The Effect of Temperature on the Leaves of a Maple Tree

Fall Color

• As days shorten and nights lengthen, maple leaves cease to produce chlorophyll, which gives them their green color. The remaining pigments are red, purple and orange. Warm fall days increase the amount of sugar produced in the leaves. Cool fall nights slowly cause the leaf veins to close, causing sugar to remain in the leaves. The combination of warm sunny days and cool fall nights creates fiery color.

Dormancy

• In late fall, temperatures continue to drop. Veins in the maple leaves that carry water and nutrients completely close and the leaves die and drop to the ground. The tree enters dormancy, a state that allows it to rest and avoid damage from winter weather and freezing temperatures.

Spring

• Look at the branches of a maple tree, and you'll notice tiny, hard buds. As the temperature increases and days become longer in the spring, growth regulator hormones are sent to the buds. The buds begin to swell and slowly unfurl, forming new leaves, in response to warm, spring temperatures and sunlight.

Seasonal Variances

• Fall colors may vary slightly from year to year, depending on environmental conditions. A warm, wet spring followed by a mild summer and warm fall usually leads to the best fall foliage. During periods of drought, foliage may be less spectacular. An early fall storm may kill maple leaves before they reach the height of the color change. Late spring frosts or cold weather may delay the appearance of new leaves.

Varieties

• Maple trees vary widely in fall color foliage, depending on the variety of the tree. Crimson King, red maple, vine maple, Japanese maple and amur maple have leaves that range from yellow to orange or red. Plane tree maple, sugar maple and silver maple have fall foliage that is typically greenish yellow to brown. When selecting a maple tree, consider fall foliage, as well as the tree's adaptability to growing conditions in your area. Silver maples, for example, do not tolerate alkaline soils and are prone to branch breakage.