The thrill of correctly identifying trees can be enhanced by properly collecting leaves to make a tree leaf collection and then mounting them in an exhibit. Some properly prepared collections have survived for over a century in botanical sections of museums.
Obviously, the best time to collect green leaves is early in the leafing season but not so early that immature leaves can confuse the collector. The months of June and July provide the best leaf samples but you can find great leaf samples throughout the summer. To make a fall color collection you have to collect the leaf in autumn. I have seen many beautiful fall color collections.
Collecting the Leaves for a Tree Leaf Collection
When selecting leaves for your collection, avoid leaves damaged by insects, disease or the environment. Try to select leaves of about the same size and shape as a majority of the leaves on the tree. Make sure that the complete leaf is collected.
Remember, simple leaves have only one blade or leaflet. Compound leaves have several to many leaflets. You must know these two leaf characteristics. Please review Parts of a Tree - The Leaf if you need more help on tree leaf and twig structures. Good leaf collections include the entire leaf attached to a small part of the twig with a lateral or terminal bud.
The collected leaves should be handled carefully before being placed in a leaf press (more on this later) for final drying. Leaf specimens can be protected while collecting in the field by placing them between the pages of a magazine. All specimens should be removed from this temporary magazine press as soon as possible and placed in a leaf press. You should have identified and noted each leaf name and these names should follow the specimen until it is exhibited.
Before leaves are prepared for the collection, they need to undergo a final drying and preserving process which can take up to six weeks. The best way to do this is by using a leaf press. The press not only preserves much of the leaf's color and shape, it also reduces moisture to a point where mold and spoilage is minimized.
Students given an assignment to make a leaf collection generally don't have weeks to prepare a collection. However, you must dedicate at least three to five days of "press" time for each leaf depending on its size and moisture content. Leaf exhibits become more attractive as the length of pressing time is extended.
Although I recommend you use a real leaf press for best results, there is a 'low cost' method used to press leaves. This method requires no special equipment and is outlined below. The method does demand a lot of space, a flat surface and a tolerant family.
- Select a flat area on the floor, desk, or tabletop in a room with good air circulation.
- Prepare necessary sheets of unfolded newspaper adequate for the number of leaves you have collected. You want several paper thicknesses per layer between each pressing.
- Place the fresh leaf specimen(s) to be pressed on the first sheet layers. Be careful not to let leaves overlap or wrinkle by overcrowding. Then simply use additional layers of paper between more pressings.
- Cover the top and final layer of newspaper with stiff cardboard or plywood, which has been cut to the same size as the paper.
- Place sufficient weight (books, bricks, etc.) on top of the plywood/cardboard to press leaves flat and hold them in position.
Exhibiting the Leaves
These collected dried leaves are brittle and do not withstand repeated handling or rough treatment. You should keep the leaves in the press until time to mount them on the exhibit board (if that is what you are using). To preserve the beauty of the collection and add strength to the leaves, a clear plastic or acrylic spray finish may be added to them. To do this:
- Place leaves flat on a piece of newspaper or 'butcher paper'.
- Apply the spray in a thin coat to the leaf surface.
- Allow leaves to dry completely between coats and before handling.
- Turn leaves over and apply a thin coat of acrylic spray to underside of leaf.
- Handle sprayed leaves only after they have dried completely.
Either mount your entire collection on an exhibit board or place each leaf on a separate sheet of poster board or art paper (all cut to a size which will hold the largest leaf). Prepare the leaf for mounting by applying several drops of clear-drying glue to the back, place the leaf on the mounting surface and place weight on leaf until dry. Add an attractive label to each leaf and you are done! In the very least you should have included both the common tree name and the scientific name to each specimen (ex: Sweetgum or Liquidambar styraciflua).