Department of Bioscience and Territory, University of Molise, Contrada Fonte Lappone snc, 86090 Pesche (IS), Italy.
Department of Geography, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
Sci Total Environ. 2016 Nov 1;569-570:1064-1076. doi: 10.1016/j.scitotenv.2016.06.167. Epub 2016 Jul 1.
Deadwood is known to significantly contribute to global terrestrial carbon stocks and carbon cycling, but its decay dynamics are still not thoroughly understood. Although the chemistry of deadwood has been studied as a function of decay stage in temperate to subalpine environments, it has generally not been related to time. We therefore studied the decay (mass of deadwood, cellulose and lignin) of equal-sized blocks of Picea abies wood in soil-mesocosms over two years in the Italian Alps. The 8 sites selected were along an altitudinal sequence, reflecting different climate zones. In addition, the effect of exposure (north- and south-facing slopes) was taken into account. The decay dynamics of the mass of deadwood, cellulose and lignin were related to soil parameters (pH, soil texture, moisture, temperature) and climatic data. The decay rate constants of Picea abies deadwood were low (on average between 0.039 and 0.040y(-1)) and of lignin close to zero (or not detectable), while cellulose reacted much faster with average decay rate constants between 0.110 and 0.117y(-1). Our field experiments showed that local scale factors, such as soil parameters and topographic properties, influenced the decay process: higher soil moisture and clay content along with a lower pH seemed to accelerate wood decay. Interestingly, air temperature negatively correlated with decay rates or positively with the amount of wood components on south-facing sites. It exerted its influence rather on moisture availability, i.e. the lower the temperature the higher the moisture availability. Topographic features were also relevant with generally slower decay processes on south-facing sites than on north-facing sites owing to the drier conditions, the higher pH and the lower weathering state of the soils (less clay minerals). This study highlights the importance of a multifactorial consideration of edaphic parameters to unravel the complex dynamics of initial wood decay.
枯立木被认为是全球陆地碳储量和碳循环的重要组成部分，但它的腐烂动态仍未被完全理解。虽然已经研究了在温带到亚高山环境中作为腐烂阶段的功能的枯立木化学性质，但通常与时间无关。因此，我们在意大利阿尔卑斯山的土壤中进行了为期两年的实验，研究了大小相同的云杉木块的腐烂（枯立木、纤维素和木质素的质量）。选择的 8 个地点沿海拔序列排列，反映了不同的气候带。此外，还考虑了暴露（北坡和南坡）的影响。枯立木、纤维素和木质素质量的腐烂动态与土壤参数（pH 值、土壤质地、水分、温度）和气候数据有关。云杉枯立木的腐烂速率常数较低（平均在 0.039 和 0.040y(-1)之间），木质素接近零（或无法检测到），而纤维素的反应速度要快得多，平均腐烂速率常数在 0.110 和 0.117y(-1)之间。我们的野外实验表明，局部尺度因素，如土壤参数和地形特征，影响了腐烂过程：较高的土壤水分和粘粒含量以及较低的 pH 值似乎会加速木材腐烂。有趣的是，空气温度与腐烂速率呈负相关，与南坡站点的木材成分量呈正相关。它的影响主要是由于水分可用性，即温度越低，水分可用性越高。地形特征也很重要，由于南坡站点的条件较干燥、pH 值较高以及土壤风化状态较低（较少的粘土矿物），因此南坡站点的腐烂过程通常较慢。本研究强调了多因素考虑土壤参数的重要性，以揭示初始木材腐烂的复杂动态。
