Gaps in a gappy forest: plant resources, longleaf pine regeneration, understory response to tree removal in longleaf pine savannas

• Published in: Canadian journal of forest research Vol. 31; no. 5; pp. 765 - 778
• Main Authors: McGuire, J.P, Mitchell, R.J, Moser, E.B, Pecot, S.D, Gjerstad, D.H, Hedman, C.W
• Format: Journal Article
• Language: English
• Published: Ottawa, Canada NRC Research Press 01.05.2001; National Research Council of Canada; Canadian Science Publishing NRC Research Press
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; artificial regeneration; Biological and medical sciences; Canopies; canopy gaps; Coniferous forests; establishment; Evergreen trees; Forest management. Stand types and stand dynamics. Silvicultural treatments. Tending of stands. Natural regeneration; Forestry; Forests; Fundamental and applied biological sciences. Psychology; Grasslands; growth; light intensity; Mineralization; mortality; nitrogen; Pine trees; Pines; Pinus palustris; plant competition; Plant resources; R&D; Research & development; Resource availability; Savannahs; savannas; Seedlings; Stand types and stand dynamics. Silvicultural treatments. Tending of stands. Natural regeneration; Synecology; Terrestrial ecosystems; Understory; Vegetation; Georgia; United States; North America; America; Deforestation; Natural resources; Subtropical zone; Forests; Savannah; Natural forest regeneration; Experimental study; Canopy gap; Pinus palustris; Understory; Forestry; Gymnospermae; Softwood forest tree; Response modality; Coniferales; Spermatophyta
• ISSN: 0045-5067; 1208-6037
• DOI: 10.1139/x01-003

Resource availability and planted longleaf pine (Pinus palustris Mill.) seedling and understory vegetation response within and among three sizes of experimentally created canopy gaps (0.11, 0.41, 1.63 ha) in a mature longleaf pine savanna were investigated for 2 years. Longleaf pine seedlings and understory vegetation showed increased growth in gaps created by tree removal. Longleaf pine seedling growth within gaps was maximized approximately 18 m from the uncut savanna. Increased longleaf pine seedling survival under the uncut savanna canopy observed after the first year suggests that the overstory may facilitate establishment of longleaf pine seedlings rather than reduce survival through competition. Despite the relative openness of the uncut longleaf pine forest, light quantity was increased by tree removal. Light was also the resource most strongly correlated with seedling and understory vegetation growth. Although net N mineralization was correlated to seedling response, the amount of variation explained was low relative to light. Belowground (root) gaps were not strong, in part because of non-pine understory roots increasing in biomass following tree removal. These results suggest that regeneration of longleaf pine may be maximized within gap sizes as small as approximately 0.10 ha, due largely to increases in light availability.