Dead ash trees in a floodplain at Oak Openings Metropark near Toledo, OH. Photo by Kathleen Knight, U.S. Forest Service.

Replacing Dead and Dying Ash Trees

Recently, some of the LMWCC members asked what tree species private landowners should look to plant to replace the ash trees that are currently dying. The question was posed to some of our MDNR Foresters, and the response is below. Thanks to Forester Blair Tweedale for a well-thought response!

In regards to your email, I would plant a mixture of black spruce and tamarack (50:50); with white pine in some areas. Black spruce and tamarack will do well in areas with a high water table. Black spruce thrive in poor soils, but can be found on some richer soil types, along with tamarack. White pine could also do good in certain locations. White pine grows on all soil types, and will do best mostly on the edges of the flood plain and on little ridges throughout. They can survive in higher water table areas also. The following notes should help determine where and how to plant these trees so they survive, and become beneficial to the watershed.

Black spruce is shade tolerant, so you can plant these trees in open sunlight, dead ash snag areas, or somewhat shaded stands. Where we have lost large expanses of our ash, plant a black spruce and tamarack mix, with approximately 8 ft X 8 ft spacing (this will give you about 680 trees per acre) on hummocks or dryer patches, not in standing water. Planting at this volume should result in a fully stocked stand, creating shade along our trout streams in the near future. Deer will not (well, should not) browse black spruce or tamarack. However, planting these trees in areas of thick grasses and sedges will inhibit their growth. I would recommend trimming the grasses around these planted trees 3 feet in all directions. Of course, trimming the grasses would not “control” competition. There are also tree mats (Vispore Tree Mats ) that I have seen used in areas where grasses and sedges are a problem. These add initial cost to a project, but can maximize your seedling growth and survival.

Planting white pine is another option. Planting white pine in areas that are on the edge of the flood plain, and on higher spots (hummocks or ridges) throughout. White pine is much more likely to survive than black spruce and tamarack on areas that are a little direr. However, deer may or may not browse white pine in these areas. I have seen deer browse white pine in some areas, and leave it alone in others. White pine can be longer lived and more readily reproduce naturally. Once large white pine are established on site, expect new seedlings to show up. Sedges and grasses with inhibit the initial growth, but white pine are probably more tolerant to the grass competition. Tree mats would help their initial survival.

A mixture of these three tree species, given the location, would be my recommendation.

Tree mats (bundle of 100): http://www.forestry-suppliers.com/product_pages/Products.asp?mi=16221&itemnum=43586

http://pacforest.com/Item/87

Craft paper mulch mats: http://pacforest.com/Item/85

100’ roll: http://www.gardeners.com/buy/biodegradable-weed-mat/37-434.html

Tree mat staples (box of 1000): http://www.forestry-suppliers.com/product_pages/Products.asp?mi=67411&itemnum=25019&redir=Y

tree-mat

 

Blair A. Tweedale Jr.
Forester
Michigan Department of Natural Resources