Ali Babaei Ahmadabad; Meghdad Jourgholami
Abstract
Natural restoration of forest after harvesting operations is one of the most important goals in forest sustainability. Forestry machine traffic by considering weight, speed, and intensity have significant impact on forest regeneration and consequently, biodiversity indices such as dominance, and equitability ...
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Natural restoration of forest after harvesting operations is one of the most important goals in forest sustainability. Forestry machine traffic by considering weight, speed, and intensity have significant impact on forest regeneration and consequently, biodiversity indices such as dominance, and equitability in the plant communities of forest floor drastically influenced. The current study has been carried out in the watershed no. 45 in the Hyrcanian forest and aim to study the skidding operation effect on diversity and tree species regeneration over a long-term period. Hence, four compartments with time since harvest of 7, 10, 15, 20 year in the Kheyrud forest (compartments no. 316, 317, 220, and 221) were selected and sampled. Also, the effect of soil physical properties (porosity and peneteration resistance), pH, litter (C, N, N/N), and light under different traffic intensity (landing, low, medium, high), and its influence on biodiversity indexes using dominance, Shannon, Simpson, Margalef, and equitability were assessed. Results revealed that skidding operations had drastic effect on forest regeneration and change species composition as well as plants quantitate. Velvet maple as light-demanding species increased by 8 percent and shade-tolerant species such as beech diminished by 68 percentages, which can be considered as ecological alarm in the Hyrcanian forest. Results demonstrated that traffic intensity and time since harvest significantly influenced on forest regeneration, and also all on the environmental factors were influenced by these parameters. PCA analyses showed that soil properties including soil penetration resistance and biodiversity indexes significantly influenced by skidding operations. There was a positive correlation between litter properties, light and porosity.
Nadia Kamali; Hossein Azarnivand; Shervin Ahmadi; Mohammad Ali Zare Chahouki; Ahmad Sadeghipour
Abstract
This study was conducted to evaluate the effect of polymer mulches and plant mulch on some soil physical properties. For this purpose, effects of synthetic polymer, natural polymer, natural - synthetic polymer, and litter, On some physical properties of soil at two depths (0-5 cm and 5-30 cm) and two ...
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This study was conducted to evaluate the effect of polymer mulches and plant mulch on some soil physical properties. For this purpose, effects of synthetic polymer, natural polymer, natural - synthetic polymer, and litter, On some physical properties of soil at two depths (0-5 cm and 5-30 cm) and two time periods in a completely randomized design with four replications was studied. 10*10 meter experimental plots were considered and mulches covered 2 cm of the soil surface in each plot. The results showed that the use of mulches in the first week of applying, affected the bulk density (3.6% increase in synthetic polymer), porosity (6.01% increase in synthetic polymer), temperature (2.52% increase in litter and 1.85 decrease in natural polymer) and humidity (16.67% increase in synthetic polymer) at the layer of 0-5 cm, Soil moisture (16.67% increase in synthetic polymer) was also affected at the depth of 5-30 cm. Six months after the experiment began, mulches were applied, made a significant difference compared to control in the bulk density (4.81% and 2.12% decrease in synthetic polymer for 1st and 2nd layers respectively), porosity (8.23% increase in synthetic polymer for 1st layer and 4.12% increase in natural - synthetic polymer for 2nd layer) and moisture content of both surface and beneath soil (103.53% and 48.6% increase in natural - synthetic polymer for 1st and 2nd layers respectively), also the electrical conductivity of the first depth of soil (6.23% decrease in natural - synthetic polymer) was affected.
