The vascular cambium is a thin layer of dividing cells. What does it produce?
- Heartwood toward the inside and cork toward the outside
- Phloem toward the inside and xylem toward the outside
- Xylem toward the inside and phloem toward the outside
- Bark toward the inside and pith toward the outside
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C. Xylem toward the inside and phloem toward the outside
The cambium lays down new xylem (wood) on its inner side and new phloem (inner bark) on its outer side, which is how the trunk grows in girth. The reversed order is a common mix-up.
Reference: Arborist certification study guide: Tree Biology (meristems)
How deep should a tree be planted?
- So the trunk flare is at or just above grade
- So the top of the root ball is 4 inches below grade
- So the lowest branch is level with the finished grade
- So the graft union is buried at least 2 inches deep
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A. So the trunk flare is at or just above grade
The trunk (root) flare should be visible at or just above the soil surface, with the ball resting on undisturbed soil. Planting too deep is a leading cause of decline and girdling roots.
Reference: Arborist certification study guide: Installation and Establishment (planting depth)
Where should a support cable generally be installed between two codominant stems?
- At the very tips of the stems, in the smallest sound wood
- About one third of the distance from the union to the branch tips
- Directly through the union, at the point where the stems meet
- About two thirds of the distance from the union to the branch tips
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D. About two thirds of the distance from the union to the branch tips
Placing the cable roughly two thirds of the way up gives good leverage while still anchoring in wood large and sound enough to hold the hardware. Rods, not cables, are installed at or near the union.
Reference: ANSI A300 (Part 3) Supplemental Support Systems; arborist study guide: Cabling and Bracing