Significance and limitation of scarification treatments on early establishment of Betula maximowicziana, a tree species producing buried seeds: effects of surface soil retention

Abstract

Significance and limitation of scarification treatments on early establishment of Betula maximowicziana, a tree species producing buried seeds: effects of surface soil retention We compared early establishment of B. maximowicziana, a commercially valuable tree species producing buried seeds, among the standard scarification and three alternative treatments in which surface soil was retained (soil replacing, screening and plowing). We found the efficiencies of the soil retention for the seedling emergence were clearly different among the treatments; the replacing and plowing caused significantly richer seedling emergence, whereas the screening resulted in lower emergence than the standard treatment. In total, the most abundant seedling emergence was estimated to have occurred in the case of higher soil water content with lower soil hardness. These seemed to be attributed to soil properties, induced differently by each treatment, and relatively high water demand characteristics of B. maxomowicziana. On the other hand, plowing showed low seedling density at the end of the second growing season despite its greater emergence, probably because of suppression from understory vegetation recovered from undisturbed root system. We conclude that replacing would be a best alternative for regeneration of B. maxomowicziana. The scarification treatments in which surface soil is retained can be evaluated to be positive or negative according to the site conditions, physiological characteristics of the target tree species, and recovery of other vegetation.

Various scarification treatments produce different regeneration potentials for trees and forbs through changing soil properties

“…3b) despite the differences in their residual pseudo-buried seed density suggests that the germination and survival rates were higher with the replacing than with the screening. This tendency is consistent with the findings of a previous study considering the appearance of B. maximowicziana seedlings from buried seeds (Yamazaki and Yoshida 2018). We think that this is caused by the increased soil water content, which also closely related to the soil hardness and plant-debris density, in the replacing (Fig.…”

“…We found that there is no clear advantage of selecting the standard scarification treatment over the other two treatments, as it results in a lower density of pseudo-buried seeds (Fig. 3a) and growth of tree seedlings (Yamazaki and Yoshida 2018), and importantly, does not necessarily bring about a greater reduction in the reproduction of tall forb species (Fig. 4).…”

“…We previously compared two different practices for leaving the surface soil known as "screening" and "replacing" (see the Materials and methods section for details), and unexpectedly found that the number of seedlings that germinated from buried seeds varied significantly between these, possibly indicating that both the amount and quality of the soil that is left is important (Yamazaki and Yoshida 2018).…”

Photosynthetic and Growth Responses in a Pioneer Tree (Japanese White Birch) and Competitive Perennial Weeds (Eupatorium sp.) Grown Under Different Regimes With Limited Water Supply to Waterlogging

“…Sasa bamboo is a major competitor against birch regeneration, since sasa bamboo quickly occupies an open site with rhizomes, which creates a dense vegetation cover and a thick litter layer, which prevents germination and growth of light-demanding species such as Japanese white birch ( Koike, 1988 ; Koike et al, 2001 ; Doležal et al, 2009 ; Seiwa et al, 2009 ). Therefore, soil scarification is expected to be an empirical treatment to promote Japanese white birch regeneration by removing rhizomes of sasa bamboo ( Yamazaki and Yoshida, 2018 , 2020 ). However, even when rhizomes of sasa bamboo are successfully removed by scarification, other weed species would outcompete regenerating seedlings of Japanese white birch.…”

Evaluating Soil–Root Interaction of Hybrid Larch Seedlings Planted under Soil Compaction and Nitrogen Loading

“…High soil hardness can inhibit root development, resulting in the inhibition of physiological activities and growth suppression of trees [4]. Soil hardness means pressure resistance and it is a general physical parameter [11][12][13]. The effects of soil compaction on tree growth vary depending on soil type, condition, and tree species [14][15][16].…”