{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/132193"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/132193","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Crop tree release impacts both the understory and overstory in mixed oak stands of the southern Appalachian Mountains","abstract":"Crop tree release (CTR) is an intermediate silvicultural treatment that can be used by woodland owners to achieve multiple management goals. Our study addresses a knowledge gap regarding the understory response to CTR in the Appalachian Mountains of southwest Virginia. An increase in understory species composition and abundance is expected, as CTR increases the availability of light and nutrients to the understory. Increased understory growth and abundance can improve habitat for some wildlife species. However, the magnitude of change, longevity and composition of any increase in understory vegetation is unknown. We sampled locations on the George Washington and Jefferson National Forests that had received CTR treatments over the past ten years (between 2014 and 2024). Understory data were collected within one-meter square sampling areas near released and non-released trees to determine woody plant species abundance and composition. Crown widths, diameter at breast height, crown height and total height of crop trees were measured, and epicormic branching was ranked. Understory vegetation was dominated by five species: teaberry (Gaultheria procumbens), greenbrier species (Smilax spp.), red maple (Acer rubrum), eastern white pine (Pinus strobus), and blueberry species (Vaccinium spp.). We found that at two, three, five, and seven years post-release there was a significantly more understory stems surrounding released trees compared to non-released trees. Moreover, we found species richness to be greater around release trees one, five, and seven-years post-release, while species diversity was only greater around released trees one-year post-release. We also found that the crowns of released trees were significantly wider than that of non-released trees and that epicormic branching did not differ between released and non-released trees.","abstract_html":"Crop tree release (CTR) is an intermediate silvicultural treatment that can be used by woodland owners to achieve multiple management goals. Our study addresses a knowledge gap regarding the understory response to CTR in the Appalachian Mountains of southwest Virginia. An increase in understory species composition and abundance is expected, as CTR increases the availability of light and nutrients to the understory. Increased understory growth and abundance can improve habitat for some wildlife species. However, the magnitude of change, longevity and composition of any increase in understory vegetation is unknown. We sampled locations on the George Washington and Jefferson National Forests that had received CTR treatments over the past ten years (between 2014 and 2024). Understory data were collected within one-meter square sampling areas near released and non-released trees to determine woody plant species abundance and composition. Crown widths, diameter at breast height, crown height and total height of crop trees were measured, and epicormic branching was ranked. Understory vegetation was dominated by five species: teaberry (Gaultheria procumbens), greenbrier species (Smilax spp.), red maple (Acer rubrum), eastern white pine (Pinus strobus), and blueberry species (Vaccinium spp.). We found that at two, three, five, and seven years post-release there was a significantly more understory stems surrounding released trees compared to non-released trees. Moreover, we found species richness to be greater around release trees one, five, and seven-years post-release, while species diversity was only greater around released trees one-year post-release. We also found that the crowns of released trees were significantly wider than that of non-released trees and that epicormic branching did not differ between released and non-released trees.","abstract_has_math":false,"creators":["Holloway, Austin Wayne"],"institution":"Virginia Tech","degree_name":"Master of Science","degree_level":"masters","degree_discipline":"Forestry","degree_department":"Forest Resources and Environmental Conservation","school":null,"contributors":[],"advisors":[],"committee_chairs":["Seiler, John R."],"committee_members":["Ford, W. Mark","Carter, David Robert James","Gagnon, Jennifer L."],"year":2025,"date_issued":"2025-05-12","date_published":"2025-05-12","updated_at":"2026-07-22T22:19:38Z","subjects":["Crop tree release","canopy gaps","hardwood silviculture","oak","Quercus","southern Appalachians","understory vegetation","wildlife value"],"languages":["en"],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["vt_gsexam:43203"],"render_values":[{"text":"vt_gsexam:43203","href":null,"code":true}]}]},"links":{"outbound_url":"https://hdl.handle.net/10919/132193","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["Seiler, John R."]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Ford, W. 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Our study addresses a knowledge gap regarding the understory response to CTR in the Appalachian Mountains of southwest Virginia. An increase in understory species composition and abundance is expected, as CTR increases the availability of light and nutrients to the understory. Increased understory growth and abundance can improve habitat for some wildlife species. However, the magnitude of change, longevity and composition of any increase in understory vegetation is unknown. We sampled locations on the George Washington and Jefferson National Forests that had received CTR treatments over the past ten years (between 2014 and 2024). Understory data were collected within one-meter square sampling areas near released and non-released trees to determine woody plant species abundance and composition. Crown widths, diameter at breast height, crown height and total height of crop trees were measured, and epicormic branching was ranked. Understory vegetation was dominated by five species: teaberry (Gaultheria procumbens), greenbrier species (Smilax spp.), red maple (Acer rubrum), eastern white pine (Pinus strobus), and blueberry species (Vaccinium spp.). We found that at two, three, five, and seven years post-release there was a significantly more understory stems surrounding released trees compared to non-released trees. Moreover, we found species richness to be greater around release trees one, five, and seven-years post-release, while species diversity was only greater around released trees one-year post-release. We also found that the crowns of released trees were significantly wider than that of non-released trees and that epicormic branching did not differ between released and non-released trees."]},{"key":"dc:description.abstractgeneral","label":"General Abstract","values":["Crop tree release (CTR) is a forestry practice that allows landowners to encourage the best trees in their forest by removing any trees that are directly competing with their selected crop tree. The gaps left in the canopy once competing trees are removed allow light to reach that forest floor which could potentially promote understory vegetation growth that typically wouldn't occur in a closed canopy forest. Our study evaluated the understory vegetation surrounding released crop trees and non-released trees in stands that had CTR applied to them over the past ten years in the Eastern Divide Ranger District of the George Washington and Jefferson National Forest in the Ridge and Valley of Virginia. We collected data using small sampling plots around released crop trees and non-released trees. We also measured changes in growth and ranked a defect known as epicormic branching of each sampled tree. We found the understory vegetation surrounding released crop trees and non-release trees to be dominated by five species: teaberry (Gaultheria procumbens), greenbrier species (Smilax spp.), red maple (Acer rubrum), eastern white pine (Pinus strobus), and blueberry species (Vaccinium spp.). At post-release years one, two, five, and seven we found more understory growth around released crop trees compared to non-released trees. Additionally, we found more species around released crop trees compared to non-released trees at post-release years one, five, and seven. Species diversity was only greater around released crop trees one-year post-release. Lastly, the crown width of released trees was wider than that of non-released trees and epicormic branching did not differ between released crop trees and non-released trees."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science"]},{"key":"dc:format.medium","label":"Dc Format Medium","values":["ETD"]},{"key":"dc:title","label":"Title","values":["Crop tree release impacts both the understory and overstory in mixed oak stands of the southern Appalachian Mountains"]}]}],"canonical_facts":{"dc:contributor.committeechair":["Seiler, John R."],"dc:contributor.committeemember":["Ford, W. Mark","Carter, David Robert James","Gagnon, Jennifer L."],"dc:contributor.department":["Forest Resources and Environmental Conservation"],"dc:creator":["Holloway, Austin Wayne"],"dc:date.accessioned":["2025-05-13T08:01:04Z"],"dc:date.available":["2025-05-13T08:01:04Z"],"dc:date.issued":["2025-05-12"],"dc:description.abstract":["Crop tree release (CTR) is an intermediate silvicultural treatment that can be used by woodland owners to achieve multiple management goals. Our study addresses a knowledge gap regarding the understory response to CTR in the Appalachian Mountains of southwest Virginia. An increase in understory species composition and abundance is expected, as CTR increases the availability of light and nutrients to the understory. Increased understory growth and abundance can improve habitat for some wildlife species. However, the magnitude of change, longevity and composition of any increase in understory vegetation is unknown. We sampled locations on the George Washington and Jefferson National Forests that had received CTR treatments over the past ten years (between 2014 and 2024). Understory data were collected within one-meter square sampling areas near released and non-released trees to determine woody plant species abundance and composition. Crown widths, diameter at breast height, crown height and total height of crop trees were measured, and epicormic branching was ranked. Understory vegetation was dominated by five species: teaberry (Gaultheria procumbens), greenbrier species (Smilax spp.), red maple (Acer rubrum), eastern white pine (Pinus strobus), and blueberry species (Vaccinium spp.). We found that at two, three, five, and seven years post-release there was a significantly more understory stems surrounding released trees compared to non-released trees. Moreover, we found species richness to be greater around release trees one, five, and seven-years post-release, while species diversity was only greater around released trees one-year post-release. We also found that the crowns of released trees were significantly wider than that of non-released trees and that epicormic branching did not differ between released and non-released trees."],"dc:description.abstractgeneral":["Crop tree release (CTR) is a forestry practice that allows landowners to encourage the best trees in their forest by removing any trees that are directly competing with their selected crop tree. The gaps left in the canopy once competing trees are removed allow light to reach that forest floor which could potentially promote understory vegetation growth that typically wouldn't occur in a closed canopy forest. Our study evaluated the understory vegetation surrounding released crop trees and non-released trees in stands that had CTR applied to them over the past ten years in the Eastern Divide Ranger District of the George Washington and Jefferson National Forest in the Ridge and Valley of Virginia. We collected data using small sampling plots around released crop trees and non-released trees. We also measured changes in growth and ranked a defect known as epicormic branching of each sampled tree. We found the understory vegetation surrounding released crop trees and non-release trees to be dominated by five species: teaberry (Gaultheria procumbens), greenbrier species (Smilax spp.), red maple (Acer rubrum), eastern white pine (Pinus strobus), and blueberry species (Vaccinium spp.). At post-release years one, two, five, and seven we found more understory growth around released crop trees compared to non-released trees. Additionally, we found more species around released crop trees compared to non-released trees at post-release years one, five, and seven. Species diversity was only greater around released crop trees one-year post-release. Lastly, the crown width of released trees was wider than that of non-released trees and epicormic branching did not differ between released crop trees and non-released trees."],"dc:description.degree":["Master of Science"],"dc:format.medium":["ETD"],"dc:identifier.other":["vt_gsexam:43203"],"dc:identifier.uri":["https://hdl.handle.net/10919/132193"],"dc:language.iso":["en"],"dc:publisher":["Virginia Tech"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:subject":["Crop tree release","canopy gaps","hardwood silviculture","oak","Quercus","southern Appalachians","understory vegetation","wildlife value"],"dc:title":["Crop tree release impacts both the understory and overstory in mixed oak stands of the southern Appalachian Mountains"],"dc:type":["Thesis"],"thesis:degree_discipline":["Forestry"],"thesis:degree_level":["masters"],"thesis:degree_name":["Master of Science"],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:19:38Z"}