Defoliation

alainleon1983 wrote: The thing is I was just very happy of not having kill my tree just yet, but as the winter comes I´ll start to get more and more worry about him.

There's life, so there is hope. Please do understand that what I wrote as a response to Bob is by no means meant to discourage you.

alainleon1983 wrote: Now that the autumn is coming and winter is nearing I would like to know around what temperatures Acer Palmatum begin their dormancy period? I mean

I need to look this one up for Acers to be completely sure, but for most trees temperatures are not relevant when it concerns going into dormancy - it's the light level (days shortening).

[Edit] Should have Googled that... the main factor is day length, but both play a role .
There are differences per tree species (again I would have to look that up, but I'm sure you know how to do that yourself )
For example: we had an early spring and summer (and unfortunately it seems autumn has already started so we're having an early autumn too). The high temperatures did affect many of my trees and plants, they started early. Not all of them, some of them behaved as usual and started growing around the same dates as usual, in colder springs.

BTW here early warm springs can be risky. We have had warm periods in early spring - I think two years ago - but then after that freezing temperatures. I know many bonsai growers lost large parts of their collections due to that.

That is the reason why day length is more important then temperature - as it is a more reliable trigger (temperatures can vary, day length doesn't change from year to year).

[Edit 2] It is actually not the day length, but, as I read: "it is actually the length of the night that is critical, not the length of the day" (Indeed your queston is rewarding, I learn some new things myself too, looking for documentation to support what I write )

thank you alain, i think the length of days usually tells a tree it is dormant, that is how a houseplant goes dormant, when the days shorten the tree realises it has to go dormant, i could be wrong though.

bob wrote: thank you alain, i think the length of days usually tells a tree it is dormant, that is how a houseplant goes dormant, when the days shorten the tree realises it has to go dormant, i could be wrong though.

thx for clearing that up, after Auk gave such a well-researched overview of factors influencing dormancy. :whistle:

I know what you may be thinking,but a funny thing happened with the computer, it went totally crazy and it glitched so not registering any new comments or I went blind fora few minutes but all in all, auks info is way more reliable than mine on this as clearly viewed for a mear second lol!!

Auk wrote:
There's life, so there is hope. Please do understand that what I wrote as a response to Bob is by no means meant to discourage you.

Worry not Auk, I didn't take it that way, it didn't even cross my mind. The concern I expressed earlier is genuine, because I know that my tree still has a long winter to endure and even if I´m happy that doesn't blind me from the fact it is not over yet.

Auk wrote:
the main factor is day length, but both play a role.

And now just came from reading this article you posted and by far, it is the best piece of explanation I´ve ever read about dormancy. Quite technical and instructive. Now I see, for instance, why nitrogen free fertilizer is mandatory in autumn or why daylength (or nightlength for that matter) will remain critical for my trees. Seriously... That was one heck of a reading.

Thanks man!

bob wrote: thank you alain

None need it Jaimin... Just expressing a heartfelt opinion