Root biomass and distribution of aPicea—Abiesstand and aLarix—Betulastand in pumiceous Entisols in Japan

Abstract

Root biomass and root distribution were studied in Entisols derived from the thick deposition of volcanic pumice on Hokkaido Island, Japan, to examine the effect of soil conditions on tree root development. The soil had a thin (<10 cm) A horizon and thick coarse pumiceous gravel layers with low levels of available nutrients and water. Two stands were studied: a Picea glehnii-Abies sachalinensis stand (PA stand) and a Larix kaempferi-Betula platyphylla var. japonica stand (LB stand). The allometric relationships between diameter at breast height (DBH) and aboveground and belowground biomass of these species were obtained to estimate stand biomass. The belowground biomass was small: 30.6 Mg ha −1 for the PA stand and 24.3 Mg ha −1 for the LB stand. The trunk/root ratios of study stands were 4.8 for the PA stand and 4.3 for the LB stand, which were higher than those from previous studies in boreal and temperate forests. All species developed shallow root systems, and fi ne roots were spread densely in the shallow A horizon, suggesting that physical obstruction by the pumiceous layers and their low levels of available water and nutrients restricted downward root elongation. The high trunk/root ratios of the trees may also have resulted from the limited available rooting space in the study sites.

Soil CO&lt;sub&gt;2&lt;/sub&gt; efflux of a larch forest in northern Japan

“…Such a proportion indicates that the organic soil layer with a depth of 0.13 m produced 72% of total CO 2 emitted to the atmosphere. The vertical distribution of CO 2 efflux can be explained by those of soil carbon content and root biomass, which were localized in surface soil (Sakai et al, 2007). The annual ecosystem respiration (RE) of this site was 1493 gC m −2 y −1 in 2003 (Hirata et al, 2007).…”

“…The soil is weakly acidic (pH 5.0-6.0) and poor in nutrients. Sakai et al (2007) reported that the densities of total and fine root biomass were 24.3 and 6.9 t ha −1 and more than 80% of root biomass was distributed in the topsoil with a thickness of 0.15 m. Total soil organic carbon (SOC) and nitrogen storage were about 36 tC ha −2 and 300 gN m −2 , respectively, and about 90% of SOC accumulated in the surface layer between 0-0.30 m (Sakai et al, 2007). 2 A·h) lead-acid battery that drives the system; Cmp = air compressor; P Air = compressed air from the air tank to the pneumatic cylinders for opening and closing the chamber lids; F 2 = air filter (0.5 mm mesh); S = sample air from the chamber; P = sample pump; W T = water trap; F 1 = air filter (1 µF mesh); IRGA = infrared gas analyzer; R = sampled air returned to the chamber.…”

Biomass Accumulation and Net Primary Production during the Early Stage of Secondary Succession after a Severe Forest Disturbance in Northern Japan

“…The A horizon and C horizon were stratified in order [34]; the B horizon was lacking. According to the record of Tomakomai Meteorological station (located 13 km south of the study site) for 1981-2010 [35], the annual mean air temperature was +7.6 • C, with monthly mean air temperatures of −3.8 • C (January) through +20.3 • C (August).…”

“…Soil was classified as a pumiceous volcanogenous regosol with high water permeability and poor nutrients [31,34], with 1-2 cm of a fresh litter layer and 5-10 cm of a decomposed organic layer (A horizon). The A horizon and C horizon were stratified in order [34]; the B horizon was lacking.…”

Carbon and nitrogen status of decomposing roots in three adjacent coniferous plantations

“…However, root decomposition rates are affected by biotic factors, such as decomposer organisms present in the soil (King et al 1997, Silver & Miya 2001, Mao et al 2011, by abiotic factors, such as soil temperature, soil moisture and nitrogen availability; and by for-est management activities, such as fertilization and thinning (Silver & Miya 2001, King et al 2002. In addition, tree species can infl uence C and nitrogen (N) inputs from roots because the root litter produced by different species differs in quantity and quality of substrate (Sakai et al 2007, Mao et al 2011. Thus, the balance between roots and their decomposition controls the development of soil organic matter and the soil C and N content (Silver & Miya 2001).…”