Determinants of leaf litter patchiness in mixed species New Jersey pine barrens forest and its possible influence on soil and soil biota

We have identified the importance of ground layer ericaceous shrub density as a determinant of leaf litter patch size in upland oak/pine communities o f the New Jersey pine barrens. Litter patch area is directly proportional t o the number of ericaceous stems. This observation has been confirmed by ex perimentation where leaf litter patches accumulated under artificial stems for a period of 2 years. Leaf litter patches of different sizes contain dif fering proportions of leaf species. Large patches contain a significantly h igher proportion of oak leaves than small patches. Difference in physical s tructure of large and small patches, due to leaf species composition and du e to differential leaf chemistries, result in differences in soil character istics and soil biota under the patches. Soil moisture and organic matter c ontent of upper soil layers are greater under large litter patches than und er small ones. We have preliminary evidence that these changes influence th e community structure of ectomycorrhizae developing under patches of differ ent sizes.