Do evergreens photosynthesize in winter?

Wyatt B. from Hibbard Elementary in Rexburg asks:
Why do evergreens stay green all year round?

Answer…
The reason evergreens stay green all year is not simple. Evergreen trees (trees that keep their leaves year-round instead of losing them all at once) originated in cold, northern climates. In the north, the growing season (spring/summer) is very short compared to that of the south. Trees use light to make food through photosynthesis. In order to survive in the shorter growing seasons, trees needed to gather light all year long. The only way to do this was to gather light for photosynthesis in the winter. (However, trees can only photosynthesize when water is available in a useful form, so when the only available water is snow or ice, even evergreen trees are dormant. They rest until conditions are right for photosynthesis to start again.)

Full answer can be found at http://www.idahoforests.org/ask/trees/f_tf_17.htm?OpenScript=12858

:)

Yes, they do.

@jeffgoldblumsprivatefacilities No they don’t.

Evergreens in cold climates shut down photosynthesis in the winter, so they really aren’t making food all year. They have the advantage of not needing to regrow all of their leaves, but the disadvantage of needing their leaves to be protected from the elements and herbivory, which makes them less efficient at photosynthesis.

@clarice Yes, they do. For many evergreen species, the rate of photosynthesis in evergreen trees is much lower in the winter, because water is less available in useable form. However, when water is available, the chlorophyll in evergreen needles is able to accept light energy and use it in the production of sugars, i.e. photosynthesis.

Edit: Next time you copy and paste what someone else has written, make sure it’s the right answer.

@jeffgoldblumsprivatefacilities. No. what she copied and pasted was right.

“Trees can only photosynthesize when water is in useful form”, meaning that when they CAN do it in the winter they will, but they are usually dormant because ice is not useful water.

EDIT: Next time you bash someone, make sure it isn’t the EXACT same thing you are saying.

@FlutherMe No, they are not just “usually dormant”. Obviously ice isn’t useful for photosynthesis, but what you are forgetting about is groundwater. When temperatures are high enough, snowmelt will accumulate into groundwater, which can then be used for photosynthetic activity. Just because there is ice or snow aboveground, does not mean that evergreen trees have no access to water, and therefore cannot photosynthesize. They are not just in a dormant period throughout the entire winter. When light and water resources are available they will actively photosynthesize, and when they are not, trees rely on carbon sugars from storage.

I didn’t say EXACTLY what @clarice said. She said that evergreen trees don’t photosynthesize in winter, and I said that they do. Saying that resources are limiting, and that photosynthesis is occurring at lower rates than in other months is not the same thing as saying it doesn’t occur at all.

Conifers do undergo photosynthesis in the winter, hence their needle-like leaves being green. The green needles are not green just because they like the colour and it attracts all the ladies.

As the needles on the Conifer are plentiful and very thin, they can attract sunlight more easily in small doses. As far as water goes, the water isn’t frozen all the way down to the centre of the earth, all of the minerals allow it to freeze at much lower temperatures.

The water also must get from the root system up to the leaves to bring up nutrients for the photosynthesis process and transport the sugars produced to parts of the tree that need them. On very cold days, the tree can’t move liquid water from underground up to its needles because the cold air temperature freezes the sap inside its trunk. So in very cold climates, photosynthesis may be on hold a good deal of the time, but whenever conditions allow it, it happens; all year round.

They can, but only in warm spells when the sap can flow, but in deep cold it cannot work. These trees go in and out of dormancy throughout the winter.
As a side issue, sugar maples make their major “sap runs” before the leaves are developed to do anything with the sap. That’s why we can harvest maple without harming the trees in the least.We’re getting ready to start our harvest in about 3–4 weeks. Spouts, tubing, tanks and boilers all needing set up. Helen and Scott Nearing wrote a great book about it “The Maple Sugar Book”

You know, the term depends on your humor. Once you get it, you just make sure that you have not screwed it up.