FNR 119
forestry & natural resources
WOODLAND MANAGEMENT 
Black Walnut Plantation Management
by Walter F. Beineke Associate Professor of Forest Genetics Department of Forestry and Natural Resources
This report is a state-of-the-art manual for black walnut plantation management based on findings of many individuals over the past 20 years. There are alternatives to some of the recommended practices, but the purpose is to give the landowner a straight-forward set of guidelines that have provided good results under most circumstances. Alternative practices are mentioned where appropriate, but the author’s opinion is the determining factor in cases where one practice is recommended over another. Aggressive black walnut plantation management will produce rapid growth, good form, and marketable products much faster than plantations allowed to grow without intensive culture. A brief summary of black walnut plantation management activities is provided in Table 1.
Site Selection
Site selection should be the first consideration in deciding where to plant walnut. Professional help is a must; black walnut should not be planted without first seeking the assistance of an Indiana Division of Forestry District Forester, a Soil Conservation Service (SCS) professional, or consulting forester. In general, soils should be deep (at least 36 inches), well-drained, and have good moisture-holding capacity. Fertile loams and sandy loams with high organic matter and pH from 6.5 to 7.2 are usually best. Bottom land soils often meet these requirements, but you should be aware of possible detrimental factors in such soils because of flooding, poor internal drainage, and bedrock or gravel deposits close to the surface. Flooding can kill young walnut trees during the growing season. If water remains over the tops of trees for more than 2 days, the trees usually
die. Flooding for 3 to 5 days during the dormant season is tolerated, but logs and other debris will often break or bend trees. Young trees recover rapidly from such treatment, but older trees may sustain permanent damage to bark, providing an avenue of entrance for decay.
Ridgetops, south- and west-facing slopes, and swampy areas usually are poor walnut sites. A soil producing good yields of corn or soybeans may or may not be a good walnut soil, since walnut’s extremely deep taproot utilizes a much greater proportion of the soil profile than does corn or beans.
Some level upland fields may be suitable walnut sites if internal drainage is good. A mottled appearance (alternating spots of gray and brown or orange color) indicates poor internal drainage. In many parts of Indiana and the Midwest, heavy clay layers and fragipans are common in level upland soil. These layers impede drainage and root penetration. On some of the clay-loam soils walnut will grow well with intensive management, particularly weed control. The better Indiana soil types for walnut plantations are listed on page 2.
You should realize that even though a soil type is listed as suitable for walnut, individual fields vary considerably in terms of past soil management, including erosion, compaction, fertilization, liming, drainage tile, etc. Also, other soil types covering fewer than 5 acres might occur and not be listed in county soil surveys. These “inclusions” might be unfavorable for black walnut. Care should be taken to have a soil scientist identify these soils in a potential black walnut planting area. Walnut may be growing in a nearby fence row or woods, but
PURDUE UNIVERSITY COOPERATIVE EXTENSION SERVICE • WEST LAFAYETTE, INDIANA