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      • KCI등재

        삼림환경인자에 의한 굴참나무임분의 (林分) 생산력추정

        이동섭,정영관 ( Dong Sup Lee,Young Gwan Chung ) 한국산림과학회 1986 한국산림과학회지 Vol.75 No.1

        This study was initiated to estimate productivity of Quereus variabilis stand. However the practical objective of this study was to provide some information to establish the basis of selecting the suitable site for Quercus variabilis. The productivity measured in terms of DBH, height, basal area and stem volume was hypothesized, respectively, to be a function of a group of factors. This study considered 32 factors, 20 of which were related to the forest environmental factors such as tree age, latitude, percent slope, etc. and the rest of which were related to soil factors such as soil moisture, total nitrogen, available P₂O_5, etc. The data on 4 productivity measurements of Quercus variabilis growth and related factors cited were collected from 99 sample plots in Kyeongbook and chungbook provinces. Some factors considered were, in nature, discrete variables and the others continuous variables. Each kind of factor was classified into 3 or 4 categories and total numbers of such categories were eventually amounted to 110. Then each category was treated as an independent variable. This is amounted to saying that individual variable was treated a dummy variable and assigned a value 1 or 0. However the first category of each factor was deleted from the normal equation for statistical consideration. First of all, each of 4 productivity measurements of Quercus variabilis growth was regressed and, at the same time, those 110 categories. Secondly, the partial correlation coefficients were measured between each pair of 4 productivity measurements and 32 individual foctors. Finally, the relative scores were estimated in order to derive the category ranges. The result of these statistical analyses could be summarized as follows: 1) Growth measurement in terms of height seems to be a more significant criterion for estimation of productivity of Quercus variabilis. 2) Productivity of forest on stocked land may better be estimated Sn terms of forest environmental factors, on the other hand, that of unstocked land may be estimated in terms of physio-chemical factors of soil. 3) The factors that a strongly positive relation to all growth factors of tree are age group, effective soil, soil moisture, etc. This implies that these factors might effectively be used for criteria for selecting the suitable site for Quercus vdriabilis. 4) Patent rock, latitude, total nitrogen, age group, effective soil depth, soil moisture, organic matter, etc., had more significant category range for tree growth. Therefore, the. suitable site for Quercus variabilis may be selected, based on this information. In conclusion, the above results obtained by the rnultivsriable analysis can be not only the important criteria for estimating the growth of Quercus variabilis but also the useful guidance for selecting the suitable sites and performing the rational of Quercus variabilis forest.

      • KCI등재

        임목의 (林木) 개체간 경쟁효과 추정에 대한 고찰

        이동섭,이여하 ( Dong Sup Lee,Yeo Ha Lee ) 한국산림과학회 1985 한국산림과학회지 Vol.71 No.1

        This study was carried out to know the difference in growth and degree of competition between individuals of thinned and unthinned larch stands. Annual increment and total growth were obtained from the cores sampled at breast height. The correlation between adjacent individual trees was investigated. 1) The correlation between radius growth and basal area was used to estimated the degree of competition among individual trees. 2) In estimating the degree of competition the correlation between two individual trees was better method than others. 3) Up to 9 years after planting no competition between individual trees occurred and the Night positive correlation was shown. 4) High degree of competition was observed at age of 10 years after the planting, as the correlation coefficient was getting smaller. 5) The degree of competition among individual trees increased with increase of the growth of total stand.

      • KCI등재

        여름과 겨울철 남해의 영양염 분포 특성

        이동섭,Lee, Tong-Sup 한국해양학회 1999 바다 Vol.4 No.4

        여름과 겨울철 남해의 해수에 포함되어 있는 영양염의 분포 특성을 수온, 염분, 겉보기 산소 소모량, pH 등의 환경 인자들과의 상관도를 통해 파악하고자 하였다. 여름철에 영양염의 분포는 염분보다는 수온과 양호한 상관도를 보였으며 생물 활동과 관련이 갚은 pH, 겉보기 산소 소모량과 유의한 상관관계를 보였다. 이로 보아 여름철에 형성되는 염전선역에서 일차생산자에 의한 영양염 소비가 활발하여 염분과 영양염과의 상관성을 강력하게 변형시키는 것으로 판단된다. 겨울철에는 수온이 영양염과 가장 유의한 상관관계를 나타내어 수직 혼합된 냉수와 북상하는 난류의 세력이 만나는 열전선의 위치가 영양염 분포에 가장 중요한 요인으로 분석되었다. 여름철에 가장 우수한 상관도를 보였던 ($R^2$ >0.6) pH의 경우 겨울철에 생물 활동이 미약하여 상관도가 크게 낮아졌다($R^2$ <0.5). 수심에 대해 적분한 질산염+아질산염 인산염 규산염의 값은 각기 여름철에는 321 $mmol{\cdot}m^{-2}$, 23 $mmol{\cdot}m^{-2}$, 637 $mmol{\cdot}m^{-2}$이었고 겨울철에는 261 $mmol{\cdot}m^{-2}$, 31 $mmol{\cdot}m^{-2}$, 742 $mmol{\cdot}m^{-2}$로 계산되었다. 영양염의 질소 대 인의 비는 여름철에는 인이 상대적으로 부족한 반면 겨울철에는 이와 반대로 질소가 결핍되어 우기에 강우와 하천을 통한 질소의 유입이 남해 생태계 유지에 중요한 역할을 하는 것으로 판단된다. This paper presents the results of recent nutrients measurement and analysis in relation to other environmental parameters such as temperature, salinity, AOU and pH in the South Sea, Korea. In summer, temperature showed stronger correlation with nutrients than salinity and also did the parameters related to biological activities such as pH and AOU. Implications of above results exemplify that primary producers in the vicinity of salt front actively consumed nutrients so that nutrients-salinity correlation is strongly modified in the salt front. Nutrient in winter showed significant correlation only with temperature. Nutrient distribution seems governed by the location of thermal front between vertically mixed cold water in northern area and warm waters flowing north. Due to weak biological activity in winter pH-nutrients correlation, which was strongest in summer ($R^2$ >0.6) dropped sharply in winter ($R^2$ <0.5). Depth integrated nitrate+nitrite, phosphate and silicate values are 321 $mmol{\cdot}m^{-2}$, 23 $mmol{\cdot}m^{-2}$, 637 $mmol{\cdot}m^{-2}$ in summer and 261 $mmol{\cdot}m^{-2}$, 31 $mmol{\cdot}m^{-2}$, 742 $mmol{\cdot}m^{-2}$ in winter, respectively. NIP values in summer exhibit phosphorus deficiency, however, winter situation is reversed for nitrogen. Nitrogen input via precipitation and riverine discharge in wet season seems potentially critical for maintaining the South Sea ecosystem.

      • KCI등재

        $^{228}Ra$를 이용한 이상 저염 대마난류수의 기원 추적 연구

        이동섭,김기현,Lee, Tong-Sup,Kim, Ki-Hyun 한국해양학회 1998 바다 Vol.3 No.4

        동해의 울릉분지 표층에서 1996년 9월 초부터 11월 사이에 염분$^*$ 32 이하의 저염 해수가 출현했음이 최근 학계에 보고되었으며, 이 해수의 기원으로 여름철에 제주도 부근까지 세력을 확장하는 장강 유출수가 지목되었다. 대한해협의 서수로를 통과하는 해수가 두 단성분(장강 회석수와 쿠로시오 해수) 간의 단순한 혼합에 의한다는 가정하에 $^{228}Ra/^{226}Ra$ 방사능 비를 보존적 추적자로 활용하여, 두 수괴가 대한해협 서수로를 통과하는 표층수를 형성하는데 얼마나 기여하는가를 산정하였다. 알려진 두 단성분의 $^{228}Ra$, $^{226}Ra$ 방사능 측정값과 대한해협 서수로에서 측정한 $^{228}Ra/^{226}Ra$ 방사능 비로써 계산한 결과, 장강 희석수는 평균 염분이 32.17이었던 1996년 9월에 대한해협 서수로 표층수의 $58{\pm}3%$ 그리고 평균 염분이 34.53이었던 1997년 2월에는 $10{\pm}3%$ 기여하였던 것으로 나타났다. 이것은 제한된 자료와 매우 단순한 모델로부터 얻은 결과이지만 장강 유출수가 동해 내부에까지 영향을 주고 있음을 지시하며, 현재 장강 수계에 건설중인 삼협댐이 완공되면 장강 희석수 자체의 변화로 인해 북부 동중국해와 울릉분지 부근에 걸쳐 수십년 시간 규모의 해양 환경 변화가 일어날 것으로 판단된다. Recently it is reported that anomalously low saline surface waters (salinity < 32) occurred at the Ulleung Basin in the East Sea-Japan Sea, during early September to November 1996. Apparent source of such a low saline watermass seems remotely linked to the Changjiang Dilute Water (CDW), which expands to the vicinity of Cheju Island during a flood season. Based on the assumption that waters passing through the Western Channel of the Korea Strait are formed by a mixing of Kuroshio Water and CDW, simplified two end-member mixing model using $^{228}Ra/^{226}Ra$ as a conservative tracer is applied to calculate the contribution of each end member for the formation of low saline surface seawater. Model calculations show CDW contributes $58{\pm}3%$ in September 1996 (S=32.17) and $10{\pm}3%$ in February 1997 (S=34.53) in the formation of surface water flowing into the Western Channel of the Korea Strait. Although results arc deduced from a simplified model with limited data, this study demonstrates that Changjiang discharge is clearly traceable to the interior of the East Sea-Japan Sea in fall season. Undergoing Three Valley Dam construction in the Changjiang River would invoke inevitable changes in the nature and discharge of CDW and its impacts on the marine environment might be significant in the northern East China Sea and even in the Ulleng Basin for coming decades.

      • KCI등재

        울릉 분지 저층수의 아질산염

        이동섭,김일남,강동진,김동선,Lee, Tong-Sup,Kim, Il-Nam,Kang, Dong-Jin,Kim, Dong-Seon 한국해양학회 2007 바다 Vol.12 No.3

        울릉분지의 일부 저층수에서 아질산염의 존재가 확인된 것은 용존산소가 매우 풍부한 환경에서 예상되지 않던 결과로서 괄목할만한 사실이었지만 과학적으로 설명되지 않았다. 오캄의 제안에 따르면 가능한 몇 가지 설명 가운데 대륙사면 표층 퇴적물 안에서 일어나는 탈질산화의 중간산물로써 해수로 유출되는 것이 제반 여건과 가장 잘 부합된다. 그런데 울릉분지에서는 이런 탈질산화에 따른 무기질소의 손실을 보상하는 특별한 방법이 존재하지 않은 것으로 보이며 이는 현재 심해수의 낮은 질소: 인의 비와 일맥상통한다. 여기에 열염순환을 약화시키는 온난화의 효과가 가중될 경우 현재의 생물펌프가 위축될지 또는 현재 식물플랑크톤 군집을 대체하는 새로운 군집으로 바뀌게 될지도 모른다. 그 경우 이는 동해 생태계가 직면하게 될 심각한 도전이 될 것이다. 한편으로는 수중에 산화제가 풍부함에도 불구하고 표층 퇴적물의 유기탄소함량이 아주 높게 나타나서 울릉분지에서 질소(유기물)의 순환에 대해 풀리지 않는 문제가 여전히 남아있다. Presence of bottom water nitrite in the Ulleung Basin was remarkable because it is totally unexpected phenomenon at such an oxygen-rich environment. Yet no scientific explanation was set forward. Of several plausible explanations, following the Ockham's suggestion, a leaching of nitrite as an intermediate product of denitrification in the top sediment at the slope is most agreeable to given environmental settings. There seems no complementary process to make up the loss of N in the Ulleung Basin, which seems contribute to the characteristically low N:P ratio in the deep waters. If warming proceeds that weakens the thermohaline circulation, a current biological pump may stall and the phytoplankton assemblage might replaced drastically. If so this will pause an utmost challenge to the ecosystem of the East/Japan Sea. Still there remains a contradictory sedimentary signature that requests further explanation regarding the N (or organic C)-cycle such as extraordinarily high organic carbon content despite abundant oxidants in the overlying waters.

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