Urban Tree Placement Reading
A student is preparing a debate about city heat and finds this passage: “City parks departments often plant trees to cool neighborhoods, but not all planting plans deliver the same benefit. A five-year study compared two streets in one city. Street A received 40 young trees spaced evenly along both sidewalks. Street B received 25 trees planted in clusters near intersections. Both streets had similar summer temperatures before planting. After five years, Street A’s afternoon surface temperature was 3.1°F lower than before, while Street B’s was 1.4°F lower. The researchers noted that Street A’s trees formed a more continuous canopy, shading pavement that would otherwise absorb heat. Street B’s clusters created cooler spots but left long stretches of exposed asphalt. The study’s author cautions that tree survival matters as much as placement: 34 of Street A’s trees survived, compared with 24 on Street B. The author concludes that spreading trees evenly can outperform clustering them, provided maintenance keeps survival high.” The opponent claims clustering is better because mature trees together create shade.
1. State the main idea and cite two numbers that support it.
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Main idea: in the study, spreading young trees evenly along a street cooled the pavement more than clustering them, but survival and maintenance also matter.
Support: Street A’s afternoon surface temperature fell 3.1°F, compared with 1.4°F on Street B. Also, 34 of Street A’s trees survived, versus 24 on Street B.
The passage does not say clustering is useless; it says clusters made cooler spots while leaving exposed asphalt. The author’s conclusion is conditional: even spacing can outperform clustering provided survival stays high.
2. What can be inferred about the opponent’s claim that clustering is better because mature trees together create shade?
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The claim is not supported by this study as stated. The study compared young trees and found the evenly spaced street had a larger temperature drop, because the trees formed a more continuous canopy over pavement. Clustering did create cooler spots, but long stretches of exposed asphalt remained.
However, the passage does not test mature trees, so the opponent could be right about a different age or density. The student should challenge the claim as an overgeneralization from the study, not as a proven falsehood.
3. Explain the meaning of continuous canopy in context.
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It means the tree crowns along the street touch or overlap enough to form a nearly unbroken layer of shade. The passage contrasts this with Street B’s clusters, which left long stretches of exposed asphalt.
Continuous does not mean the trees are the same species or planted at the same height; it refers to shade coverage over the pavement. This coverage helps explain why Street A’s surface temperature dropped more.