Root Space: The Underground is the Real Issue

An underground cross-section perspective of a street tree, contrasting two approaches. On the left is the common mistake: the tree pit is only one meter square, surrounded by compacted aggregate and concrete foundations, leaving no space for roots, which coil and knot in the limited area. Some roots push upwards, causing the pavement to bulge and crack, and the tree canopy is noticeably sparse. On the right is the correct approach: the tree pit extends laterally with connected structural soil or soil cells, forming a continuous underground soil strip running through the entire row of street trees, two meters wide and one meter deep; roots can grow freely horizontally and connect with neighboring trees; the pavement above is supported by a structural layer, not compacting the soil; thus, the tree canopy is noticeably lush. Avoid: making the two look similar, only drawing the ground without showing underground, eliminating the contrast of pavement bulging, or making the canopies of the two trees the same size.

Translated from Chinese by AI.

一棵行道樹的地下剖切透視,對照兩種做法。左側是常見的錯誤:樹穴只有一米見方,四周被壓實的級配與混凝土基礎包圍,根系無處可去,在有限的空間裡盤繞打結,部分根往上頂起鋪面造成隆起龜裂,樹冠明顯瘦小。右側是正確的做法:樹穴以連通的結構土或土壤細胞向兩側延伸,形成一條貫穿整排行道樹的地下土壤帶,寬度達兩米、深度一米;根系可以自由橫向生長並與鄰樹相連;上方的鋪面由結構層承載不壓實土壤;因此樹冠明顯茂盛。避免:讓兩者看起來相似、只畫地面看不到地下、消除鋪面隆起的對比、讓兩棵樹的樹冠大小相同。