Survival calls for change

摘要

At the recent Dwarf Fruit Tree Association conference, GARY LANGFORD gave the following address. The conference was held in the Grand Rapids, Michigan, United States. Michigan ranks third in apple production in the United States behind Washington and New York states. The winters are very severe compared with those here in Tasmania. The temperature only rose above 0 deg Celsius once during my visit, and then it was only for a short time one morning. The temperature was generally about -5 deg C to -10 deg C, with wind chill dropping it to -25 deg C at times. It is only possible to grow pome and stone fruit along the eastern shore of Lake Michigan, which is 320 kilometres long in a belt of 15 to 50 kilometres wide, taking advantage of the lake effecton the weather. The lake warms up the very cold air off the plains to the west (only slightly, by my reckoning), ensuring temperatures do not fall low enough to kill the trees. This effect also causes a large amount of snow to fall in this area as moisture is picked up when the air crosses the lake. This 'lake-effect snow' acts as insulator once it covers the ground and the trees. The area gets in excess of three metres of snow per year. The soils are generally very sandy and large, rolling sand dunesare present along many parts of the lake shore. There are very few intensive plantings because of poor soil.