Thinning is a commonly used treatment in forest management which affects the tree root systems. The effects of thinning on element concentrations and seasonal change of roots were evaluated in adjacent oak (Quercus frainetto Ten.) and hornbeam (Carpinus betulus L.) stands according to the different root diameter classes. Two replicated control and thinning plots (50 m × 50 m) were set for each species (hornbeam and oak). Thinning treatments (November 2010) reduced 50% of the basal area in both oak and hornbeam stands. Roots were assessed by seasonal collection over 2 years (from October 2010 to October 2012). The roots were then sorted into diameter classes of 0–2 mm (fine roots), 2–5 mm (small roots) and > 5 mm (coarse roots). C, N, P, K, Ca, Na, Mg, S, Mn, Fe, Al, Zn, Pb, Ni, Cu and Cd were analyzed. Except coarse roots, the highest root biomasses were determined in April-2011 in all plots. Fine-root biomass in oak was found significantly higher in control plots. In contrast to the oak, the fine-root biomass in the thinned hornbeam plots was higher than in the controls. The small-root biomass did not significantly differ between the thinned and the control plots in both oak and hornbeam stands. However, the coarse-root biomass showed significant differences between the control (1989 g∙m− 2) and thinned plots (1060 g∙m− 2) in oak, while no difference was detected in hornbeam. The concentrations of C, Al, Pb, Cd, Ni, Zn, Mn, Na, K, Mg and P in the fine roots of oak were significantly higher in the thinned plots. However, the concentration of Pb, Cd and Fe in the fine roots was significantly higher in the thinned plots of hornbeam. Significant differences were observed between the species for all elements in the fine roots except for C, N and P. In particular, elements in the fine roots tended to increase in July in the oak. In the hornbeam, all element concentrations in the fine roots (except C, N, and S) in the thinned plots showed a tendency to increase in April. The concentrations of Pb, Ni, Al, Fe, Cu, Ca, Na, K, Mg and P in the hornbeam control plots increased during the April 2011 period. The results indicated that thinning effects on temporal changes and concentrations of elements in the roots could be attributed to species-specific characteristics.

中文翻译：

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间伐对土耳其伊斯坦布尔相邻角树和橡树林根系生物量和元素浓度的影响

间伐是影响树木根系的森林管理中常用的一种处理方法。根据不同的根系直径等级，在相邻的橡树（Quercus frainetto Ten。）和角树（Carpinus betulus L.）林分中评估了间伐对根系元素浓度和季节变化的影响。为每种树种（角树和橡树）设置了两个重复的对照和间伐图（50 m×50 m）。疏伐处理（2010年11月）减少了橡树和角树立木的基础面积的50％。通过两年（从2010年10月到2012年10月）的季节性收集来评估根。然后将根分类为0–2 mm（细根），2–5 mm（小根）和> 5 mm（粗根）的直径类别。分析了C，N，P，K，Ca，Na，Mg，S，Mn，Fe，Al，Zn，Pb，Ni，Cu和Cd。除了粗根 2011年4月在所有样地中确定了最高的根生物量。在对照地块中发现橡木中的细根生物量明显更高。与橡木相反，在变薄的角树样地中，细根生物量高于对照。在橡树和角树林中，稀疏和对照样地的小根生物量没有显着差异。然而，橡木的粗根生物量在对照（1989 g∙m-2）和稀疏地块（1060 g∙m-2）之间显示出显着差异，而在角树中则未发现差异。在稀疏地块中，橡木细根中C，Al，Pb，Cd，Ni，Zn，Mn，Na，K，Mg和P的浓度显着较高。然而，在细束的角树中，细根中的Pb，Cd和Fe浓度显着较高。对于细根中除C，N和P以外的所有元素，在物种之间观察到显着差异。特别是，七月份橡木中细根中的元素趋于增加。在角树中，稀疏地块中细根中所有元素的浓度（C，N和S除外）都显示出4月份增加的趋势。在2011年4月的期间，角树控制区的Pb，Ni，Al，Fe，Cu，Ca，Na，K，Mg和P的浓度增加。结果表明，稀疏效应对根的时间变化和元素浓度的影响可归因于特定物种的特征。在稀疏地块中，细根中所有元素的浓度（C，N和S除外）均显示4月份增加的趋势。在2011年4月的期间，角树控制区的Pb，Ni，Al，Fe，Cu，Ca，Na，K，Mg和P的浓度增加。结果表明，稀疏效应对根的时间变化和元素浓度的影响可归因于特定物种的特征。在稀疏地块中，细根中所有元素的浓度（C，N和S除外）均显示4月份增加的趋势。在2011年4月的期间，角树控制区的Pb，Ni，Al，Fe，Cu，Ca，Na，K，Mg和P的浓度增加。结果表明，稀疏效应对根的时间变化和元素浓度的影响可归因于特定物种的特征。