Abstract Ungulate browsing limits forest regeneration on many reforestation and restoration sites. Silviculture can be used to mitigate the effects of ungulate damage by promoting rapid early growth of planted seedlings, but benefits may depend upon site characteristics and ungulate browse pressure. We studied the interactions among browsing by white-tailed deer (Odocoileus virginianus), use of genetically select seed sources, controlled-release fertilization (CRF) at planting, and site type (harvest openings and plantations) in a nine-year hardwood forest regeneration study. The experiment consisted of paired deer exclosure and control plots, with fertilization and seed source, established at two reforested clearcut sites and three afforested agricultural field sites in Indiana, USA. Our objectives were to examine treatment effects on growth (height and diameter), survival, and stem quality of four temperate deciduous hardwood species (northern red oak, white oak, black walnut, and black cherry). For all species, fencing had the greatest significant positive influence on survival (non-fenced: 50–72%, fenced: 71–75% by year 8) and growth (81–178% greater height and 90–167% greater diameter by year 8), as well as stem quality ratings. Fencing also increased (by 50–78%) the probability that black cherry and black walnut at afforested sites (as well as northern red oak at both site types) would reach free-to-grow status by year 5. We observed gains in height and diameter from CRF only during the first three years for fenced black cherry (11% greater height and 14% greater diameter in year 3), and for white oak regardless of fencing (13% greater height and 10% greater diameter in year 3). Genetically select seed sources had the greatest and most consistent growth benefit for black walnut (81% greater height and 50% greater diameter by year 8). Early growth was improved in genetically select P. serotina vs. non-select sources (11% greater height in year 3) but differences faded by the fifth growing season, while superior growth of genetically select Q. rubra began to manifest only after year 5 (16% greater height 21% greater diameter by year 8). In addition, select northern red oaks had an 8% greater probability of reaching free-to-grow status by year 5 and black walnuts at afforested sites had a 13% greater probability of reaching free-to-grow status. Without protection from herbivory, genetically improved sources did not realize their full potential for enhanced growth. Our results from this nine-year-long hardwood plantation experiment confirm that without browse protection, additional silvicultural treatments are unlikely to improve regeneration performance.

中文翻译：

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在有鹿食的情况下，建立硬木种植园的造林相对无效

摘要 有蹄类动物浏览限制了许多重新造林和恢复地点的森林再生。造林可通过促进种植幼苗的快速早期生长来减轻有蹄类动物损害的影响，但收益可能取决于场地特征和有蹄类动物的觅食压力。我们研究了白尾鹿 (Odocoileus virginianus) 浏览、使用遗传选择种子来源、种植时控释施肥 (CRF) 和场地类型（收获开口和种植园）在九年阔叶林再生过程中的相互作用学习。该实验包括成对的鹿圈地和对照地块，施肥和种子来源，建立在美国印第安纳州的两个重新造林的清除地和三个造林的农田地。我们的目标是检查处理对四种温带落叶硬木树种（北红橡木、白橡木、黑胡桃木和黑樱桃木）的生长（高度和直径）、成活率和茎质量的影响。对于所有物种，围栏对生存（非围栏：50-72%，围栏：第 8 年为 71-75%）和生长（高度增加 81-178%，直径增加 90-167%）的积极影响最大8 年），以及茎的质量评级。围栏还增加了（增加 50-78%）绿化地点（以及两种地点类型的北部红橡树）的黑樱桃和黑胡桃在第 5 年达到自由生长状态的可能性。我们观察到高度的增加和 CRF 的直径仅在围栏黑樱桃的前三年（第 3 年高度增加 11%，直径增加 14%），对于白橡木，不考虑栅栏（第 3 年高度增加 13%，直径增加 10%）。遗传选择的种子来源对黑胡桃具有最大和最一致的生长益处（到第 8 年，高度增加了 81%，直径增加了 50%）。与非选择来源相比，遗传选择的 P. serotina 的早期生长得到改善（第 3 年的高度增加了 11%），但差异在第 5 个生长季节消失，而遗传选择的 Q. rubra 的优越生长仅在第 5 年之后才开始显现（到第 8 年，身高增加 16%，直径增加 21%）。此外，选定的北方红橡树在第 5 年达到自由生长状态的可能性要高 8%，绿化地点的黑胡桃达到自由生长状态的可能性要高 13%。没有食草动物的保护，基因改良的来源没有充分发挥其促进生长的潜力。我们从这项为期 9 年的硬木种植园实验中得出的结果证实，如果没有森林保护，额外的造林处理不可能提高再生性能。