본 연구는 저관리 경량형 옥상녹화에 이용되고 있는 지피식물인 맥문동(Liriope platyphylla), 울릉국화(Chrysanthemum zaqadskii), 비비추(Hosta longipes), 돌나물(Sedum sarmentosum), 잔디(Zoysia japonica) 의 온열환경을 비교하여 향후 온도저감을 위한 옥상녹화 조성 시 기초자료를 제공하고자 수행하였다. 온열환경 측정은 옥상녹화 및 토양의 표면, 하부 그리고 대조구 표면에 T형 열전대를 설치하여 데이터로거로 연속 측정하였다. 온열환경 측정결과 표면온도는 대조구가 가장 높았으며, 그 다음으로 토양, 맥문동, 잔디, 울릉국화, 돌나물, 비비추 순으로 나타났다. 하부온도는 대조구가 가장 높았으며, 그 다음으로 잔디, 토양, 맥문동, 돌나물, 울릉국화, 비비추 순으로 나타났다. 실험구의 일일 온도변화 폭은 대조구가 가장 높은 변화를 기록하였으며, 그 다음으로 토양, 잔디, 맥문동, 울릉국화, 돌나물, 비비추의 순으로 나타나 옥상녹화 식물로 온도변동 폭이 작아지는 경향을 보였다. 본 연구의 결과 저관리 경량형 옥상녹화를 조성할 시 온도저감 효과가 확인할 수 있었으며, 그 효과는 식재 식물 종에 따라 달라지는 것을 알 수 있었다. 그러나 본 연구는 옥상녹화에 이용되고 있는 수많은 식물들 중 극히 일부를 대상으로 하고 있어 향후 다양한 식물들에 관한 연구가 필요할 것으로 판단된다.

도심에 녹지공간 확보를 위한 방안으로 저관리 경량형옥상정원이 많이 조성되고 있으나 토심이 낮아 활용할 수 있는 식물종이 매우 제한되어 있다. 따라서 중부지방의 저관리 경량형옥상정원에 활용할 수 있는 다양한 식물자원을 선발하기 위하여 곤달비와 금낭화 등 초본성 자생식물 82종에 대한 생육 및 월동특성, 지피특성, 적용 후 온도 및 토양수분 등의 변화를 조사하였다. 실험결과 생육특성, 생존율, 월동전의 생육상태, 지피특성 등을 고려하여 잔대, 산부추, 두메부추, 벼룩이울타리, 참당귀, 개미취, 참취, 범부채, 섬초롱꽃, 패 랭이, 금낭화, 윤판나물, 용머리, 원추리, 붉은단풍취, 비비추, 흰줄무 늬비비추, 옥잠화, 꽃창포, 붓꽃, 노랑꽃창포, 곤달비, 맥문동, 하늘나 리, 참나리, 꽃무릇, 돌단풍, 강활, 수호초, 작약, 수크령, 도라지, 둥굴레, 무늬둥굴레, 양지꽃 물싸리, 할미꽃, 오이풀, 황금, 기린초, 애기기린초, 섬기린초, 세잎꿩의비름, 산비장이, 섬백리향을 선발하 였다. 또한 식물이 식재된 후의 콘크리트 표면과 토양의 온도편차는 여름철 최고 20 ~ 35οC이였으며, 토양습도는 6월과 9월 비가 많이 내리지 않는 건조기에는 5%미만으로 떨어지는 기간이 1주 이상 지 속되어 자생 초본식물의 도입시 관수를 필요로 하였다.

본 연구는 지속가능한 옥상녹화 식재계획을 위하여 관리조방형 옥상녹화 식재식물에 대한 다년간 조사결과를 토대로 피복률 변화의 양상을 분석하고 피복특성을 유형화하였다. 실험대상지는 2007년에 조성된 서울여자대학교 행정관 옥상녹화지이며 식물은 기린초 등을 포함한 4종류의 세덤류와 층꽃나무 등 다년생 초화류 14종을 포함하여 총 18종 이식재되었다. 식재식물 피복변화 모니터링은 2007년부터 2009년까지 3년간 실시하였다. 조사결과 피복률은 식재 후2년이 경과한 2008년에는 전반적으로 안정세를 보이거나 다소 증가한 반면 2009년 들어서는 세덤류와 섬백리향 등총 6종을 제외하고는 대다수 감소하는 양상을 보였다. 피복양상을 관찰한 결과 크게 4가지 유형으로 식재지유지형, 인접지역 잠식형, 포복 확산형, 산발 확산형으로 분류하였다. 또한 주요기간의 피복률 데이터를 종속변수로 하여 식재후 경과 시간과 단순회귀분석을 실시하였으며, 최종적으로 총 8종에서 통계적 유의수준 하에서 피복률 변화양상 예측모델이 도출되었다. 향후 다양한 식물들에 대한 장기적인 피복특성 모니터링을 통해 지속가능한 옥상녹화 식재계획을 위한 다양한 식물정보 구축이 필요할 것으로 생각된다.

The purpose of this study was to assess drought tolerance of groundcover plants for extensive green roof. Form July to November 2013, plant height, chlorophyll content, soil moisture, evapotranspiration and survival rate was measured. As results, after unirrigation started, Aster koraiensis reached 0% of soil moisture earliest followed by Sedum kamtschaticum, Hemerocallis fulva, Hylotelephium spectabile, Iris sanguinea, Hosta longipes and control. Among the plants, A. koraiensis withered earliest on 19th day of unirrigation experiment, followed by H. longipes and H. fulva (27th day); and I. sanguinea (29th day). S. kamtschaticum and H. spectabile survived even after 120th day of the experiment. As for chlorophyll content, I. sanguinea showed constant values in early stage than rapidly decreased right before its withering. Chlorophyll content of A. koraiensis and H. fulva showed rapid decrease from the beginning, while that of H. spectabile and S. kamtschaticum showed continuous reduction for first 30 days and the reduction was slowed down since then. In conclusion, H. longipes, I. sanguinea and H. fulva were found most applicable for extensive green roof considering scenic aspect.

This study was carried out to assess the covering of 11 Sedum species on an extensive green roof system under the urban climate of South Korea for 2 years. The eleven Sedum species which came up to the criteria were selected: S. acre, S. album, S. kamtschaticum, S. oryzifolium, S. polystichoides, S. reflexum, S. rupestre, S. sarmentosum, S. sexangulare, S. spurium, and S. telephium. The plants were planted in the extensive green roof system with the substrate of porous glass+bark+field soil (v:v:v, 3:2:5) and then evaluated. The covering area of the Sedum species were about 72㎠ at the start after the establishment. When a year had passed since the systems were established, S. acre, S. oryzifolium and S. sexangulare maintained 200-500㎠/plant of covering area and the others maintained 800-1200㎠/plant. Most covering area increased continuously for about two years and showed a large quantity of increment in summer season with the exception of S. kamtschaticum, S. polystichoides, S. sarmentosum, and S. telephium, whose above-parts were not alive in winter.

This study as a part of an extensive green roof system development was carried out to assess the heat tolerance of 11 species Sedum spp. on the extensive green roof system: S. kamtschaticum, S. oryzifolium, S. polystichoides, S. sarmentosum, S. acre, S. album, S. reflexum, S. rupestre, S. sexangulare, S. spurium, and S. telephium. Electrolyte leakage evaluation was used to estimate the heat tolerance level of each Sedum at 40°C, 45°C, 47.5°C, 50°C, 52.5°C, 55°C, and 57.5°C. The critical temperatures at the midpoints of sigmoidal curves fitted through electrolyte leakage (EL) were predicted with the range of 54.0°C to 65.2°C. S. album, S. telephium, and S. sexangulare were more tolerant of high temperature than the others. In field condition, the heat tolerance of 11 species Sedum spp. applied to the suggested extensive green roof system was also estimated by EL evaluation. The EL (%) values of 11 species Sedum spp. subjected to maximum temperature (46.7°C) recorded during the experimental periods were lower than 50% except S. kamtschaticum and S. spurium. Especially, S. album, S. rupestre, and S. telephium were ranked higher than the others in heat tolerance. The most Sedum spp. would show good heat tolerance on the extensive green roof system if the maximum temperature on rooftop was below 50°C in summer season.

This study investigated the effects of soil depths and soil organic fertilizer application on the growth characteristics of Spiraea bumalda ‘Gold Mound’ in a extensive green roof system. The treatments were 3 soil depths (10, 15 and 25 cm) and 5 soil types in mixture of artificial soil and organic fertilizer. We measured plant height, leaf width, leaf length, number of flowers, visual quality and survival rate from March to October in 2011. The growing medium of 10 cm soil depth showed the highest plant growth in A1 (amended soil 100%), and the lowest plant growth in O1A4 (organic fertilizer 20% + amended soil 80%) treatment. In case of 15 cm soil depth, Spiraea bumalda ‘Gold Mound’ showed a high leaf length and visual quality in O1A2(organic fertilizer 33% + amended soil 67%) treatment and high leaf width and number of flowers in O1 (organic fertilizer 100%) treatment. A1 treatment without organic fertilizer showed the lowest leaf length and poorest visual quality, and O1A4 treatment showed the lowest plant height and lowest number of flowers. At soil depth 25 cm, O1A1 (organic fertilizer 50% + amended soil 50%) treatment showed greater plant height, visual quality and number of flowers than other treatments. The leaf length and leaf width were more effective in O1 treatment. A1 treatment showed a relatively low leaf length, leaf width and visual quality. The higher the organic conditioner, the better the plant growth. And, survival rates of Spiraea bumalda ‘Gold Mound’ showed 92%, 88% and 76% at soil depths of 25 cm, 15 cm and 10 cm, respectively, in this a extensive green roof system. Therefore, the results showed that the growth of Spiraea bumalda ‘Gold Mound’ was affected by both soil quality and soil depth. Different optimal mixtures of organic fertilizer and amended soil were determined, depending upon soil depth.

The objectives of this study were to compare growth of Pllioblastus pygmaed and soil characteristics as affected by difference of soil thickness and mixture ratio in shallow-extensive green roof module system, and to identify the level of soil thickness and mixture as suitable growing condition to achieve the desired plants in green roof. Different soil thickness levels were achieved under 15cm and 25cm of shallow-extensive green roof module system that was made by woody materials for 500×500×300mm. Soil mixture ratio were three types for perlit: peatmoss: leafmold=6:2:2(v/v/v, P6P2L2), perlit: peatmoss: leafmold=5:3:2(v/v/v, P5P3L2) and perlit: peatmoss: leafmold=4:4:2(v/v/v, P4P4L2 ). On June 2006, Pllioblastus pygmaed were planted directly in a green roof module system in rows. All treatment were arranged in a randomized complete block design with three replication. The results are summarized below. In term of soil characteristics, Soil acidity and electric conductivity was measured in pH 6.0∼6.6 and 0.12dS/m∼0.19dS/m, respectively. Organic matter and exchangeable cations desorption fell in the order: P4P4L2> P5P3L2> P6P2L2. P6P2L2 had higher levels of the total solid phase and liquid phase, and P4P4L2 had gas phase for three phases of soil in the 15cm and 25cm soil thickness. Although Pllioblastus pygmaed was possibled soil thickness 15cm, there was a trend towards increased soil thickness with increased leaf length, number of leaves and chlorophyll contents in 25cm. The growth response of Pllioblastus pygmaed had fine and sustain condition in order to P6P2L2 = P5P3L2 > P4P4L2. However, The results of this study suggested that plants grown under P4P4L2 appear a higher density ground covering than plants grown under P6P2L2. Collectively, our data emphasize that soil thickness for growth of Pllioblastus pygmaed were greater than soil mixture ratio in shallow-extensive green roof module system.

This study focused on the characteristics of change soil water with respect to soil thickness and soil mixture ratio, in order to effectively carry out an afforestation system for a roof with a low level of management and a light weight. Soil hardness tended to increase as sand particle was increase regardless soil thickness and soil porosity had more higher artificial soil than natural soil mixture. In case of soil pH, natural soil mixture had between 6.7 and 7.4, and artificial soil mixture had 6.0∼6.8. Organic matter, electrical conductance and exchangeable content were highest in L10, which it had the highest leafmold ratio. Soil moisture tension(kPa) in 15cm soil thickness was observed natural soil mixture had a considerable change but artificial soil mixture had a gradual change when non-rainfall kept on. In the experimental L10, S10, S7L3 and S5L5 object, the amount of moisture tended to rapidly decrease. However, in the experimental P7P1L2, P6P2L2, P5P3L2 and P4P4L2 objects, which contained pearlite and peat moss, the amount of moisture tended to gradually decrease. As a result, the use of a artificial soil mixture soil seems to be required for the afforestation of a roof for a low level of management.