We used long-term litter decomposition data to estimate final decomposition levels using an asymptotic function. The estimated final limit values for decomposition were compared with available chemical data for the different litter types. A total of 41 limit values were estimated from as many different decomposition studies, and 20 different litter types were incubated in eight different forest systems. The limit values estimated varied with litter type. They ranged from about 35 to about 100% decomposition and were linearly related to the initial litter concentrations of N, Mn, and Ca in the newly shed litter. For these three nutrients, there are causal relationships to lignin degradation and to the lignin-degrading microbial community. Using all available data, we made simple and multiple linear regressions and obtained a negative linear relationship between limit value and initial N concentration ([ ]; n = 41; p < 0.001). For needle litter alone, we obtained a better relationship ([ ]; n = 23; p < 0.001). Manganese concentrations in litter gave a positive relationship ([ ]; n = 25; p < 0.001), with a clear improvement when needle litter was tested for alone ([ ]; n = 16; p < 0.001). Calcium alone gave a barely significant relationship. When combining nutrients in multiple linear relationships we obtained high R² values, indicating that the models were good. Thus for all sites and litter types, N, Mn, and Ca combined gave an [ ] value of 0.640 with n = 25 (p < 0.001). All needle litters combined gave an [ ] of 0.745 (n = 16; p < 0.001). The significance of this finding is discussed. Keywords: litter decomposition, limit values, maximum decomposition, nitrogen, manganese, calcium.

Fire is a disturbance in the Mediterranean region associated with frequent drought periods, and can affect the soil microbial community, which plays a fundamental role in nutrient cycling. In the present study the effect of low- and high-severity experimental fires on the soil microbial community was evaluated in an Italian Mediterranean maquis. Burned and unburned soils were compared for functional diversity, specific activities, microbial biomass, fungal mycelia and fungal fraction of microbial carbon, during the first year after fire. In the first week after fire, changes in the functional diversity were observed in burned soils, differing also between low- and high-severity fires. Respiration responses to specific organic compounds were generally lower in burned soils during the whole study period, with a percentage of changed responses from 2 to 70%. The general reduction in burned soils of the fungal fraction of microbial carbon (19–61%) and active mycelia (16–55%), together with the increase in microbial biomass carbon (29–42%) during the first 3 months after fire, suggest a larger and longer effect of fire on fungi than on bacteria. The results indicate a rapid recovery of functional diversity in soil after burning despite the persistent reduction of microbial community activity and the change in its structure.