Gap structure and establishment of Silver birch regeneration ( Betula pendula Roth.) in Norway spruce stands ( Picea abies L. Karst.)

• Published in: Forest ecology and management Vol. 229; no. 1; pp. 314 - 324
• Main Authors: Huth, Franka, Wagner, Sven
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.07.2006; Elsevier
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Betula pendula; Biological and medical sciences; canopy gap size; canopy gaps; coniferous forests; equations; forest trees; Fundamental and applied biological sciences. Psychology; Gap; Ground vegetation; measurement; natural regeneration; old-growth forests; Picea abies; Regeneration; seedlings; shade tolerance; spatial data; Synecology; Terrestrial ecosystems; tree and stand measurements; tree growth; understory; Germany; United States; North America; America; Regeneration; Betula pendula; Picea abies; Ground vegetation; Gap; Competition; Litter; Growth; Plant juvenile growth stage; Ecology; Substrate; Karst; Dicotyledones; Angiospermae; Gymnospermae; Vegetation; Tree; Coniferales; Spermatophyta; Primary forest; Betulaceae; Age; Canopy(vegetation)
• ISSN: 0378-1127; 1872-7042
• DOI: 10.1016/j.foreco.2006.04.010

To describe the characteristics of gaps in Picea abies L. (Karst.) stands (>80 years) and gain an understanding of their effects and importance for natural regeneration of Silver birch ( Betula pendula Roth.), seven even-aged spruce stands were investigated. Regeneration of Birch was analysed for 495 gaps, which were sampled by the line intersect method. A gap was defined as expanded gap, which includes the ground area under a canopy opening extending to the bases of canopy trees surrounding that opening [ sensu Runkle, J.R., 1981. Gap regeneration in some old-growth forests of the eastern United States. Ecology 62 (4), 1041–1051]. The gap size ranged from 21 to 2157 m 2, with a median of 75 m 2. Fraction of land area in gaps was between 7 and 11% of total stand area according to evaluation method. Most of Silver birch seedlings surveyed had an age between 2 and 4 years. Significant differences ( P ≤ 0.05) in growth reaction caused by gap size were observed. Seedlings were most common and grew faster in larger gaps (>50 m 2), but they were rare in gaps >1000 m 2, because of the increased competition of grass. Analyses of field vegetation/substrate were included and it was obvious that Silver birch seedlings were more abundant in needle litter and mosses, although the most wide-spread vegetation group was grass.