By Mike Hillstrom, forest health specialist, Fitchburg, Michael.Hillstrom@wisconsin.gov, 608-513-7690
It’s another wet year in many parts of Wisconsin with water levels in lakes and rivers remaining very high. Seasonally wet areas are staying wet for longer, and areas that have not been wet for years are flooding or experiencing rising ground water levels. DNR forest health staff are increasingly noticing tree mortality due to these hydrologic issues. This occurs because flooding and high water reduces the amount of oxygen in the soil, depriving trees with submerged roots of the oxygen needed for growth and respiration. Along with submerged roots, trees can also die from uprooting and from subsequent insect and disease attack following flooding stress.
It may become necessary to conduct salvage harvests in flooded stands. Of course, the flooding also makes site access difficult. This is particularly concerning in stands where salvage harvests are needed to capture value, such as stands impacted by insects like emerald ash borer and eastern larch beetle.
Please let your local forest health specialist know if you are seeing flood-damaged stands. It is recommended to keep setting up salvage sales where appropriate. Access to wet or flooded sites can be difficult and may require frozen ground conditions if the site is expected to remain wet in the near-term.