# Why are the leaves still green? **URL:** \ **Category:** In My Humble Opinion\ **Created:** [October 23, 2018, 9:05am UTC](https://boards.straightdope.com/t/why-are-the-leaves-still-green/823375 "2018-10-23T09:05:10Z")\ **Posts on this page:** 17\ **Page:** 1
**Author:** ![panache45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/panache45/32/64_2.png) [@panache45](https://boards.straightdope.com/u/panache45)\ **Post date:** [October 23, 2018, 9:05am UTC](https://boards.straightdope.com/t/why-are-the-leaves-still-green/823375/1 "2018-10-23T09:05:10Z")
It’s late October, and most trees still have green leaves. One exception is my dogwood tree that began to change in late August. In what way is this year different from other years? Is this related to climate change, and is it a permanent change? ---
**Author:** ![PoppaSan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/poppasan/32/189_2.png) [@PoppaSan](https://boards.straightdope.com/u/PoppaSan)\ **Post date:** [October 23, 2018, 9:14am UTC](https://boards.straightdope.com/t/why-are-the-leaves-still-green/823375/2 "2018-10-23T09:14:04Z")
A good many of my leaves have fallen or will in the next stiff breeze. Right about the same 2 week window as every other year. Kids around here tricker treat in ankle deep leaves. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [October 23, 2018, 9:52am UTC](https://boards.straightdope.com/t/why-are-the-leaves-still-green/823375/3 "2018-10-23T09:52:34Z")
Not all plants use the same signal from the environment about when to go into autumn mode. Some use temperature, some the amount of light. So if the temp is warm for this time of year, some plants will have delayed color changing. And yes, global warming will change how late in the year you still get warm temperatures. ---
**Author:** ![Wendell\_Wagner](https://avatars.discourse-cdn.com/v4/letter/w/8491ac/32.png) [@Wendell\_Wagner](https://boards.straightdope.com/u/Wendell_Wagner)\ **Post date:** [October 23, 2018, 11:09am UTC](https://boards.straightdope.com/t/why-are-the-leaves-still-green/823375/4 "2018-10-23T11:09:55Z")
According to several news stories I’ve read, it’s because both the temperatures and the amount of rainfall have been more than usual this year. ---
**Author:** ![senoy](https://avatars.discourse-cdn.com/v4/letter/s/dbc845/32.png) [@senoy](https://boards.straightdope.com/u/senoy)\ **Post date:** [October 23, 2018, 12:55pm UTC](https://boards.straightdope.com/t/why-are-the-leaves-still-green/823375/5 "2018-10-23T12:55:40Z")
Leaf change is impacted by lots of things. Rainfall is certainly one of them. 2015 with its summer drought had an early September change date. This year around here, the rainfall was not intense, but nearly constant, so it took them a long time to leave their growing mode and temps were still very high even two weeks ago. My lawn was still doing spring growth all through August and only tailed into summer growth in September and never hit that golden time when it stops growing and I can put the mower away for a couple of weeks. That said, the high mountains started their shift in early October and the highlands followed a week after, it’ll trickle down to us within a week or two. Next week will probably be peak color in the highlands, maybe another two weeks for us to peek. I just hope they can drop before we get the big freezes and the branches start collapsing. ---
**Author:** ![JohnT](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnt/32/15048_2.png) [@JohnT](https://boards.straightdope.com/u/JohnT)\ **Post date:** [October 23, 2018, 1:30pm UTC](https://boards.straightdope.com/t/why-are-the-leaves-still-green/823375/6 "2018-10-23T13:30:12Z")
Because it’s San Antonio TX and the poor trees here are all stupid and confused, meaning that from October to May we have a situation where _most_ of the trees are green, but there are always _some_ trees which are losing their leaves because of whatever trigger. Makes raking leaves a 6-month chore. ---
**Author:** ![DrFidelius](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/drfidelius/32/3447_2.png) [@DrFidelius](https://boards.straightdope.com/u/DrFidelius)\ **Post date:** [October 23, 2018, 2:09pm UTC](https://boards.straightdope.com/t/why-are-the-leaves-still-green/823375/7 "2018-10-23T14:09:27Z")
The leaves are still green because I live in Florida. The licence plates are changing as expected. ---
**Author:** ![kayaker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kayaker/32/441_2.png) [@kayaker](https://boards.straightdope.com/u/kayaker)\ **Post date:** [October 23, 2018, 2:14pm UTC](https://boards.straightdope.com/t/why-are-the-leaves-still-green/823375/8 "2018-10-23T14:14:53Z")
Comparing pictures of our place on the same day, different years, it is amazing how different everything is. Some years on a certain date the rhododendrons are at their peak, but 5 years ago they were just beginning to bloom and 7 years they were dropping their blossoms. Our dogwoods also differ a lot. Rain patterns are a big contributor I would guess. ---
**Author:** ![zimaane](https://avatars.discourse-cdn.com/v4/letter/z/a3d4f5/32.png) [@zimaane](https://boards.straightdope.com/u/zimaane)\ **Post date:** [October 23, 2018, 2:25pm UTC](https://boards.straightdope.com/t/why-are-the-leaves-still-green/823375/9 "2018-10-23T14:25:40Z")
Same thing here on the east coast. Still mostly green, attributed to very wet weather in late summer/early fall. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [October 23, 2018, 2:58pm UTC](https://boards.straightdope.com/t/why-are-the-leaves-still-green/823375/10 "2018-10-23T14:58:51Z")
Since the answer to this will vary by location, let’s move this to IMHO. Colibri General Questions Moderator ---
**Author:** ![Yllaria](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/yllaria/32/3452_2.png) [@Yllaria](https://boards.straightdope.com/u/Yllaria)\ **Post date:** [October 23, 2018, 3:10pm UTC](https://boards.straightdope.com/t/why-are-the-leaves-still-green/823375/11 "2018-10-23T15:10:29Z")
We’re still getting highs in the mid eighties and the leaves aren’t even thinking of turning. The valley oaks are dropping occasional leaves, but they do that year round. They also drop branches from time to time. ---
**Author:** ![DSYoungEsq](https://avatars.discourse-cdn.com/v4/letter/d/c6cbf5/32.png) [@DSYoungEsq](https://boards.straightdope.com/u/DSYoungEsq)\ **Post date:** [October 23, 2018, 3:57pm UTC](https://boards.straightdope.com/t/why-are-the-leaves-still-green/823375/12 "2018-10-23T15:57:27Z")
[Here is a primer on leaf color changes and leaf fall](https://blog.nwf.org/2014/09/why-leaves-fall-from-trees-in-autumn/). I was just out in California last week. The Eastern Sierra aspens were changing color right on schedule. [Here is a blog of fall color changes in Michigan](http://www.fallcolorblog.com/?p=854). There are suggestions that some parts of the state are seeing early color changes. In short, it would be a gross over-simplification to say that global warming (or anything else) is prolonging greeness in the US this year. ---
**Author:** ![BrickBat](https://avatars.discourse-cdn.com/v4/letter/b/ac91a4/32.png) [@BrickBat](https://boards.straightdope.com/u/BrickBat)\ **Post date:** [October 23, 2018, 4:09pm UTC](https://boards.straightdope.com/t/why-are-the-leaves-still-green/823375/13 "2018-10-23T16:09:54Z")
I note the same thing. While the days were getting shorter ( less sunlight for photosynthesis ) it was unseasonably warm…even hot. I mean, the heat and humidity of summer didn’t break, even slightly, till the 11th or 12th of October here. Not even a little taste of fall till then. The ground was plenty moist from rain, and so the vegetation and foliage was bright green and grew like gangbusters. Arrival of seasonal weather 10 days ago or so, I am seeing the foliage begin to change color. ---
**Author:** ![bob\_2](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bob_2/32/3341_2.png) [@bob\_2](https://boards.straightdope.com/u/bob_2)\ **Post date:** [October 23, 2018, 10:27pm UTC](https://boards.straightdope.com/t/why-are-the-leaves-still-green/823375/14 "2018-10-23T22:27:17Z")
> [@PoppaSan](#): > > A good many of my leaves have fallen or will in the next stiff breeze. Right about the same 2 week window as every other year. Kids around here tricker treat in ankle deep leaves. You do know it’s _trick or treat_, don’t you? You are supposed to be given a choice…🙂 “Give us a treat or we will egg your car.” ---
**Author:** ![Gatopescado](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gatopescado/32/5711_2.png) [@Gatopescado](https://boards.straightdope.com/u/Gatopescado)\ **Post date:** [October 24, 2018, 5:01pm UTC](https://boards.straightdope.com/t/why-are-the-leaves-still-green/823375/15 "2018-10-24T17:01:00Z")
It’s supposed to be 80 here this weekend. :mad: ---
**Author:** ![nightshadea](https://avatars.discourse-cdn.com/v4/letter/n/7ba0ec/32.png) [@nightshadea](https://boards.straightdope.com/u/nightshadea)\ **Post date:** [October 24, 2018, 5:15pm UTC](https://boards.straightdope.com/t/why-are-the-leaves-still-green/823375/16 "2018-10-24T17:15:50Z")
here in the desert the leaves usually freeze on the tree …… ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [October 24, 2018, 6:24pm UTC](https://boards.straightdope.com/t/why-are-the-leaves-still-green/823375/17 "2018-10-24T18:24:27Z")
Trees are applauding the change in US environmental policy (warmer, wetter weather, more C02). IDK