Pil Sun Park

Carbon and nitrogen storage in an age-sequence of Pinus densiflora stands in Korea

The carbon (C) and nitrogen (N) storage capabilities of Pinus densiflora in six different stand ages (10, 27, 30, 32, 44, and 71 years old) were investigated in Korea. Thirty sample trees were destructively harvested and 12 were excavated. Samples from the above and belowground tree components, coarse woody debris (CWD), forest floor, and mineral soil (0–30 cm) were collected. Tree biomass was highest in the 71-year-old stand (202.8 t ha−1) and lowest in the 10-year-old stand (18.4 t ha−1). C and N storage in the mineral soil was higher in the 71-year-old stand than in the other stands, mainly due to higher soil C and N concentrations. Consequently, the total ecosystem C and N storage (tree+forest floor+CWD+soil) was positively correlated with stand age: increasing from a minimum in the 10 year old stand (18.8 t C ha−1 and 1.3 t N ha−1) to a maximum in the 71-year-old stand (201.4 t C ha−1 and 8.5 t N ha−1). The total ecosystem C storage showed a similar sigmoidal pattern to that of tree C storage as a function of the age-sequence, while N storage in the CWD, forest floor and mineral soil showed no significant temporal trends. Our results provide important insights that will increase our understanding of C and N storage in P. densiflora stands and our ability to predict changes according to stand age in the region.

Temporal and spatial characteristics of forest fires in South Korea between 1970 and 2003

Information on the temporal and spatial patterns of forest fires can contribute to efficient forest fire management. To evaluate the readjustment of forest fire precautionary periods and to provide information for forest fire prevention and suppression strategies, the temporal and spatial characteristics of forest fire occurrences and spread in Korea were analysed using statistics from 1970 to 2003. Monthly forest fire occurrences and burned area were examined using time-series analysis, and F-tests were conducted among forest fire occurrences, burned area, and fire area growth rate to understand monthly forest fire characteristics. To understand the spatial characteristics of forest fires, cities and counties with similar forest fire characteristics were grouped based on cluster analysis of forest fire occurrences and spread characteristics. A seasonal exponential smoothing model was selected for forest fire occurrences and burned area. The number of mean annual forest fire occurrences was 429, and mean annual burned area was 2908 ha year–1 in Korea. The seasonal differences in forest fire characteristics were clearly distinguished, with 61% of total forest fire occurrences and 90% of total burned area being in March and April. Forest fire precautionary periods are suggested based on forest fire occurrence patterns. A total of 226 cities and counties throughout the country were classified into three groups. Group 1, which had frequent forest fire occurrences with smaller burned areas and slower fire growth area rates, was distributed in the western part of Korea and metropolitan regions. Group 3, which had a relatively small number of forest fire occurrences but larger burned areas and fast growth rates, was located in the central inland region and the eastern part of the Taeback Mountain Range. Group 2 had characteristics intermediate between those of group 1 and group 3.

Effect of Acacia plantations on net photosynthesis, tree species composition, soil enzyme activities, and microclimate on Mt. Makiling

To determine the effectiveness of rehabilitation on improving ecosystem functions, we examined net photosynthetic rate (PN), tree species composition, soil enzyme activities, and the microclimate (air and soil temperature, relative humidity) of an area on Mt. Makiling that has been rehabilitated and protected from fire for over 12 years. After it was last burned extensively in 1991, restoration was initiated by planting Acacia mangium and Acacia auriculiformis. We selected three areas to study in 2003. Two areas were rehabilitated with A. mangium and A. auriculiformis, and one was still dominated by Imperata cylindrica and Saccharum spontaneum. PN of A. mangium and A. auriculiformis showed significantly lower values than those of I. cylindrica and S. spontaneum. The Acacia plantations had more naturally regenerated tree species than the grassland. Additionally, more tree species appeared in the A. mangium plantation than in the A. auriculiformis plantation. Ficus spetica was present in all of the study sites. Dehydrogenase and phosphatase activities were significantly higher in soil under the Acacia plantations than under grassland. Grassland showed higher air temperature, relative humidity, and soil temperature as well as a larger variation per hour in these parameters compared to the Acacia plantations. The highest air temperature, relative humidity, and soil temperature were measured in April during the dry season. From the regression analysis, soil temperature was significantly correlated with air temperature. Hence plantations, as a rehabilitation activity for grassland, promote natural regeneration and stabilize the microclimate. This stabilization of the microclimate affects establishment and growth of naturally occurring tree species.

Effects of Experimental Early Canopy Closure on the Growth and Reproduction of Spring Ephemeral Erythronium japonicum in a Montane Deciduous Forest

Spring leaf flush and changes in the understory radiation in montane deciduous forests are major determinants of the life cycle of spring ephemerals, which complete their epigeous growth before canopy closure in spring. We compared the growth, carbon allocation, and reproduction of a spring ephemeral, Erythronium japonicum (Balrer) Decne., between the ambient (control) and early shade treatments in the field during the flowering (early-May), fruiting (mid- May), and fruit ripening periods (late-May), under the assumption of early spring canopy closure due to climate change. Carbon allocation was investigated using a 13C labelling experiment. Both sterile (non-flowering) and fertile (flowering) E. japonicum under the shade treatment showed higher specific leaf area and earlier leaf senescence than those in the ambient conditions (p < 0.05). The flowering E. japonicum concentrated on biomass allocation to the aboveground vegetative organs prior to fruiting and to reproductive and storage organs from fruiting. E. japonicum used carbohydrates stored during the previous year for vegetative growth, while the current-year photosynthates were used for the current-year reproduction. Carbon allocation to fruit began earlier under the shade treatment, demonstrating that E. japonicum allocated the current-year photosynthates more to reproduction than to vegetative organs under the early shade conditions. However, the seed size (p = 0.012) and germination rate (p = 0.008) were significantly lower under the shade treatment than under the ambient conditions, implying a potential decrease in viable seed production in the shorter high-light period. The earlier leaf flush could be a critical threat to the population maintenance of spring ephemerals such as E. japonicum.

Biomass and carbon storage in an age-sequence of Japanese red pine (Pinus densiflora) forests in central Korea

The biomass and carbon (C) storage of the main ecosystem components were examined in an age-sequence of six Japanese red pine forest stands in central Korea. The tree biomass was determined by the destructive method, and the C storage of the tree biomass, forest floor and mineral soil was estimated by analyzing the C concentration of each component. The above-ground and total tree biomass increased from 21.76 and 28.82 Mg ha−1 in the 17-year-old stand to 308.83 and 385.74 Mg ha−1 in the 73-year-old stand. The comparisons of above-ground tree and tree root biomass in replicate stands indicated that stand density has an effect on tree biomass partitioning for Japanese red pine, especially on the biomass allocation of above-ground tree and tree roots. The C concentrations were lowest in the tree roots while the highest concentrations were found in the foliage across the six Japanese red pine forest stands. The C storage in the forest floor and mineral soil were age-independent. The above-ground and total ecosystem C stocks increased from 19.40 and 43.49 Mg ha−1 in the 17-year-old stand to 162.72 and 247.39 Mg ha−1 in the 73-year-old stand. Although the total tree biomass C showed considerable accumulation with stand age, the relative contribution of the below-ground ecosystem to the total ecosystem C storage demonstrated large variation. The results of this study assist in understanding C storage and its change with stand development in Japanese red pine forests, which makes this species a large sink for atmospheric C at the regional scale.

Antifungal activities after vaporization of ajowan (Trachyspermum ammi) and allspice (Pimenta dioica) essential oils and blends of their constituents against three Aspergillus species

Abstract The fumigant antifungal activities of ajowan (Trachyspermum ammi), and allspice (Pimenta dioica) essential oils and their constituents were tested against three Aspergillus species: A. ochraceus, A. parasiticus, and A. niger. Ajowan essential oil demonstrated a 100% inhibition rate against these three Aspergillus species at an air concentration of 56 × 10−3 mg/mL. The fumigant antifungal activities of allspice essential oil against A. niger, A. ochraceus, and A. parasiticus were 100, 84.4, and 83.5%, respectively. Gas chromatography-mass spectrometry analysis led to the identification of twelve compounds in ajowan oil and six compounds in allspice oil. Of the compounds tested, thymol, carvacrol, and eugenol showed strong inhibitory activity against the three Aspergillus species. The fumigant antifungal activities of blends of the constituents identified in ajowan and allspice oils indicated that thymol and eugenol were the major contributors to the fumigant antifungal activities of ajowan and allspice oils, respectively.

Climate–growth relationships of relict Picea jezoensis at Mt. Gyebang, South Korea

A study was conducted to evaluate climatic variation at Mt. Gyebang, South Korea, and its influence on the modelled and observed growth of its relict Picea jezoensis population. Using the MT-CLIM and Biome-BGC models, year-to-year meteorological variation and subsequent changes in growing season, primary productivity and water balance were simulated. These were compared with the observed growth of sample P. jezoensis trees at the site. According to weather data and model calculations, the P. jezoensis stand at Mt. Gyebang was exposed to significant climate variations affecting growing season, carbon balance, and water balance. Although the length of growing season showed an increasing trend over time, the observed growth of P. jezoensis was unaffected by the length of growing season. Probably due to the sites shallow soil depths and species’ shallow rooting depth, the modelled increase in productivity caused by climate variation was not manifested in an increase in growth of P. jezoensis. These findings imply that the competitiveness of P. jezoensis at this site has declined over time and that an active approach to conservation planning for this species and site is warranted.

The Spatial Distribution of Quercus mongolica and Its Association with Other Tree Species in Two Quercus mongolica Stands in Mt. Jiri, Korea

Stand structure and spatial associations of the dominant tree species in Quercus mongolica stands were investigated to understand interspecific relationships and the persistent dominance of Q. mongolica. We examined the species composition, DBH (diameter at breast height) distribution, and spatial distribution of trees (≥ 2.5 cm DBH) in two permanent 100 m x 100 m plots in Q. mongolica-dominant stands on the western part of Mt. Jiri. Ripleys K-function was used to characterize the spatial patterns and associations of dominant tree species. Q. mongolica showed a continuous and reverse-J shaped DBH distribution with clumped spatial distribution in both study sites. Q. mongolica and Abies koreana exhibited a negative association implying potential interspecific competition. The positive spatial association between Q. mongolica and Alnus hirsuta var. sibirica and Fraxinus sieboldiana were affected by site characteristics: limited habitat conditions with a large proportion of rock surface. Our results suggest that interactions among species were complex and ranged from positive to negative. Differences in stand and site characteristics and regeneration mechanisms among the species play an important role in regulating their spatial distribution patterns, while competition between individuals also contributes to spatial patterning of these communities. The high density and the early developmental stage of spatial distribution and structural characteristics of Q. mongolica and the relatively low importance values of other species in the stands imply that Q. mongolica will remain dominant in the study sites in the near future.

Flowering phenology and the growth of three native Anemone species in a montane deciduous forest on Mt. Joongwang, Korea

Anemone is a representative spring ephemeral in Korea, flushing immediately after the snow melts and flowering in early spring. This study investigated the spring flush, stem growth, flowering, and fruiting of three Anemone species (A. amurensis, A. raddeana and A. koraiensis) in a montane deciduous forest on Mt. Joongwang over two consecutive years (2014 and 2015). We sought to expand our understanding of the flowering phenology and environmental effects on growth of the species. The three species showed sequential flowering: A. amurensis flushed and bloomed first, followed by A. raddeana and A. koraiensis at 1-2 week intervals for about 37 days. The duration of flowering for each species was similar, and lasted about 24-25 days. High temperatures advanced plant emergence and the first-flowering time by 5-7 days in 2014 compared to 2015. The temperature at the time of first flowering for the three species was around 4.0°C. The mean environmental temperature during the flowering stage ranged from 5 to 10°C for all three species, indicating that they needed lower temperatures than common flowering cultivars in April. The plants grew to 13-18 cm for A. amurensis and A. raddeana, and 17-21 cm for A. koraiensis. The growth and flowering patterns of the three Anemone species indicate their potential for use as floriculture plants in cold seasons and early spring.

Nutrient Use Strategy of Carpinus cordata Saplings Growing under Different Forest Stand Conditions

This study aimed to understand the nutrient absorption, usage and allocation of Carpinus cordata in different soil and light environments. Seasonal changes of foliar nitrogen, phosphorous, chlorophyll contents, leaf mass per area (LMA) and nutrient retranslocation rates were investigated for C. cordata saplings growing in a natural deciduous broadleaved forest and an Manchurian fir (Abies holophylla) plantation in Gwangneung, Kyunggido. The deciduous forest had lower leaf area, higher light penetration, and better soil fertility than the Manchurian fir forest. However, available soil phosphorous content in the deciduous forest was only one third of that in the Manchurian fir forest, which caused lower foliar phosphorous content and higher P retranslocation rate of C. cordata in the deciduous forest than that in the Mancurian fir forest. Soil nitrogen contents in the deciduous forest were higher than that in the Manchurian fir forest, however, no differences in foliar nitrogen content and retranslocation rate in C. cordata between the two stands were found. C. cordata in the Manchurian fir forest with high LAI throughout a year, had lower LMA, foliar nitrogen content and chlorophyll a/b, while had higher total chlorophyll content and chlorophyll/N than that in the deciduous forest. These results implied C. cordata under different environments are using different strategies for nutrient use and allocations.