Phosphorus and Base Cation Inputs through Litterfall Components in Pine Forests after Tree Removal Due to Pine Wilt Disease Disturbance

( Gyeongwon Baek ),( Seongjun Kim ),( Choonsig Kim ) 한국산림과학회(구 한국임학회) 2019 한국산림과학회지 Vol.108 No.3

This study was conducted to measure litterfall and nutrient (P, K, Ca, Mg) inputs under varying degrees of disturbance by pine wilt disease in pine forests in southern Korea. Litterfall was collected to evaluate nutrient responses at different intensities of disturbance (various levels of basal area) by pine wilt disease across 2 years. Phosphorus, Ca, and Mg concentrations in needle litterfall were positively correlated (p < 0.05) with decreased disturbance intensities (increased basal area) depending on the time of sampling, whereas the nutrient concentrations in other litterfall components (branches, bark, reproductive organs, and miscellaneous litterfall) were not significantly correlated (p > 0.05) with the intensity of pine wilt disease disturbance. Dry weight and nutrient inputs through litterfall components decreased linearly with increasing intensity of disturbance by pine wilt disease (p < 0.05), except for the nutrient inputs of branch (K, Ca, Mg) and reproductive organ (K, Ca) litterfall. These results indicate that decreased litterfall across different levels of disturbance may be related to the reduced soil nutrients in pine wilt disease forests.

Comparisons of Nutrient Concentration of Leaves, Roots, and Soils in Three Bamboo Stands

Baek, Gyeongwon,Yoon, Jun-Hyuck,Bae, Eun Ji,Lee, Jihyun,Kim, Choonsig Korean Society of Forest Science 2022 한국산림과학회지 Vol.111 No.1

In bamboo, the nutrient status of tissues and associated soil is an important indicator of nutrient uptake by various bamboo species. In this study, the nutrient concentrations of leaves, roots, and mineral soil at 0-10 cm depths were examined in three bamboo stands [Phyllostachys bambusoides S ieb. et Zucc, Phyllostachys nigra var. henonis Stapf ex. Rendle, and Phyllostachys pubescens (Mazel) Ohwi] at a broad regional scale in southern Korea. In the three bamboo species, species-specific differences were observed in the carbon (C) and calcium (Ca) concentrations of leaves and in the nitrogen (N) and magnesium (Mg) concentrations of roots. Ca concentrations in leaves were significantly higher in P. bambusoides (11.94 g Ca kg^-1) than in P. pubescens (7.83 g Ca kg^-1), whereas potassium (K) concentrations were lowest in P. bambusoides among the three bamboo species. N concentrations in the roots were significantly lower in P. pubescens (5.23 g N kg^-1) than in P. nigra var. henonis (7.72 g N kg^-1). In contrast to bamboo tissues, soil nutrients, such as total N, organic C, exchangeable Ca²⁺, and Mg²⁺, did not differ significantly among the bamboo species. These results suggest that species-specific practices will be required for nutrient management of bamboo stands because nutrient concentrations vary considerably in the tissues of the three studied species.

Phosphorus and Base Cation Inputs through Litterfall Components in Pine Forests after Tree Removal Due to Pine Wilt Disease Disturbance

Baek, Gyeongwon,Kim, Seongjun,Kim, Choonsig Korean Society of Forest Science 2019 한국산림과학회지 Vol.108 No.3

This study was conducted to measure litterfall and nutrient (P, K, Ca, Mg) inputs under varying degrees of disturbance by pine wilt disease in pine forests in southern Korea. Litterfall was collected to evaluate nutrient responses at different intensities of disturbance (various levels of basal area) by pine wilt disease across 2 years. Phosphorus, Ca, and Mg concentrations in needle litterfall were positively correlated (p < 0.05) with decreased disturbance intensities (increased basal area) depending on the time of sampling, whereas the nutrient concentrations in other litterfall components (branches, bark, reproductive organs, and miscellaneous litterfall) were not significantly correlated (p > 0.05) with the intensity of pine wilt disease disturbance. Dry weight and nutrient inputs through litterfall components decreased linearly with increasing intensity of disturbance by pine wilt disease (p < 0.05), except for the nutrient inputs of branch (K, Ca, Mg) and reproductive organ (K, Ca) litterfall. These results indicate that decreased litterfall across different levels of disturbance may be related to the reduced soil nutrients in pine wilt disease forests.

소나무와 굴참나무 임분의 시비에 따른 토양 CO₂ 방출 동태

백경원 ( Gyeongwon Baek ),김춘식 ( Choonsig Kim ) 한국산림과학회(구 한국임학회) 2020 한국산림과학회지 Vol.109 No.3

본 연구는 유사한 입지에서 생육한 소나무와 굴참나무 임분을 대상으로 시비에 따른 토양 CO₂ 방출량을 비교하기 위해 수행하였다. 성숙한 소나무와 굴참나무 임분을 대상으로 시비처리 전 캘리브레이션 기간(2015년 3월~2016년 2월)을 가진 후, 2016년 3월에 복합비료를 표면 시비하였다. 토양 CO₂ 방출량은 2015년 3월부터 2017년 2월까지 2년 동안 매월측정하였다. 토양 CO₂ 방출량의 월별 변동은 굴참나무와 소나무 임분 모두 시비 전(2015~2016년)과 시비 후(2016~2017년) 유사하였다. 연평균 토양 CO₂ 방출량의 경우 소나무 임분의 시비구는 2015~2016년 1.620 μmol m^-2 s^-1였으나2016~2017년 2.180 μmol m^-2 s^-1로 유의적으로 증가(P < 0.05)하였으며, 굴참나무 임분의 시비구도 2015~2016년 1.557 μmol m^-2 s^-1에서 2016~2017년 1.977 μmol m^-2 s^-1로 약 0.420 μmol m^-2 s^-1 정도 증가하였다. 그러나 비시비구는 두 임분 모두 2015~2016년과 2016~2017년 사이 토양 CO₂ 방출량에 유의적인 차이가 없었다. Q₁₀ 값은 굴참나무 임분의 시비구가 2015~2016년 3.14에서, 2016~2017년 3.41로 증가하였으나 소나무 임분의 시비구는 Q₁₀ 값에 변화가 없었다. 비시비구의 Q₁₀ 값의 경우 굴참나무 임분은 2015~2016년에 3.85였으나, 2016~2017년은 3.69로 감소하였으며, 소나무 임분은 2015~2016년은 3.15였으나, 2016~2017년은 3.65로 증가하였다. 본 연구 결과에 따르면 유사한 입지환경에서 생육한 소나무와 굴참나무 임분의 토양 CO₂ 방출량은 시비 후 증가하였으며, 시비에 따른 토양 CO₂ 방출은 소나무 임분이 굴참나무 임분에 비해 반응이 크게 나타났다. This study compared soil CO₂ efflux rates after fertilization, in Pinus densiflora and Quercus variabilis stands. Compound fertilizers were applied to the forest floor in March 2016, following a one-year calibration period (from March 2015 to February 2016). In situ soil CO₂ efflux rates were measured every month during the two-year study periods, using an infrared gas analyzer with a closed chamber system. Mean annual soil CO₂ efflux rates were higher following fertilizer application in the P. densiflora and Q. variabilis stands (P. densiflora: 2.180 μmol m^-2 s^-1; Q. variabilis: 1.977 μmol m^-2 s^-1) as compared with the rates measured during the calibration period (P. densiflora: 1.620 μmol m^-2 s^-1; Q. variabilis: 1.557 μmol m^-2 s^-1). The mean annual soil CO₂ efflux rates in the unfertilized treatments of both stands were not significantly different between the two-year study periods. The Q₁₀ values of fertilized treatments in Q. variabilis stands were higher in the fertilization period (3.41) than in the calibration period (3.14), whereas the Q₁₀ values in P. densiflora stands did not change between the fertilization and calibration periods. The Q₁₀ values of unfertilized treatments in the Q. variabilis stands were lower during the 2016-2017 period (3.69), than in the 2015-2016 period (3.85), whereas the Q₁₀ values in P. densiflora stands were higher during the 2016-2017 period (3.65), than in the 2015-2016 period (3.15). These results indicate that the increase in soil CO₂ efflux rates in P. densiflora stands could be more sensitive to fertilization compared with the rates in Q. variabilis stands.

소나무와 굴참나무 임분의 토양 환경요인과 토양 이산화탄소 방출의 계절적 변화

백경원 ( Gyeongwon Baek ),조창규 ( Chang Gyu Jo ),김춘식 ( Choonsig Kim ) 한국농림기상학회 2016 한국농림기상학회지 Vol.18 No.3

본 연구는 유사한 입지에서 생육한 소나무와 굴참나무 임분의 토양 이산화탄소(CO₂)와 이들 방출에 영향을 미치는 환경요인인 토양 온도, 토양 수분, 토양 pH, 전기전도도, 토양 유기탄소 농도 등을 2015년 3월부터 2016년 2월까지 1년 동안 조사하였다. 토양 CO₂ 방출량의 월별 변화는 두 임분 사이에 차이가 있어 하절기인 6월과 7월의 경우, 굴참나무 임분이 소나무 임분에 비해 유의적으로 높았으나, 타 계절은 차이가 없었다. 연 평균 토양CO₂ 방출량의 경우, 굴참나무 임분이 2.27±0.22 μmol m^-2 s^-1로 소나무 임분의 1.63±0.12 μmol m^-2 s^-1 에 비해높게 나타났으며, 연 평균 토양 온도와 토양 수분함량도굴참나무 임분이 소나무 임분에 비해 높았다. 토양 환경요인 중 토양 온도와 토양 CO₂ 방출량은 지수함수 관계(P<0.05)가 있었으며, Q₁₀ 값의 경우, 굴참나무 임분이3.35로 소나무 임분 2.72에 비해 높아 토양 온도 상승 시, 굴참나무 임분의 토양 CO₂ 방출량이 소나무 임분에 비해 더 크게 증가하는 것으로 나타났다. This study was carried out to examine the relationships between seasonal variations of soil CO₂ efflux rates and soil environmental factors in matured Pinus densiflora and Quercus variabilis stands in the Wola national experimental forests, southern Korea. Soil CO₂ efflux rates were measured monthly from March 2015 to February 2016. Mean soil CO₂ efflux rates during the study period were significantly higher in the Q. variabilis (mean±standard error; 2.27±0.22 μmol m^-2 s^-1) than in the P. densiflora (1.63±0.12 μmol m^-2 s^-1) stands. Mean soil water content and pH were also significantly higher in the Q. variabilis (26.96±0.93%, pH 5.19) than in the P. densiflora (21.32±0.89%, pH 4.87) stands, while soil temperature was not significantly different between the P. densiflora (13.92±0.67°C) and in the Q. variabilis (13.52±0.70°C) stands. Q<sub>10<sub> values were higher in the Q. variabilis (3.35) than in the P. densiflora (2.72) stands. The results indicate that soil CO₂ efflux rates in Q. variabilis stand could be more sensitive by the change of soil temperature compared with P. densiflora stand under a similar site environmental condition.

Free-Standing, Single-Monomer-Thick Two-Dimensional Polymers through Covalent Self-Assembly in Solution

Baek, Kangkyun,Yun, Gyeongwon,Kim, Youngkook,Kim, Dongwoo,Hota, Raghunandan,Hwang, Ilha,Xu, Dan,Ko, Young Ho,Gu, Gil Ho,Suh, Ju Hyung,Park, Chan Gyung,Sung, Bong June,Kim, Kimoon American Chemical Society 2013 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.135 No.17

<P>The design and synthesis of two-dimensional (2D) polymers is a challenging task, hitherto achieved in solution only through the aid of a solid surface “template” or preorganization of the building blocks in a 2D confined space. We present a novel approach for synthesizing free-standing, covalently bonded, single-monomer-thick 2D polymers in solution without any preorganization of building blocks on solid surfaces or interfaces by employing shape-directed covalent self-assembly of rigid, disk-shaped building blocks having laterally predisposed reactive groups on their periphery. We demonstrate our strategy through a thiol–ene “click” reaction between (allyloxy)<SUB>12</SUB>CB[6], a cucurbit[6]uril (CB[6]) derivative with 12 laterally predisposed reactive alkene groups, and 1,2-ethanedithiol to synthesize a robust and readily transferable 2D polymer. We can take advantage of the high binding affinity of fully protonated spermine (positive charges on both ends) to CB[6] to keep each individual polymer sheet separated from one another by electrostatic repulsion during synthesis, obtaining, for the first-time ever, a single-monomer-thick 2D polymer in solution. The arrangement of CB[6] repeating units in the resulting 2D polymer has been characterized using gold nanoparticle labeling and scanning transmission electron microscopy. Furthermore, we have confirmed the generality of our synthetic approach by applying it to different monomers to generate 2D polymers. Novel 2D polymers, such as our CB[6] derived polymer, may be useful in selective transport, controlled drug delivery, and chemical sensing and may even serve as well-defined 2D scaffolds for ordered functionalization and platforms for bottom-up 3D construction.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/2013/jacsat.2013.135.issue-17/ja4002019/production/images/medium/ja-2013-002019_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja4002019'>ACS Electronic Supporting Info</A></P>

Hollow nanotubular toroidal polymer microrings

Lee, Jiyeong,Baek, Kangkyun,Kim, Myungjin,Yun, Gyeongwon,Ko, Young Ho,Lee, Nam-Suk,Hwang, Ilha,Kim, Jeehong,Natarajan, Ramalingam,Park, Chan Gyung,Sung, Wokyung,Kim, Kimoon Nature Publishing Group, a division of Macmillan P 2014 Nature chemistry Vol.6 No.2

Despite the remarkable progress made in the self-assembly of nano- and microscale architectures with well-defined sizes and shapes, a self-organization-based synthesis of hollow toroids has, so far, proved to be elusive. Here, we report the synthesis of polymer microrings made from rectangular, flat and rigid-core monomers with anisotropically predisposed alkene groups, which are crosslinked with each other by dithiol linkers using thiol-ene photopolymerization. The resulting hollow toroidal structures are shape-persistent and mechanically robust in solution. In addition, their size can be tuned by controlling the initial monomer concentrations, an observation that is supported by a theoretical analysis. These hollow microrings can encapsulate guest molecules in the intratoroidal nanospace, and their peripheries can act as templates for circular arrays of metal nanoparticles.

Quantifying Litterfall Input from the Stand Parameters of Korean Red Pine (Pinus densiflora S. et Z.) Stands in Gyeongnam Province

( Choonsig Kim ),( Gyeongwon Baek ),( Byeonggil Choi ),( Gyeongrin Baek ),( Hojin Kim ) 한국산림과학회 2021 한국산림과학회지 Vol.110 No.4

This study developed an estimation model for litterfall input using the stand parameters (basal area, stand density, mean DBH, and carbon stocks of the aboveground tree biomass) collected from the Korean red pine (Pinus densiflora S. et Z.) stands of seven regions in Gyeongsangnam-do. The mean annual litterfall was 2,779 kg ha^-1 year^-1 for needles, 883 kg ha^-1 year^-1 for miscellaneous, 611 kg ha^-1 year^-1 for broadleaved, 513 kg ha^-1 year^-1 for branches, and 340 kg ha^-1 year^-1 for bark litter. The mean annual total litterfall was 5,051 kg ha^-1 year^-1. Litterfall components were significantly correlated with stand parameters, except for broadleaved litter. A stronger correlation was observed between the carbon stock of the aboveground tree biomass and all the litterfall components compared with the other stand variables. The allometric equations for all the litterfall components were significant (P < 0.05), with the stand parameters accounting for 5%-43% and 8%-42% of the variation in the needle litter and total litterfall, respectively. The results indicated that the annual litterfall inputs of the Korean red pine stands on a regional scale can be effectively estimated by allometric equations using the basal area and carbon stocks of the aboveground tree biomass.

Comparison of allometric equations and biomass expansion factors for six evergreen broad-leaved trees in subtropical forests in southern Korea

Kim, Choonsig,Baek, Gyeongwon,Yoo, Byung Oh,Jung, Su Young,Lee, Kwang Soo,An, Ki Wan Informa UK (TaylorFrancis) 2019 Journal of sustainable forestry Vol.38 No.3

소나무와 굴참나무 임분의 가지 분해율과 탄소 및 질소 동태 비교

최병길 ( Byeonggil Choi ),백경원 ( Gyeongwon Baek ),김형섭 ( Hyungsub Kim ),손요환 ( Yowhan Son ),김춘식 ( Choonsig Kim ) 한국농림기상학회 2021 한국농림기상학회지 Vol.23 No.2

본 연구는 경상남도 산청과 진주 지역으로부터 서로 인접하여 생육하고 있는 소나무와 굴참나무를 대상으로 기질의 특성, 임분 종류, 토양 및 기상 환경요인 등이 가지의 분해율과 탄소 및 질소 동태에 어떠한 영향을 끼치는지 알아보기 위해 수행하였다. 직경 2.0∼4.0cm, 길이 10cm의 가지 시료를 30cm × 30cm 크기의 매쉬 백에 넣은 후 2018년 5월 각 임분의 임상에 매설하였으며 2018년 8월과, 11월, 그리고 2019년 2월과, 5월에 각 조사구에서 회수하여 가지의 분해율과 탄소 및 질소 동태를 조사하였다. 매설 12개월 후 가지 분해율은 산청-소나무(4.49 %) < 진주-소나무(5.75 %) < 산청-굴참나무(20.01 %) < 진주-굴참나무(24.68 %) 순서로 나타나 두 지역 모두 굴참나무 가지가 소나무에 비해 빠른 분해를 보였다. 탄소 및 질소의 경우 굴참나무는 순 무기화를 나타냈으며, 소나무는 탄소 및 질소의 축적 및 저장이 나타나 수종 간 다른 경향을 보였다. 본 연구 결과에 따르면 서로 인접하여 생육하고 있는 두 수종의 분해율과 탄소 및 질소 동태는 지역·환경적 요인보다 수종 간 초기 질소 농도, C/N율과 같은 기질의 특성이 더 큰 영향을 미치는 것으로 나타났다. This study was carried out to understand how factors of decomposition such as quality of the substrate (tree species), forest types, and soil·meteorological conditions affect decomposition rates and dynamics of carbon (C) and nitrogen (N) of branches in adjacent Pinus densiflora and Quercus variabilis stands in Sancheong and Jinju in Southern Korea. The branch bags (30 cm × 30 cm) with branch samples (a diameter of 2.0 - 4.0 cm and length of 10 cm) were placed on the forest floor at each stand in May 2018. The branch bags were collected in August and November 2018, February and May 2019, respectively. The decomposition rates of branches in P. densiflora stands were 4.49 % for Sancheong, and 5.75 % for Jinju. Whereas, the decomposition rates in Q. variabilis were 20.01 % for Sancheong, and 24.68 % for Jinju, respectively. The decomposition of branches was more rapid in Q. variabilis compared with P. densiflora in both regions. C and N in decomposed branches were more mineralized in Q. variabilis, whereas C and N were more accumulated in P. densiflora. These results indicated that the decomposition rates, C and N of decomposed branches may be affected by differences in substrate quality such as initial N concentration and C/N ratio rather than differences between both regions including different environmental factors.