The implementation of the Millennium Forestry Plan was accompanied by growth discomfort exhibiting varying degrees of symptoms in some coniferous forests after the rainy season.
High soil water content affects the underground root growth and distribution characteristics of conifers, and the above-ground parts show corresponding variability. To determine the factors contributing to the significant growth disparities among the three conifers in Xiong’an New Area after the rainy season, we conducted a study investigating the growth characteristics of conifers. This study involved analyzing the external morphology of the plants, assessing leaf pigment content, measuring the root morphological index and root vigor, as well as respiratory characteristics, to evaluate the growth attributes of their root systems in a high soil moisture environment.
In the “Millennium Forest” area of Xiong’an New Area, we selected three coniferous trees,
(1) The growth of the three conifers displayed discernible differences in external morphology. Moreover, a decrease in growth condition corresponded to a reduction in crown size, ground diameter, diameter at breast height, leaf length, and new growths. (2) The root biomass, length, surface area, and root volume of conifers growing N class were significantly reduced than those of L class conifers. Conifers with a higher proportion of root systems in the 40-60 cm soil layer experienced more severe stress. (3) The significant decline in root respiration and vigor among all three conifer growth classes (M and N) suggested that the root system was undergoing anoxic stress, particularly at a soil depth of 40-60 cm where root respiration and vigor were notably reduced. (4) The persistent anoxic stress created by long-term exposure to high soil moisture content primarily impacted