I did not realize conifers change colors, most all our vegetation is deciduous. The one that I did know about is not grown in your zone. Cryptomeria go from a bronze winter color to green.Cryptomeria color changesCryptomeria.

I asked Copilot about color change mechanisms in conifers and in deciduous plants. Here are the answers. conifers first, deciduous plants further down.

FWIW, they look like different mechanisms to me, but of course, with summaries of such broad topics, the difference might be caused (at least in part) by taking different points of view.

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Certainly! Evergreen conifer forests, which are prevalent in North America, exhibit seasonal changes in canopy color. These variations have been documented using near-surface remote sensing. However, the underlying physiological mechanisms and their implications for photosynthetic uptake have not been fully elucidated. Let’s delve into the details:

1. Independent of New Leaf Production:

• Seasonal changes in canopy color occur independently of new leaf production.
• This means that the color shifts are not solely due to the emergence of new leaves.

2. Tracking Changes:

• The color changes are closely linked to specific factors:

  • Chlorophyll Fluorescence: A measure of chlorophyll activity in leaves.
  • Photochemical Reflectance Index (PRI): An index related to photosynthetic pigments.
  • Leaf Pigmentation: The presence of pigments like carotenoids and anthocyanins.

3. Predicting Photosynthesis:

• At winter-dormant sites, the seasonal changes in canopy color can be used to predict:

  • The onset of canopy-level photosynthesis in spring.
  • The cessation of photosynthesis in autumn1.

In summary, understanding the color change mechanisms in evergreen conifers involves a combination of ground observations, physiological measurements, remote sensing, and predictive modeling. These insights contribute to monitoring and modeling seasonal variations in photosynthetic activity using color-based vegetation indices. If you’d like more detailed information, feel free to explore the research articles linked below:

• Read the full article1
• Additional resource2

Feel free to ask if you have any further questions! 😊

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Certainly! Let’s explore the fascinating process of leaf color change in deciduous plants during the fall season:

1. Chlorophyll Loss:

• During the growing season, leaves produce food for the plant through photosynthesis.
• As temperatures begin to cool, deciduous plants instinctively start shutting down food production.
• Leaves gradually lose chlorophyll, the green pigment responsible for capturing sunlight and converting it into energy.
• This orderly chlorophyll loss accelerates before leaf fall.

2. Carotenoids and Yellow Colors:

• Carotenoid pigments are also lost from the plastids during aging.
• Some carotenoids are retained in the plastids even after chlorophyll is removed.
• This retention produces autumn leaves with yellow colors.

3. Anthocyanin Synthesis and Red Colors:

• Most interestingly, some leaves turn red.
• This vibrant red color results from the active synthesis of anthocyanin pigments just before the leaves fall from the trees.
• About 70% of shrubs and trees at the Harvard Forest produce anthocyanins during leaf senescence.
• The actual shades of red depend on the amounts of anthocyanin, the retention of carotenoids, and sometimes a little remaining chlorophyll.
• Anthocyanins and carotenoids together produce orange hues.

4. Variability and Beauty:

• In some plants, the color production is quite uniform (as seen in hobblebush or blueberry).
• In others, leaves vary between individuals (like sugar maples) or even dramatically within an individual (as in red maples).
• The spectacular display of fall colors is a result of this intricate interplay of pigments and physiological changes.

So, next time you admire the vibrant autumn foliage, remember that it’s not just a random occurrence—it’s a beautifully orchestrated process! 🍂🍁

If you’d like to explore further, you can read more about the science of leaf color change at the Harvard Forest1. Enjoy the seasonal beauty! 😊