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.

최근 국내외적으로 저영향개발(Low Impact Development, 이하 LID) 기법을 비롯하여 도시화에 따른 영향을 최소한으로 하면서 도시를 개발하고자 하는 개념이 도입되고 있다. 하지만 이러한 LID 기법을 적용하기에는 도심부의 공간은 이미 고밀도 건축되어 있고 오픈 스페이스(Open Space)가 부족하여 녹지로 대체할 수 있는 공간의 확보에도 한계가 있으며, 높은 지가로 인하여 추가적인 녹지 공간의 확보가 어려운 것이 현실이다. 옥상녹화 사업의 효과는 해당 건물뿐 아니라 공공의 이익에 영향을 미치는 공공재로서의 역할을 수반하기 때문에 사업에 대한 타당성을 확보하고, 이를 통해 좀 더 효율적인 옥상녹화 사업을 유도할 필요가 있다. 이를 위해 본 연구에서는 우리나라의 옥상녹화 설계 기준을 살펴보고, 상대적으로 간단한 모형을 구축하여 설계(토양층의 깊이 변화)에 따른 유출 및 비점오염물질의 배출 거동을 모의하고 결과를 분석하여 옥상녹화의 최적 토양층 깊이를 산정하는 방안을 제시하였다.

This study, the urban energy used office building green roof type composition of the target by analyze building energy reductions. Green roof is total 6 types(type A~F) were selected, EnergyPlus the energy simulation programs were used. Top floor of green roof types evaluation, the reduction of the cooling peak load type E(1.26%), type D(1.30%), type C(1.37%), type B(1.45%), type F(1.49%), and heating peak load is type D(1.32%), type E(1.40%), type C(1.47%), type F(1.69%), type B(2.13%) order. Annual cooling load of heating load is reduced more than about 1% effect. The heating load reduction ratio for a maximum of 9% respectively. Cooling peak load of the building energy performance evaluation of type F ＞type B ＞type C ＞type D ＞type E in the order and in the case of peak loads heating type B ＞type F ＞type D ＞type E ＞type C order. Annual total energy use reduction of 1.07 to 1.22% and earn, type B in the best good. In primary energy use reductions in the presence of a green roof were in the 4249~4876 kWh/yr. Annual CO2 emissions reductions of unapplied type A were analyzed on average 469.78 kg.

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.

This was an experimental study to evaluate temperature reduction and evapotranspiration of extensive green roof. Three test cells with a dimension of 1.2(W)×1.2(D)×1.0(H) meters were built using 4-inch concrete blocks. Ten-centimeter concrete slab was installed on top of each cell. The first cell was control cell with no green roof installed. The second and third cells were covered with medium-leaf type Zoysiagrass (Zoysia japonica) above a layer of soil. Soil thickness on the second cell was 10cm and that on the third cell was 20cm. Air temperature, relative humidity and solar irradiance were measured using AWS (automatic weather system). Temperature on top surface and ceiling of the control cell and temperature on top surface, below soil and ceiling of green roof cells was measured. Evapotranspiration of the green roof cells were measured using weight changes. Compared with temperature difference on the control cell, temperature difference was greater on green roof cells. Between two green roof cells, the temperature difference was greater on the third cell with a thicker soil layer. Temperature differences below soil and on ceilings of green roof cells were found greater than those of the control cell. Between the green roof cells, there was no difference in the temperature reduction effects below soil and on ceilings based on substrate depth. In summary, green roof was found effective in temperature reduction due to evapotranspiration and shading effect.

This study is the development to standard for evaluation performance of the waterproofing and root resistance combined membrane layer on the green roof system, and it is especially to evaluate to chemical resistance of it

Green roof policies has helped to advance urban greening by creating green spaces on previously unused rooftops. However, there are no requirements covering matters such as greening methods, operation and maintenance obligations and many problems for sustainability and functioning of green roof and green space have been pointed out. This research is intended to clarify the contents and criteria of green roof policies currently implemented in Korea, Japan and other countries, compare them with the evaluation criteria for sustainable and public benefit rating systems and propose comprehensive indices for evaluating the multidimensional functions of green roof from the perspective of urban open space. As a result, it is found that obligation, grant, reimbursement, density bonus and tax credit are frequently used as green roof policies and 41 criteria including percentage of greening area, percentage of trees or shrubs, reduction of heat island effect, open space, landscape, and promotion of biodiversity are identified as criteria applicable to evaluating the multidimensional functions of green roof from the perspective of urban open space, respectively.

4가지 인공배합토 모두는 용적밀도와 포장용수량을 고려할 때에 초본류를 적용한 저관리․경량형 옥상녹화뿐만 아니라 관목류를 적용한 혼합형 또는 관리․중량형 옥상녹화에도 활용 가능할 것이다. 전반적으로 시간이 경과하며 인공배합토 모두는 산성화되며 펄라이트 소립과 펄라이트 소립+일반토양(v/v, 2:1)은 적정한 수준을 나타냈고, 세라소일과 세라소일+자연토양(부피비, 2:1)은 알칼리성을 나타냈다. 펄라이트 소립과 펄라이트 소립+일반토양(v/v, 2:1)은 유기물 함량이 낮게 나타났다. 식재 후 1년이 경과한 후에 4가지 인공배합토 모두는 척박하며 건전한 생육을 저해할 것으로 판단된다. 식재 후 1년이 경과한 후에 4가지 인공배합토에서 자란 3종의 상록활엽수는 먼저 6개월이 경과한 후에서의 식물체와 비교하여 불량한 생육을 보였고, 4가지 인공배합토 상호간에도 서로 다른 생육특성을 나타냈다. 구체적으로 다정큼나무는 세라소일, 세라소일+일반토양(v/v, 2:1)에서 상대적으로 높은 생육량을 나타냈고, 남천은 4종의 인공배합토 모두에서 일반토양과 비교하여 상대적으로 낮은 생육량을 나타냈으며, 영산홍은 펄라이트, 펄라이트+일반토양(v/v, 2:1)에서 상대적으로 높은 생육량을 나타냈다. 이것은 보다 건전한 식물생육을 유도하기 위해서 각각의 상록활엽관목의 생육특성을 고려한 인공배합토의 선정이 필요함을 의미한다고 해석할 수 있으며, 또한 보다 다양한 종류의 상록활엽관목을 옥상녹화에 도입하기 위하여 각각의 인공배합토에서 그 생육특성을 평가하는 것이 필요함을 보여주고 있다.

The purpose of this study was to identify the irrigation intervals and the amount of suitable growing substrate needed to achieve the desired shallow-extensive green roof system during a dry summer in Korea. In terms of treatment, three types (SL, P6P2L2, P4P4L2) with varying soil mixture ratios and two types (15 cm, 25 cm) with varying soil depths were created. The results have been analyzed after measuring growth and soil water contents. The difference of growth by treatment was significant in terms of green coverage, height, leaf width and photosynthesis. In measurement of chlorophyll content, no difference was detected when measured against soil depth. According to the growth measurement of Zoysia japonica with respect to differing soil mixture ratios in the 15 cm-deep treatment, a statistical difference was detected at the 0.05 significance level in photosynthesis. In case of green coverage, height, chlorophyll content and leaf width, no statistical significance was observed. In case of the 25 cm-deep treatment, a statistical significance was observed in height and photosynthesis. In terms of green coverage, chlorophyll content and leaf width, no statistical significance was detected. In comparisons of soil moisture tension and soil water contents, the irrigation interval and amount were 8 days and 14.9 L in the SL (15 cm) treatment, respectively. The irrigation interval showed for 10 days a 1.3-fold increase, and the irrigation amount was 27.4 L 1.8-fold more than SL (25 cm), respectively. For P6P2L2 (15 cm) treatment, the irrigation interval and amount were 12 days and 20.7 L, respectively. However, an irrigation interval under P6P2L2 (25 cm) was for 15 days 1.3 times longer than P6P2L2 (15 cm), and an irrigation amount of 40 L was 1.9 times more than that under P6P2L2 (15 cm). In P4P4L2 (15 cm) treatment, it was indicated that the irrigation interval was 15 days, and the irrigation amount was 19.2 L. It was not needed to irrigate for 16 days under P4P4L2 (25 cm) treatment during the dry summer and the longest no-rain periods. The irrigation interval and amount under P4P4L2 were 1.8-fold and 1.3-fold, respectively, more than SL treatment as affected by soil mixture ratio. Comparatively P4P4L2 had more 1.3-fold and 0.9-fold in irrigation interval and amount more than P6P2L2. Therefore, it can be noted that different soil depth and soil mixture ratios had a significant effect on the irrigation interval and amount.

본 연구는 옥상녹화에 관한 국내 상위법, 지자체 조례 및 국외 사례를 분석하고 주된 경향을 파악함으로써 옥상녹화가 도시환경개선에 지속적으로 기여하기 위한 법 ･ 제도적인 개선방향을 제시하고자 하였다. 국내는 비교적 옥상녹화의 법적인 제도화가 진행된 단계이나 건축물 단위에만 직접적인 영향을 주고 있으므로 옥상녹화가 가진 도시적인 효과를 증진하기 위해서는 녹지를 도시적인 규모로 다루고 있는 법률들에서도 옥상녹화를 직접적으로 규정하는 것이 필요하며, 옥상녹화를 지표로 활용하는 대표적인 제도인 생태면적률이 현재의 권고적인 단계에서 발전하여 근거법을 갖도록 해야 한다. 또한 지자체의 규정들 대부분이 실행력이 매우 낮거나 간접적인 언급에 그치고 있어 이에 대한 개선도 시급할 것이다. 그럼에도 ‘공원녹지기본계획’ 등에서 도시녹화계획의 요소로 옥상녹화를 적용하려는 노력이 서울시 등을 필두로 시작하고 있다는 점은 긍정적이라 평가할 수 있다. 이는 옥상녹화를 하나의 건축물 혹은 필지 단위에서 조성하기 위한 기존의 계획방식에서 탈피하여 지구단위, 도시단위 등으로 계획 범위를 확대함과 동시에, 옥상녹화가 도시환경개선에 밀접하게 연관되도록 조성하게 됨을 의미하기 때문이다. 향후 옥상녹화가 열섬완화, 우수유출저감, 생물다양성 확보, 녹색 인프라 기능제고 등을 위하여 보다 심도있는 법적 개선사항들에 관한 연구들과 아직은 국내에서 부족한 각 지자체별 특성에 맞는 도시구조적, 기후적, 지형적 변수들을 조사하고, 이를 통합하여 도시계획을 위한 모델로 활용하는 연구 등도 필요할 것이다.

본 연구는 무관수 옥상녹화시스템 식재기반 차이에 따른 돌나물의 생육 변화를 살펴보고, 적합한 토심과 토양배합비를 제시함으로써 무관수 옥상녹화 식물소재로 활용성을 높이고자 수행하였다. 토심(15㎝, 25cm)과 토양배합비(SL, P7P1L2, P6P2L2, P5P3L2, P4P4L2)를 각각 다르게 실험구를 조성하였으며, 내건성이 뛰어난 돌나물을 식재한 후 초장, 녹피율, 엽록소 함량, 생체중과 건조중 등 생육변화를 측정하였다. 토심 15㎝처리구에서 토양배합비에 따른 돌나물의 초장은 인공배합토가 자연토보다 높았으며, 인공배합토 중 P5P3L2에서 초장이 가장 길었다. 토심 25㎝처리구도 같은 경향을 나타내었다. 녹피율과 엽록소함량은 경우 자연토보다 인공배합토에서 대체로 높았으나, 토심에 따른 차이는 뚜렷하지 않았다. 생체중과 건물중은 토심 25cm가 토심 15cm보다 높았으며, 인공배합토가 자연토에 비해 높았다. 이상의 결과에서 무관수 옥상녹화시스템에 돌나물을 적용함에 있어, 토양배합비는 피트모스함량을 높인 인공배합토가 자연토보다는 바람하고 토심은 15cm가 토심 25cm보다 초장, 녹피율, 엽록소 함량 등 외형적인 생육상태가 양호하였다. 하지만, 토심 25cm에서는 생체중 및 건조중 등과 같이 현존량(Biomass)을 향상시킬 수 있어 조성목적에 따라 구분적용하는 것이 바람직하다. 이는 무관수 옥상녹화시스템에서 단기적인 녹피율을 높이고자 할 때 토심 15cm가 25cm보다 바람직하나, 장기적인 생육을 고려해볼 때, 토심 25cm가 15cm보다 유리함을 보여준다고 하겠다. 추후, 토양수분변화 및 각 옥상녹화시스템의 요소들과 생육요소들 간에 상관성 및 요인분석에 대한 분석이 좀 더 조사되어야 할 것으로 보인다.

This study proposes a guideline of a green roof system suitable for the local environment by verifying the growth of Zoysia japonica in a shallow, extensive, green roof system under rainfed condition. The experimental soil substrates into which excellent drought tolerance and creeping Z. japonica was planted were made with different soil thicknesses(15cm, 25cm) and soil mixing ratios(SL, P7P1L2, P6P2L2, P5P3L2, P4P4L2). The plant height, green coverage ratio, fresh weight, dry weight and chlorophyll contents of Z. japonica were investigated. For the soil thickness of 15cm, the plant height of Z. japonica was significantly as affected by the soil mixing ratio and it was shown in the order SL= P4P4L2 < P7P1L2 = P5P3L2 < P6P2L2. For the soil thickness of 25cm, the plant height was increased in order to SL < P7P1L2, P6P2L2, P5P3L2 < P4P4L2. The green coverage ratio was not observed by soil the mixing ratio or soil thickness. However, the green coverage ratio was 86∼90% with a good coverage rate overall. The chlorophyll contents of Z. japonica were not significantly affected by the soil mixing ratio in the soil thickness of 15cm, but were higher in the natural soil than in the artificial soil at 25cm soil thickness. The fresh weight and dry weight of Zoysia japonica were heavier in the 25cm thickness than in the 15cm thickness and in the artificial soil mixture than in the natural soil. The result indicated that the growth of Zoysia japonica was more effective in the 25cm soil thickness with artificial soil than in the 15cm soil thickness with natural soil in the green roof system under rainfed condition.