Joo-Hoon Lim

Effects of heterogeneity of pre-fire forests and vegetation burn severity on short-term post-fire vegetation density and regeneration in Samcheok, Korea

This study investigated the combined effects of heterogeneity of pre-fire forest cover and vegetation burn severity on post-fire vegetation density and regeneration at an early stage in Samcheok, Korea. To measure the spatial heterogeneity of pre-fire forests, spatial pattern metrics at a landscape level and class level were adopted, and a regression tree analysis for post-fire vegetation density and regeneration was used to avoid spatial autocorrelation. Two regression tree models were estimated for post-fire vegetation density and post-fire vegetation regeneration with the same independent variable sets, including heterogeneity of pre-fire forest cover and vegetation burn severity. The estimated model suggested that the percentage of Japanese red pine and burn severity were the most significant variables for post-fire vegetation density and regeneration, respectively. The compositional and spatial heterogeneity of pre-fire forest and burn severity, as well as the degree of burn severity, was found to have significant impacts on post-fire vegetation density and regeneration. Overall, more rapid vegetation regeneration can be expected in more severely burned areas. However, this rapid vegetation regeneration at an early stage is due mostly to perennials and shrubs, not to the sprouting or regrowth of trees. The study results strongly indicated that a susceptible forest cover type and its spatial patterns directly influence the heterogeneity of burn severity and early vegetation density and regeneration. Hence, the management of susceptible forest cover types is particularly critical for establishing more fire-resilient forests and for post-fire forest restoration.

Fine structure and X-ray microanalysis of silicified woods from a Tertiary basin Pohang, Korea by scanning electron microscopy.

Anatomical descriptions are provided on silicified woods from a Tertiary basin Pohang, Korea by scanning electron microscopy and X-ray microanalysis. The silicified woods appeared to retain the original exterior morphology of the once grown trees, and exhibited various colors on the surface. As a component of the axial system in the secondary xylem, pores were oval to globose and measured approximately 200-300 microm in diameter in transverse planes. Seemingly bordered pits were also frequently observed in the tracheary elements. As a component of the axial system in the secondary phloem, sieve elements were found to have many sieve pores that were filled with numerous fine particles. In tangential planes, rays in the vascular cambium were approximately 500 microm long, and usually several cells wide (multiseriate). Meanwhile, several forms of microbial growth such as bacterial chains and hyphal growth of either fungi or actinomycetes were evident in the vessel lumens of unpolished silicified wood pieces. Some fracture surfaces were mainly characterized by the occurrence of polyhedral crystals, probably quartz, in the fissures. By X-ray microanalysis, iron was detected from the brown-colored regions, whereas calcium was also detected together with iron in the black-colored regions. Based on the rare occurrence of tracheids as the axial system in the secondary xylem, the silicified woods in this study can be intrinsically categorized into angiosperm groups in the region.

Erratum to: Effects of forest fires on forest ecosystems in eastern coastal areas of Korea and an overview of restoration projects

Recent large fires have highlighted the importance of understanding post-fire processes in forest ecosystems, in order to implement ecologically sound post-fire forest restoration practices. Restoration principles should be based on a thorough understanding and appropriate integration of the ecological, social, and economic factors associated with forest ecosystems. In Korea, forest fires mainly affect pine forests, which provide habitats for pine mushrooms, a major source of income for local residents. Curculionid beetles can easily attack fire-damaged trees because of the trees’ weakened defense mechanisms. On the other hand, fire accelerates the decomposition of organic matter and nutrient release, thereby improving forest productivity. Natural restoration after large fires depends on regeneration (e.g., from seeds and sprouts) of the remaining trees that have sustained less damage, until secondary forests are established. However, severely burned areas may require rapid artificial regeneration depending on the specific climatic (e.g., summer rainy season), geographic (e.g., shallow surface soil and land erosion), and economic (e.g., local mushroom harvesting) objectives. A restoration plan should include constructing fuel breaks to reduce the fire risk if the area is replanted mainly with pine species.

High abundance and role of antifungal bacteria in compost-treated soils in a wildfire area.

Compost has been widely used in order to promote vegetation growth in post-harvested and burned soils. The effects on soil microorganisms were scarcely known, so we performed the microbial analyses in a wildfire area of the Taebaek Mountains, Korea, during field surveys from May to September 2007. Using culture-dependent and -independent methods, we found that compost used in burned soils influenced a greater impact on soil fungi than bacteria. Compost-treated soils contained higher levels of antifungal strains in the genera Bacillus and Burkholderia than non-treated soils. When the antifungal activity of Burkholderia sp. strain O1a_RA002, which had been isolated from a compost-treated soil, was tested for the growth inhibition of bacteria and fungi isolated from burned soils, the membrane-filtered culture supernatant inhibited 19/37 fungal strains including soil fungi, Eupenicillium spp. and Devriesia americana; plant pathogens, Polyschema larviformis and Massaria platani; an animal pathogen, Mortierella verticillata; and an unidentified Ascomycota. However, this organism only inhibited 11/151 bacterial strains tested. These patterns were compatible with the culture-independent DGGE results, suggesting that the compost used in burned soils had a greater impact on soil fungi than bacteria through the promotion of the growth of antifungal bacteria. Our findings indicate that compost used in burned soils is effective in restoring soil conditions to a state closer to those of nearby unburned forest soils at the early stage of secondary succession.

The Effect of Dredged Soil Improvement on Soil Chemical Conditions and Plant Growth at the Slope of Saemangeum Sea Dike

This study was conducted to determine the changes in soil chemical properties and the growth of seedling according to the different dredged soil improving methods at slope of Saemangeum sea dike. Undersea dredged soil was improved by five different methods. Seedlings of Ulmus davidiana var. japonica, Chionanthus retusa, Celtis sinensis, and Pinus thunbergii were planted after 9 month of experience site installation, then soil pH, NaCl concentration in soil, soil organic matter (SOM), and survival rate and height of seedling was measured. Initial soil pH was highest in the control plot but it decreased to the similar level with other soil improving plots after 35 months. There were no differences in NaCl concentration between the control and soil improving plots, and it showed decreasing tendency during the study period. In the control plot, initial SOM was lowest among that of other plots during the study period. The survival rate of 36 months after planting of P. thunbergii was highest among the species. The gap of the tree growth of P. thunbergii between the control plot and the soil improving plots was small, however, other species showed relatively higher tree height in the soil improving plots than the control plots. Creation forest with P. thunbergii might be a cost effective afforestation in coastal reclaimed land since it rarely needs additional improvement of dredged soil.

Natural Regeneration Patten of Pine Seedlings on the Burned Forest Site in Gosung, Korea

This study was conducted to determine the natural succession process after forest fire by comparing height, relative growth rates in height (RGH), and tree density of pine seedlings with different fire severity. In the area damaged by surface fire, tree density was highest during the first 5 years after fire. However, in the area damaged by crown fire, tree density rapidly increased during first 5 years after fire. Pine seedlings were found only on the place with ridges, barren soil, and the aspect of north. Annual height growth of pine seedlings was decreased with time in all study sites. The empty space in pine stands gradually decreased by the invasion of Quercus species. The forest fire altered the pine forest into oak forest rapidly. In contrast, pine seedlings invaded steadily on the oak forest in the rocky area or the area with ridges.

Oak sprout dynamics after a 1996 stand-replacing fire in Korea

Sprouting is an effective means to re-establish a forest after forest fires. However, these sprouts are vulnerable to fungi-related infection (e.g., discoloration, heart rot, and decay) through wounds on primary stumps or root systems to produce low-quality timber. A stand-replacing fire consumed 3762 ha of pine-dominated forests in Goseong-gun, Gangwon-do in 3 days in 1996 and a low-intensity fire swept the area again in 2000. We established five 9 × 9 m2 plots in the area designated for natural regeneration, where oak species (i.e., Quercus dentata Thunb., Q. mongolica Fisch. ex Ledeb, Q. serrata Thunb. ex. Murray, Q. variabilis Blume) replaced Japanese red pine (Pinus densiflora Siebold & Zucc.) forests. All the measurements were carried out in April 2010. The objectives of the study were to evaluate the natural regeneration patterns of oak species and to assess the factors associated with oak sprout discoloration. Sprout production was the highest in the third growing season from each fire in 1996 and 2000, implying that oak species might focus more on root development for the first few years and move onto sprout production. A t-test was employed to evaluate the difference between normal and discolored sprouts. There were significant differences in height, DBH, and age between normal and discolored sprouts (P < 0.05), except for those of Q. dentata. Additionally, correlation analysis was conducted between sprout discoloration occurrences and sequentially shifted annual sprout production to assess the time-lagged relationship. Discoloration occurrences showed the highest correlation coefficient with annual sprout production at a 2-year advance (r = 0.36, 0.82, 0.62, and 0.80 for Q. dentata, Q. mongolica, Q. serrata, and Q. variabilis, respectively), indicating that discoloration tended to occur within 2 years after the sprout production. Approximately 50% of sprouts were discolored showing that discoloration is a common phenomenon in oak sprouts after fire and oak sprouts would likely produce less desirable timbers. The results suggest that fire-induced oak forests should be managed for small timber forests with short rotation.

Wind Stability of Commercially Important Tree Species and Silvicultural Implications, Daegwallyeong Korea

This study compares the wind stability of Larix kaempferi (Lamb.) Carr., Pinus koraiensis Sie. & Zucc. and Abies holophylla Maxim. to understand and inform wind risk management of these plantation trees at Daegwallyeong, Korea. Temporary square plots of () were laid out, and DBH (Diameter at Breast Height) and height for trees greater than 10 cm in DBH were measured by species. A total of 15 plots with 5 plots each in L. kaempferi, P. koraiensis and A. holophylla stands were sampled at random. Among the species, A. holophylla and P. koraiensis have comparatively lower h/d (Height/DBH) ratios than L. kaempferi. These results indicate that the former two species are more wind firm than the latter species. About 9% of the L. kaempferi trees have higher h/d ratios than the critical threshold limit 80. These trees are vulnerable to wind damage and should be removed in the next thinning regime. The analysis of variance detected a significant difference (p

Effects of Forest Restoration Methods and Stand Structure on Microclimate in Burned Forest Stand

The study was conducted to determine the effects of forest restoration methods and stand structure on solar radiation, air temperature, relative humidity, soil temperature, and soil water content, based on volume, in forest stand after forest fire. The changes of the micro-climate elements in naturally and artificially restored forest after forest fire were measured in Goseong and Samcheok, Gangwon province. Pinus spp. were commonly appeared in ridges, barren lands or planted areas of the study sites while the other areas were dominated by Quercus spp. In the early stage, trees in the naturally regenerated site grow better than the trees in artificially rehabilitated site. However, the growth ratio rapidly decreased by time passed in natural regeneration area. The environmental conditions (solar radiation, air temperature, relative humidity, soil temperature and soil water content) were significantly different by the regions and the methods (p<.05). However, the coefficients of variations of the environmental conditions were not significantly different at 95% confidence level. As the coverage and tree height in crown layer increased, the relative humidity and soil water content were increased while the temperature and solar radiation were decreased. Especially, the relative humidity, solar radiation, and soil water content were clearly affected by the tree height and coverage ratio (R 2 means from 0.628 to 0.924). Even though the data should have collected at least more than 5 years in meteorological analysis, the two year results show some clear relationship between forest structure and microclimate elements.

Effect of Wind Break on the Early Growth of Pinus thunbergii at Saemangum Sea-wall

Department of Forest Science, Sangji University(Received August 30, 2013; Revised October 1, 2013; Accepted November 10, 2013)ABSTARCTThe sea breeze shows different characteristics compared to land breeze, such as high wind speed andmore rapider shift period. One of the major factors affecting plant early growth is wind speed. In theearly growth stage, tree growth-rates rise with decreasing wind speed. Thus, the study was performedto identify wind break effects on wind characteristics and tree growth. The wind break used in thisstudy was about 130 meters length and 3 meters height, made up with poly-ethylene (with 40%openness). We installed one vane and fifteen anemographs at three different heights (1, 2 and 3meters) on the inner and outer wind break areas. The wind characteristic and plant growth data werecollected from Jun. 2011 to Oct. over 2012. The wind rose of the Saemangum seawall area presentedthe north (21.5%) and it was followed by north-west (18.1%), east (14.9%) and north-east (13.7%)and the remainder with other directions. Wind speeds at height were different. The tree height was159.6 cm at inside and 129.6 cm at outside. The diameter at root-collar was 36.9 mm at inside and32.6 mm at outside from wind break. Key words: Sea breeze, Wind rose, Wind speed decrease, Pinus thunbergii