• Journal of Korean Society of Water and Wastewater
• /
• v.29 no.6
• /
• pp.693-702
• /
• 2015

The objective of this study is to investigate and evaluate that a roadside tree root intrudes sewer network systems. Two approaches were performed to assess the characteristics of tree root intrusion. First, the characteristics of tree roots that had invaded sewers were directly observed by means of closed-circuit television inspection robot. Second, the intrusion proportions of tree root into rain gutters in the sampling area were investigated. As tree species of low intrusion proportions, the results indicated that Ginkgo biloba Linn. and Acer buergerianum Miq. were 1.7% and 4.3%. On the other hand, tree species of high intrusion proportions were Metasequoia glyptostroboides Hu et Cheng, Ulmus davidiana var. japonica Nakai and Zelkova serrata Makino as 22.2%, 20.4%, and 17.6% respectively. In particular, sewers and gutters around Zelkova species should be the focus of maintenance work because of the high proportion of these trees on roadsides.

• Journal of Korean Society of Forest Science
• /
• v.85 no.3
• /
• pp.496-505
• /
• 1996

Soil respiration was measured every two weeks from May through November 1995 using the soda lime method in 40-Year-old Pinus rigida and Larix leptolepis plantations on a similar soil in Yangpyeong, Kyonggi Province. Treatments included control and no-roots(plots trenched and root regrowth into plots prevented). Root respiration was evaluated by comparing no-roots sub-plots to control plots. Mean soil respiration showed highly significant species effects(p<0.01) and was highest at the Pinus rigida control plot($0.38g/m^2/hr$) and lowest at the Larix leptolepis no-roots plot($0.31g/m^2/hr$). High soil respiration in Pinus rigida may be related to aboveground litter production. The annual $CO_2$ fluxes ranged from 23 to 27t/ha/yr. We found significant correlations between temperatures(air : $R^2$=0.53, soil : $R^2$=0.55) and soil respiration(p<0.01), but no significant correlations between soil moisture and soil respiration(p>0.1). Root respiration was 3% of total soil respiration. We might underestimate rapt respiration because of shallow trenches and $CO_2$measurements right after trenching. Factors controlling soil respiration including belowground litterfall(especially fine roots) inputs, litter quality should be well understood to predict soil carbon fluxes and relative contributions to total soil respiration in forest ecosystems.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.3 no.3
• /
• pp.12-19
• /
• 2000

The purpose of this study is to evaluate the channel changes according to the temporal and spatial distribution of the deposition area by the vegetation invasion in Kyesung-river. The deposition area mainly occurred by landslide and debris flow from the headwater channel. And also the movement of subsequent downstream depends upon the site of deposits by a varity erosional processes. As the age of deposition area is older, it had a tendency to stable by plant invasion relatively. The vegetations grown in deposition area were very effective to estimate a historical deformation process of river-bed occurred by landslide. The vegetations around deposition area consisted of the same as tree species grown in forest area of circumference like Pinus densiflora, Styrax japonica, Quercus acutissima and Salix gracilistyla. If the torrential stream is flooding, the deposition area of 1 to 5 years can be change to the channel easily. Deposition area of 11 to 23 years had a high river-bed because it passed long time since deposited, and amount of sedimention is much more in wide than in narrow channel. It is consider that the change of channel had many influenced by the span of survial time, scale and movement frequency of deposition area after the vegetation invasion.

• Journal of Korean Society of Forest Science
• /
• v.98 no.1
• /
• pp.16-25
• /
• 2009

Cauliflower mushroom (Sparassis crispa) is recently recognized as a new edible and/or medicinal mushroom cultivated with conifers. By the way, the mushroom is notorious as a brown-rot fungus that causes a buttrot of larch. So, there should be a careful consideration to apply the mushroom cultivation in coniferous stand. This study was conducted to clarify the seriousness of heartwood decay on conifers such as larch by cauliflower mushroom with surveying the mushroom producing environment and to examine whether the cultivation of cauliflower mushroom produce any problem in conifer stands or not. The mushroom occurred in various coniferous stands such as Larix kaempferi, Pinus koraiensis, P. densiflora and Abies holophylla on fertile soils with adequate moisture. Soil texture of the mushroom producing site was comparatively fine compared to general forest soils; sandy loam, loam and silty loam. Soil pH ranged from 4.6 to 5.2, and organic matter contents were 4~11%, which showed relatively wide range. We could find S. crispa by a DNA technique from the wood that seemed to have no heartwood decay by naked eyes. The damaged wood showed 30% higher moisture contents than that of sound wood, while the compressive strength was 30% lowered down compared to that of sound wood. The fungus may invade conifers through the scars occurred on roots or stems, in this case spore dispersion of the mushroom takes a great role. Thus, we concluded that forest tending activities need to be applied with considering the invasion of S. crispa, and cultivation of cauliflower mushroom in forest should be attempted very carefully. By the way, we also infer that conifer stands can be nurtured without heartwood decay by S. crispa if the stand be managed in good aeration conditions by proper silvicultural practices such as sanitary thinning.

• Research in Plant Disease
• /
• v.18 no.2
• /
• pp.101-108
• /
• 2012

In 2006, pinewood nematode, Bursaphelenchus xylophilus, was isolated from about 50 years old trees of Pinus densiflora and P. koraiensis showing leaf-wilt and -drying symptoms in Gwangju, Gyeonggi-do and Chuncheon, Gangwon-do. Isolation of pinewood nematodes from sapwood of infected pine trees showed no difference in population density between tree species and among the sampling heights on the main stem. Migration of pinewood nematodes in the host tree were investigated by inoculation of red pine (P. densiflora, 3 years old) seedlings with B. xylophilus. The nematodes seemed to move in red pine seedlings prior to multiplication and it might have taken about 20 days to start multiplication and expression of symptoms including wilt and dieback. In initial time after inoculation, nematodes started migration through the cortical resin canal from inoculated site and further showed upward and downward movements. More nematodes were observed in cortical resin canal during early period of inoculation and later in resin canal of xylem and tracheid also while, the pith still remained free from nematode. The density of B. xylophilus was higher in seedlings of low-vigor with poor root growth than in seedlings of normal root growth. Seedlings showing high density of B. xylophilus exhibited stem discoloration and secondary infection by fungus at the inoculation site.