Trees and Picking Leaves
Date: Fall 2009
Does it harm a tree to pick its leaves?
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:
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.
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
Anthony R. Brach, PhD
Missouri Botanical Garden
c/o Harvard University Herbaria
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
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.
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Update: June 2012