The decomposition (meaning disappearance) of different leaf types and artificial leaves made from cellulose hydrate foil was studied in three forests - an alluvial forest (Ulmetum), a beech forest on limestone soil (Melico-Fagetum), and a spruce forest in soil overlying limestone bedrock.Fine, medium, and coarse mesh litter bags of special design were used to investigate the roles of abiotic factors, microorganisms, and meso- and macrofauna in effecting decomposition in the three habitats. Additionally, the experimental design was carefully arranged so as to provide information about the effects on decomposition processes of the duration of exposure and the date or moment of exposure. 1. Exposure of litter samples oor 12 months showed: a) Litter enclosed in fine mesh bags decomposed to some 40-44% of the initial amount placed in each of the three forests. Most of this decomposition can be attributed to abiotic factors and microoganisms. b) Litter placed in medium mesh litter bags reduced by ca. 60% in alluvial forest, ca. 50% in beech forest and ca. 44% in spruce forest. c) Litter enclosed in coarse mesh litter bags was reduced by 71% of the initial weights exposed in alluvial and beech forests; in the spruce forest decomposition was no greater than observed with fine and medium mesh litter bags. Clearly, in spruce forest the macrofauna has little or no part to play in effecting decomposition. 2. Sequential month by month exposure of hazel leaves and cellulose hydrate foil in coarse mesh litter bags in all three forests showed that one month of exposure led to only slight material losses, they did occur smallest between March and May, and largest between June and October/November. 3. Coarse mesh litter bags containing either hazel or artificial leaves of cellulose hydrate foil were exposed to natural decomposition processes in December 1977 and subsampled monthly over a period of one year, this series constituted the From-sequence of experiments. Each of the From-sequence samples removed was immediately replaced by a fresh litter bag which was left in place until December 1978, this series constituted the To-sequence of experiments. The results arising from the designated From- and To-sequences showed: a) During the course of one year hazel leaves decomposed completely in alluvial forest, almost completely in beech forest but to only 50% of the initial value in spruce forest. b) Duration of exposure and not the date of exposure is the major controlling influence on decomposition in alluvial forest, a characteristic reflected in the mirror-image courses of the From- and To-sequences curves with respect to the abscissa or time axis. Conversely the date of exposure and not the duration of exposure is the major controlling influence on decomposition in the spruce forest, a characteristic reflected in the mirror-image courses of the From-and To-sequences with respect to the ordinate or axis of percentage decomposition. c) Leaf powder amendment increased the decomposition rate of the hazel and cellulose hydrate leaves ...

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In the "Solling-Projekt" (IBP) of the "Deutsche Forschungsgemeinschaft" the decomposition of different qualities of leaves in acid soil (Solling) and in lime soil (Göttinger Wald) was studied under various conditions (October 1973-October 1974).Plastic rings were used as litter bags in the following way: on the bottom side they were covered with gauze of different mesh sizes (50, 1120, or 6000 μm), after they had been filled with leaves the upper sides were closed by a gauze with an equal mesh size (about 1200 μm). The effects of abiotic factors, microorganisms, meso- and macrofauna, phytophagous-excrements, and leaf-powder are shown by the following results: 1. In lime soil the decomposition was higher than in acid soil. 2. The decomposition effected by microorganisms alone was less than that by microorganisms and mesofauna; this, however, was less than the one by microorganisms, meso- and macrofauna. 3. Shade-leaves were decomposed more than sun-leaves and these more than leaves 1 year old. 4. In acid soil phytophagous-excrements effected a very high decomposition while in lime soil an effect was not to be found. 5. Leaf-powder effected a very high decomposition of sun-leaves and leaves 1 year old in both forests, of shade-leaves, however, in acid soil only. 6. In the Solling (acid soil) and in the Göttinger Wald (lime soil) shadeleaves from the Solling as well as from the Göttinger Wald were decomposed equally. 7. In the Solling the decomposition of leaves with phytophagous-excrements or leaf-powder compared with the decomposition in the Göttinger Wald without phytophagous-excrements or leaf-powder was nearly the same if mesofauna was allowed to enter, but the decomposition was highly significantly smaller if macrofauna was allowed to enter, which was rather scarce. 8. In the winter half-year the decomposition was smaller than in the summer half-year. The decomposition in the winter- and the summer half-year together (October 1973-April 1974 and April 1974-October 1974) was considerably higher than the decomposition of that litter which had been exposed for a whole year without interruption. 9. Some of the leaves sprayed with Toluol were partly destroyed more than those sprayed with Naphthalin.

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