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Volume 53 (2011)
- Issue 2 Pages 41-
- Issue 1 Pages 1-
Volume 53, Issue 1
Displaying 1-4 of 4 articles from this issue
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Hitomi Furusawa, Teruaki Hino, Shinji Kaneko, Makoto ArakiArticle type: Article
2011 Volume 53 Issue 1 Pages 1-8
Published: June 25, 2011
Released on J-STAGE: April 03, 2017
JOURNAL FREE ACCESSAccording to some studies, herbivores reduce plant productivity, N input to the soil, and soil N mineralization, hence decelerating N cycling in forest ecosystems. However, few studies have been conducted on plant productivity and N dynamics in forest ecosystems, where herbivores have grazed on understory plants. In the temperate mixed forests of Ohdaigahara in central Japan, sika deer (Cervus Nippon centralis, Temminck, hereafter "deer") graze on understory dwarf bamboo (Sasa nipponica, Makino et Shibata, hereafter "sasa"). We studied the effects of deer grazing on the aboveground N input to the soil and soil N mineralization at the deer exclosure in the forest for 4 years. Deer exclusion increased the aboveground biomass of sasa, and thus the N input from sasa litter to the soil. The N input from the aboveground sasa litter inside the exclosure was nearly twice the sum of the N input from the aboveground sasa litter and the N input from the deer excrement outside the exclosure. This suggests that deer grazing decreased the aboveground productivity of sasa. We could not verify that deer grazing decelerated the soil N mineralization rate. Because the difference in the total N input was relatively small when N from woody litter was added to the N input, and the acceleration of the soil N mineralization rate by N input through excrements may partly compensate for depression by the decrease in the total aboveground N input. Long-term monitoring is needed to understand the effect of grazing on N dynamics in forest ecosystems.View full abstractDownload PDF (1165K) -
Chisato Takenaka, Naoko Hayakawa, Motoharu Kobayashi, Shotaro Kanaya, ...Article type: Article
2011 Volume 53 Issue 1 Pages 9-15
Published: June 25, 2011
Released on J-STAGE: April 03, 2017
JOURNAL FREE ACCESSGamblea innovans (taxonomically revised from Evodiopanax innovans), is a deciduous tree species with a wide distribution in secondary forest of Japan, and has been reported as an accumulator of Cd and Zn in heavy metals-contaminated area. In order for this species to be effectively used for phytoremediation, characteristics related to heavy metal accumulation and transport need to be defined. We conducted three kinds of experiment, including one field observation of metal accumulation in G. innovans in uncontaminated field sites and two pot experiments using G. innovans saplings. To elucidate the transport and uptake of heavy metals in G. innovans, saplings raised in contaminated soils were cultivated in uncontaminated soils and saplings raised in uncontaminated soils were treated with a CdCl_2 solution. Field observations showed that the accumulation of Cd, Mn and Zn was a general feature of G. innovans, and was not limited to plants grown in contaminated soils. From the pot experiments, we found that the heavy metals accumulated in roots and stems were mobile, and were transported to newly developed leaves. This transport of heavy metals from root to shoot through the xylem occurred slowly.View full abstractDownload PDF (1062K) -
Keizo Hirai, Kyotaro Noguchi, Takashi Yamanaka, Shinji Kaneko, Masamic ...Article type: Article
2011 Volume 53 Issue 1 Pages 17-22
Published: June 25, 2011
Released on J-STAGE: April 03, 2017
JOURNAL FREE ACCESSMost of litter returned by non-commercial thinning was existed without contact onto the forest floor. We discussed nitrogen dynamics with decomposing litter after thinning with a focus on the site difference of litter existence in this study. The amount of nitrogen returned by thinning was 84kg ha^<-1> and 67% of them were existed in the air without contact onto the floor. Litterbag containing green needles was installed in the air and on the surface in forest floor, and decomposition rate and nitrogen supply with decomposing of green needles into the soil were investigated. Decomposition rate was not differed among treatments after one year installation but was higher in the surface than the air in two year after. Nitrogen concentration in the remaining green needles was increased from just after installation in both of treatment, and was statistically higher in the surface than in the air. After decomposition, amounts of nitrogen containing in the remaining green needles were gained by immobilization until six month after in the air and one year after in the surface. Nitrogen supply into the soil with green needle decomposition started early in the air compared in the ground. Contribution of nitrogen supply into the soil from green needles installed on the surface during two years was 64%. Because decomposition rate of green needles installed on the surface between one and two year after higer than those of in the air.View full abstractEditor's pickDownload PDF (1202K) -
Yoshiyuki Inagaki, Kyotaro Noguchi, Shinji Kaneko, Toru Hashimoto, Sat ...Article type: Report
2011 Volume 53 Issue 1 Pages 23-29
Published: June 25, 2011
Released on J-STAGE: April 03, 2017
JOURNAL FREE ACCESSAboveground net primary production and its allocation to different organs were evaluated along the gradient of stand density in three thinned and three control plots at a Japanese cedar plantation in northern Ibaraki Prefecture. The aboveground net primary production rate after thinning differed 1.9-fold among six study plots. The mean biomass allocations to stems, leaves, cones, and male flowers for the six plots were 64.7%, 27.3%, 3.0% and 3.0%, respectively. The plot with the lowest relative yield index had lower allocation to stems (54%). Two other thinned plots had higher allocation to stems (71-72%). Allocation to stems in the unthinned plots had intermediate values (61-67%). By excluding one control plot with high male flower production, allocation to male flowers was higher where the relative yield index was lower. These results suggest that strong thinning promotes allocation to male flowers but not to stems, and that stand density should be maintained at a certain level as the relative yield index is 0.75 to maintain allocation to stems and inhibit increase in male flower production.View full abstractDownload PDF (1114K)
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