Influence of Edaphic Factors on Sugar Maple Nutrition and Health on the Allegheny Plateau

Abstract

Sugar maple (Acer saccharum Marsh.) decline has been a problem on the Allegheny Plateau for the last two decades. Previous work found that sugar maple is predisposed to decline by poor nutrition and incited to decline by severe insect defoliation. Nutritional diagnoses have been based on foliar chemistry; there is little information on soil attributes that influence susceptibility. We evaluated relationships among soil characteristics, foliar chemistry, and sugar maple decline for 43 stands on the Allegheny Plateau in New York and Pennsylvania using correlation and stepwise regression techniques. Foliar Ca and Mg concentrations correlated with soil exchangeable cations expressed on a concentration or site capital basis. Expression of base cation availability as a saturation value, or in ratio with Al, slightly improved the relationships, suggesting that antagonistic cations are important to sugar maple nutrition. The best predictions of foliar chemistry were made by regressions that considered soil chemistry across the depth of the B horizon, suggesting the importance of looking at more than one depth to assess nutrition. Landscape position and glacial history determined whether weathering products were effectively delivered to the rooting zone, resulting in the observed landscape gradients. All declining stands were on unglaciated upper landscape positions where soils had lower Ca and Mg levels compared with other landscape positions. Declining stands had <2% Ca saturation and <0.5% Mg saturation in the upper B and <4% Ca saturation and <0.6% Mg saturation in the lower B. These thresholds may be useful in predicting susceptibility to sugar maple decline.