Spatio‐temporal patterns of throughfall (TF) have often been studied under forest canopies. Few reports, however, have been made on small‐scale TF variability in deciduous forest stands. In the present research, the spatial heterogeneity and temporal stability of TF under five individual persian oak trees (Quercus brantii var. Persica) was quantified. The research site was in the Zagros forests in western Iran, where mean annual precipitation and temperature are equal to 587.2 mm and 16.9 °C, respectively. Data from 23 rainfall events were aggregated to assess the spatial correlation of TF. Variograms for TF beneath two of the five trees reached a stable sill at the range of 5–6 m. The redistribution of TF within the canopy was highly variable in time, attributable to seasonal variation in canopy foliation and meteorological factors. As the length of the sampling period increased, the spatial variability of TF decreased and the temporal stability of the TF pattern increased. Time stability plots of TF normalized with respect to mean and variance showed a moderate general persistence for all individual trees. We conclude that single trees modify the spatial distribution of TF reaching the forest floors. Copyright © 2012 John Wiley & Sons, Ltd.

Abstract& Key message Throughfall nutrient fluxes were generally higher in a mixed stand than in a pure stand of Oriental beech. Throughfall fluxes were higher than bulk precipitation fluxes except for nitrogen and indicate higher canopy uptake of this element in the pure stand compared to the mixed stand.

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Several studies emphasize the effects of slope position on divergences of soil properties in forest ecosystems, but limited data is available on the impact of slope position on recovery levels of soil, which were exposed to compaction due to machine traffic. This study examined the effects of slope position (i.e., S; summit, BS; backslope, and TS; toeslope) on recovery rate of soil properties and enzyme activity four years after ground-based harvesting operations were performed on machine operating trails, compared to the undisturbed areas (UND) in the Hyrcanian forests (north of Iran). Soil properties and enzyme activity of compacted soil in machine operating trails showed significant trend differences among the slope positions. A significantly lower soil bulk density, penetration resistance, soil moisture, aggregate stability, pH, sand, and C/N ratio were found in TS compared to the values recorded in the BS and S treatments. Conversely, total porosity, macroporosity, silt, clay, organic C, total N, available nutrients (i.e., P, K+, Ca2+, and Mg2+), fulvic and humic acid, earthworm density and dry mass as well as fine root biomass were higher in TS than in the BS and S treatments. Soil microbial respiration, MBC, NH4+, NO3−, N mineralization, and MBN were significantly higher in the UND areas followed by TS > BS > S treatment. The highest activity levels of enzymes (i.e., urease, acid phosphatase, arylsulfatase, invertase, and ß-N-acetylglucosaminidase) were detected in the UND areas, followed by TS > BS > S treatment. The highest recovery levels of all soil properties and enzyme activity were found in TS, followed by BS > S treatment. However, the full recovery of soil properties did not occur even after a 4-year period, compared to the UND areas. Our study results highlight the significance of the slope position in augmenting divergence in soil properties and enzyme activity after ground-based machine traffic.

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