TY - JOUR
T1 - The devil is in the small dense saplings
T2 - A midstory herbicide treatment has limited effects on short-term regeneration outcomes in oak shelterwood stands
AU - Hutchinson, Todd F.
AU - Rebbeck, Joanne
AU - Stout, Susan L.
N1 - Funding Information:
We thank the Ohio Department of Natural Resources, Division of Forestry for providing the study sites, and marking and implementing the shelterwood harvests. We thank David Hosack, William Borovicka, David Runkle, and Levi Miller for leading the field work effort throughout the study. Aaron Iverson and Wynn Johnson collected the pre-treatment data. Also, a cadre of students from Hocking Technical College, Ohio University, and Ohio State University contributed to posttreatment data collection. We thank John Kabrick, Tom Schuler, Patrick Brose, and Gary Miller for reviewing earlier drafts of this manuscript. Two anonymous reviewers provided useful comments on the original submission. John Stanovick provided statistical support and a biometrics review of the manuscript. Funding was provided by the USDA Forest Service, Northern Research Station .
Publisher Copyright:
© 2016.
PY - 2016/7/15
Y1 - 2016/7/15
N2 - On intermediate quality sites, where oak advance regeneration often accumulates, we tested whether a low-intensity herbicide treatment of shade-tolerant saplings and poles (injection of stems >5 cm DBH with glyphosate), conducted just prior to a shelterwood harvest, could increase the proportion of oak (and hickory) in the regeneration layer after the harvest. Control and herbicide units were established at four study sites in southern Ohio. Advance reproduction was measured before and 4-6 years after a shelterwood harvest that reduced basal area by 50%. Before the harvest, shade-tolerant species, mainly red maple, blackgum, and sourwood, dominated the sapling layer but established oak-hickory seedlings were present at moderate densities. After the harvest, the proportion of oak-hickory did not change significantly on either control or herbicide units and non-oaks were dominant in the majority of plots. However, larger oak-hickory regeneration (>70 cm height) developed on nearly 50% of the sampling units (2-m radius subplots) and oak-hickory regeneration was dominant on a greater proportion of subplots in the herbicide units (26%) than in the control units (13%). Herbicide effects were limited due to the large number of smaller non-oak stems (<5 cm DBH) that were not treated and also the ineffectiveness of glyphosate to prevent red maple stump sprouting. The heavy shelterwood first removal cut stimulated the growth of both oak seedlings and competing stems, and the herbicide treatment resulted in very limited improvements in the competitive position of the oaks. However, because the oaks did survive and grow, additional treatments may still change the outcome on these sites.
AB - On intermediate quality sites, where oak advance regeneration often accumulates, we tested whether a low-intensity herbicide treatment of shade-tolerant saplings and poles (injection of stems >5 cm DBH with glyphosate), conducted just prior to a shelterwood harvest, could increase the proportion of oak (and hickory) in the regeneration layer after the harvest. Control and herbicide units were established at four study sites in southern Ohio. Advance reproduction was measured before and 4-6 years after a shelterwood harvest that reduced basal area by 50%. Before the harvest, shade-tolerant species, mainly red maple, blackgum, and sourwood, dominated the sapling layer but established oak-hickory seedlings were present at moderate densities. After the harvest, the proportion of oak-hickory did not change significantly on either control or herbicide units and non-oaks were dominant in the majority of plots. However, larger oak-hickory regeneration (>70 cm height) developed on nearly 50% of the sampling units (2-m radius subplots) and oak-hickory regeneration was dominant on a greater proportion of subplots in the herbicide units (26%) than in the control units (13%). Herbicide effects were limited due to the large number of smaller non-oak stems (<5 cm DBH) that were not treated and also the ineffectiveness of glyphosate to prevent red maple stump sprouting. The heavy shelterwood first removal cut stimulated the growth of both oak seedlings and competing stems, and the herbicide treatment resulted in very limited improvements in the competitive position of the oaks. However, because the oaks did survive and grow, additional treatments may still change the outcome on these sites.
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U2 - 10.1016/j.foreco.2016.04.016
DO - 10.1016/j.foreco.2016.04.016
M3 - Article
AN - SCOPUS:84962921221
SN - 0378-1127
VL - 372
SP - 189
EP - 198
JO - Forest Ecology and Management
JF - Forest Ecology and Management
ER -