Spatial patterns of oak ( Quercus crispula ) regeneration on scarification site around a conspecific overstory tree

Abstract

Spatial patterns have been a major topic regarding natural regeneration of oak species, but the effects may differ considerably in sites subjected to intense forestry practices, which greatly alter many aspects of site conditions. We examined the hypothesis that the regeneration of oak (Quercus crispula Blume) following scarification (displacement of inhibiting vegetation and surface soil using machinery) is enhanced at a certain distance from a conspecific overstory tree, depending on the stage of development. We conducted both field surveys in scarification sites with different stand ages (1-16 year-old) and a laboratory seeding experiment to clarify factors contributing to its early establishment. The results demonstrate that the spatial relationship between the regeneration of oak and the conspecific overstory tree at scarification sites changes considerably among stages of the establishment. In the initial stage (0-1 years after the scarification), a location beneath the crown provided favorable conditions, whereas at subsequent stages (2-4 years), the distance-dependent effects were unclear, until eventually (8-16 years) a location outside the crown became more favorable. The condition produced by the scarification was basically competition-free and resource-rich, but it can also be harsh for acorns and small seedlings, imposing a requirement for shading to moderate the environment in the initial stage. Such an effect of facilitation was found also in the later (sapling) stage via the existence of neighbors of the other regenerated fast-growing species. The current findings supported the effectivity of a shelter-wood system, in which the regeneration starts from shaded condition followed by a gap status created by a successive felling. The area away from the conspecific crown would have a potential if acorns are plentifully supplied (e.g. by direct seeding) and they withstand the initial negative factors at the initial stage of development.

The 30-year impact of post-windthrow management on the forest regeneration process in northern Japan

“…This indicates that the establishment of Q. crispula after scarification was clearly unsuccessful at our study site. The capacity of oak to become established might be reduced because scarification creates an increased light intensity and dry conditions (Wetzel and Burgess 2001;Asada et al 2017), while Betula spp. gain an advantage as light-demanding species.…”

Regeneration Dynamics on Treefall Mounds and Pits for 10 Years after a Windfall in a Natural Mixed Forest

“…Although initially negatively impacted, on a 10-year time scale, given the small decrease in the density on the mounds, intense light conditions favor regeneration of Betula sp. A similar effect can be exerted on Q. crispula [30]. In contrast, it was demonstrated that A. sachalinensis on tip-up mounds is advantageous under limited conditions; its regeneration is promoted under conditions where there is a shade of surrounding canopies, and the soil moisture content is not too high.…”

Spatial pattern dynamics of <i>Cyclobalanopsis myrsinifolia</i> in mixed broad-leaved forests on Tianmu Mountain, eastern China, 1996–2012

“…Woody plants have a dominant status in a forest ecosystem, which spatial distribution patterns could indicate the mechanism of population structure formation and potential ecological process (Ripley 1977;Barot et al 1999). Trees are the major woody plant species within the forest communities, of which the dominant species also have important significance in the formation and maintenance of the community structure (Asada et al 2017). The dominant species usually account for a high proportion of the biomass.…”