Joo Han Sung

Diversity decrease of ant (Formicidae, Hymenoptera) after a forest disturbance: different responses among functional guilds

BackgroundDisturbance is one of the main causes for determining diversity of natural communities. A 3-year (2003 to 2005) monitoring of ant communities at a Long-Term Ecological Research (LTER) site in South Korea revealed a drop of ant diversity due to a forest disturbance which was evidenced by decrease of leaf area index (LAI) associated with the dropping of tree branches. In order to determine the process of the decrease in diversity, we compared the annual change of functional ant guilds, which are composed of forest ground foragers (FGF), forest vegetation foragers (FVF), soil and litter dwellers (SLD), and open-land foragers (OF).ResultsFour functional guilds of ants responded differently to the forest disturbance; FGF and SLD decreased, but OF and FVF increased. Species richness decreased, due to the decrease in SLD, and species evenness decreased mainly due to a sudden increase in an OF species, Formica japonica. Based on these findings, a mechanism is proposed for the decrease in ant diversity after the forest disturbance.ConclusionsAnt communities responded significantly to even a slight forest disturbance of branch dropping with decrease in diversity and change in functional guild structures.

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.

Comparing Connectivity in Forest Networks of Seven Metropolitan Cities of South Korea

This quantitative research aims to examine the connectivity of forest networks in seven metropolitan cities of South Korea using a graph-theoretical approach. We first estimated an overall network connectivity at multi-scales (i.e., dispersal distances), ranging from 100 m to 20 km, and quantified the contribution of small forest patches (less than 10 ha) to the overall network connectivity by comparing networks according to the presence and absence of small ones. As a result, the cities were divided into two groups depending on the network connectivity; one group of cities with high connectivity such as Daegu, Daejeon, and Ulsan and the other group of cities with low connectivity including Gwangju, Busan, Seoul, and Incheon. The result showed that small forest patches, especially in the cities with low connectivity, played a key role as stepping stones that connect large forested patches, thereby contributing to maintaining connectivity. This study also suggests that large and well-connected forest areas may be the key factor to preserve the connectivity in the cities with high connectivity, while the cites with low connectivity are in need of some complementary strategies. Through the study, we suggest that the creation of new forest patches in the areas where a gap in connectivity presents is needed in order to improve connectivity; and that the conservation of the existing small forest patches is essential in order to maintain the current connectivity level.

Evaluation of air quality using lichens in three different types of forest in Korea

There is little available information on lichen diversity and air quality in forests in South Korea. To address this, the present study aims to correlate corticolous lichen diversity with air quality in selected forests in South Korea. Two sites located on Jeju Island and one site located at Mt. Hambaek, Kangwon Province were selected for this study. Twenty trees representing two species (Quercus sp. and Pinus japonica) were chosen at each site. The coverage and frequency of corticolous lichens found on the selected trees were recorded by using 2500 cm2 grids. Ambient SO2, NO2, and O3 levels at each site were determined using Ogawa™ passive samplers having filter pads coated with absorbing reagents. Lichen diversity data collected on selected trees were used to formulate the index of atmospheric purity (IAP). A total of 65 lichen species were found. A negative correlation was observed between lichen diversity expressed as IAP and the concentrations of SO2, NO2, and O3 levels. The results revealed that corticolous lichens could be used as indicators to monitor the air quality of forests in South Korea on a large scale.

Analysing the Relationship Between Tree-Ring Growth of Quercus acutissima and Climatic Variables by Dendroclimatological Method

This study was conducted to analyze the relationship between tree-ring growth of Quercus acutissima and climatic variables by dendroclimatological method. Annual tree-ring growth data of Quercus acutissima collected by the 5 th National Forest Inventory (NFI5) were organized to analyze the spatial distribution of the species growth pattern. To explain the relationship between tree-ring growth of Quercus acutissima and climatic variables, monthly temperature and precipitation data from 1950 to 2010 were compared with tree-ring growth data for each county. When tree-ring growth data were analyzed through cluster analysis based on similarity of climatic conditions, four clusters were identified. In addition, index chronology of Quercus acutissima for each cluster was produced through cross-dating and standardization procedures. The adequacy of index chronologies was tested using basic statistics such as mean sensitivity, auto correlation, signal to noise ratio, and expressed population signal of annual tree-ring growth. Response function analysis was conducted to reveal the relationship between tree-ring growth and climatic variables for each cluster. The results of this study are expected to provide valuable information necessary for estimating local growth characteristics of Quercus acutissima and for predicting changes in tree growth patterns caused by climate change.

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.

Predicting the Changes of Yearly Productive Area Distribution for Pinus densiflora in Korea Based on Climate Change Scenarios

Division of Forest Ecology, Korea Forest Research Institute, Seoul 130-712, Koera(Received February 26, 2014; Revised March 26, 2014; Accepted March 28, 2014)ABSTRACTThis study was conducted to predict the changes of yearly productive area distribution for pinusdensiflora under climate change scenario. For this, site index equations by ecoprovinces were firstdeveloped using environmental factors. Using the large data set from both a digital forest site mapand a climatic map, a total of 48 environmental factors including 19 climatic variables were regressedon site index to develop site index equations. Two climate change scenarios, RCP 4.5 and RCP 8.5,were then applied to the developed site index equations and the distribution of productive areas forpinus densiflora were predicted from 2020 to 2100 years in 10-year intervals. The results from thisstudy show that the distribution of productive areas for pinus densiflora generally decreases as timepasses. It was also found that the productive area distribution of Pinus densiflora is different over timeunder two climate change scenarios. The RCP 8.5 which is more extreme climate change scenarioshowed much more decreased distribution of productive areas than the RCP 4.5. It is expected thatthe study results on the amount and distribution of productive areas over time for pinus densifloraunder climate change scenarios could provide valuable information necessary for the policies ofsuitable species on a site.Key words : Climatic change scenario, Digital site map, Climatic map, Site index equation, Productive area

Understory Vegetation Structure by Altitude and Azimuth Slope and Indicator Species Analysis in Mt. Gyebang

본 연구는 유전자원보호구역 및 국립공원으로 지정된 계방산의 하층식생구조와 고도 및 사면별 지표종을 구명하기 위해 실시하였다. 조사지 출현식물은 80과 203속 303종 38변종 5품종 4아종 총 350분류군으로 확인되었다. 중요치 분석결과, 관목층에서는 미역줄나무(9.143%), 당단풍나무(7.594%), 노린재나무(6.347%) 등이 우점 하였고, 초본층에서는 조릿대(8.653%), 오리방풀(2.936%), 대사초(2.897%) 등이 우점 하는 것으로 나타났다. NMS 분석결과, 주요종의 분포범위는 고도별 영향이 있는 것으로 밝혀졌다(관목층: R2>0.3, 초본층: R2>0.6). Plexus diagram 분석결과, 당단풍나무는 함박꽃나무, 청시닥나무, 참회나무 등과 연관성이 있으며, 초본층의 벌깨덩굴은 투구꽃, 박새, 귀룽나무등과 연관성이 있는 것으로 분석되었다. 고도에 따른 유의성 있는 지표종은 60종, 사면방위별 유의성 있는 지표종은 30종이 분석되었다. MRPP-test 결과, 고도에 따른 집단 간 종조성은 이질적이며, 사면방위에 따른 종조성은 NE와 SW 간에 이질성이 큰 것으로 분석되었다.

Seed Biology, Stand Characteristics, and Regeneration of Fraxinus rhynchophylla Hance

Fruit size and seed moisture content were measured and seed production and dispersal were monitored to understand the seed biology of the Korean ash (Fraxinus rhynchophylla Hance) in two Korean ash forests. A combination of four ground treatments and four crown closure levels were created in a natural forest to understand the site conditions needed for seedling emergence in natural stands and to determine practical regeneration methods for direct seeding. The seed size of Korean ash increased until late May and its moisture content decreased rapidly in early November. Prolific seed bearing occurred every 3 yr. The distance of seed dispersal by wind was about 30 m, but more than 90% of the seeds dispersed within 10 m from the seed trees. Twenty-five seed trees per hectare provided for successful natural regeneration. The seedling emergence in the natural stands was best with scarification treatment and 25∼50% of crown closure.