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Takuhiko M.,Niigata University | Shigejiro Y.,Kyushu University | Tetsuji O.,Kyushu University | Nobuya M.,Kyushu University | And 8 more authors.
Nihon Ringakkai Shi/Journal of the Japanese Forestry Society | Year: 2011

To quantify non-reforested ested area (NRA) in the Kyushu region, we analyzed the occurrence rate of NRAs in each prefecture and their spatial distribution. To determine reforestation after coniferous plantation forest clear cutting, we analyzed images to determine changes in area using multi-temporal remotely sensed imagery. We studied two periods, from 1998 to 2002 (first period) and after 2002 (second period), to determine changes in NRA between the two periods. Point-based analysis showed that the NRA occurrence rate for the entire Kyushu main island in the first and second periods was 30.9 and 24.3%, respectively. Mapping the NRA spatial distribution using GIS showed that NRAs were concentrated in specific areas in both the first and second periods, rather than being distributed uniformly in the forested regions of Kyushu. The cut area of coniferous plantation forests and NRA were totaled using the Japanese secondary mesh unit, with the NRA occurrence rate calculated via mesh unit. In comparing the first and second periods, we found that most of the meshes showing extremely high NRAs (occurrence rate >50%) were not located in the same place in the two periods. Thus, the occurrence of NRAs shifted between the two periods, with NRAs distributed more widely in the second period.

Tsuyoshi K.,Kyushu University | Shigejiro Y.,Kyushu University | Keiko N.,Kyoto Prefectural University | Takuhiko M.,Niigata University | And 9 more authors.
Nihon Ringakkai Shi/Journal of the Japanese Forestry Society | Year: 2011

Since 1990's, In Kyushu region, the abandonment of sites after clear-cutting plantations is increasing rapidly in Japan. Abandoned clear-cut sites may result in reduced soil and water conservation. In this study, we investigated erosions, osions, landslides and factors limiting vegetation recovery (e.g. Damage caused by browsing by sika deer and invasion by bamboo and luxuriant vine species) in 199 abandoned clear-cut sites in the Kyushu region. Among 199 sites, 8 sites (4.2%) showed severe erosions and landslides. However, 125 sites (62.8%) showed some factors limiting vegetation recovery. Thus, the abandoned clear-cut sites are problematic, and browsing by sika deer and invasion by bamboo or vine may add limiting vegetation recovery to this problem, although a few of severe erosions and landslides currently.

Kanetani S.,Japan Forestry and Forest Products Research Institute | Higashi M.,Kagoshima Prefectural Forestry Technology Center | Usui Y.,Kagoshima Prefectural Forestry Technology Center | Kawaguchi E.,Kagoshima Prefectural Office | And 3 more authors.
Nihon Ringakkai Shi/Journal of the Japanese Forestry Society | Year: 2013

To evaluate the effect of volcanic ash deposits and pine wilt disease on Pinus densiflora mortality in the Kirishima Mountains one year after the 2011 Shinmoe-dake eruption, we investigated the mortality rate in 84 P. densiflora forest stands and measured the depth of volcanic ash deposits from the 2011 eruption in those stands and around 117 dead P. densiflora trees which were examined for the presence of Bursaphelenchus xylophilus. Although mortality rate was less than 20% in stands with volcanic ash depths shallower than 20 cm, it ranged from 60 to 100 in three stands along a hiking trail located at altitudes above 1,000 m where the volcanic ash stood depths were deeper than 25 cm. B. xylophilus was not detected in any dead P. densiflora tree sampled along the hiking trail, but was found in 86 dead trees below c.a. 950 m where the volcanic ash deposits were shallow. This evidence indicated that heavy volcanic ash deposits might cause extensive damage to P. densiflora without pine wilt disease. But some dead P. densiflora trees infected by pine wilt disease were found around the damaged P. densiflora forests where the forest floor was covered by a deep layer of volcanic ash. The results suggested the importance of controlling pine wilt disease in the region to preserve the surviving P. densiflora trees as a seed source for natural regeneration of P. densiflora forests damaged by the 2011 Shinmoe-dake eruption.

Kawaguchi E.,Kagoshima Prefectural Forestry Technology Center | Ichihara Y.,Japan Forestry and Forest Products Research Institute
Nihon Ringakkai Shi/Journal of the Japanese Forestry Society | Year: 2010

The effect of the nodes and their characteristics in Pinus thunbergii seedlings on the migration of the pinewood nematode, Bursaphelenchus xylophilus, were examined. We counted the number of nematodes that passed through stem-cuttings with nodes having different numbers of whorled branches (WBs) and those without nodes. Additionally, we studied the anatomical characteristics of the cortical resin canals CRCs at the nodes. We inoculated nematodes into seedlings of P. thunbergii to investigate the relationship between the number of WBs and symptom development. Fewer nematodes passed through the stem-cuttings with nodes than through the stem-cuttings without nodes, and these numbers decreased as the number of WBs increased. These results indicate that the migration of nematodes through the stem-cutting via the nodes is inhibited and the effect enhanced when WBs are more. The CRCs near the nodes were connected, and they curved at the base of the whorled branches. The number and size of the CRCs in the cross-section of nodes were smaller than those of CRCs in the cross-section of the stem away from the nodes. Such CRCs structures were promising as a factor for the inhibited the migration of the nematodes. The beginning of the foliage discoloration delayed in the seedlings with large number of WBs comparing to those with fewer WBs. This suggests that the inhibition of nematode migration at the nodes with many WBs may lead to the delay of the symptom development.

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