expense of many that came to your state and spent plenty of money in your economy. If the trees are so fragile then perhaps they should be protected better. Those of you that have family roots since before the Alamo should have spoke up long before a Sunday morning. Just because you and your kin have been there since we stole Texas from Mexico does not make you an expert in trees. Even disappointment is bigger in Texas!

Lars Halstrom

Having worked on Forest Service timber sales preparation and administration, I can tell you we go to great lengths to mitigate soil compaction from rubber tire skidders, dozers and logging trucks. We usually log a really sensitive area when the ground is frozen or has snow on it or is dry. If it's too steep we use cable to bring logs into a landing by lifting them partially or totally off the ground. To mitigate the compaction, we run a dozer over the compacted areas with rippers to break up the compaction when it's done. Now trails commonly go near trees for the past thousands of years. You usually pass the tree on one side of it where the roots may suffer from compaction, depending on the soil type, however the other 75% of the roots are doing just fine and will allow the tree to grow normally. The problem with trails is that they are worn into a middle depression so that when it rains, the water moves to the center of the trail and if it's on a slope, the water moves downhill creating erosion and sediment in the runoff water that goes into fisheries habitat. To mitigate the erosion possibilities, we build trails that aren't too steep and follow the contour and we put waterbars across them to deflect the water over the downhill side. The steeper the trail, the more waterbars it has to have. Should CX courses avoid going near trees? I would think yes, because if you locate a path where people are riding as fast as they can amongst them, your chances of getting severely injured are much greater and the chances of litigation increased. I don't have any idea how many MTB's have hit trees but I can tell you that my 20 years on the ski patrol I've seen plenty of skiers hit them, including fatalities. I would design a CX course so that it goes uphill adjacent to trees so that the riders are going slow, and downhill on open slopes without trees.