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Abstract：
The recovery of soil properties and the proper growth of natural tree regeneration are key elements for maintaining forest productivity after selective logging operations. This study was conducted on the soil properties and natural growth of two pioneer seedling species of alder and maple which were on skid trails in the mixed beech forests of northern Iran. To examine the long-term effects, we randomly selected six skid trails, with two replicates established for each of three time periods since last use (10, 20, and 30 years ago). Random plots 4 m × 10 m in size, three plots on each skid trail and six plots on areas without soil compaction (control), were selected. Measurements included the physical and chemical properties of the soil and the growth, and the architectural and qualitative characteristics of the seedlings. The results showed that all the soil properties of the 10- and 20-year-old skid trails were significantly different from the control area (except for the soil moisture in the 20-year-old skid trail). The 30-year-old skid trail showed values of other soil properties which were not significantly different from the control area, except for the amounts of organic matter and soil nitrogen, which was less than the control. The skid trails had a negative effect on all of the growth, qualitative, and architectural indices of seedlings. The characteristics of seedlings were related to soil characteristics and had the highest correlation with the soil penetration resistance (R-value from -0.41 to -0.63 for stem growth, p < 0.05; -0.57 to -0.90 for root growth, p < 0.01; and -0.76 to -0.86 for biomass, p < 0.01). The correlation coefficient between soil penetration resistance and the Dickson quality index of alder and maple seedlings was, respectively, -0.74 and -0.72, p < 0.01. The negative effect of soil compaction on root growth (-27.69% for alder seedlings and -28.08% for maple seedlings) was greater than on stem growth (-24.11% for alder seedlings and -16.27% for maple seedlings). The amount of growth, qualitative, and architectural indices of alder seedlings were higher than that of maple seedlings. Although alder is a better choice as compared to maple seedling in the initial year, the results of our study show that it is recommended to plant both alder and maple on skid trails after logging operations.
摘要：
土壤特性的恢复和自然树木再生的适当生长是选择性伐木作业后保持森林生产力的关键要素。这项研究是针对伊朗北部山毛榉混交林的滑道上的Alder木和枫木两种先锋幼苗的土壤特性和自然生长进行的。为了检查长期影响，我们随机选择了六条滑道，自上次使用（10、20和30年前）以来的三个时间段中的每一个都建立了两个重复。大小为4m×10m的随机地块，每个滑道上有三个地块，没有土壤压实的区域上有六个地块（对照），被选中。测量包括土壤的物理和化学性质以及生长，以及幼苗的建筑和质量特征。结果表明，10和20年生滑道的所有土壤特性均与控制区存在显着差异（20年生滑道中的土壤水分除外）。30年的滑道显示其他土壤特性的值与控制区没有显着差异，除了有机质和土壤氮的含量，比对照组少。滑道对所有的生长都有负面影响，定性，和幼苗的建筑指数。幼苗的特性与土壤特性有关，并且与土壤渗透抗性的相关性最高（茎生长的R值从-0.41到-0.63，p<0.05；根生长为-0.57至-0.90，p<0.01；生物量为-0.76至-0.86，p<0.01)。Alder木和枫木幼苗的土壤渗透阻力与Dickson质量指标之间的相关系数为，分别,-0.74和-0.72，p<0.01。土壤紧实度对根系生长的负面影响（al木幼苗为-27.69％，枫树幼苗为-28.08％）大于对茎生长的负面影响（al木幼苗为-24.11％，枫树幼苗为-16.27％）。量的增长，定性，and木幼苗的建筑指数高于枫木幼苗。尽管与最初一年的枫树幼苗相比，al木是更好的选择，我们的研究结果表明，建议在伐木作业后在滑道上种植al木和枫木。
