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Name: Emma
Status: student
Grade: 4-5
Location: KY
Country: USA
Date: Fall 2009

Question:
Does it harm a tree to pick its leaves?



Replies:
It will kill a tree if you pick all of its leaves However, one or two leaves won't hurt it.

Here is an article that tries to explain all there is to know about leaves:

http://en.wikipedia.org/wiki/Leaf

Sincere regards,

Mike Stewart


Picking off a few leaves from a normal healthy tree will not have much effect. Squirrels, deer and other animals will remove quite a few leaves with little harm. A small or unhealthy tree that loses a lot of its leaves, for whatever reason, will be harmed.

J. Elliott


If a tree is very large, it should have the capacity to replace a few lost leaves because it is still growing and has stored food resources. However, if a tree is very young and especially if all of its leaves were removed by someone or insect damage or extreme weather events, the removal could negatively impact the tree's growth and survival. Trees regularly lose and replace leaves seasonally (for example, autumn for deciduous trees), so your question would be important in cases when most leaves were lost much earlier than usual (such as with insect damage in cases of very dry conditions (drought)). Insect damage for more than one year and other problems (such as soil and climate conditions) could make a tree more susceptible to disease and decline.

Anthony R. Brach, PhD
Missouri Botanical Garden
c/o Harvard University Herbaria


Emma,

Good question.

You can best think of the leaves of a tree as its small factories where it makes food. The tree uses leaves as the place where sunlight hits, and, using water and carbon dioxide (one of the gases in air), leaves have a special green component called chlorophyll which makes it possible to make sugar. A small tree with few leaves can only make a small amount of sugar. A large tree with many leaves can make a lot of sugar.

In the wintertime, in areas where the weather gets very cold, many trees shed their leaves. During this very cold time of the year, the tree would not be able to make sugar using leaves, mainly because the water that is needed to make food would end up freezing inside thin leaves. In fall, with the arrival of shorter daylight time and colder weather, the tree takes its chlorophyll from the leaves and then lets the leaves fall. New leaves, or food-making factories, will be produced in the spring with the arrival of longer daylight time and warmer weather.

Back to your question. If you pick leaves from a tree, you are removing some of its ability to make food. If there are a lot of other leaves on the tree, and you pick a few, it will not hurt the tree. If the tree is tiny and only has 2 leaves, removing one of the leaves would mean it now only has half of the leaves left where it can make food. Therefore, the leaf picking will probably not hurt the tree unless the tree has very very few leaves.

As I said earlier, many trees lose all their leaves in the fall. Many times you can see very colorful leaves which will soon fall from the tree. Picking those leaves will not hurt the tree at all, because they will soon fall from the tree naturally.

Thanks for using NEWTON!

Ric Rupnik



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