Growth and nutrient uptake by birch and maple seedlings on soil with patchy or homogeneous distribution of organic matter

We compare responses to soil heterogeneity of red maple (Acer rubrum L.) and gray birch (Betula pop ulifolia Marsh.). Seedlings were grown with root systems split between two pots with soil: (i) without additional organic matter or nutrients ("no-addition" treatment), (ii) with additional organic matter and nutrients distributed evenly throughout the soil ("mixed" treatment), and (iii) with additional organic matter and nutrients concentrated in one pot ("patch" treatment). Compared with the no-addition treatment, mixed and patch treatments resulted in taller plants, and greater leaf and total plant dry masses for birch, while growth of maple was mostly unaffected. Birch root biomass was significantly increased in the organic patch. Specific root length of fine roots (