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By Brian Konrad

Red, green, yellow and orange colours on display

Leaves changing colour, but not all at the same time

Sep 30, 2020 | 11:26 AM

MEDICINE HAT — The fall colours are on display across Medicine Hat, as trees begin to prepare for winter.

The change this year appears to be lasting a little longer compared with other years however.

Craig Renney, the urban forestry foreman with the city of Medicine Hat, says several factors impact when the leaves start to change colour and fall from the tree.

One of the biggest factors is the length of daylight and changes in temperature.

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” When that happens, when the temperatures drop and the daylight shortens, the leaves on these tress stop their food making process. So the chlorophyl in those leaves start to break down; chlorophyl being what keeps the leaves green will break down and then the other colours can come out to orange and yellow and stuff like that” says Renney.

Renney says ash trees are the last to leaf out in the spring and first to drop their leaves in the fall.

But even two trees of the same species can lose their leaves at different rates.

Coniferous trees also shed their needles, and Renney says sometimes they get calls from people concerned when internal needles on spruce and pine trees turn yellow and fall off.