In post-fire Japanese cedar forest, we investigated external appearance of trees just after the fire and internal conditions of survived trees after seven years. The fire arose in February 2004, and the amount of burned leaves and branches was estimated as about 10 tons per hectare. The external appearance and the internal conditions were assessed by discoloration rate of a crown (CDR), and scar position in height above the ground (SPH), and by wood decay, discoloration and wound occlusion, respectively. As a result, CDR ranged from 0 to 100% and high CDR trees densely distributed in the ridge of the slope. SPH ranged from 0.2 to 3.9 m and no trend was found in the distribution of high SPH trees. From June to August, entrance barrows of bark beetles were observed at high CDR trees. Seven years later, about 50% trees survived with large wounds. They densely distributed in the bottom of the slope, and 95% of them were decayed. Wood decay and discoloration were observed along the stems above SPH in discs cut from four sampling trees. The results indicate that forest fire may not only kill many trees but also degrade wood quality with wood decay and coloration. We propose that the sugi trees (Cryptomeria japonica D. Don) hit by the fire should be felled immediately before wood quality degrades.
The sycamore lace bug, Corythucha ciliata (Say), was originally distributed throughout North America. In Japan, this bug was found for the first time in Aichi Prefecture in 2001, and until now it has distributed to a wide area from Kyushu to Hokkaido. Both adults and nymphs of C. ciliata feed on the underside of leaves of Platanus spp. trees. Platanus spp., host tree of C. ciliata, are often planted as roadside trees in busy areas in Japan, and C. ciliata has also become a nuisance in Kyoto Prefecture, as adults fly onto laundry and bedding drying on balconies adjacent to the trees. Therefore, to establish a control technique without spraying insecticide directly onto the tree, the effectiveness of trunk injection of thiamethoxam for control of C. ciliata was evaluated in Kyoto City, Kyoto Prefecture, in 2008. It was found that C. ciliata populations were restricted to low densities in trees where thiamethoxam had been applied.