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Another bit of useless information.
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Author:  Penny Ann [ 12 Nov 2018, 22:34 ]
Post subject:  Another bit of useless information.
I love researching things. At the moment, it's all things 'tree'.
So here are some facts -
Warm autumns result in late bud break the following spring.
While day length and temperature are important final triggers, each specie has a minimum cold day time requirement. This is defined as temperatures below 12C, but ideally around 6C. So a warm autumn means the tree will remain dormant longer the following spring, until it has received enough cold days.

Maples, birch, alders, poplars etc have small 'vessels' for transporting sap etc. If these freeze and rupture due to unexpected late frosts they repair easily. So these trees can start rising sap earlier and so leaf up earlier. Oaks, ash, beech etc have large 'vessels', if these are ruptured they cause more damage, so sap rises later. Evergreens, repair damage to existing leaves first to give themselves a head start, before growing new ones.

Trees that flower before getting their leaves, use less energy reserves as the flowers are preformed the summer before. By flowering before the leaves, they make themselves more obvious to any insects while also making wind pollination more effective.

Trees from warmer parts of the world, require a shorter period of less cold days. So where as trees from cold areas may need up to six months of cold weather, some tropical plant require no dormancy period at all.
Author:  daryl [ 12 Nov 2018, 23:27 ]
Post subject:  Re: Another bit of useless information.
Interesting :smallthumb:
Author:  oakrod [ 13 Nov 2018, 08:53 ]
Post subject:  Re: Another bit of useless information.
Warm autumns result in late bud break the following spring.
While day length and temperature are important final triggers, each specie has a minimum cold day time

i am not sure this is true ..i have often brought oaks indoors in febuary to get them to leaf very early ... we are having a mild autum so next year everything as you say should be late budding up next year ..a mild end to winter and warm spring is what gets things going early ..imho... we will all find out next year :)
Author:  Brendan [ 13 Nov 2018, 10:06 ]
Post subject:  Re: Another bit of useless information.
Quote:
.i have often brought oaks indoors in febuary to get them to leaf very early


I assume that worked? I will remember that in February as I have plans for a bunch of oaks this coming summer and need a long growing season.
Author:  Penny Ann [ 13 Nov 2018, 15:29 ]
Post subject:  Re: Another bit of useless information.
The information came from several sources, some from Canada. They have done a huge amount of research with Sugar Maples. Other sources were from the UK, and all scientific papers. I think the important thing is to know how many cold days each tree requires, and since the temperature only has to drop to 12C or less to count as a cold day, us hardy lot most probably don't think of that being cold in winter. It doesn't say whether it's actually days of whether you can count cold hours, it which case it often on rises above 12C for a few hours each day.
Of course it also says that once the tree has had it's cold quota, it will then produce leaves if the temperature goes up.
Interpreting the information isn't always straight forward. I spent as much time last night looking up long words, only to find out there was a much simpler word that I did know, that they could have used.
For example. - gymnosperm ( conifers), angiosperm ( everything else)
Author:  oakrod [ 13 Nov 2018, 15:37 ]
Post subject:  Re: Another bit of useless information.
very interesting ...how many cold days do trees need ?
Author:  John M [ 13 Nov 2018, 19:07 ]
Post subject:  Re: Another bit of useless information.
Penny Ann wrote:
The information came from several sources, some from Canada. They have done a huge amount of research with Sugar Maples. Other sources were from the UK, and all scientific papers. I think the important thing is to know how many cold days each tree requires, and since the temperature only has to drop to 12C or less to count as a cold day, us hardy lot most probably don't think of that being cold in winter. It doesn't say whether it's actually days of whether you can count cold hours, it which case it often on rises above 12C for a few hours each day.
Of course it also says that once the tree has had it's cold quota, it will then produce leaves if the temperature goes up.
Interpreting the information isn't always straight forward. I spent as much time last night looking up long words, only to find out there was a much simpler word that I did know, that they could have used.
For example. - gymnosperm ( conifers), angiosperm ( everything else)


Fascinating information, P.A., and it would be really useful to have access to the sources.
Do you have any web addresses, emails, etc?

Gymnosperms include more than conifers, I think, e.g. cycads.
Angiosperms are not everything else - ferns, mosses, Selaginellas, horsetails, liverworts, are all separate groups.

J.
Author:  Penny Ann [ 13 Nov 2018, 20:07 ]
Post subject:  Re: Another bit of useless information.
Yes, I know I was being a bit general with the definitions, but they are along the right lines for plants used for bonsai. I don't have the links, as I had to download the papers, and I just wiped them after I'd read them, as I had downloaded so many, and a lot didn't give me relevant information, or had been cribbed from other papers.
Author:  John M [ 14 Nov 2018, 19:23 ]
Post subject:  Re: Another bit of useless information.
Classic error! It's so easy to do, asI know from my own experienxce over the years.

Record the sources at the time!

J.
Author:  paulpash [ 14 Nov 2018, 19:45 ]
Post subject:  Re: Another bit of useless information.
https://www.youtube.com/watch?v=breDQqrkikM
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