To investigate the impacts of various foliar fertilization levels on the carbon, nitrogen, phosphorus, and potassium content in Chinese fir cuttings, along with their ecological stoichiometry ratios, we selected pruned dwarf Chinese fir clones exhibiting different seed-setting abilities as our subjects. These clones were categorized into high-yield (group A), middle-yield (group B), and low-yield (group C) categories for nutrient assessment. Employing nine treatments of diverse fertilizers and hormones, in addition to a water control (CK), we analyzed and compared the changes in the carbon (C), nitrogen (N), phosphorus (P), and potassium (K) contents in the needles of Chinese fir clones from groups A, B, and C between 2021 and 2022. The results indicated no significant variations in the N content and C:N ratios in July among the three seed-setting characteristic Chinese fir types. However, the P content in the high-yield clones was notably higher than that in the other two types, whereas the K content was significantly lower. Following two years of continuous foliar spraying, treatments T5, T6, T8, and T9 demonstrated efficacy in enhancing the nutrient levels of branches in high-yield clones (with N content increasing by 25.07%, P content by 79.06%, and K content by 12.71%), consequently improving cone quality (as the number of cones increased by up to 256). For middle-yield clones, treatments T3, T6, and T9 exhibited promising outcomes, with respective increases in the N content, P content, and K content by 13.15%, 56.61%, and 41.31%, alongside a rise in cone number by 212. In the case of low-yield clones, the treatments T3, T4, and T5 proved effective, with increases in the N, P, and K contents by 18.54%, 36.57%, and 26.56%, respectively, as well as an increase in cone number by 82. Most treatments exhibited higher C:N ratios than the control in Chinese fir needles, whereas the N:P ratios remained below 14, indicating N limitations in the growth of Chinese fir clones. The application of N fertilizer enhanced the C:N ratios in Chinese fir needles, thereby improving nutrient absorption and utilization efficiency. Therefore, in the fertilization process of Chinese fir, tailored formulas should be employed based on the seed-setting characteristics and management objectives to achieve optimal yield enhancement.

Paeonia ostii, a significant perennial woody oil crop in China, is notable for its seeds’ high oil content and elevated levels of unsaturated fatty acids. However, there is currently a lack of scientific fertilisation protocols and targeted nutrient management for P. ostii. The concentrations of macronutrients (N, P, K, Ca, and Mg) and micronutrients (Fe, Mn, Zn, and Cu) were determined in the leaves at five distinct growth stages: flowering, initial fruit set, fruit expansion, late fruiting, and foliar senescence. The levels of N and P were found to be at their highest point during the flowering stage, after which they declined significantly. In contrast, the levels of K remained relatively stable throughout the growth phase, while Mg levels increased significantly to peak at fruit expansion. The level of Ca increased, reaching its peak at the late fruiting stage. The annual average content of micronutrients in P. ostii leaves was as follows: Fe > Mn > Zn > Cu. Furthermore, it was observed that the concentrations of Fe and Mn oscillated, while the concentration of Cu decreased significantly after flowering. Additionally, Zn concentrations remained stable throughout the various stages. Multivariate analyses, including PCA, nutrient ratio analysis, and an integrated nutrient stability index, further revealed coordinated shifts in leaf nutrient composition and indicated that May and June were relatively stable periods for nutrient assessment. Considering both the nutrient stability and the phenological relevance, June, corresponding to the fruit expansion stage, was considered a practical sampling window for foliar nutrient diagnosis. These findings contribute to the definition of an appropriate sampling window for foliar nutrient diagnosis, thereby providing a useful basis for nutrient monitoring and future fertilisation studies in P. ostii.

The phenotypic characteristics of forest seeds are the basis of germplasm innovation, genetic improvement, and biological research, and they also are the reference for the development of seed orchards. In this study, we analyzed seed quantity characteristics, phenotypic differentiation, and variation patterns in three seed-bearing clones from different crown layers of the Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) orchard located in Fujian Province, China. We divided the clones into six layers according to crown height and the sunny and shady sides, 14 phenotypic characteristics, and five quality indexes, and we measured the germination rate of seeds. The rate of seeds filled with tannin-like substance in the upper sunny layer was low, but it was high in the lower shady layer. The germination rate was highest in the upper sunny layer and lower in the middle and lower shady sides. Values of most of the 14 phenotypic traits tested differed significantly among clones and layers. The average value of the phenotypic differentiation coefficient was 81.16%, indicating that variation among clones explained most of the total phenotypic variation. The repeatability of the 14 phenotypic traits was high (R > 0.80), indicating that these traits are highly heritable. The phenotypic characteristics of cones and seeds varied from 6.86% to 129.51%. The 14 phenotypic traits exhibited different degrees of correlation, and seed weight, seed circumference, seed width, and seed area can be used to predict other seed traits. However, the correlations between cone traits were not strong. Our results show that when establishing a dwarfing Chinese fir seed orchard, the distribution and variation of seeds in different crown layers of clones should be considered, and clones with more cones in the lower crown layer should be selected as parents.

To evaluate trait variation across contrasting understory light environments in a pecan-based agroforestry system, 30 seven-year-old Paeonia ostii plants were assessed at three naturally occurring positions with high (HI), medium (MI), and low (LI) understory light intensity. Microenvironmental conditions, plant growth, leaf photosynthetic pigments and mineral nutrients, seed yield components, seed oil traits, and final germination percentage were measured. Photosynthetically active radiation consistently followed the order HI > MI > LI. Plants at LI had higher chlorophyll a, chlorophyll b, carotenoid, and leaf N, P, and K concentrations, indicating leaf-level responses to lower light availability. In contrast, plant height and crown width were lower at LI, while HI showed higher values for 100-seed weight, aggregate fruit number and fresh weight, seeds per plant, and final germination percentage. Ground diameter and seed diameter did not differ significantly among positions. Crude fat and α-linolenic acid contents also showed no significant differences. Integrated trait analysis further showed that HI was associated mainly with higher growth, reproductive, and germination traits, whereas LI was associated with higher leaf pigment and mineral nutrient concentrations. Overall, the results reveal contrasting leaf-level acclimation and whole-plant performance across a naturally occurring understory PAR gradient. Because the study was observational, these patterns should be interpreted as position-associated differences rather than causal effects of light, and they provide a basis for future replicated canopy-management experiments.