行道樹視覺景觀偏好影響因素之探討

The Factors Affecting Visual Preference of Street Trees on Sidewalks

本研究主要探討行道樹不同屬性對使用者視覺景觀偏好之影響。將17種行道樹、4種建築形式進行組合，以行道樹有無、人行道旁建築形式、樹形、枝葉密度、樹高、分枝高度、樹徑、樹冠寬度、樹冠高度及樹冠寬度／樹徑為研究變項，使用電腦模擬行道樹景觀之幻燈片為環境刺激媒體進行評估及分析。結果發現，人行道栽植行道樹會提升人行道景觀品質，且人行道旁不同建築形式，在控制樹形變項時，建築形式之差異會影響景觀偏好，行道樹之樹形、分枝高度、樹冠寬度、樹冠高度、樹冠寬度／樹徑皆會影響視覺景觀偏好，其中樹冠寬度、樹冠高度、樹冠寬度／樹徑為正向影響，分枝高度則為非線性之影響。而預測模式分析中，主要影響因素依序為樹形、人行道旁建築形式、分枝高度、樹冠寬度、樹冠寬度／樹徑，一般較喜愛圓錐形或開展形、樹冠寬度大且樹冠與樹徑比值大者，分枝高度則須適中。

The purpose of this study was to explore the influence of various street tree attributes on visual preference. This research used alternate combination among seventeen species of street trees and four kinds of building types as treatments. The variables were 'with or without street trees,' 'building type,' 'tree form,' 'foliage density,' 'tree height,' 'trunk height,' 'dbh,' 'canopy width,' 'canopy height,' and 'canopy width/dbh.' Simulation slides were used for students' questionnaire. The results are summarized as follow: l. Streets with trees possess greater scores on visual preference evaluation than without. The differences between building types have significant influences on the perception of street visual preference while the variable 'tree form' is controlled. 'Tree form ', 'trunk height,' 'canopy width,' 'canopy height' and 'canopy width/dbh' have significant influences on visual preference. Among them the 'canopy width,' 'canopies height' and 'canopy width/dbh' are linearly correlated with preferences, while the 'trunk height' presented nonlinear effect. 2.0n the predicting model been established, 'building type,' 'tree form,' 'trunk height,' 'canopy width' and 'canopy width/dbh' are main factors that affect visual preference toward street trees on sidewalks. The 'pyramidal form' or 'spreading form' street trees are commonly preferred. The greater 'canopy width' and 'canopy width/dbh' ratio, the more it is preferred. Trees with optimal 'lowest branching height' are preferred.