The Northeast Timber Growing Contest (www.timbercontest.com) is a great activity that assists landowners in learning much more about their woodlands and timber investments. I measure and track the diameter-at-breast-height (DBH) of about 2,000 trees annually and it tells me a lot about how to make TSI decisions. Once you learn to use the proper tools, it's very easy to acquire the skill of measuring tree diameter with great precision.
However, sometimes mistakes are made in measuring and one should be careful not to make big decisions using small amounts of data. The sage...."measure twice, cut once" is a good one. But when you're good at measuring and 50 out of 100 trees shrink in DBH and measure smaller after one full growing season, what the heck is going on? Does anyone here have any ideas?
It's been a very dry spring and summer here in Western NY with drought-like conditions. I looked up some research online and only found a couple links (most notably by a person named Kozlowski from Madison, WI). The papers say:
"Among well-known indications of internal water deficits in trees are shrinkage of tissues and reduction in photosynthesis." "Thus, the occurrence of decreasing values in successive forest inventories could be due to natural physiological and physical processes, and not exclusively related to human measurement errors."
Is this physical mechanism of shrinkage well known? If so, timber contesters, don't despair, your measurement technique is just fine! Next year the trees will spring back when they get "rehydrated." If not, what else other than measurement error can cause the DBH to decrease in a healthy tree?
Check out www.timbercontest.com and consider entering. Depending on category, it takes only 1 hour per YEAR to participate and you'll learn a ton. It's all about learning and using a modest level of friendly competition to make it interesting. There are now well over 30 teams across NY in the contest. Youngest contestant is 12 years old and the oldest is 80 years young!