Changes in the chemical composition of young Chinese fir wood exposed to different soil temperature and water content

The chemical composition of wood is closely related to its growing conditions, such as soil temperature and water. Four different types of soil warming and precipitation exclusion treatments were used to simulate the underground response and adaptability of Chinese fir to global warming. The compaction method was used to reclaim the Chinese fir soil from the nearby woodland to ensure that the soil bulk density was as consistent as possible. The chemical constituents of Chinese fir wood were studied by taking Chinese fir discs at breast height of 1.3 m. With changing the growth environment, the content of different extracts and the chemical composition of Chinese fir have changed. The cellulose content of Chinese fir increased significantly with precipitation exclusion − 50%. The organic extract content of Chinese fir increased in different degrees under soil warming and precipitation exclusion, which may be related to the accumulation of organic matter content and be beneficial to the improvement of the biomass of Chinese fir. Due to the change of temperature and water content in soil, the internal adaptability of Chinese fir wood cellulose like crystalline zone, overall orderliness also may decrease. Precipitation exclusion − 50% still has the greatest impact on it. The soil warming and precipitation exclusion can inhibit lignin synthesis of Chinese fir. The lignin condensation index decreased with the decrease of lignin content, possibly due to the change of syringyl lignin content. Experiments show that the underground parts of terrestrial ecosystems may provide positive effects from global warming, although the extent of such consequences is uncertain.