Sunday, May 22, 2011

Tree Problem 2: A pair of Sycamore Maples

Site: My backyard (NE Portland)
Biases:
+ Maples produce nice leaves. The trees are rather out of the way.
- If I were to plant a maple, I'd likely chose a native. These are in a part of the yard that would be a natural place for an out-building or planting bed, it being a rather flat area.



Tree Characteristics
A pair of Sycamore Maples (Acer pseudoplatanus) growing along the north fence of the property.

Tree Health
New foliage looks healthy. About 60% live crown ratio.

Site Conditions
Residential site, northern aspect, shrub border with no regular irrigation. There used to be a covered shed in maybe 10% of the dripline. No signs of recent no paving, fill, or grade work in the dripline. Slope grade is flat. Crown exposed to prevailing West winds.

Targets
Fence, landscape plants, garage.

Tree Defects
No signs of root rot, exposed roots, or root pruning. Modest lean. Crown defects: moderate co-dominant leaders; moderate crowding with multiple attachments in a few places.


Hazard Rating
Part most likely to fail: leader. Low failure potential at present with limited targets for a hazard rating of 1+1+1 = 3.


Hazard Abatement
Corrective pruning: subordinate one of the leaders. Rationale: tree seems in good shape overall.


Other Recommendations
Long term the two trees seem two close together. Probably the one closest to the wall should be removed to give the other room to grow. When pruned some attention should be paid to establish scaffold branches. There are some gaps in the radial pattern so I tried the trick of making a small incision above a bud to try to induce it to break.

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