The breakdown and decomposition of sweet chestnut (Castanea sativa mill.) and beech (Fagus sylvatica L.) leaf litter in two deciduous woodland soils : II. Changes in the carbon, hydrogen, nitrogen and polyphenol content

Abstract

Changes in the carbon, hydrogen, nitrogen and polyphenol content of chestnut and beech leaves were measured during the first year after fall.Chestnut leaves had an initial carbon, hydrogen and nitrogen content (by weight) of 48.71%, 5.56% and 0.77% respectively; beech had a similar carbon and hydrogen content (47.77% and 5.36%) but less nitrogen (0.56%).Both leaf litter types showed percentage increases in nitrogen content during the study period but only the beech showed absolute increases in nitrogen content of up to 66.7% of the initial weight present in the leaves. The percentage increases in the nitrogen content of chestnut litter were largely attributable to more rapid losses of non-nitrogenous leaf constituents while the weight of nitrogen present in the leaves remained relatively constant.The percentage carbon and hydrogen contents of the chestnut and beech litter showed changes of less than 1% throughout the year, indicating that carbohydrate losses were directly proportional to weight losses.Soil animals fed on chestnut leaves to a far greater extent than beech leaves; this difference did not appear to be directly attributable to differences between the nitrogen contents or C/N ratios of the two leaf litter species. The gross polyphenol contents of chestnut and beech litter showed an intraspecific inverse correlation with the feeding activities of soil animals on the leaves, but did not account for interspecific differences in leaf palatability since chestnut leaves were eaten when they contained higher polyphenol concentrations than beech leaves. However, there was an interspecific negative correlation between palatability and the presence of protocatechuic and gallic acids.