In the April 2016 column, we covered the benefits of using tree shelters in promoting new woodlot and forest growth. These shelters mimic natural forest regeneration by reducing light levels, increasing humidity and reducing air movement. They also protect seeds, seedlings and very young trees from dangers of the forest environment such as deer browse, vole, and other rodent damage as well as insect and bird dangers.
The shelters are often made of translucent polyethylene, either corrugated or twin-walled, and are usually about 4 inches in diameter; some less common shelters are made of PVC (polyvinylchloride) pipe. The shelters can be 4, 6, or even 7 feet tall. Generally they are held upright by securing to stakes driven a foot or more – preferably more – into the ground and fastened to the stakes with plastic or wire ties.
Terry Witzel, a forester in the Marienville Ranger District of the Allegheny National Forest in northwestern Pennsylvania, said, “I have tried many types through the years. I usually use them in fill-in planting situations. We may have some holes that didn’t come into natural tree seedlings and we are supplementing the natural regeneration. We also use them where we want to add species diversity to the stand.”
Witzel may plant cucumber (Magnolia acuminata), tulip poplar (Liriodendron tulipifera) or oak (Quercus rubra or alba) in timber stands predominated by cherry or maple.
She uses fiberglass rods instead of wood stakes. “We switched a number of years ago because of breakage with the hardwood stakes, and I see the manufacturers took our idea and are offering fiber rods now,” she said.
As a result, maintenance has gone down quite a bit. “We maintain the planting sites every other year,” Witzel said. “In large-scale applications, we have found that woven-wire deer exclusion fences are the cheaper option.”
In addition to use in woodlots, they have also been used with great success in urban environments.
Witzel generally finds that 5-foot shelters work for their applications rather than the 6-foot versions, which he finds make maintenance and tree survival counts more difficult.
“We find the best types are vented,” Witzel said. They use either Tubex brand or Plantra products.
“We use 5-foot [tubes]; 6-foot tubes tend to make tree survival counts take too long because they are too tall to see into easily,” she said. “Diameter doesn’t seem to matter.”
Timing the removal of tree tubes is just as important as when they are put on. “We pull them long before they photo-degrade,” Witzel said.
Because the sun does not get down to the first foot or so due to high grass or herbaceous vegetation, if the tubes are left out a long time that part generally does not break down as fast.
Porcupines seem to like eating the tubes. Also, deer and bear have been known to rub against them. “They come with a mesh sock that can be installed over the top to keep birds out, although I personally haven’t seen bird mortality when that type of netting is not used,” Witzel said.
Witzel recommended talking with Joe Lais, CEO of Plantra. For woodlot owners who want the science of why they work, why they are the color they are, why they have air vents in them now, etc., Lais is an excellent resource, she said. Lais came from a company that introduced and distributed Tubex products.
Allegheny National Forest continues to use the Tubex product. “Our wildlife biologists also use a product from Tree Sentry. They are concerned about rodent damage, so this product is used in areas where that is a concern to them,” Witzel said.
Lais said his company has developed shelters with a coloration that allows full-spectrum, diffused light, along with slits in the plastic. They have proven very beneficial in the promotion of proper photosynthesis, leading to remarkable growth of seedlings.
The company recommends specially designed fiberglass stakes and has designed its stakes with a shape that’s easy to drive into the ground, as well as a tube that slips over the stake for the purpose of driving them into the ground. The Plantra stakes are also clearly marked to show the installer the proper depth to reach to keep the seedling or young tree from being bent over by some accidental contact or harmed by strong winds. Fiberglass stakes also eliminate the problem of wooden stakes, which can rot over time and are inconsistent in size and quality.
The stakes, along with their accompanying shelters, are intended to be left in place longer – up to 10 years, Lais said – for the tree’s development.
Lais said his company’s product acts “like a mini greenhouse, building and growing the whole plant from roots to stems to shoots,” he said.
Tom Mills, sales manager of TreePro, another manufacturer of tree shelters, said, “What we have learned over time is compound leaf structure, fruit-, and nut-bearing species tend to do better in the TreePro protector because of the larger diameter.”
The Miracle Tube is shipped as a fully formed tube so as to save on shipping costs; they are nested one inside the other for a range of diameter of 3.5 to 4.75 inches.
Mills claims the Miracle Tube is the highest in the industry in growth and survival rates. It is also one of the easiest and fastest shelters to install, he said.
Video Explains Installation
Plantra has a new video demonstrating its product, its development, and application. The video features Babe Winkelman, host of an outdoor television show. It includes a demonstration of tree shelter installation as well as a testimonial to the effectiveness of shelters. It is available on the company’s website at http://www.plantra.com.
“The zip ties are pre-inserted so the end user just has to slide them over the support stake and pull tight,” he said. Miracle Tubes are manufactured from 100 percent recycled milk jugs.
“Our tubes include a razor line so the protector falls off of the tree as it grows. Venting is a very important aspect. It allows the tree to harden properly in the fall and come out of dormancy in the spring,” Mills said. “With nonvented tubes, sometimes they will not harden before that first frost hits because of the greenhouse effect the shelter has.”
Without use of tree shelters, the failure rate of new plantings is high.
Properly selected and installed shelters have proven, in rural forests and urban environments, to dramatically increase success rates for seedlings, while giving them a stronger start in life.
Read more: Maintaining the Portable Sawmill