Trail Cutting and Maintenance Guidelines
Trail Tree Regeneration
Trail Trees are trees within trails and glades shown on a ski area's official trail map. These can range from the occasional "character tree" to many interspersed in a glade. Character trees and glades play a important roles defining the experience, retaining natural snow, and holding soils in place. As trail trees mature and die, these functions are diminished.
Regeneration zones are a low-tech, inexpensive way to allow new trees to become established within actively-used trails. Regeneration zones are areas cordonned off from skiing/riding, and annual mowing using bamboo and rope. Regeneration zones are artificially-delineated "islands" where replacement trees can establish themselves, and grow to a size where the rope and bamboo can be removed.
Installing Regeneration Zones
It is best to establish new regeneration zones in the late summer prior to mowing, locating them around existing groups of seedlings. Each zone should be large enough so the outer trees protect the inner ones from ski and board edge damage, and other human wear-and-tear. The minimimum size is about four feet, measured across the fall line.
Regeneration zones may be individual, or laid out in groups down a trail. Using the number one rule that a trail must be fun to ski/ride, regeneration zones should be laid out to compliment the flow and rhythm of the trail. In this way they will be respected by customers. Educational signage helps. Also, regeneration zone bamboo should be a different color than ski patrol bamboo. This way customers can discern the different function, and are more likely to respect them. At Mad River Glen, ski patrol bamboo is dull orange with black stripes, and regeneration zone bamboo is solid blue.
Regeneration Zone Materials and Design
Use a dibbler (big metal pipe with a point) to sink holes in the ground, into which bamboo is placed. Simply finding soil deep enough to hold bamboo upright often determines location. Bamboo sunk eighteen inches in the ground will stay put. Use eight inch plastic zip ties, fed through drilled holes in the upper ends of the bamboo, to hold rope in place.
Experience has shown that a three-or-more pole open-ended deltoid configuration is best. The point of the triangle faces uphill, and the other poles slant out to the sides downhill. The rope should bow loosely from pole to pole, leaving the downhill side open. The rope must slide freely through the zip tie loops. Strong winds will rock the poles, and if the rope is tight or is unable to slide, the poles will work against one another and pull themselves down. It was found that the open ended design (not encircling the zone with rope) is not only easier to construct, but it makes the poles less likely to work themselves down in wind.
Finally, the rope should be marked with heavy-duty orange flagging to alert skiers and riders to its presence.
Regeneration Zone Maintenance
Regeneration zones require annual maintenance (once a year). This involves resetting and replacing aging or broken bamboo and rope, re-flagging, and adjusting their location and size as needed.
Seedlings will grow in height quickly when they are closely spaced in an individual regneration zone. However the resulting sapling stems will be rather thin and pliable - the young trees are able to withstand the rigors of weather and human activity only as a group, but not alone. Once saplings reach five feet in height, they should receive a light thinning, culling out the less vigorous and poorer form trees. The height growth rate will slow, but their stems will become thicker and stronger.
Use of fertilizer (5-5-5 for example) has not been tried, but it is easy to do and it would probably be worth it.
There is not a hard and fast rule onto when to remove the rope and bamboo. The rule of thumb is when trees reach ten or more feet in height. Managers should experiment to see how the trees hold up without delineation. Rope and bamboo can be removed from a dense zone sooner than a thinned zone, but one needs to get the trees growing in diameter so they will be strong enough to be solo out in a trail. Thus there is a balance.
The ultimate goal is to have one or more large trees, depending on zone size. Therefore thinning should occur every few years to whittle the group down to the final tree(s). Ongoing experiments at Mad River Glen indicate rope and bamboo may be removed anywhere from five to ten years when the original seedlings are a foot or so tall. It is expected that the final trees will be known in fifteen or more years.
Tree planting is significantly more expensive and riskier than regeneration zones. Trees need to purchased, and initial labor to plant and water is substantial. The benefit to planting are that once the trees are well established, maintenance is not needed, and one gets an attractive freestanding tree in a fraction of the time required for regeneration zones.
Risk of mortality is greatest during the first two years after planting. Mortality can be minimized by:
Watering is an absolute must after planting. If drought occurs in the second growing season following planting, watering should resume. Smaller trees (less than four feet tall) have a much greater survival rate than larger ones, but small trees may need to marked with flagging and/or bamboo for the first few winters.
Select native species appropriate to the forest type, balled and burlapped, from a local grower. Balsam Fir, Sugar Maple, and Paper Birch are recommended.
Planting four-foot tall, balled and burlapped Balsam Fir has been moderately successful at Mad River Glen. Twelve-foot tall Balsam Fir have also been planted, but with increased mortality rates. It must be noted that planting has only been attempted on relatively gentle terrain at mid-elevation, where some topsoil existed.
In sum, planting trees is impractical on a large scale, but it can be cost-effective to replace character trees in locations that are of aesthethic value on the trail system.