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xtremetrees
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I have been trying to read up on leafs and what they do, in particular my interest in leaf longevity. I have been searching forums and saving studies on leaf longevity. I have questions like. "why do leafs fall off the tree on some and other trees keep their leafs, etc.
Here are some of the highlights I found interesting. I will try and credit the authors.
THis is about ferns-- --------------
Jack T. Tessier2 and Matthew P. Bornn
Leaves that developed in the fall and winter had longer maximum life spans than leaves that developed during the summer.
Is this because grow less live longer theory.
It has long been hypothesized that plant species keep green leaves beyond the growing season to serve as a location for storage of nutrients (Monk, 1966)
The benefit of keeping the old fronds through winter is to serve as an energy source for the newly expanding fronds"
Wintergreen species (those that develop a set of leaves in spring and keep them for 1 year until they are replaced with a new set) are of particular interest because they serve as an intermediate phenological strategy between deciduous species (those that keep green leaves only during the growing season) and evergreen species (those that keep green leaves for more than 1 calendar year) (Tessier, 2004)
I did not know there was a wintergreen species. I thought tree were decidious or not. Is wintergreen a new name, classification?
THis is about lodgepole pines.--------
I never thought that altitude may play a part in leaf longevity it seems to.
"Leaf longevity was 38% greater and annual shoot growth increment was 33% less in trees growing at 3200 m than in trees growing at 2800 m elevation.
Leaf longevity ranged from an average of 5 to 18 years in individual trees of lodgepole pine (Pinus contorta Dougl. ssp. latifolia D.K. Bailey) "
18 year old leafs WOW !
So if a tree holds the leafs longer they grow less> Thats funny
In particular has been my question to Guy M in which I questioned, "Why do some leaves drop and some don't, esp on the lower branches.?
His response was, "Its the juvenile inability or characteristic of a tree to produce the abcissic acid to cut the leaf off"
I have tried to disagree with his statement for over a year now.
My conclusion is that I can see how the under story (lower branches) of a large mature tree holds its lower scaffolding leaves during winter but this maynot be a abcissic acid deficiency but rather a natural response of shade intolerance. If shade intolerance is related to abcissic acid then his is right
I got alot of information for free about leafs right here. http://heronpublishing.com/
Here are some of the highlights I found interesting. I will try and credit the authors.
THis is about ferns-- --------------
Jack T. Tessier2 and Matthew P. Bornn
Leaves that developed in the fall and winter had longer maximum life spans than leaves that developed during the summer.
Is this because grow less live longer theory.
It has long been hypothesized that plant species keep green leaves beyond the growing season to serve as a location for storage of nutrients (Monk, 1966)
The benefit of keeping the old fronds through winter is to serve as an energy source for the newly expanding fronds"
Wintergreen species (those that develop a set of leaves in spring and keep them for 1 year until they are replaced with a new set) are of particular interest because they serve as an intermediate phenological strategy between deciduous species (those that keep green leaves only during the growing season) and evergreen species (those that keep green leaves for more than 1 calendar year) (Tessier, 2004)
I did not know there was a wintergreen species. I thought tree were decidious or not. Is wintergreen a new name, classification?
THis is about lodgepole pines.--------
I never thought that altitude may play a part in leaf longevity it seems to.
"Leaf longevity was 38% greater and annual shoot growth increment was 33% less in trees growing at 3200 m than in trees growing at 2800 m elevation.
Leaf longevity ranged from an average of 5 to 18 years in individual trees of lodgepole pine (Pinus contorta Dougl. ssp. latifolia D.K. Bailey) "
18 year old leafs WOW !
So if a tree holds the leafs longer they grow less> Thats funny
In particular has been my question to Guy M in which I questioned, "Why do some leaves drop and some don't, esp on the lower branches.?
His response was, "Its the juvenile inability or characteristic of a tree to produce the abcissic acid to cut the leaf off"
I have tried to disagree with his statement for over a year now.
My conclusion is that I can see how the under story (lower branches) of a large mature tree holds its lower scaffolding leaves during winter but this maynot be a abcissic acid deficiency but rather a natural response of shade intolerance. If shade intolerance is related to abcissic acid then his is right
I got alot of information for free about leafs right here. http://heronpublishing.com/
