Nature’s Notebook

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Photo for species Acer_rubrum

This is one of the species in our North American forests that provides brilliant autumn coloring. The sap from this plant is suitable for syrup production, though the tapping season is shorter than sugar maple because of its earlier flowering.

Photo Credit:
© Elaine Haug, USDA-NRCS PLANTS Database. Courtesy of Smithsonian Institution, Dept. of Systematic Biology, Botany.

Acer rubrum

red maple
What does this species look like?
What does this species look like?: 

Red maple is a deciduous tree growing 30 to 90 feet tall. Its tiny, usually red, male and female flowers mostly occur separately on the same tree but occasionally can occur on different trees.

Red maple is often found in swamps and on moist soils, but can also thrive in drier habitats. It occurs on moist soils along stream banks, and in swamps, moist to drier woodlands, and occasionally on dry rocky hillsides and sand dunes. It is moderately shade-tolerant.

Where is this species found?
States & Provinces: 
AL, AR, CT, DC, DE, FL, GA, IA, IL, IN, KY, LA, MA, MD, ME, MI, MN, MO, MS, NB, NC, NH, NJ, NL, NS, NY, OH, OK, ON, PA, PE, QC, RI, SC, TN, TX, VA, VT, WI, WV
Special Considerations for Observing

 If drought seems to be the cause of leaf color or fall for a plant, please make a comment about it for that observation.

This species has separate male and female flowers. If you know whether the flowers you are observing are male or female (or both), please make a comment about it for that observation.

Note that individuals of this species with only male flowers will not produce fruit.

Which phenophases should I observe?
Leaves

Do you see...?

Breaking leaf buds
One or more breaking leaf buds are visible on the plant. A leaf bud is considered "breaking" once a green leaf tip is visible at the end of the bud, but before the first leaf from the bud has unfolded to expose the leaf stalk (petiole) or leaf base. For Acer rubrum, leaf tips may appear reddish.

How many buds are breaking?

Less than 3;3 to 10;11 to 100;101 to 1,000;1,001 to 10,000;More than 10,000

More...

Leaves
One or more live, unfolded leaves are visible on the plant. A leaf is considered "unfolded" once its entire length has emerged from a breaking bud, stem node or growing stem tip, so that the leaf stalk (petiole) or leaf base is visible at its point of attachment to the stem. Do not include fully dried or dead leaves.

What percentage of the potential canopy space is full with leaves? Ignore dead branches in your estimate of potential canopy space.

Less than 5%;5-24%;25-49%;50-74%;75-94%;95% or more

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Increasing leaf size
A majority of leaves on the plant have not yet reached their full size and are still growing larger. Do not include new leaves that continue to emerge at the ends of elongating stems throughout the growing season.

What percentage of full size are most leaves?

Less than 25%;25-49%;50-74%;75-94%;95% or more

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Colored leaves
One or more leaves show some of their typical late-season color, or yellow or brown due to drought or other stresses. Do not include small spots of color due to minor leaf damage, or dieback on branches that have broken. Do not include fully dried or dead leaves that remain on the plant.

What percentage of the potential canopy space is full with non-green leaf color? Ignore dead branches in your estimate of potential canopy space.

Less than 5%;5-24%;25-49%;50-74%;75-94%;95% or more

More...

Falling leaves
One or more leaves are falling or have recently fallen from the plant. More...

Flowers

Do you see...?

Flowers or flower buds
One or more fresh open or unopened flowers or flower buds are visible on the plant. Include flower buds or inflorescences that are swelling or expanding, but do not include those that are tightly closed and not actively growing (dormant). Also do not include wilted or dried flowers.

How many flowers and flower buds are present? For species in which individual flowers are clustered in flower heads, spikes or catkins (inflorescences), simply estimate the number of flower heads, spikes or catkins and not the number of individual flowers.

Less than 3;3 to 10;11 to 100;101 to 1,000;1,001 to 10,000;More than 10,000

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Open flowers
One or more open, fresh flowers are visible on the plant. Flowers are considered "open" when the reproductive parts (male stamens or female pistils) are visible between or within unfolded or open flower parts (petals, floral tubes or sepals). Do not include wilted or dried flowers.

What percentage of all fresh flowers (buds plus unopened plus open) on the plant are open? For species in which individual flowers are clustered in flower heads, spikes or catkins (inflorescences), estimate the percentage of all individual flowers that are open.

Less than 5%;5-24%;25-49%;50-74%;75-94%;95% or more

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Pollen release
One or more flowers on the plant release visible pollen grains when gently shaken or blown into your palm or onto a dark surface.

How much pollen is released?

Little: Only a few grains are released.;Some: Many grains are released.;Lots: A layer of pollen covers your palm, or a cloud of pollen can be seen in the air when the wind blows

Fruits

Do you see...?

Fruits
One or more fruits are visible on the plant. For Acer rubrum, the fruit is two joined seeds in a "V" shape, each seed having a wing, that changes from green or red to tan or brownish and drops from the plant.

How many fruits are present?

Less than 3;3 to 10;11 to 100;101 to 1,000;1,001 to 10,000;More than 10,000

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Ripe fruits
One or more ripe fruits are visible on the plant. For Acer rubrum, a fruit is considered ripe when it has turned tan or brownish and readily drops from the plant when touched.

What percentage of all fruits (unripe plus ripe) on the plant are ripe?

Less than 5%;5-24%;25-49%;50-74%;75-94%;95% or more

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Recent fruit or seed drop
One or more mature fruits or seeds have dropped or been removed from the plant since your last visit. Do not include obviously immature fruits that have dropped before ripening, such as in a heavy rain or wind, or empty fruits that had long ago dropped all of their seeds but remained on the plant.

How many mature fruits have dropped seeds or have completely dropped or been removed from the plant since your last visit?

Less than 3;3 to 10;11 to 100;101 to 1,000;1,001 to 10,000;More than 10,000

More...