Which statement accurately describes the best time for tree injections?

Which statement accurately describes the best time for tree injections?

• A. Best on cold, cloudy days
• B. Best when trees are bare
• C. Best on warm, sunny days with leaves
• D. Not affected by weather

Answer: (C)

Tree injections rely on the tree’s vascular system to move the pesticide, so uptake depends on sap flow. Sap movement is strongest when the tree is actively transpiring, which happens on warm, sunny days with leaves. On those days, water and nutrients move upward through the xylem, carrying the injected material to the canopy and other tissues. Cold, cloudy conditions slow sap flow, and trees that are bare and dormant have little active transport, making injections less effective. Weather thus directly affects how well the material is distributed, so the best time is warm, sunny days with leaves.

Tree injections rely on the tree’s vascular system to move the pesticide, so uptake depends on sap flow. Sap movement is strongest when the tree is actively transpiring, which happens on warm, sunny days with leaves. On those days, water and nutrients move upward through the xylem, carrying the injected material to the canopy and other tissues. Cold, cloudy conditions slow sap flow, and trees that are bare and dormant have little active transport, making injections less effective. Weather thus directly affects how well the material is distributed, so the best time is warm, sunny days with leaves.