(1) Deer damage prevention in modern orchards is expensive!

Recently, trained dogs have been used to keep deer out of orchards. A single wire is placed around the orchard border, either exposed or buried and a battery-powered collar is placed on each of one or more dogs. As the dog approaches the border wire, his collar picks up a signal from the fence, activating a buzzer. If the dog continues toward the fence the collar produces an unpleasant shock. Dogs chase deer, rabbits, and woodchuck, whose only escape is outside the orchard border, where the dog will not follow. This system has been good, but not 100% effective. The current recommendation is to use one dog for each 25 acres of orchard. Installation is quite easy, and initial cost is relatively low. A wildlife control consultant in the Hudson Valley showed a projected cost comparison of dogs versus high tensile woven wire fence for 25 acres over a 20 year period: $16,000 for the dogs, versus $11,000 for the woven wire fence. Dogs were valued at $250 each, with life expectancy of 10 years. Incidentally, vaccines are now available to treat dogs against Lyme disease. They are pretty effective, perhaps 80%, according to UConn Associate Profesor of Pathobiology, Dr. Sandra Bushmich.

Other deer-damage control methods seen at trade shows associated with these meetings included various repellants, plastic grid fence, and sound systems for broadcasting recordings of barking dogs. Entrepreneurs are taking note of the deer-damage problem, and of the frustration growers have had with most methods tried. In Tolland, where deer are frequently seen in my small orchard, I continue to note that one of the advantages of the raised-canopy training system I am researching is the near absence of browsing damage.

2) Economics of Tree Density

Dr. Terrence Robinson reported in a meeting at Kingston, New York on some 10 year old trial plantings of McIntosh and Empire in the Hudson River Valley. Four systems in the trial on either M7 rootstock, or M9/MM111 interstems, were planted at several spacings. After 10 years, none of the McIntosh plantings has yet paid its costs (net present value method). In the Empire plantings, all but the lower density M7 trial (13 ft x 20 ft) had paid for themselves. Early yields were in proportion to number of trees per acre, but early yields per tree on interstem trees were considerably greater than on M7. While the higher density interstem plantings of both varieties had higher early yields, they also had higher debt to pay back. And it now appears that per tree yields on M7 have so overtaken those on interstem trees that they will soon be the more profitable systems.

This study illustrates some facts worth remembering when trying to decide what rootstock, tree spacing, and training system will be most profitable. The system that pays for itself first is not necessarily the best choice, as it may put you much further in debt before it reaches that payback time. Also, the system that does best in the first 6 to 10 years is not necessarily the best when evaluated over a longer lifespan. One of the shortcomings of M7 rootstock is that it does not produce particularly precocious fruiting. The new rootstock CG-30, in the same vigor category as M7, has shown itself to be considerably more precocious. It looks promising as a better root for modern freestanding orchards.

3) Irrigation

Dr. Terrance Robinson, also speaking on this topic, suggested that growers determine when water is needed by measuring pan evaporation and rainfall over time. Pan evaporation indicates evapotranspiration when multiplied by the correct conversion factor. When accumulated evapotranspiration exceeds rainfall, irrigation should be applied in the same amount, to bring the soil back to field capacity.