Treeshelters Cover the English Landscape
(An oak regeneration and propagation specialist with the Integrated Hardwood Range Management Program at the Sierra Foothill Research and Extension Center in Browns Valley, California, Doug McCreary currently is on sabbatical in Surrey, England. While in England Doug is learning about English approaches for growing, planting, and protecting oaks, as well as about government-funded programs to reestablish woodlands throughout the country. He is also writing a manual on regenerating native California oaks. -eds.)
For the last several months, I have been living in southern England while working at the British Forestry Commission Research Station in Surrey. When driving around the English countryside, one notices that treeshelters seem to be everywhere. As described in previous articles in Oaks 'n' Folks, treeshelters are translucent plastic tubes placed over seedlings to protect them from animals and create a greenhouse-like environment that stimulates above-ground growth. Treeshelters initially were developed and tested in England about 20 years ago--mainly with English oaks--to enhance the growth of slow-growing hardwoods and shield seedlings from deer and rabbits, which can decimate unprotected plantings. Given such intensive protection, treeshelters are far more common here than in the United States, but I never would have expected to see the thousands per acre on hillsides adjacent to highways. Dense woodland plantations using treeshelters can appear very much like Arlington Cemetery--at least until the trees emerge through the tops of the rows-upon-rows of treeshelters. Some estimates are that between three and five million treeshelters are sold annually in this country that is half the size of California.
The other surprising observation is the great variety of shapes, colors, and designs of devices used to protect plantings. In California, the majority of treeshelters are beige tubes about four-inches in diameter and four-feet tall. In England, several sizes and colors of treeshelters commonly are used in the same planting area, as well as other types of individual plant protection devices. Shrubs might be protected with short, fat, light-green tubes that are nearly as wide as they are tall. An adjacent planting of beech, oak, and ash might have tall, narrow, brown cylinders or boxes around them. Just down the road, heavy black mesh surrounded by thin plastic sheets may cover bushy plants, while tree seedlings may be wrapped in white "spiral guards" that unravel as the trees grow larger.
Even though the sight of treeshelter forests is not the most aesthetically pleasing--and I suspect some environmental groups might prefer to see them banned from the planet forever-- they seem to be incredibly effective for reforestation in England. While recently stuck in traffic, I tried to determine how many shelters in a roadside planting had surviving plants inside. This was difficult to do without darting through traffic, but a 'windshield assessment' indicated that over 90% of the trees were growing out of the tops of the tubes. This is consistent with a large-scale survey here several years ago of over 4,000 shelters on 192 sites where 89% contained a living tree. Clearly, the success rate seems far higher than for roadside plantings along California highways. The fact that England has much more summer rainfall probably contributes greatly to excellent seedling growth and survival, but I suspect that treeshelters here are more carefully and properly installed and maintained. Thorough and regular weed control programs also help. Whatever the English do, it works, and we have much to learn from their many years of experience with these devices that, so far, seem particularly useful for regenerating oaks in California as well.
prepared and edited by Richard B. Standiford, Justin Vreeland, Bill Tietje