Forests of the eastern United States (US) mostly comprise a mix of stands managed following silvicultural
principles and stands managed with exploitative timber harvesting practices. These stands can have similar stand
densities (e.g., basal area per hectare) but vary vastly in structure, composition, and biomass and carbon storage.
High grading, a prevalent exploitative timber harvesting practice in the eastern US, is of particular concern
because it can negatively affect future forest health and productivity. This study quantifies differences in forest
structure, composition, and biomass and carbon storage between high graded stands and stands that received a
seed/establishment cut of a uniform shelterwood regeneration sequence treatment, which is a comparable and
well-established silvicultural method used to regenerate mixed-oak forests. It focuses on mixed-oak forests
(mixed-Quercus), where the effects of high grading have been understudied, and uses a sample with broader
spatial coverage than previous studies. The sample comprised nine stands that were known to have been high
graded 8–15 years ago and nine stands that received the seed/establishment cut of a uniform shelterwood
regeneration sequence. Stand were systematically sampled using fixed-area plots. Field measurements were
collected and used to calculate metrics describing forest structure and function. The structure of high graded
stands was characterized by a higher proportion of trees with poor health and/or form compared to shelterwood
stands, with 18.3 % less acceptable growing stock and trees with lower crown compaction. Diameter distributions
of high graded stands were characterized by numerous small trees and few large-diameter trees. Spatial
variability of overstory trees was contingent on the tree size range evaluated, with a larger variability of
sawtimber-sized trees (trees ≥ 29.2 cm in diameter at breast height) in high graded stands. High graded stands
also had 2.2 times fewer oak trees (Quercus spp.) in the overstory canopy, 17,897 fewer seedlings per hectare
(ha), and 45 Mg/ha less biomass than shelterwood stands. These results indicate that high grading generally
degrades mixed-oak forests and impairs their long-term capacity to supply vital ecosystem services such as
habitat for specific wildlife species, carbon storage, and high-quality wood products.
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