Willow removal and tree plantings
The Sharp Leaf Willow tree on the private leasehold on the corner of Bear Street Mall has been assessed by a certified arborist due to deterioration.
The arborist rated the health and location of these trees with a "below fair" rating. Analysis from 2009 onwards indicates that the tree has been showing signs of stress and is in declining state, otherwise referred to as a mortality spiral. The willow is approximately 75 to 80 years old, but the expectation is that it may only survive an additional 3 to 10 years.
The arborist anticipates that the willow will continue down the mortality spiral, and therefore, recommends the removal of the willow during street renewal construction.
The cause for the deterioration is a combination of tree form, tree location, development, and maintenance issues:
The tree has two stems/trunks which have grown together creating a weak and fragile ‘V’ connection (bark inclusion). This is undesirable as there is no room for the tree to grow and expand without the risk of splitting, likely a reason why there is evidence of tree cabling (cabling is installed to help mitigate risk of failure where weak points exists).
There is also a hollow cavity at the base of the tree, where heartwood is slowly disintegrating due to pocket rot. The compacted ground of the adjacent development has restricted area for root development. The structural root plate and the critical root zone was likely reduced and compromised. Wounds have been unable to properly heal due to pruning issues. Flush cuts and subsequent tearing of bark destroyed the trees’ natural defense mechanisms to adequately heal in the past.
The decline of this beautiful tree is unfortunate. The project team hopes the additional plantings will help mitigate the loss.
Bear Street had approximately 25 trees in the original design. The reconstruction project will plant 110 trees, 640 shrubs and 730 grasses and perennials in the irrigated landscape planters. The 37 planters will include about three trees (depending on size of planter), 17 shrubs and 20 grasses. Deciduous trees will be planted instead of coniferous trees planted on Banff Avenue. The soil cells, irrigation and drainage system will help the trees grow quickly and maintain health, which will accelerate the time for the canopy to provide shade and rise above window level.