Plan C: Direct Tree Seeding Under Box Elder Trees
The thick stand of young box elder trees in Research Area C07 was thinned to no closer than 4 feet apart, and the lower branches on the remaining trees were removed to a height of 7 feet to allow the area to be prepared by a small tractor and tiller. The site was tilled in mid September, 2007 and direct seeded to a mixture of Burr Oak, White Oak, Swamp White Oak, Black Walnut, Butternut, Bitternut Hickory, Kentucky Coffee Tree, Ohio Buckeye, Chokecherry, Wild Plum, dogwood, Redbud, Ninebark and False Indigo seeds in late September and early October. Refer to the Minnesota DNR Direct Seeding website for recommended tree species and seeding rates. We seeded 15 bushels of walnuts and 5 bushels of acorns per acre and lesser amounts of the other species listed above based on the site and seed availability. One bushel equals four gallons in volume. The people doing the planting carried buckets of seeds and spread them on the tilled soil. The larger seeds were worked in with the tiller running at a slow speed. The smaller seeds were sown on top of the ground. This winter the Box Elder trees will be treated with Garlon herbicide before they are cut down to prevent resprounting after they are cut down. The trees will be dropped and left on the seeded area. Box Elder trees are native to Minnesota and are a pioneer species in old fields and former pastures. However, they have little wildlife or economic value and when growing in a dense stand will shade out most understory growth, making the soil subject to erosion from flooding. The removal of the canopy will allow sunshine to reach the new tree seedlings and we hope that the tangle of branches from the dropped trees will discourage the deer from browsing the new trees. When tree seedlings become available in the spring of 2008, willow, cottonwood and Tamarack seedlings will be planted. Silver Maple seed will be sown on the area when those seeds are ripe, in June of 2008.
Suggestions
If collecting your own seeds, prepare your seed storage early, as seed collection times can vary from year to year. We use a chest freezer modified with an override thermostat to convert it to a refrigerator and store the early collected seeds at 40 degrees. Oak, dogwood, Choke Cherry, Wild Plum and other early maturing seeds may need to be collected up to 6 weeks before the later maturing seeds are ready. Since some of the larger seeds, including the walnuts, mature later but need to be planted first in a direct seeding, the earlier collected seeds will need proper storage. Scout out seed trees ahead of time. When the acorns and later walnuts begin to fall, you will be in a race with deer, squirrels, lawnmowers and desiccation to gather seeds. Seeds need to be kept moist and cool to maintain viability. Soak acorns in cold water prior to storing to chill and hydrate them. If using a freezer modified to work as a refrigerator, set the thermostat at 60 degrees (or 10 degrees less than the temperature of the acorns if lower than 60 degrees) and lower it 10 degrees each day until you reach 40 degrees. This will allow the cold to spread from the walls of the freezer to the middle where the thermostat sensor is located without freezing the acorns next to the freezer walls. Look for the freezer/refrigerator override thermostat where wine and beer making supplies are sold.
We use a tool called a Nut Wizard to collect acorns, hickory nuts, butternuts and walnuts. The Nut Wizard saves considerable time and effort compared to picking by hand or raking and it is available in several sizes for various sized nuts. It works best on mowed areas, and we found a good supply of acorns and walnuts on lawns, golf courses and cemeteries. Most people are glad give you their acorns and nuts if you pick them up.
If your planting is near an existing forest, squirrels may view your direct seeding as an easy food source. To avoid the loss of planted seeds, provide an even easier food supply by making several piles of walnuts around the edge of the planting. Hopefully the squirrels will take these and leave your planted tree seeds in the ground.