Wood properties have an influence on the safety around the tree itself as well as on actual possibilities of using wood. The article focuses on the wood properties of the Norway spruce (Picea abies (L.) Karst.) in reference to the time since the tree has decayed. The study was conducted among mature tree stands of spruce in Białowieża Forest, where over the last 10 years there has been a weakening of spruce tree stands due to water deficiency which has contributed to the gradation of the European spruce bark beetle (Ips typographus). The study focused on spruce wood of living and healthy specimens as well as the wood of standing trees which has decayed between one and five years before the sample was collected. The findings indicate a gradual decrease in wood properties as time passed since the physiological decay of the tree. Significant differences in the decrease of mechanical wood properties have been observed in trees which had been decayed for 3 years and they should be considered life and health hazard for people and animals.

中文翻译：

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树木腐烂持续时间对挪威云杉木材（Picea Abies（L.）Karst。）的机械稳定性的影响

木材特性会影响树木本身的安全性以及实际使用木材的可能性。本文着眼于挪威云杉（Picea abies（L.）Karst。）木材腐烂以来的木材特性。这项研究是在Białowieża森林的成熟云杉林中进行的，在过去的十年中，由于缺水，云杉林分的弱化导致欧洲云杉树皮甲虫（Ips typographus）。这项研究的重点是活的和健康的标本的云杉木材，以及在采集样品之前的一到五年之间已经腐烂的立木。这些发现表明自树的生理衰退以来，随着时间的流逝，木材特性逐渐下降。在已经腐烂三年的树木中，观察到机械木材性能下降的显着差异，应将其视为对人和动物的生命和健康危害。