Acorn Collection Protocol
Authors: Cavender-Bares Lab; Updated: April 2019 by Cathleen Lapadat; Associated Project: FAB-ACE
Goals
We are a collaborative group of scientists interested in establishing a series of common gardens with Bur Oak (Quercus macrocarpa) seedlings across a latitudinal gradient to test for genetically based variation among families and populations and determine the physiological adaptations of these trees to climate.
Numbers of acorns, trees and locations
We are aiming to collect more than 160 acorns from each of 20 mother trees in each of four regions (Minnesota, Illinois and Oklahoma). For each region, we need 160 x 20 = 3,200 acorns.
In each region, 20 trees should be selected from four or five different sites, such that seeds from an individual tree are unlikely to have the same father (>20 m apart). It is important to put acorns from one mother tree in an individual bag and label it by site and mother. At the location of each tree, please record the geographic coordinates (latitude and longitude); google map coordinates are sufficient. Take photos of each tree, if possible. If you are in doubt about the identify of the tree, please send a pressed specimen from the tree for us to verify identification.
How to collect acorns
Acorn viability is greatest when mature acorns are collected directly from the tree. If they are freshly fallen, they will still be viable. If they have been on the ground a while, they are likely to be infested and rotting on the inside.
Acorn storage
Collect and store acorns, if possible, in very light weight plastic bags. These should be thin enough to allow the acorns to “breathe”. Freezer bags tend to be too heavy. Paper is not recommended because it will allow acorns to dry out, and they are also likely to rip with moisture/condensation. Remove the caps of the acorns after collection to allow aeration and prevent rotting. Acorns can be stored in the refrigerator (~6oC) until you are ready to ship them. If you are storing them for several weeks or more before shipping them, it helps to put them in slightly damp sterile sand.
Leaves for DNA extraction/Branch Specimens for Identification
Please send one or more fresh, healthy leaves from each tree for DNA extraction in the JCB lab. These should be kept refrigerated until shipping.
If you have time, you may also wish to send pressed specimens. To make a pressed specimen, snip a branch with 5-10 leaves (preferably a sunlit branch) and place it in between 2 or more sheets of newspaper (or other paper). Use a standard herbarium press or simply pile heavy books on top until the specimen is flattened and dry or can be bound to send. Sheets can be trimmed to be the size of standard printer paper (8 x 10”). One specimen from each tree would be ideal, one specimen per site would be a good idea.
Labeling system
Each bag should contain acorns from only one mother tree. It should be labeled with the state, site name, species name and the tree number that you have assigned it.
Specimens should be labeled with permanent marker using the same label.
Shipping
To FedEx acorns, check bill recipient on the FedEx form and enter account number 1081-3386-4. If you prefer we can email you a printable FedEx label, if you provide us with your address and the approximate weight of your box. Specimens can be sent via snail mail and we will reimburse costs.
Send to:
Jeannine Cavender-Bares
Dept. of Ecology, Evolution and Behavior
100 Ecology Bldg
1987 Upper Buford Circle
Saint Paul, MN 55108
Questions?
Email: Jeannine Cavender-Bares
at cavender@umn.edu
612-624-6337 (office)
or contact:
Cathleen Lapadat
nguye618@umn.edu