Effect in the PNW?
• Predicted warming of 2.7ºF by 2030 & 5.4ºF by 2050
• Changes in precipitation?
• Increased extreme weather events?
(From: Scientific Consensus Statement on theLikely Impacts of Climate Change on the Pacific Northwest, 2004)
How could this affect our gardens?
• Plant phenology changes
• Exposed to new/different pest pressure
R. Bisgrove and P. Hadley. 2002. Gardening in the Global Greenhouse: The
impacts of climate change on gardens in the UK. Technical report online.
What is plant phenology?
Study of cyclic & seasonal natural phenomena
• Bud break timing
• Leaf expansion
• Fall leaf color
• Dry matter
“Future projections suggest that warmer
temperatures, longer growing seasons, and increased
drought severity will stress Douglas-fir that are
adapted to current climate conditions.”
-Considering Assisted Migration for Trees in a Changing Climate on
Effect of climate change on pest problems?
Photo: Griffin Stewart via Flickr CC BY-NC-ND 2.0
1st: Separate the effect of global trade & travel
2nd: Effects on pest phenology?
Increased generations within
a growing season?
Stressed trees are more vulnerable
Many insect species are attracted to stressed trees
Precipitation can increase disease spread
Phytophthora ramorum spread facilitated by heavy
rain events (Rizzo & Garbelotto, 2003)
What will the future hold for our gardens?