Evaluation of suitable conditions for natural regeneration of Picea jezoensis on fallen logs

Abstract

The abundance of Picea jezoensis, a major conifer tree species in Hokkaido, northern Japan, is currently decreasing due to the lack of suitable conditions for recruitment and intensive harvests. To contribute to the development of sustainable forest management in Hokkaido, suitable substrates for natural regeneration of P. jezoensis were evaluated during a 4-year experimental study using seed additions in a natural coniferous forest. The environmental conditions (moss height, log hardness, extent of the humus layer, and light conditions) of fallen logs were measured. Moss height was categorized into three groups: 0 mm, Bark; 0 - 20 mm, Mthin; and ≥ 20 mm, Mthick. The germination rates of P. jezoensis were highest on Mthin, intermediate on Bark, and lowest on Mthick. Survival rates were low on Mthick, did not differ between Bark and Mthin, and increased with enhanced light. Growth increased with light, but the root allocation of seedlings was not affected by any environmental conditions. From these results, we determined that fallen logs with no or thin moss cover under bright conditions were most suitable for P. jezoensis regeneration. We discussed the generality of our results in relation to a co-occurring tree species in Hokkaido and the results of other regions

The Effects of Multilocus Heterozygosity on the Longevity of Seedlings Established on Fallen Logs in <i>Picea jezoensis</i> and <i>Abies sachalinensis</i>

“…Well-decomposed fallen logs with moss cover show reduced evaporation and contain water-soluble nutrients (Takahashi et al, 2000). However, seedling densities differ markedly among fallen logs, and not all fallen logs provide safe sites (Takahashi et al, 2000;Narukawa et al, 2003;Iijima & Shibuya, 2010). In addition to the fallen log conditions, genetic factors of each seedling may also impact tree recruitment success.…”

“…(Yezo spruce) and Abies sachalinensis Masters (Todo fir) are two major coniferous species in the mixed forests of Hokkaido, northern Japan (Takahashi et al, 2000;Narukawa et al, 2003). Studies have revealed that survival of P. jezoensis and A. sachalinensis seedlings is affected significantly by fallen log conditions, which include the hardness of the log surface (Narukawa et al, 2003;Iijima et al, 2007), moss coverage and/or moss height (Takahashi et al, 2000;Iijima et al, 2007;Iijima & Shibuya, 2010), and light conditions (Iijima & Shibuya, 2010). A microsatellite analysis revealed that P. jezoensis predominantly outcrosses (Tomita et al, 2008).…”

Effects of gap microsites and bamboo onAbies faxonianaregeneration in a subalpine forest, China

“…On the one hand, the positive role of decaying logs is obvious. Decaying logs with moss layer provide moist environment for seedling growth and survival, especially in summer (Iijima & Shibuya 2010). However, A. faxoniana saplings obviously preferred to establish on decaying logs in AF gaps, while distributed relatively evenly among different microsites in A gaps.…”

“…and Tsuga spp. (Bace et al 2012), usually rely on elevated surfaces to successfully regenerate (Iijima & Shibuya 2010). In contrast, larger-seeded species, such as Abies spp., with longer tap roots and longer shoots, are resistant to various stresses and generally do not require very specific substrates (Arbour & Bergeron 2011).…”

European beech, silver fir, and Norway spruce differ in establishment, height growth, and mortality rates on coarse woody debris and forest floor—a study from a mixed beech forest in the Western Carpathians

“…In the case of some genera, such as Picea sp., the density of seedlings established on CWD can increase during decomposition and slightly decreases on the most decayed CWD (Mori et al 2004;Zielonka 2006), but less is known about the colonization pattern of other species, such as broadleaves. Previous studies have shown that the enhanced growth and survival of conifers on elevated microsites may be attributed to less competition with shrubs and herbs (Zielonka 2006;Iijima and Shibuya 2010;Ota et al 2012) and a better nutrient and moisture supply (Brunner and Kimmins 2003;Baier et al 2006). However, in mixed broadleaf forests, these mechanisms may act differently for each species because largeseeded species are generally known to be more resistant to environmental stresses (Carlton and Bazzaz 1998;Moles and Westoby 2004).…”