"Have you noticed street trees looking oddly sad? You’re not alone. Normally,
spring means fresh green leaves and flowers. But this year, the heat has come
early, stressing some trees.
But there’s more going on – insects are on the march. Many eucalypts are
showing signs of lerp or psyllid attack. These insects hide underneath leaves
and build little waxy houses for themselves. But as they feed on the sap, they
can give the leaves a stressed, pinkish look. When they appear in numbers – as
they are this year – they can defoliate a whole tree with a serious
How did we get here? Milder, wetter summers during three successive La Niña
years mean boomtime for insects. This year, we’ve had a warm winter and a warm
spring, meaning insects are up and about early and in large numbers.
This summer will be an El Niño, which usually means drier and hotter weather
for most of Australia. For those of us interested in urban trees, these
conditions are troubling.
But it’s more than that. The fact our urban trees are in danger should tell us
something – we need to value and protect them better. As the world heats up,
our urban forests will be even more at risk."
*** Xanni ***
Chief Scientist, Xanadu
Partner, Glass Wings
Manager, Serious Cybernetics