Tree heights at the northern edge of their range   Lee Frelich   Jun 06, 2004 10:43 PDT  ENTS: After watching mulberry and catalpa trees in Minneapolis and red maples and red oaks in the Boundary Waters of northern Minnesota for more than decade, I am beginning to understand how extreme cold limits tree heights to a heights much less than the potential for the soils conditions. This last winter we had an extreme cold spell, and most mulberries and catalpas in Minneapolis this spring have lost 5-10 feet in height due to dieback. This seems to happen every 5 years or so. I wonder if most trees routinely lose a small amount of height quite often due to dieback from cold in the northern edge of their range, thus contributing to the pattern of shorter heights with increasing latitude. Next Saturday I will check some of the red maples and red oaks at Hegman Lake in northern MN, where it was down to -50 last January. It will be interesting if they have died back again like they did after the cold winter of 1995. Lee RE: Tree heights at the northern edge of their range   Gary A. Beluzo   Jun 06, 2004 16:20 PDT  Lee: So you are hypothesizing that the shorter overall height gain of the red maples, red oaks, and mulberries results more from natural "pruning" rather than altered physiology due to the cold? That is really interesting Lee, I look forward to further posts on this topic. Gary Gary A. Beluzo Professor of Environmental Science Holyoke Community College RE: Tree heights at the northern edge of their range   Lee E. Frelich   Jun 07, 2004 06:01 PDT  Gary: Yes, for some species pruning by freezing of the upper crown appears to limit height. For other species, and perhaps for these same species further south, there is probably still a height limitation caused by length of growing season. Lee   Home