Crop Tree Management of Upland Hardwoods in West Tennessee

A 40-year-old upland hardwood stand in west Tennessee was selected to test the effectiveness of crop tree management techniques. The stand consisted of 20 acres with each acre having the potential to contain 36 crop trees. Treatments consisted of: 1) a crown release, 2) fertilization (150 lbs. N and 35 lbs. P₂0₅ per acre) and 3) a combined release and fertilizer treatment.

A severe ice storm struck west Tennessee the winter following the study's initiation. Results indicated that release greatly increased a crop tree's susceptibility to severe ice damage and that black cherry (Prunus serotina Ehrh.) was particularly susceptible with only 6 of the original 28 trees surviving the storm.

Covariate analyses were conducted to account for the differences in initial volume among the treatments due to the ice storm. These results showed that cumulative 2 year growth per acre in the combined treatment (46.28 cu. ft.) was significantly greater than growth in all other treatments. Cumulative 2 year growth in the release treatment (39.03 cu. ft.) was significantly greater than growth in the control (29.97 cu. ft.) but not the fertilizer treatment (35.09 cu. ft.). There was no significant difference in cumulative 2 year volume growth per acre between the fertilizer and the control treatments.

Cumulative 2 year diameter growth of white oak (Quercus alba L.) in combined treatment was 0.679 inches followed by the release treatment (0.568in.), the fertilizer treatment (0.468 in.) and the control (0.3955 in.). All means were statistically different. Basal area growth followed a similar pattern: combined treatment 0.0801 sq. ft., release treatment 0.0664 sq. ft., fertilizer treatment 0.0532 sq. ft., and the control 0.0440 sq. ft.

Cumulative 2 years diameter growth of southern red oak (Quercus falcata Michx.) in the combined treatment (0.787 in.) was significantly greater than growth in all other treatments: release (0.560 in.), fertilizer (0.550 in.), and control (0.433 in.) Basal area growth in the combined treatment (0.0960 cu. ft.) was also greater than growth in the other treatments: release (0.0648 sq. ft.), fertilizer (0.0650 sq. ft.), and control (0.0458 sq. ft.).

Crop tree management concepts, as developed in this study seem to have far ranging practicality for non-industrial forest landowners. These concepts can be easily conveyed to the landowner and tailored to meet his/her management objectives.