All trees produce leaves with individual life spans. Evergreen means there is a substantial coverage of leaves throughout the year. It does not mean each leaf remains on the tree indefinitely. Since the shoots grow out from the center of the tree, the youngest leaves are on the outside and the oldest on the inside of the canopy. That is why conifers such as pine trees have leaves on the inside that turn yellow etc. and drop each year, to leave the innermost portions eventually more or less completely bare of leaves.

"no conifer holds its needles more than 3 years..."

I know this should be true since I read it on the internet

I know this has to be true since it was posted by Ken on G-web

But my brain is flashing Pinus aristata. But I could be wrong. It is old (my brain) !

Here is a link that might be useful: find your own due diligence

*few* conifers hold their leaves more than 3 years

Besides P. aristata, Araucaria and Sciadopitys come to mind.

no conifer holds its needles more than 3 years... Great example of what I call a "scroll-worthy" post.
It seems to me like posters with such a gigantic knowledge deficit might be better off to listen, read and learn.

soo.. wizards of smart.. the ones you mention.. hold their needles forever??? .. they are evergreen forever???? isnt that the premise of OPs post????

i ALWAYS ... get in trouble when i posit an absolute ... let me rephrase.. what i meant to say:

MOST conifer lose there needles within one to 3 years ...

crikey..

ken

ps: and i thought you all would argue over this part: the word evergreen.. is a description.. not a botanical term

Sometimes, usually...something like that. I take part in my fair share.

At least you take the time to get the conversation going vs flaming others.

Why one would tell someone to keep their mouth shut due to knowledge defecit on a forum is beyond me.

This is the very reason others don't post. We are here to learn from each other. We need participation whether it be absolute or not.

Pinus longaeva has the longest-lived needles, with 45 years needle retention recorded.

Lots of other conifers have up to 5-10 years retention, and a few up to 20-30 years. In general, needle retention is longer in high altitude / cold climate conifers, and in shade-tolerant conifers; and shorter in warm, moist climates, but there's plenty of exceptions to the general rule.

Resin

My experience is:
1-araucarias drop lower branches, not leaves, every 2-3 years
2- I am still waiting for my kauris to drop a leaf. They are going to be 3 years old in january
3- Juniperus chinensis - kaizuka - drops very few, small branches and only when shadowed, the same for my sequoiadendrum, cupressus sempervirens, spruces
4- All the pinus I have drop last year or older leaves after summer,
5-larch, metasequoia and bald cypress are not evergreens in this sense, they can, or can not, drop all leaves depending on the climate during winter.

but even if they hold them 45 years...

one can presume.. they lose needles every year ... and some years are worse than others, for a variety of reasons .. etc????? .. right????

and the bean thought they asked a simple question ... lol ...

ken

If a Pine has a good growing season it will drop a lot of needles three years later or whatever the retention time for that species is.
Bad growing season, then less needles drop two or three years later. Lots of reasons for the variability of needle drop, but I believe usually this to be the main one.
Mike

In a conifer (or other tree) that grows from dormant buds formed the previous year, good growing conditions when the bud is being formed produce lots of leaves or needles for the following growth year.
When that cohort of needles reaches the end of its life, there are simply that many more needles that can fall together.