Abstract

Under temperate climatic conditions, temperature is a key abiotic factor that controls the decomposition of coarse woody debris including bark. Using aspen bark (AB), we have carried out a 12-month laboratory experiment at three contrasting temperatures (2, 12, and 22°C) and constant sufficient moisture to quantify the temperature effect on the decomposition rate (DecR) and decay constant (k) of aspen bark. The effect of temperature on the total loss of C–CO₂ and changes in the chemical composition of AB throughout the experiment are also estimated. An increase in the incubation temperature from 2 to 12°C and from 12 to 22°C induces a similar increase in the average (over 12 months) value of the DecR: the Q₁₀ values are 1.30 and 1.41 in these temperature intervals, respectively. The most significant effect of temperature on the DecR dynamics is revealed during the 1st and 2nd months of the experiment. The maximum losses of C–CO₂ (284 ± 16 mg C g bark^–1, or 55.2 ± 3.2% of the initial C content) are observed at 22°C. The decay constants of AB, calculated by the one-component exponential model, significantly increase with the growth of the incubation temperature: from 0.46 ± 0.01 yr^–1 at 2°C to 1.02 ± 0.09 yr^–1 at 22°C. Changes in the chemical composition of aspen bark due to the processes of biogenic decomposition include a significant reduction in the amount of alcohol-soluble organic compounds and cellulose to 18–32 and 41–57% of their initial amount, respectively. Lignin losses are less significant, being only 9–18% of their content in AB before the incubation. The quantitative changes in the chemical composition of aspen bark are similar at 2 and 12°C and less pronounced than those at 22°C, which may be explained by an increase in the growing activity of organisms, are actively involved in bark decomposition at 22°C.

中文翻译：

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温度对白杨皮生物分解强度的影响

摘要

在温带气候条件下，温度是控制包括树皮在内的粗木屑分解的关键非生物因素。使用白杨树皮（AB），我们在三个相反的温度（2、12和22°C）和恒定的水分条件下进行了为期12个月的实验室实验，以量化温度对分解速率（DecR）和衰变常数的影响（k）白杨树皮。在整个实验过程中，温度对C–CO ₂的总损失和AB的化学组成变化的影响也得到了估计。孵育温度从2升高到12°C和从12升高到22°C会引起类似的DecR平均值（超过12个月）升高：Q ₁₀在这些温度间隔中，该值分别为1.30和1.41。在实验的第一个月和第二个月，温度对DecR动力学的影响最大。在22°C时可观察到C–CO ₂的最大损失（284±16 mg C g树皮^–1，或初始C含量的55.2±3.2％）。由单组分指数模型计算的AB的衰减常数随孵育温度的升高而显着增加：从2°C时的0.46±0.01 yr ^–1到2°C的1.02±0.09 yr ^–1在22°C下。由于生物分解过程而引起的白杨树皮化学成分的变化包括，将醇溶性有机化合物和纤维素的量分别显着减少至其初始量的18–32和41–57％。木质素的损失不太明显，仅占孵化前AB中含量的9-18％。白杨树皮化学成分的定量变化在2和12°C时相似，但不如22°C时明显，这可能是由于生物体生长活性的增加所致，并在22°C时积极参与了树皮的分解。 ℃。