For sustainable production of wood in short-rotation coppices and agroforestry systems, it is necessary to optimize the storage processes to achieve low dry matter losses together with low-cost drying. The harvesting of the trees can be carried out very efficiently with modified forage harvesters or tractor-powered mower-chippers. The wood chips produced can be dried naturally at low cost in open-air piles. However, this type of storage is connected with high dry matter losses of up to about one fourth in the course of seven-month storage. Although harvesting whole trees is connected with significantly higher costs, lower dry matter losses are to be expected from storing the trees in piles. Consequently, in this study, the storage and drying behavior of poplar under different German weather conditions and depending on the structure of the storage piles has been examined in detail. After a seven-months storage period, the trees still displayed moisture contents of 41–44% following an initial moisture content of 56% but achieved very low dry matter losses of only 4–7%. Moisture contents of 35–39% could only be achieved in October after a further two-months drying period under favorable weather conditions. All storage piles were built up on approximately 30 cm high support timbers for better ventilation. Additionally, covering the ground with a fleece did not have any influence on the drying behavior, nor did different pile heights. Smaller tree trunk diameters are not only connected with a higher share of bark or ash, but also thinner trunks tend to become damp again more quickly after rainfall. That is why whole-tree storage is suitable above all for medium or longer rotation periods with which, under favorable conditions, the higher harvesting costs can be compensated by a higher wood chip quality and lower storage losses.

中文翻译：

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在德国短轮伐木的杨树整树贮藏中优化干燥工艺并减少干物质损失的选项

为了在短旋转期和农林业系统中可持续生产木材，有必要优化存储过程，以实现低干物质损失和低成本干燥。可以使用改良的牧草收割机或拖拉机驱动的割草机非常有效地进行树木的采伐。所生产的木片可以在露天堆中以低成本自然干燥。但是，这种类型的存储与七个月的存储过程中高达约四分之一的高干物质损失有关。尽管收获整棵树木会带来高得多的成本，但是通过将树木成堆存储，可以减少干物质损失。因此，在这项研究中 详细研究了在德国不同天气条件下以及根据存储桩的结构，杨树的存储和干燥行为。在七个月的存储期后，树木的初始含水量为56％，但仍显示其含水量为41-44％，但干物质损失非常低，仅为4-7％。在有利的天气条件下，又经过两个月的干燥期后，只有在十月份才能达到35-39％的水分含量。所有存储桩都建在大约30厘米高的支撑木材上，以提供更好的通风。另外，用羊毛覆盖地面对干燥行为没有任何影响，不同的绒头高度也没有影响。较小的树干直径不仅与更大比例的树皮或烟灰有关，而且更细的树干往往会在降雨后很快变得潮湿。这就是为什么整树存储尤其适合于中等或更长的轮换周期，在有利条件下，较高的采伐成本可以通过较高的木片质量和较低的存储损耗来补偿，因此整棵树都可以存储。