Above is a picture taken from tree, which leafs are turned from green to yellow. The spectrum measured from a yellow leaf can be seen below.

Color coordinates calculated from the spectrum
Spectrum Yellow
x 0.4621
y 0.4727
z 0.0652
X 54.3729
Y 55.6186
Z 7.6711
R 75.1172
G 51.9972
B 7.2235
L* 79.3962
a* 4.0319
b* 81.8294
u' 0.2386
v' 0.5491
u* 42.1979
v* 83.1706

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