[CANUFNET] Norway Maples

[Alison Bond]

The main street in Collingwood was revamped in the early 80's and planted
mainly with Norway maple and littleleaf linden (with a few honeylocusts and
red oaks).  Many of the original lindens are still in existence while
several of the maples have been replaced (with more Norway Maples.)  Over
the past two growing seasons, there has been a dramatic decline in nearly
all Norway maples (across age classes) with some lindens also affected.

There is evidence that salt has played a role because many of the cracks in
the trunk (which in some cases continue into the heartwood) are on the side
exposed to the road.  The droughts experienced recently would likely
exacerbate any problems with salt in the soil.  Other symptoms among Norways
include small leaves or no leafing out in the spring with entire limbs being
affected while other limbs appear relatively healthy.  The leaves tend to
have scorched margins if they aren't completely brown.  A few maples are
also heavily infested with powdery mildew.

Has anyone else seen such a dramatic decline in Norway maples?

(The lindens that are affected have similar symptoms in the canopy but
typically show no cracking of the trunk - which is funny because I thought
lindens were less tolerant of salt than Norway Maples.)

Any help would be appreciated.

Thanks.
Alison

Landscape Architect / Arborist
Envision-Tatham
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