By: Steve Rasmussen
NFS District Forester
With the heat of summer now mostly done, the trees and shrubs will begin to get prepared for the fall and winter months. Fall is a transition time for long lived plants like trees that are switching over from the active growing season to the season of dormancy and maintenance through the winter. With only a couple of months left before a hard freeze for the above ground plant tissue followed by soil freeze-up that shuts down the root systems, it is important to help keep the tree healthy and growing up until the temperatures stop growth for the year. The more energy and water the plant can store up in the fall, the better it will look next spring.
If September and October are dry, then watering young and establishing trees is important during this time to keep the root system healthy and growing up until the ground freezes. Having a good moist soil will keep the roots growing until the ground temperatures drop into the upper 30 degrees. This will allow the roots to keep sending water up to the buds that have already been set for next year and keep evergreen needles hydrated so they do not “winter burn.” Good moisture in the buds (vegetative and flower) will help them make it through the dry winter months. Do not wait until November and right before ground freeze-up since that will not allow the tree time to get the water up to the buds.
Do not fertilize during late fall since that could stimulate green tissue growth in the crown of the tree that would then be killed with an early frost. Wait until the tree is dormant and early spring is a good time for fertilization if needed. Fertilize only if there is a need for additional nutrients for healthy tree growth.
Another good project to do in the fall for trees is to check the organic mulch around the base of the trees. This mulch will insulate the ground and keep the roots healthy going into the winter and starting up growth in the spring. Place the woodchips out to the dripline of small trees or out two to four feet radius on larger trees. Coarse woodchips are the best since they hold in place, allow oxygen to the soil, and decompose over time to introduce nutrients to the soil. Avoid grass clippings since they can mat down. This restricts oxygen to the soil and sheds off the water.
Finally, if you have young trees and there are rabbits or deer that come around your property, you may want to put a cage, a tree shelter or tree wrap around the tree. Deer, rabbits, and rodents will eat the green tissue of plants during the winter months as a food source. Buck deer will also use younger trees for rubbing the velvet off the antlers and to mark their territories. Tree wraps on thin bark trees like maples and lindens can help against potential frost crack damage during the winter months. These wraps should be taken off during the summer.
This is the last Tree Tips column for the year. If you need forestry assistance or have tree questions, you can visit the Nebraska Forest Service website at nfs.unl.edu or contact me at my office number of 402-375-0101. Have a wonderful fall.