Growth and Survival of Tall Tree Seedlings 6∼8 Years after Soil Scarification in Hokkaido

Journal of Forest Research

Kamitani

2009

We examined an alternative natural regeneration practice with a scarification treatment, in which removed soil is replaced on the scarified area, in northern Japan. The effect of the soil replacement on tree establishment was quite obvious; the basal area of trees, composed mostly of Betula ermanii, in the soil-replaced site was about 150-fold greater than that of the normally treated site. The greater growth rates together with higher density, both of which seemed to be enhanced by improved (i.e., deeper, tender, and nutrient-rich) soil properties, produced the marked difference to the normally treated site. The expected enhancement of species diversity owing to utilizing buried seeds in the replaced soil was not found. The current study revealed that the soil replacement could substantially improve forest restoration management with emphasis on biomass production for large nonwooded sites.

Section: Discussionmentioning

confidence: 95%

An alternative of soil scarification treatment for forest restoration: effects of soil replacement

Aoyama

Journal of Forest Research

Kamitani

2009

“…Our study also suggests that absolute dependence on advanced seedlings has a risk for continuous regeneration of this type of stand. Management practices associated with artificial planting or introduction of soil disturbance such as mechanical site preparation (Nakagawa and Kurahashi 2005;Yoshida et al 2005;Harada et al 2008) should be taken into consideration to enhance new establishment of seedlings of tall tree species (including A. sachalinensis) to compensate for the possible decrease in density.…”

Section: Discussionmentioning

confidence: 99%

Growth and survival of Abies sachalinensis seedlings for three years after selection harvesting in northern Hokkaido, Japan

Noguchi

2009

Landscape Ecol Eng

Previous studies have indicated that recruitment of Abies sachalinensis, a representative conifer species of northern Japan, decreased following single-tree selection harvesting in stands with dense dwarf bamboo understory. We tested the hypothesis that growth and survival of A. sachalinensis seedlings are reduced by canopy opening in that type of stand. A 0.75 ha study plot was examined, and all the seedlings (defined as trees with height 0.5-2 m) were identified and their shoot extensions measured for three years after single-tree selection harvesting (26% intensity in terms of basal area). The leader extensions of A. sachalinensis seedlings that experienced canopy opening were greatly improved. However, a negative effect on survival was also apparent; nearly 40% of seedlings died at the sites that experienced canopy opening. These results were supported by generalized linear models that examined variations of local harvesting intensity for individual seedlings. Despite the ability of A. sachalinensis to respond rapidly to exposure, some physiological stresses may have appeared, and presumably were amplified by cooccurring dwarf bamboos. With regard to the low seedling density (156 stems ha -1 ), common in this type of stands, local harvesting intensity in the selection system should be reduced to maintain survival of advanced regeneration, thus sustaining stand structure and composition.

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

Asada

Yamazaki

Forest Ecology and Management

2017

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.