Beech bark disease (BBD), a Neonectria fungal disease mediated by an invasive sap-feeding beech scale insect (Cryptococcus fagisuga Lind.), continues to affect American beech (Fagus grandifolia) in North America. Beech scale was first identified in Upper and Lower Michigan in 2000. Annual monitoring indicates the rate of spread of the advancing front (beech scale infestation) from 2005 to 2012, varies among Lower Michigan populations, ranging from <1 km to 14.3 km per year. Spread rates are more consistent in Upper Michigan, ranging from 3 to 11 km per year.In 2002, 62 long term impact sites were established in areas with low, moderate or high beech basal area and beech scale infestations ranging from absent to heavy to collect baseline data on beech condition, overstory and understory species composition and coarse woody material (CWM). Twelve beech trees per site (744 total) were also tagged for future evaluation. In 2012, I re-visited the original 62 sites to assess impacts of BBD and determine if beech basal area, initial beech scale infestation (in 2002) or differences between Upper and Lower Michigan affected beech mortality, CWM or related variables. In Upper Michigan, up to 55.6% of beech stems and 92.4% of beech basal area have died. In Lower Michigan, however, the highest mortality recorded in a site was 38.9% and dead beech basal area did not exceed 25.6% in any site. Overall, 18.7% of the beech tagged in 2002 have died. Abundance of fresh CWM has doubled since 2002 and 68.2% of the fresh material is beech.
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