The Minnesota Tree Improvement Cooperative has led efforts to improve the quality of tree seed across northern Minnesota and Wisconsin since 1981. Five tree species are utilized in the Co-op: white spruce, black spruce, red pine, jack pine, and white pine. Improved white spruce seedlings grow 25-30% faster than seedlings derived from wild stands. Jack pine seedlings have moderate improvements for height (10-12%) and are vastly improved with respect to stem form. White pine orchards were established with families containing putative rust resistance and improved growth. The Co-op has progressed into second generation material for jack pine and white spruce. Ongoing projects include breeding white pine for improved disease resistance and establishing improved clonal orchards.
The Co-op has focused primarily on improving height growth, but diameter and volume are now being considered in selections. Stem form is a trait used to improve the straightness of tree stems, particularly for jack pine. Wood quality may be improved by increasing branch angles (to reduce the size of branch knots), fiber length (to improve paper strength), and specific gravity (to increase overall volume). These traits may be considered in future selections. A broad genetic base comprised mainly of local material is maintained to ensure genetic diversity and adaptability so that future needs can be met.