Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Tree leaves in the winter
Name: ethel
Location: N/A
Country: N/A
Date: N/A 

Why do leaves fall off of some trees in the winter?

An interesting question, Ethel. Biologists generally try to explain behavior in terms of a response or adaptation to an environmental challenge. The challenge in this example is thought to be snowfall. The idea is that a massive accumulation of snow in a large tree canopy would lead to mechanical damage or breakage of tree limbs or the trunk. Most deciduous trees (those that lose leaves in fall) have broad flat leaves that catch snow quite well. The advantage of this type of leaf is that they also catch the sunlight well in the summer growing season, allowing efficient photosynthesis to support rapid summer growth. The leaves are not needed in the winter because cold temperatures inhibit the enzymes of photosynthesis and prevent significant growth. Another interesting question is how evergreen trees have adapted to similar environmental challenges using a different strategy. Ask me a about it if you are interested.


Click here to return to the Biology Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (, or at Argonne's Educational Programs

Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory