Sunday, May 22, 2011

Tree Problem 4: A European White Birch

Site: E side of my backyard (NE Portland)

+ One of the few trees on this side of the house. Probably is a nice tree for the neighbor providing shade and screening from the East.
- It and the fence are trying to occupy the same space. It wouldn't be so nice for the neighbor if the tree chopped their house in half.

Tree Characteristics
Presumably a volunteer European White Birch (Betula pendula) a young-mature tree with a single trunk DBH 7". Live crown ratio is around 40%.

Tree Health
New foliage looks healthy. No significant signs of decay.

Site Conditions
Residential site, tucked between the top of a 1 foot retaining wall and a wooden fence, shrub border with no regular irrigation. No signs of recent site disturbance, no paving, fill, or grade work in the dripline. Slope grade is dominated by the retaining wall and otherwise mostly level. Protected by houses on the East and West.

Two houses, fence, landscape plants, retaining wall.

Tree Defects
Very constrained root space to the West by the retaining wall. Some exposed roots running parallel to the fence. Notch in bark about 1 inch deep and wide at top of fence.

Hazard Rating
Part most likely to fail: root failure. Moderate failure potential on moderate parts with significant targets for a hazard rating of 2+2+4 = 8.

Hazard Abatement
Remove tree. Rational: It seems unlikely the tree roots will be able to provide much anchoring against a strong West wind once the crown gets well established above the roof line. The biggest risk would be a fall storm before leaf drop.

Other Recommendations
There might be time to wait, but it doesn't seem like there is much prospect for this becoming a well adapted tree and the longer we wait the greater the exposure to the environmental causes and the more potential energy for damage should it fail. That said, it is a pretty tree.

1 comment:

  1. Our poor birch tree. Looks like most of our trees are doomed.