气候变化领域集成服务门户(CCPortal): Effects of conversion harvests on light regimes in a southern pine ecosystem in transition from intensively managed plantations to uneven-aged stands

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DOI	10.1016/j.foreco.2018.09.019
	Effects of conversion harvests on light regimes in a southern pine ecosystem in transition from intensively managed plantations to uneven-aged stands
	Sharma A.; Bohn K.K.; McKeithen J.; Singh A.
发表日期	2019
ISSN	0378-1127
起始页码	140
结束页码	149
卷号	432
英文摘要	Uneven-aged silviculture is increasingly viewed as ecologically and economically appropriate strategy to manage forest ecosystems. Consequently, there is interest in converting intensively managed pine plantations to uneven-aged stands in the southeastern United States. Understanding biophysical factors that determine performance and growth of desirable species is critical to success of such conversions. We initiated a replicated, long-term, operational-scale stand conversion experiment in mature slash pine (Pinus elliottii Engelm.) plantations in mesic-wet flatwoods sites in northwest Florida, and examined how five conversion harvests (shelterwood, group selection, staggered third row thin, third row thin, cut 2 leave 3 thin harvests), in addition to an uncut control, affected understory light availability in these forests. Light availability was measured in terms of leaf area index, sky, and fractions of Absorbed Photosynthetically Active Radiation (both direct and diffuse). The values of these variables were derived by analyzing a total of 880 (450 in the harvest treatment plots and additional 430 in the gaps of group selection) Digital Hemispherical Photographs using image analyzing software CAN-EYE. We found that shelterwood harvest resulted in highest light availability, whereas greatest variability in light conditions was observed following group selection harvests. Among the four circular gap sizes (0.1, 0.2, 0.4 and 0.8 ha) we studied, gaps of larger sizes had greater light availability. Light availability increased as the distance from the gap edge increased and was highest either in the center of the gap or slightly towards northern and western sides of the gap center. Variability in light availability increased as gap size increased from 0.1 to 0.4 ha but was reduced in the 0.8 ha gap. In shade-intolerant species like slash pine in wet flatwoods– where soil moisture and nutrients are generally not limiting– light availability could be the most critical factor determining the success of regeneration and stand conversion. Overall, the results indicated that shelterwood harvest resulted in highest average light availability which would be conducive to slash pine regeneration while group selection harvest created the most diverse light environment during the stand conversion which may promote a broader diversity of groundcover species. Long-term monitoring of regeneration growth and recruitment following prescribed burning and over multiple cutting cycles will determine if slash pine can be sustainably managed using uneven-aged silviculture. © 2018 Elsevier B.V.
英文关键词	Gap dynamics; Group selection; Leaf area index; Natural regeneration; Shelterwood; Slash pine; Stand conversion; Uneven-aged silviculture
语种	英语
scopus关键词	Ecosystems; Plants (botany); Reforestation; Soil moisture; Gap dynamics; Group selection; Leaf Area Index; Natural regeneration; Shelterwood; Slash pines; Uneven-aged silviculture; Harvesting; coniferous tree; cutting (process); forest ecosystem; forest management; group selection; growth; leaf area index; light availability; photosynthetically active radiation; plantation forestry; prescribed burning; silviculture; soil moisture; stand structure; understory; wood; Conversion; Ecosystems; Harvesting; Light; Natural Reforestation; Pinus Elliottii; Shelterwood; Florida [United States]; United States; Pinus echinata; Pinus elliottii
来源期刊	Forest Ecology and Management
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/156401
作者单位	West Florida Research and Education Center, University of Florida, 5988 U.S. 90, Building 4900, Milton, FL 32583, United States; Department of Agricultural and Biological Engineering, University of Florida, 261 Rogers Hall, 1741 Museum Rd., Gainesville, FL 32611, United States; Penn State Extension, The Pennsylvania State University, Rt. 6, 17129, Smethport, PA 16749, United States
推荐引用方式 GB/T 7714	Sharma A.,Bohn K.K.,McKeithen J.,et al. Effects of conversion harvests on light regimes in a southern pine ecosystem in transition from intensively managed plantations to uneven-aged stands[J],2019,432.
APA	Sharma A.,Bohn K.K.,McKeithen J.,&Singh A..(2019).Effects of conversion harvests on light regimes in a southern pine ecosystem in transition from intensively managed plantations to uneven-aged stands.Forest Ecology and Management,432.
MLA	Sharma A.,et al."Effects of conversion harvests on light regimes in a southern pine ecosystem in transition from intensively managed plantations to uneven-aged stands".Forest Ecology and Management 432(2019).