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The
Arborist's Report
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Grand Army of the Republic Cemetery Park Tree Inventory and Analysis
The attached spreadsheet, table and narrative includes: No trees are recommended for removal based on current hazard potential. Native trees include Bigleaf maple, Douglas-fir, Pacific dogwood and Mountain ash. Tree Count at GAR Cemetery Park
SUMMER IRRIGATION The young trees are suffering most from lack of summer water, specifically the red maple, sugar maples and the kousa dogwood. I recommend regular supplemental watering through the dry summer months, at least every 10 - 14 days. Water to a soil depth of 12 inches. I
recommend avoid watering near the
cypress trees during summer months.
Pythium and phytophthora, two deadly
soil borne fungi, are encouraged by
summer watering and particularly enjoy
trees in the genus Chamaecyparis.
Mower damage has occurred on the trunks of some of the trees. To avoid this, and to create a more root-friendly growing site, I recommend removing turf in a circle around the trees and mulching with wood chips 3-4 inches deep. As a guide, create the circular turf-free zone as large a diameter in feet as the tree's trunk is in inches. PRUNING RECOMMENDED: WHAT DOES IT MEAN? Pruning is recommended for several trees in the attached spreadsheet. Nearly all the pruning needed is the limited to the removal of dead limbs two inches in diameter and greater. The potential for deadwood falling and hitting a park user is the biggest hazard currently identified by this inspection.
A small handful of trees have included bark at branch attachments. When the bark of adjacent branches or stems is included, it prevents a structurally stronger wood-to-wood attachment. The amount of included bark identified in the inspection is a slight amount for each tree and currently does not pose a significant hazard from failure potential. Monitoring is recommended.
Cherry bark tortrix (CBT) is an insect new to this region. (Attached is a fact sheet that will provide more details about this pest.) The larva of this moth feed in the bark of trees in the genus Prunus. This includes the English laurel along the north of the park, and the Portugal laurel hedge surrounding the cemetery, which are both in the cherry family. The current CBT infestation is limited to the flowering cherry trees. If the population soars, the moth begins to lay eggs in the laurels. There
is currently no biological control
available. The recommended chemical
control is the insecticide Talstar
or Tempo applied to drench the frass
tubes (see fact sheet) during the
first week of October. Repeat applications
are made as needed every 3-5 years.
The elm trees growing in this park are unlike any other elms in the region. According to Arthur Lee Jacobson, who has been studying these trees since the 80's, they are genetically separate individuals and not clones of a single cultivar. Aside from their historic significance in their placement in this park, it is possible that their genetics may play a role in Dutch elm disease (DED ) resistance. Currently Seattle Parks and Recreation Department are treating the elm trees for DED. Some
of the elms prefer to grow low branches
along their trunks. I recommend retaining
some low limbs on these trees, rather
than trimming them clean. |
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