Suggestions for collecting and Preserving Leaves
- Seeds - Woods for your study kit are given, below.
Leaves
References: "Introductory Forestry" (4-H 641) pg 7,
11 and "General Forestry" (4-H 642) pg 3
Collecting - The best time to collect leaves
is early to mid-summer when they are full grown, but not yet
full of insect holes, spots, and bumps. Collect the terminal
twigs with at least two leaves, preferably more, from mature
trees in full sunlight. Look the tree over and collect typical
leaves for that species. Collect at least two specimens of each
species and mount the best specimen. Specimens collected in midsummer
are easier to press than those collected earlier (but may have
more damage).
Pressing - Place the leaves between two layers
of newspaper with cardboard or a blotter on the outside of each
paper. Put a heavy weight such as a brick or heavy book on top
of your homemade leaf press. Be sure to change the newspapers
every day or two for at least two weeks because they absorb moisture
from the leaves. If you don't change the newspapers your leaves
may turn dark or spoil. One way to hasten the drying is to place
your leaf press in front of a fan or air conditioner. Another
method used to press leaves is to place the leaves between two
layers of waxed paper and then press them with a hot iron. Sometimes
this makes the leaves smoother and helps them keep their color.
Mounting - Fasten your leaves to paper with
clear rubber cement or strips of transparent tape. Traditionally
we have used herbarium paper (16.5 x 11.5) but many leaves will
fit on regular 8.5 x 11 if you choose to make a more compact,
storable kit. If you make a smaller kit please be aware that
some trees have leaves that are quite large and may not fit well.
However, most leaves will fit and then can easily be kept in
a notebook. When pressing one leaf of each specimen should be
pressed with the underside of the leaf up (so students can see
the back). Cover the front of the paper for protection. Note
- I have been doing some experiments with lamination and it appears
to work very well. We used 3 ml thickness because it bends around
the specimens better than thicker laminate. I have not yet tried
it on samples with thicker stems (like conifers have) and suspect
that these stems might need to be split long-ways to lay them
flat. The laminate holds the sample well, gives some stiffness,
and should delay deterioration considerably. You may want to
affix the sample to a piece of heavy cardboard to keep from bending
and breaking the specimens.
Seeds
Collect several representative seeds from the trees listed.
Collect seeds when they are ripe and dry. Continue to dry after
collection, for at least a week. Seeds collected in the fall
should be stored over winter in a dry place in paper bags or
similar containers.
Woods
Resources:
• Iowa State has an interactive tree ID website
that you might find helpful in preparing your team for the contest
(www.extension.iastate.edu/pages/tree/)
• VPI has put out great forestry/ecology
website for younger 4H’ers, or youth in general (www.ext.vt.edu/resources/4h/virtualforest/)
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