Exposure to outdoor conditions can cause chemical components on wood surfaces to deteriorate. To develop effective wood protection methods, a deep understanding of the mechanisms of weathering-induced wood surface degradation is required. However, the effects of outdoor exposure on wood at the cellular level have not been investigated in detail. Additionally, a comparative study of the degradation behavior of sapwood and heartwood has also not been conducted. This paper investigated the chemical changes in cell walls in Japanese cedar (Cryptomeria japonica D. Don) sapwood and heartwood during natural weathering using confocal Raman microscopy. Spectral and chemical mapping revealed that heartwood had higher weather durability than sapwood due to the large extractives content in heartwood. Although there were differences in the rates of lignin reduction between sapwood and heartwood, the molecular structures and lignin-degraded sites of the weathered samples were almost identical. The degradation patterns of naturally weathered wood were also similar to that of artificially weathered wood. The knowledge revealed here will help in the development of more effective wood protection methods.

暴露在室外条件下会导致木质表面上的化学成分劣化。为了开发有效的木材保护方法，需要深入了解风化引起的木材表面降解的机理。但是，尚未详细研究室外暴露对木材在细胞水平上的影响。另外，还没有对边材和心材的降解行为进行比较研究。本文研究了日本雪松（Cryptomeria japonica）细胞壁的化学变化D. Don）使用共聚焦拉曼显微镜在自然风化过程中边材和心材。光谱和化学图谱表明，由于心材中的大量提取物，心材比边材具有更高的耐候性。尽管边材和心材之间木质素的还原速率存在差异，但风化样品的分子结构和木质素降解位点几乎相同。自然风化木材的降解方式也与人工风化木材的降解方式相似。这里揭示的知识将有助于开发更有效的木材保护方法。