Download A study of growth initiation timing in coast - Kevin Ford

Will changes in phenology track climate change?
A study of growth initiation timing in coast Douglas-fir
Kevin R. Ford ([email protected]), Constance A. Harrington, Sheel Bansal
USDA Forest Service Pacific Northwest Research Station
Introduction
Plants require more forcing at low chilling
• The timing of annual growth initiation in plants has large
impacts on species distributions and ecosystem function,
and is sensitive to climate
• Warmer spring temperatures that trigger the beginning
of growth and have generally led to earlier growth
initiation in temperate plants
• But many species also require exposure to cool
temperatures (“chilling”) as well as warm temperatures
(“forcing”) during the winter/spring to initiate growth in
sync with favorable climatic
conditions
• Warmer winters could disrupt
this process and prevent plants
from tracking climate change
Photo credit: Teresa Vail
Study design
turtle
We studied height- and diameter-growth initiation
timing in coast Douglas-fir by combining data from 9
climatically diverse field sites (where plants experienced
medium to large amounts of chilling) and greenhouse
studies (where we manipulated the amount of chilling
plants experienced from low to medium).
Study map
Height-growth initiation:
Diameter-growth initiation:
Climate change and phenological
responses together determine growing
conditions plants experience
𝐶γ
w= γ
β + 𝐶γ
ln 𝐹 = 𝑎 − 𝑏ln𝐶
𝐹 = 𝑎1 − 𝑏1 𝐶 1 − w +
𝑎2 − 𝑏2 𝐶 w
𝑑𝑠𝑎𝑓𝑎𝑠𝑑𝑓𝑎d
𝑑𝑠𝑎𝑓𝑎𝑠𝑑𝑓𝑎d
Climate change affects growth initiation
timing differently across the range
Calculating chilling and
forcing units
Conclusions
𝑑𝑠𝑎𝑓𝑎𝑠𝑑𝑓𝑎d--
• In the higher latitude/elevation portions of the
coast Douglas-fir range, climate change will likely
lead to earlier growth initiation, with plants tracking
shifts in the onset of favorable climatic conditions
• However, towards lower latitude/elevation range
limits, climate change could lead to delayed growth
initiation and plants failing to track shifts in the
timing of favorable conditions
• These maladaptive phenological responses could
reduce the resilience of coast Douglas-fir to climate
change near the warm edges of its range
My website: kevinford.weebly.com