Western Larch Question

[Alex Harmon]

Would a Western Larch (tree) NOT lose its needles during fall and winter if it was kept indoors? / what causes it to lose its needles(temperature change, change in length of days)? IF YOU KNOW THE ANSWER PLEASE REPLY!!!!!! NOT KNOWING IS KILLING ME!!

[Ely McLaughlin]

That is an interesting question.  I don't think anyone truly knows what cause trees to lose their leaves in the winter, but it is generally explained as a way for the tree to save nutrients that would be wasted if they were being sent to the leaves when there isn't enough light for photosynthesis.  To put it simply, it is mostly because of the shorter days.  That being said, changing day length doesn't explain why fall foliage season sometimes starts in early-September after a freeze, but sometimes waits until mid-month or later if it has been a mild season.  

If you grew a larch indoors and kept it well-lit, I would assume that both of these factors would be eliminated, and the tree would keep leaves year-round, but I also wouldn't want to be the one to get blamed if you ended up having to clean a bunch of needles off the floor.

To further answer your question, here is a short USFS publication on why larch loses its leaves.  It is basically to give it a competitive advantage in nutrient-poor and snow-heavy environments.

https://www.fs.fed.us/rmrs/why-do-larches-turn-yellow

[Pamela Dallaire]

Take a look at this article to learn more about Larches.The needle drop is an adaptation to fire.  Just like deciduous trees go dormant, Larches go dormant during the winter.  I'm assuming it is due to day/night light cycles because spring buds appear at times when they can freeze on the tree, meaning it isn't really responding to the temperature.  It also uses less nitrogen by not staying green all year, allowing it to survive where other trees can't.  Insufficient light affects growth, which is fast during the short summer months, so I don't think keeping one indoors would be a good idea.  I hope this helps.