wwcd101

a quick question about trees and fall.

if you took a 5 year old maple tree from a back yard in Indianapolis and planted it in a greenhouse, kept year round at a constant temperature of 70 degrees f., would it continue to lose its leaves each fall?

thanks for listening.

the_marq

Yes it would. Its my understanding that trees regulate the seasons based on the hours of daylight, not so much the temperature of the air. So if you grew it in your basement with no natural light, you might have better luck. Assuming of course you want to invest in grow lights and the like.

However, there is still no gaurantee. Most trees need to go thru a winter/summer cycle to grow properly, so you might just kill it.

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Sargeman

It's called photosynthesis. Vegetation react to it and that's how they know when fall and spring come around.

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saltfish

It's more an issue of photoperiods rather than photosynthesis itself. Yes you do need the photosynthesis the entire time, though the periods of light are the determining factor in the trigger of 'de-leafing.'

-SF

wwcd101

So it's a light thing, not a temperature thing! And, see if i've got it right, if you kept light constant the tree wouldn't experience "fall" but the leaves would fall off, because it is likely to die.

Basically, one way or another, it appears the tree needs a nap.

Thanks for listening.

Sargeman

You're right. Thank you for correcting me.

Photosynthesis is the process of synthesizing water and CO2 using light. While photoperiod is the duration of the tree or other vegetation to the light.



Temperature does play some part in it.

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theburner

You can fool plants, but in some cases it will take a pretty decent amount of power.
I had a buddy that used to fool plants into thinking it was spring time for 2 months, then early fall for one month. All of this done indoors.

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teopatl

as Sargeman pointed out, photosynthesis requires CO2 and water. Water comes from the ground...if the ground freezes, water can't be obtained, and the tree can't support leaves with food.

...I think...makes sense anyway.

runtuff

I believe the loss of leaves and the vibrant colors of fall are caused by the colder temperatures killing the chloroplasts in the leaves which contain the chlorophyll. When the green of the chlorophyll is gone the other vibrant colors are seen.

saltfish

This is totally a chicken and egg situation. The places on our globe that experience a seasonal change in photoperiod are the same places that will get very cold. The idea behind having less direct sunlight for a part of the year tends to leave an area colder than where there is a longer photoperiod with more intense light.

Naturally, places near the equator that see the same amounts of light all year long, often do not have an abundance of trees that shed their leaves on a seasonal basis. We can chalk this up to an evolutionary process. Plants in those latitudes take advantage of the constant photoperiod by growing sturdy leaves that are used all of the time.

So you say, a tree is losing it's leaves b/c it's cold, well kinda, you say that a tree is losing it's leave b/c of the shortened photoperiod, well kinda. What are you are witnessing is an organism, per se, that has evolved in a very efficient way to allow itself to survive in the best way that is has found in the adverse conditions that are presented to it.

-SF

gonadman

If I remember my Botany correctly, the chloroplasts die because the tree forms a barrier at the base of the leaf, obstructing the flow of nutrients. I'm not sure if the temps or the light trigger this barrier, but I tend to think it is the light.

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LeviticusMky

Trees are tough buggers, but they definately evolved for the outdoors.

Bonsai trees are great for those of us who have a green thumb, but most species of Trees will die in less than 2 months if kept indoors. Only the really hearty ones can live inside, and then only if they get a lot of sunlight and water. They all go dormant for the winter though, regardless of the fact that it's a comfortable 70 degrees in the house all the time.

Sucks that I live in an apartment cause I don't have an outdoor area during the winter!

Stompy

If I'm not mistaken, it depends on the length if time light is applied to the plant (or tree, in this case).

If you had sufficient lighting and a decent temperature, I don't see why it wouldn't perpetually continue to grow under 24/7 light. The second you start changing things up... say, 12 hrs light, 12 hrs dark, THEN the plant will change it's behavior because it thinks it's a different season.

From what I know of plantlife, you could, hypothetically, take a tree from a cold climate, put it in a greenhouse, apply 24/7 light and a proper temperature, and it will just grow as if it was summer forever.

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klo

o so basically its all dependent on light.. so if u gave it 2 hours of light a day... itd be like oging through winter everyday...

wwcd101

It looks as if we have come full circle on this discussion.

Is the concensus then that if we could mimic midsummer temperature, light and water conditions for extended periods of time, we could keep certain hardy varieties of trees in perpetual "summer"?

Less hardy trees would simply die.

It might be fun to try with 3 or 4 trees, if you had the space and the time and the greenhouse.

Thanks for listening.

braindamage351

Actually it's just a matter of survival. If the leaves start becoming a liability instead of helpful they are dropped. When there is too little light the tree drops them to make it to a time when there is light again. Temperature and time has nothing to do with it.

xepherys

Actually, it's at least equal parts light and temperature. There are certain regions that have much more drastic (or much less drastic) changes in daylight lengths, but still have seasons as viewable by deciduous foliage.

Also note that a VERY cool dip in early fall will trigger leaves to change much more quickly (happens in Michigan every few years). On a simliar note, warm spurts early in spring will cause trees to bud pre-maturely. Some trees will actually drop their buds when it starts getting frosty again, only to produce new buds when it resettles into a warmer season.

Braindamage351 - I can't say I agree with your argument at all. The leaves change color and eventually drop as a result of the sugar-process slowing. The trees could viably live with leaves year-round, but the leaves don't have the nutrients to carry on. The tree could care less about the leaves, which happens to be why they die. The tree would carry on regardless.

rfra3645

mmm sounds like red hair ......sticky stuff....