Selecting Coniferous Planting Stock for Michigan Soil Management Groups By Lester Bell (Retired), Contact: Melvin Koelling

Soils are one of the most important considerations in selecting forest species for reforestation.  Table I lists the major soil management groups in Michigan.   Used in combination with Table II, planting guides for conifers are given for all soil areas of the state.

If the series and management groups are not known, recommendations can be determined from the texture of the soil profile and the drainage condition in the field.

Fine-textured or imperfectly and poorly drained soils are not normally planted with conifers.  On such soils, herbaceous competition and/or drainage are not favorable for their growth.  Better drained, sandy-textured soils are better adapted for most conifers.

Planting may be desirable under partial overstory, such as underplanting, or interplanting small openings in fairly well-stocked timber stands.  Species of trees recommended for such situations are white pine 2-0, white spruce 2-1, or Norway spruce 2-1.  It is not recommended that underplanting be done unless plans are made for a liberation cutting, depending upon the species of trees in the overstory.

Table I - Soil Management Grouped Identification Chart

*  The (2) group listed in EB-159 has  been sub-divided into Clay Loams (1.5) and Loams (2.5) since both would be undrained for forestry purposes.

Selecting Species for Planting

Table II gives the recommendations for species and minimum age class of planting stock for soil groups.  The first figure following the species for soil groups.

Table II - A guide to the Selection of Coniferous Planting Stock for Various Sites in Michigan

** Scalps-sod removed by hand, plow or planting machine.
*** These well-drained soils from stratified, very fine sand and silts have been shifted from the 2a to 3a group to simplify group relationships.  Austrian pine and red cedar on sites with high pH. Red cedar makes best growth on good loams, but is valuable for cover on alkaline sites.  Scotch pine is used mostly for Christmas trees.  Red pine will not grow well on alkaline soils.  Douglas fir is a poor risk in the upper peninsula due to freezing back of spring growth.

Aspect and Slope

Hilltops and south and west slopes are drier than valleys or north and east slopes.   Moisture requirements of various species of trees must be considered when planting hilly ground.  As a rule, jack and Scotch pine will grow on the driest sites; red pine and Austrian pine on dry but more favorable sites; white pine, white spruce and Norway spruce on the better sites.

Drainage

Drainage, depth of water table, and depth of hardpan are important factors in reforestation.  Poorly-drained sites with heavy ground cover are the most difficult to plant successfully with trees.  In most cases, they should be left unplanted, as potential wildlife food and cover areas.

A cemented layer of sand (ortstein), sometimes referred to as hardpan, occurs in some sandy soils, making them wet in the spring and dry in the summer.  These extreme moisture conditions make it difficult to establish a stand of trees.  Plowing furrows in the summer and planting trees on the furrow slice the following spring is one solution.   Jack pine and white pine seedlings are recommended for reforestation of this site condition and Scotch pine for Christmas trees.

Unstable Soils

Unstable soils, dunes and inland blow holes are common throughout Michigan.  They occur primarily along the shores of the Great Lakes and in dry, sandy plains of Lower Michigan.  Many open areas, smaller than 1/4 acre, or with existing thin cover of dry-land moss, or scattered grasses, do not need site preparation prior to tree planting.   In years of most favorable growing conditions, trees  may be established successfully on larger sandblows with no advance soil stabilization.  However, in most cases, trees will survive better if planted after primary stabilization is assured through the use of mulching materials, establishment of natural or planted vegetative cover, or windbreaks.

Planting beachgrass (Amophila breviligulata) is the cheapest method of stabilization.  About 1,200 clumps of grass per acre are planted in various patterns such as squares, circles or bands, depending on the shape of the blow hole.  On the windward side, close spacings of grass, 18 inches by 18 inches, is recommended, with the rest of the area planted in bands of 2 or 3 rows spaced 20 to  40 feet apart.   Trees are planted after the sand movement has been stopped and before the grass grows thick.

Mulching materials will provide immediate but less permanent stabilization than beachgrass.  Brush, straw, hay or gravel can be used, but vast quantities are required for large open areas.  Brush should be used by laying the butts toward the prevailing wind, and placing the tops over the butts like shingling.  The trees should be planted after the mulch has been placed.

Windbreaks have been used successfully in soil stabilization by planting bands of Jack or Scotch pine trees on the windward side at right angles to the prevailing wind, and at intervals of from 100 to 300 feet.  The intervening spaces are planted after the windbreak trees reach an effective height.