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Seedling Shelter 

A BC company has developed a new type of fabric plant shelter to protect seedlings. 

By Jim Stirling

They may look like vertically staked windsocks but a new kind of plant shelter indicates a new direction toward more efficient tree seedling protection and growth enhancement. Freegro Enterprises says it designed its shelters to protect vulnerable seedlings from animal browse, to be easy to transport and cheap to install. Better yet, when their job is done, the shelters degrade on their own and disappear, making costly retrieval unnecessary. "We'll have about 40,000 of them in the field by this fall and everyone seems to like them," reports Neil Forman, who oversees their assembly at Certified Plant Shelters in Prince Rupert, British Columbia. For years, foresters have sought better ways to protect newly planted tree seedlings from animal browse. Deer are the main culprits but rabbits, voles and porcupine are partial to the young seedlings' sugar laden leaders and terminal shoots. 

Some methods of protecting the investment made in seedlings have worked better than others but all have been accompanied by high installation and labour costs. Forman is a partner in the Freegro Enterprises system of plant shelters with John Randall, a consulting forester based in Greater Victoria. Randall was looking to develop a new type of tree shelter and dropped into Forman's Prince Rupert machine shop to get a part made. The pair got to talking about tree shelters generally and the ideas gradually flowed on how to make them better. That was a couple of years ago. Now, several prototypes later, the Freegro system continues to evolve. Certified Plant Shelters has become the licenced manufacturer. 

The Freegro plant shelters, which are produced in BC, are designed to protect vulnerable seedlings from animal browse, yet be easy to transport and cheap to install. The company says it takes about 10 seconds to install the shelters, which are customized to growing conditions and tree species. 

The basic shelter design has two rims equipped with friction clips that can be fitted with a variety of fabric like claddings to protect the plant. The clips attach the shelter near the top and bottom to a support stake driven into the ground. An auxiliary peg or pegs can be added to the bottom rim to provide additional support where wind firmness is an issue or soils are shallow. The key to the system is its flexibility. The types and treatments of claddings vary with tree species and their growing environments. A fine mesh is best suited to browse protection, allowing air and light through but resilient enough to be too much work for the deer to bother with. 

"We use a wide range of textiles suitable for exterior use," says Randall. "The companies supplying the textiles know how much ultraviolet inhibitors to put in and we're able to adjust those inhibitors into the polymer of the high density polyethylene." The UV rate of degradability needs to be different between, say, the Queen Charlotte Islands and southern California. But the shelter fabrics are chosen carefully to last long enough to allow the seedling to grow beyond the point where it is food to animals while providing it protection from weather and competing plant life. At the point of built-in degradability, the rims and fabric sock breakpoints ensure the plant is released from its protective cocoon. No maintenance or removal of plant shelter components is required. 

The stakes rot and the rims and clips eventually rust. The shelters also provide a greenhouse effect, accelerating early growth. The concept of browse protection and enhanced growth is proven, says Randall, but they will always be running trials on the varying degrees of performance of the claddings for a target species. "We want to achieve the best growth without compromising the plant ." A plastic tube, for example, is a plant crematorium in a hot climate. Randall reckons it takes about 10 seconds to install a Freegro plant shelter and it costs between 30 and 60 per cent less compared with other types of protectors. The Freegro shelters are customized to requirements but most are around four feet in length with a 4.5inch diameter sock, notes Forman and he adds red cedar makes the most durable stakes. "A big advantage is our packaging, where we provide 100 shelters in a 22x11x6 inch deep box weighing only about 25 pounds," says Forman. "It's much easier to transport and move around in the bush." 

Certified Plant Shelters employs about a dozen people banding, sewing and packaging the plant shelters. Production of 1,500 shelters from five sewing machines is feasible in a 7.5 hour shift, says Forman. Major suppliers of fabrics are ABC Netting of Toronto and Plaspack Industries in Austria. For most of the first two years, the partners financially supported Freegro's development. Lately, they've been successful in impressing various funding sources with their system. These include the BC Technical Assistance Program administered through the National Research Council and Human Resources Development Canada's local labour market partnership. Loans through the Community Futures Development Corp of the Pacific Northwest and Forest Renewal BC have helped scaleup the company's production capability. 

Although the Freegro plant shelters are designed and assembled in BC and the technology is owned in the province, a much broader marketplace exists. The plant shelters have stimulated interest in North America and several European countries. One intriguing application is in viticulture. Evidence shows a speciallydesigned sock can keep inside vine temperatures cooler on hot days, allow removal for pruning and significantly accelerate grape growth. "There's no end to how far we'll be able to go with these plant shelter systems," says Forman.  

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