Fifteen seed sources of black walnut were planted at Manhattan, Kansas (39.2°N and 96.5°W) in 1967, the western edge of its natural range. After 22 years, height, dbh, and survival measurements revealed that local trees (Kansas) and trees from within 200 miles south of the planting site grew tallest. Height and dbh correlations were highly significant and increased when compared to successive 5-yr interval measurements. Geographic and climatic variables of seed sources did not provide a significant predictive regression model. Low survival limited the success of some sources, such as two from Indiana, in this Kansas plantation. North. J. Appl. For. 9(2):41-43.
Green ash trees from 18 provenances were planted in a seed-source test in 1971 near Manhattan, Kansas, in the central part of the Great Plains Region. Most seed sources were from north of the planting site. After 20 years, growth measurements revealed that the tallest trees were from more southerly sources and/or those near the plantation site. Trees from moderate distances north (150 miles) of the planting site also showed adequate growth. Height and dbh age-age correlations were highly significant and increased when compared to age measurements of earlier intervals.
Silver maple (Acer saccharinum L.) goes dormant in the autumn and is greatly delayed in bud break unless the buds are exposed to prolonged low temperature. Approximately 1000 hours below 4°C (39°F) under natural conditions (early March in southern Illinois) will bring about bud break 2 to 3 weeks after juvenile plants are put under favorable growing conditions. Chilling in a dark cold room at 4°C (39°F) separated from natural changes required a greater number of hours, approximately 2000, for a similar response. Bud break for subterminal buds was earlier than for terminal buds on insufficiently chilled stem segments or larger plantlets. Terminal buds broke first with longer chilling periods. Rooted cuttings from adult trees had a greater chilling requirement than juvenile plant material, either micropropagated plantlets or segments from shoots. No geographic or provenance variation in response to chilling was observed within 11 provenances ranging from Mississippi to central Ontario to New Hampshire to West Virginia. Silver maple was similar to sugar maple and basswood in its chilling requirement. It was unlike red maple which has a chilling requirement in some but not all parts of its range.
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