Abstract
The goal of this research is to examine air temperature changes according to tree type, plantation type, roadside green area structure, and green volume of street green area within a city. The plantation type that could be analyzed for comparison by tree type with over 3 species was 1 rows of tree+shrubs. The results of analysis of average air temperature difference between pedestrian and car streets vis-a-vis 1 row of tree+shrub in high air temperature areas were: Pinus densiflora, $1.35^{\circ}C$; Zelkova serrata, $1.84^{\circ}C$; Ginkgo biloba, $2.00^{\circ}C$; Platanus occidentalis, $2.57^{\circ}C$. This standard large wide canopy species was analyzed by the roadside to provide shade to have a significant impact on air temperature reduction. In terms of analysis of the relationship between plantation type of roadside trees and air temperature, the average air temperature difference for 1 row of tree type was $1.80^{\circ}C$; for 2 rows of trees it was $2.15^{\circ}C$. In terms of analysis of the relationship between the roadside green area structure and air temperature, for tree type, average air temperature $1.94^{\circ}C$: for tree+shrub type, average air temperature $2.49^{\circ}C$; for tree+mid-size tree+shrub type, average air temperature $2.57^{\circ}C$. That is, air temperature reduction was more effective in a multi-layer structure than a single layer structure. In the relationship analysis of green volume and air temperature reduction, the air temperature reduction effect was enlarged as there was a large amount of green volume. There was a relationship with the green volume of the road, the size of the tree and number of tree layers and a multi-layer structured form of planting. The canopy volume was large and there were a great number of rows of the tree layer and the plantation type of multi-layer structure, which is what is meant through a relationship with the green volume along the roadside. Green composition standards for air temperature reduction effects and functional improvement were proposed based on the result. For a pedestrian street width of 3m or less in the field being ideal, deciduous broadleaf trees in which the canopy volume is small and the structure of the tree+shrub type through the greatest 1m green bend were proposed. For a pedestrian street width of over 3m, deciduous broadleaf trees in which the canopy volume is large and is multi-layer planted with green bend over 1m, tree+mid-size tree+shrub type was proposed.
본 연구는 도시 내 가로수 및 가로녹지의 수종, 식재유형, 가로녹지 구조, 녹량(녹지용적)에 따른 기온 변화량을 규명하고자 하였다. 수종별 비교 가능한 3종 이상의 가로수가 식재된 유형은 교목 1열+관목이었으며, 보차간 기온차이 평균값 간 분석에서 소나무 $1.35^{\circ}C$, 느티나무 $1.84^{\circ}C$, 은행나무 $2.00^{\circ}C$, 양버즘나무 $2.57^{\circ}C$이었다. 규격이 크고 수관폭이 넓은 수종은 가로변에 그늘을 제공하여 기온 저감에 상당한 영향을 주는 것으로 분석되었다. 가로수 식재유형과 기온과의 관계 분석결과는 교목 1열 유형은 평균기온 차이 $1.80^{\circ}C$, 교목 2열 유형은 평균기온 차이 $2.15^{\circ}C$로 교목 열수 증가에 따라 보차간 기온차이 평균값이 큰 것을 알 수 있었다. 가로녹지 구조별 기온 저감 효과 분석결과는 교목 유형 $1.94^{\circ}C$, 교목+관목 유형 $2.49^{\circ}C$, 교목+아교목+관목 유형 $2.57^{\circ}C$이었으며, 기온저감은 단층구조보다 다층구조에서 효과적이었다. 녹량(녹지용적량)과 기온저감량과의 관계 분석에서는 녹량이 많을수록 기온저감 효과가 커지는 것으로 분석되었다. 연구 결과 수관용적이 크고 교목층의 열수가 많으며, 다층구조인 식재형태는 가로 내 녹량과 관계가 있음을 의미하였다. 본 결과를 바탕으로 기온 저감 효과와 기능 강화를 위한 가로녹지 조성 기준을 제안하였다. 보도폭 3m 이하인 경우에는 수관용적이 작은 낙엽활엽수와 최대 1m의 띠녹지 조성을 통한 교목+관목의 구조를 제시하였다. 보도폭 3m 이상인 경우에는 수관용적이 큰 낙엽활엽수 다열 식재 및 1m 이상의 띠녹지 조성, 교목과 관목뿐만 아니라, 아교목 성상의 수목 식재를 통한 다층구조 녹지조성이 가능할 것으로 판단되었다.
