Showing papers on "Cunninghamia published in 2023"
2 citations
TL;DR: Wang et al. as discussed by the authors investigated the role of soil carbon and nutrients and their stoichiometric characteristics in indicating the soil interior nutrient cycling and plant nutrient supply of forest ecosystems, whereas it has been less explored when considering the influencing factors regionally.
Abstract: The crucial roles of soil carbon (C) and nutrients and their stoichiometric characteristics in indicating the soil interior nutrient cycling and plant nutrient supply of forest ecosystems have been widely verified, whereas it has been less explored when considering the influencing factors regionally, especially for the widely cultivated plantation tree species. In the current study, the patterns of soil organic C (SOC), total nitrogen (TN), and total phosphorus (TP) stoichiometry in Chinese fir [Cunninghamia lanceolata (Lamb.) Hook] plantations across subtropical China were analyzed, and their influencing factors were also investigated. The results showed that the range of SOC: TN (C:N), SOC: TP (C:P), and TN: TP (N:P) ratios were 7.32–18.27, 20.15–230.48, and 2.11–15.05 with a mean value of 13.22, 83.50, and 6.05, respectively. Well-constrained correlations were found in SOC and TN, as well as in TN and TP. Soil TN and TP contents increased with increasing altitude, whereas soil C:N, C:P, and N:P ratios decreased. Soil TP content decreased, and the C:P ratio increased with increasing mean annual temperature (MAT) and annual total solar radiation (ATSR). Soil C:N, C:P, and N:P ratios increased with increased mean annual precipitation (MAP) and mean annual evaporation (MAE). Overall, our findings suggested that the soil nutrient supply is relatively adequate in Chinese fir plantations across subtropical China. Meanwhile, soil C, N, and P stoichiometric characteristics were affected by geographical and climatic variables to different degrees.
2 citations
TL;DR: Wang et al. as mentioned in this paper investigated the relationship between the functional traits leaves and C, N, P stoichiometry of Chinese fir from different geographical provenances and their relationship with the main environmental factors of provenance.
Abstract: Studies on intra-specific variability in leaf functional traits is important to evaluate adaptation of the species to predicted climate change, and to develop long-term conservation strategy. The main objectives were to investigate the relationship between the functional traits leaves and C, N, P stoichiometry of Chinese fir from different geographical provenances and their relationship with the main environmental factors of provenance.In this study, we measured 12 leaf functional traits on 36-year-old Cunninghamia lanceolata trees from 13 provenances. Analysis of variance (ANOVA) was performed to examine the variability. Redundancy analysis (RA) was computed to examine the relationship between geo-climatic factors of provenance origin and leaf functional traits while Pearson's correlation coefficient was computed to assess inter-trait correlations. The results showed statistically significant differences (P < 0.01) in intraspecific leaf traits among provenances, except leaf P content. The relationships among leaf traits are consistent with the general trend observed in the leaf economic spectrum. Mean annual temperature appeared to be a key factor that influences intraspecific leaf traits variability compared to mean annual precipitation.These results provide useful insights about adaptation of leaf trait of Chinese fir in a changing climatic condition. Thus, our findings shed light on the importance of interspecific trait variability in Chinese fir and the potential effect of climate change.
2 citations
2 citations
TL;DR: In this paper , the effects of soil warming and nitrogen addition on the morphological and chemical characteristics of fine roots in different order classes of the Chinese fir have been investigated in different countries.
1 citations
TL;DR: In this paper , the effects of drought stress on mineral uptake, accumulation, and distribution in Chinese fir organs were determined under different drought stress regimes for 0-45 days, and a treatment of 80% of soil field maximum moisture capacity was used as control.
Abstract: Mineral accumulation in plants under drought stress is essential for drought tolerance. The distribution, survival, and growth of Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.), an evergreen conifer, can be affected by climate change, particularly seasonal precipitation and drought. Hence, we designed a drought pot experiment, using 1-year-old Chinese fir plantlets, to evaluate drought effects under simulated mild drought, moderate drought, and severe drought, which corresponds to 60%, 50%, and 40% of soil field maximum moisture capacity, respectively. A treatment of 80% of soil field maximum moisture capacity was used as control. Effects of drought stress on mineral uptake, accumulation, and distribution in Chinese fir organs were determined under different drought stress regimes for 0–45 days. Severe drought stress significantly increased phosphorous (P) and potassium (K) uptake at 15, 30 and 45 days, respectively, within fine (diameter < 2 mm), moderate (diameter 2–5 mm), and large (diameter 5–10 mm) roots. Drought stress decreased magnesium (Mg) and manganese (Mn) uptake by fine roots and increased iron (Fe) uptake in fine and moderate roots but decreased Fe uptake in large roots. Severe drought stress increased P, K, calcium (Ca), Fe, sodium (Na), and aluminum (Al) accumulation in leaves after 45 days and increased Mg and Mn accumulation after 15 days. In stems, severe drought stress increased P, K, Ca, Fe, and Al in the phloem, and P, K, Mg, Na, and Al in the xylem. In branches, P, K, Ca, Fe, and Al concentrations increased in the phloem, and P, Mg, and Mn concentrations increased in the xylem under severe drought stress. Taken together, plants develop strategies to alleviate the adverse effects of drought stress, such as promoting the accumulation of P and K in most organs, regulating minerals concentration in the phloem and xylem, to prevent the occurrence of xylem embolism. The important roles of minerals in response to drought stress should be further evaluated.
1 citations
TL;DR: Wang et al. as discussed by the authors investigated the relationship between leaf, litter, and soil stoichiometry, microbial community status, and microbial resource limitation of Chinese fir after continuous planting, and showed that successive planting resulted in a leaf and litter imbalance, further affecting community composition and resource limitation.
Abstract: Chinese fir (Cunninghamia lanceolata) is a kind of evergreen coniferous tree species, the expansion of its pure forest area and multiple generations of continuous planting has led to a decline of stand quality and woodland fertility. To further investigate the relationship between leaf, litter, and soil stoichiometry, microbial community status, and microbial resource limitation of Chinese fir after continuous planting. We studied the C, N, and P stoichiometries of leaf, litter, and soil from successive rotations of Chinese fir plantations. In addition to this, soil microbial biomass C, N, and P, extracellular enzymes, as well as the soil microbial community composition, were determined. The continuous planting of Chinese fir significantly increased the leaf N and P contents and decreased the C content of litter, and the soil C:N and C:P ratios, thus leading to a soil stoichiometric imbalance. The continuous planting of Chinese fir plantations significantly increased the soil microbial biomass. Compared with the first-generation plantations, the N and P contents of the second- and third-generation plantations increased by 37.11%, 21.83% and 46.28%, 73.38%, respectively, thus alleviating the restriction of microbial N and P. Under continuous planting, the extracellular enzyme activities of N (NAG+LAP) and P (AP) were significantly decreased, and those of the second- and third-generation plantations were significantly decreased by 7.05%, 9.43% and 11.79%, 48.94%, respectively, compared with those of the first-generation plantations, resulting in an increase of 7.85 and 3.19% in carbon-use efficiency. The fungi:bacteria (F:B) ratio of the soil microbial community was elevated in successive plantations. The least squares pathway model (PLS-PM) indicated that the stoichiometric ratio of ecological enzymes had an indirect negative effect on CUE, and was the strongest predictor. This study showed that the successive plantation of Chinese fir resulted in a leaf, litter, and soil stoichiometric imbalance, further affecting community composition and resource limitation of soil microorganisms.
1 citations
TL;DR: Wang et al. as mentioned in this paper studied the diversity and distribution of Calonectria in soils from plantations of different tree species in different geographic regions. But their focus was on the identification of 1270 isolates from 1270 soil samples.
Abstract: The species of Calonectria include many notorious plant pathogens and are widely distributed around the world. Leaf blight caused by Calonectria species is considered one of the most prominent diseases in Eucalyptus plantations in China. Some Calonectria species isolated from soils in Eucalyptus plantations are highly pathogenic to inoculated Eucalyptus genotypes. In southern China, the plantation trees Cunninghamia lanceolata, Eucalyptus spp., and Pinus massoniana are always adjacently planted, especially in FuJian, GuangDong, GuangXi, and YunNan Provinces. The aim of this study was to understand the diversity and distribution of Calonectria in soils from plantations of different tree species in different geographic regions. Soil samples were collected from 12 sampling sites in Eucalyptus urophylla × E. grandis, P. massoniana, and C. lanceolata plantations in FuJian, GuangDong, GuangXi, and YunNan Provinces. Approximately 250 soil samples were collected from each sampling site, and a total of 2991 soil samples were obtained. A total of 1270 Calonectria isolates were obtained from 1270 soil samples. The 1270 isolates were identified based on DNA sequence comparisons of the partial gene regions of act, cmdA, his3, rpb2, tef1, and tub2. These isolates were identified as 11 Calonectria species: Calonectria aconidialis (69.50%), C. kyotensis (13.10%), C. hongkongensis (10.80%), C. ilicicola (2.50%), C. asiatica (2.36%), C. curvispora (0.31%), C. chinensis (0.24%), C. pacifica (0.24%), C. yunnanensis (0.16%), and C. canadiana (0.08%) in the C. kyotensis species complex and C. eucalypti (0.71%) in the C. colhounii species complex. The three dominant species, C. aconidialis, C. kyotensis, and C. hongkongensis, were widely distributed. The richness of Calonectria (percentage of soil samples that yielded Calonectria) in soils in the eastern regions (relatively humid regions) was higher than that in the western regions. The Calonectria richness of E. urophylla × E. grandis, P. massoniana, and C. lanceolata plantations decreased gradually. For each of the three dominant species, its richness in the eastern regions was generally higher than that in the western regions; the species richness was highest in E. urophylla × E. grandis plantations for C. aconidialis, while for each of C. kyotensis and C. hongkongensis, its species richness was highest in P. massoniana plantations. The genetic variation in C. aconidialis, C. kyotensis, and C. hongkongensis was more greatly affected by geographic region than by plantation tree species. This study expanded our understanding of the richness, species diversity, and distribution characteristics of Calonectria in soils from the plantations of different tree species in different geographic regions in southern China. Results in this study enhanced our understanding of the influencing characteristics of geographic region and tree species on the species and genetic diversity of soilborne fungi.
1 citations
TL;DR: Wang et al. as discussed by the authors used the UAV image as the data source and developed a method to extract crown information of individual tree based on deep learning method and watershed algorithm, which was an efficient and low-cost method of extracting tree crown parameters.
Abstract: As one of the important timber species in China, Cunninghamia lanceolata is widely distributed in southern China. The information of tree individuals and crown plays an important role in accurately monitoring forest resources. Therefore, it is particularly significant to accurately grasp such information of individual C. lanceolata tree. For high-canopy closed forest stands, the key to correctly extract such information is whether the crowns of mutual occlusion and adhesion can be accurately segmented. Taking the Fujian Jiangle State-owned Forest Farm as the research area and using the UAV image as the data source, we developed a method to extract crown information of individual tree based on deep learning method and watershed algorithm. Firstly, the deep learning neural network model U-Net was used to segment the coverage area of the canopy of C. lanceolata, and then the traditional image segmentation algorithm was used to segment the individual tree to obtain the number and crown information of individual tree. Under the condition of maintaining the same training set, validation set and test set, the extraction results of the canopy coverage area by the U-Net model and traditional machine learning methods [random forest (RF) and support vector machine (SVM)] were compared. Then, two individual tree segmentation results were compared, one using the marker-controlled watershed algorithm, and the other using the combination of the U-Net model and marker-controlled watershed algorithm. The results showed that the segmentation accuracy (SA), precision, IoU (intersection over union) and F1-score (harmonic mean of precision and recall) of the U-Net model were higher than those of RF and SVM. Compared with RF, the value of those four indicators increased by 4.6%, 14.9%, 7.6% and 0.05, respectively. Compared with SVM, the four indicators increased by 3.3%, 8.5%, 8.1% and 0.05, respectively. In terms of extracting the number of trees, the overall accuracy (OA) of the U-Net model combined with the marker-controlled watershed algorithm was 3.7% higher than that of the marker-controlled watershed algorithm, with the mean absolute error (MAE) being decreased by 3.1%. In terms of extracting crown area and crown width of individual tree, R2 increased by 0.11 and 0.09, mean squared error decreased by 8.49 m2 and 4.27 m, and MAE decreased by 2.93 m2 and 1.72 m, respectively. The combination of deep learning U-Net model and watershed algorithm could overcome the challenges in accurately extracting the number of trees and the crown information of individual tree of high-density pure C. lanceolata plantations. It was an efficient and low-cost method of extracting tree crown parameters, which could provide a basis for developing intelligent forest resource monitoring.
1 citations
TL;DR: Zhang et al. as discussed by the authors developed 343,644 high-quality single nucleotide polymorphism (SNP) markers to resolve the genetic diversity and population genetic structure of 233 Chinese fir selected individuals from the 4th cycle breeding program, representing different breeding generations and provenances.
Abstract: Studying population genetic structure and diversity is crucial for the marker-assisted selection and breeding of coniferous tree species. In this study, using RAD-seq technology, we developed 343,644 high-quality single nucleotide polymorphism (SNP) markers to resolve the genetic diversity and population genetic structure of 233 Chinese fir selected individuals from the 4th cycle breeding program, representing different breeding generations and provenances. The genetic diversity of the 4th cycle breeding population was high with nucleotide diversity (Pi ) of 0.003, and Ho and He of 0.215 and 0.233, respectively, indicating that the breeding population has a broad genetic base. The genetic differentiation level between the different breeding generations and different provenances was low (Fst < 0.05), with population structure analysis results dividing the 233 individuals into four subgroups. Each subgroup has a mixed branch with interpenetration and weak population structure, which might be related to breeding rather than provenance, with aggregation from the same source only being in the local branches. Our results provide a reference for further research on the marker-assisted selective breeding of Chinese fir and other coniferous trees.
1 citations
TL;DR: Wang et al. as discussed by the authors constructed core collections representing the genetic diversity of Chinese fir seed orchard resources based on SSR data, and compared and analyzed nine methods for constructing core collections.
Abstract: Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) is one of the most important tree species for afforestation in China. First-, second-, and third-generation seed orchards of Chinese fir have been established successively, and rich germplasms have been accumulated in the process of genetic improvement. It is necessary to build a core collection of germplasms from Chinese fir seed orchards. In this work, we constructed core collections representing the genetic diversity of Chinese fir seed orchard resources based on SSR data. A total of 607 seed orchard materials from three generations were used to determine the best sampling method and intensity by comparing and analyzing nine methods for constructing core collections. Core Hunter’s multi-strategy optimizes allele coverage and the distance criterion under a 30% sampling intensity (weight: A–NE, 0.7; CV, 0.3 and E–NE, 0.5; CV, 0.5), which is superior to other strategies and was selected as the best method. The two core collections (A–NE&CV73, E–NE&CV55) constructed contained all the alleles of the whole collection and effectively limited the homology in the core collections; each core collection contained 182 accessions. Our findings could contribute greatly towards improving the management of genetic resources in Chinese fir seed orchards and provide elite materials for future studies.
TL;DR: Wang et al. as mentioned in this paper explored how soil aggregate composition, geometric mean diameter (GMD), mean weight diameter (MWD), total nitrogen (TN), total acidolyzable nitrogen (TAN), available nitrogen (AN), amino acid nitrogen (AAN), nitrate nitrogen (NO3−-N), cidolyzably ammonia nitrogen (AMN), unknown-acidolyzables nitrogen (HUN), amino sugar nitrogen (ASN), and ammonium nitrogen (NH4+-N) contents and stocks varied with aggregate size (>2, 1-2, 0.25-1, and <0.25 mm) and stand type [Chinese fir mixed with Michelia macclurei Dandy (CF + MM), Chinese fir mixedwith Mytilaria laosensis Lecomte (CF+ ML) and pure stands of Chinese fir (CF)] in 0-20 and 20-40 cm soil depth.
Abstract: Nitrogen plays a crucial role in limiting plant growth and determining net primary productivity in forest ecosystems. However, variations and influencing factors of soil nitrogen distribution on the aggregate scale in pure and mixed Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) plantations remain unclear. This study aimed to explore how soil aggregate composition, geometric mean diameter (GMD), mean weight diameter (MWD), total nitrogen (TN), total acidolyzable nitrogen (TAN), available nitrogen (AN), nonacidolyzable nitrogen (AIN), amino acid nitrogen (AAN), nitrate nitrogen (NO3−-N), cidolyzable ammonia nitrogen (AMN), unknown-acidolyzable nitrogen (HUN), amino sugar nitrogen (ASN), and ammonium nitrogen (NH4+-N) contents and stocks varied with aggregate size (>2, 1–2, 0.25–1, and <0.25 mm) and stand type [Chinese fir mixed with Michelia macclurei Dandy (CF + MM), Chinese fir mixed with Mytilaria laosensis Lecomte (CF + ML) and pure stands of Chinese fir (CF)] in 0–20 and 20–40 cm soil depth. Soil N content in different stand types of Chinese fir plantations decreased as the aggregate size increased, whereas the soil N stock exhibited the opposite trend. In contrast to CF soil, CF + MM and CF + ML soil displayed a significant increase in MWD, GMD, and aggregate-associated TN, AN, NO3−-N, NH4+-N, AIN, AAN, ASN, and AMN contents and stocks, especially CF + MM soil. Organic N was more sensitive to the response of aggregate size and stand type than mineral N. Redundancy analysis and Pearson’s correlation analysis indicated that the 0.25–1 mm aggregate proportion was the main controlling factor for the variations in soil N content and storage. Overall, this study contributed significantly to the promotion of the sustainable use of soil resources and reference information for the scientific management and sustainable development of Chinese fir forests.
TL;DR: In this paper , the effects of different restoration approaches of subtropical degraded forests on bonding materials and stability of soil aggregate were investigated in a study conducted by the National Natural Science Foundation of China.
TL;DR: In this article , the authors used single-molecule full-length transcriptome (SMRT) sequencing technology was used to obtain full-term transcriptome data on Chinese fir and used these data to identify nine heat shock transcription factors (Hsfs) in Chinese fir, and heat stress transcriptome and real-time quantitative polymerase chain reaction (PCR) analyses revealed expression changes in response to heat stress.
Abstract: Cunninghamia lanceolata (Lamb.) Hook. (Chinese fir) is an important timber species that is widely cultivated in southern China. However, the shallow root system and weak drought resistance of Chinese fir are not enough to cope with high temperature and drought. In recent years, molecular biology has been used to modify plants to make them more resilient. Therefore, improving heat and drought resistance of Chinese fir by molecular biology technology is one of the best choices, whereas fewer genetic information resources for C. lanceolata limit more comprehensive molecular studies. In this study, single-molecule full-length transcriptome (SMRT) sequencing technology was used to obtain full-length transcriptome data on Chinese fir. A total of 21,331 transcripts were obtained via co-assembly, and 11,094 gene sets were obtained via further de-redundancy. In addition, gene function annotation and gene structure analysis were performed. We also used these data to identify nine heat shock transcription factors (Hsfs) in Chinese fir, and heat stress transcriptome and real-time quantitative polymerase chain reaction (PCR) analyses revealed expression changes in response to heat stress, indicating that these may play roles in heat resistance. These studies have enriched the genetic information resources of Chinese fir, which may be utilized for further species promotion, improvement, and application.
TL;DR: In this paper , the effects of liming on soil respiration and temperature sensitivity within the context of acid deposition were investigated in Chinese fir plantations for one year, with 0, 1 and 5 t·hm-2 calcium oxide being added in 2018.
Abstract: The primary distribution area of acid deposition coincides with areas of Chinese fir (Cunninghamia lanceolata) plantations. Liming is an effective method of restoring acidified soil. To understand the effects of liming on soil respiration and temperature sensitivity within the context of acid deposition, we measured soil respiration and its components in Chinese fir plantations for one year beginning in June 2020, with 0, 1 and 5 t·hm-2 calcium oxide being added in 2018. The results showed that liming considerably increased soil pH and exchangeable Ca2+ concentration, and that there was no significant difference among different levels of lime application. Soil respiration rate and components in the Chinese fir plantations exhibited seasonal variations, with the highest values during the summer and the lowest values during the winter. Although liming did not alter seasonal dynamics, it strongly inhibited heterotrophic respiration rate and increased autotrophic respiration rate of soil, with minor effect on total soil respiration. The monthly dynamics of soil respiration and temperature were largely consistent. There was a clear exponential relationship between soil respiration and soil temperature. Liming increased temperature sensitivity Q10 of soil respiration and autotrophic respiration but reduced that of soil heterotrophic respiration. In conclusion, liming promoted soil autotrophic respiration and strongly inhibited soil heterotrophic respiration in Chinese fir plantations, which would facilitate soil carbon sequestration.
TL;DR: Zhang et al. as mentioned in this paper 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.
Abstract: 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.
TL;DR: Wang et al. as discussed by the authors proposed a method for identifying different forms of Chinese fir and construct their respective stand volume estimation models to obtain an estimate of the forest stand volume, which can greatly reduce the working time of single tree segmentation to achieve the fast and accurate estimation of fir plantation stand volume.
Abstract: Chinese fir (Cunninghamia lanceolata) is the main fast-growing timber species in China, and studies of its stand volume are important for evaluating the effectiveness of forest management. However, it is difficult to accurately estimate stand volume from the perspective of a single tree due to the mutual concealment among Chinese fir trees. Therefore, in this study, we propose a method for identifying different forms of Chinese fir. The specific idea is to realize the accurate identification of a single Chinese fir tree, two Chinese fir trees, and three Chinese fir trees, and construct their respective stand volume estimation models to obtain an estimate of the forest stand volume. The key results are as follows: (1) the overall accuracy of recognition of different forms of Chinese fir is 79%, and the construction of different forms of Chinese fir units is beneficial for identifying forest trees; (2) a multiunit volume equation for different forms of Chinese fir is constructed; (3) based on predictions obtained with the constructed stand volume model, the difference between the estimated stand volume and the measured stand volume is small, and the average accuracy reaches 89.19%; and (4) compared to traditional volume estimation methods based on individual tree scale, the research method in this study shows a significant improvement (about 9.96%) in overall accuracy. In summary, this method can weaken the influence of erroneous individual tree segmentation on the accuracy of stand volume estimation, and can greatly reduce the working time of single tree segmentation to achieve the fast and accurate estimation of fir plantation stand volume.
TL;DR: In this article , the authors investigated the physical and chemical properties of the soil, its enzyme activities, and its microbial diversity in three adjoining plantations managed with different successive planting models (long-term continuous growth without harvest, M1; single harvest cutting followed by the construction of a pure plantation, M2; and double harvest cutting, M3) to evaluate the impact of these forest management practices.
Abstract: Successive planting is the main pattern for cultivating Chinese fir (Cunninghamia. lanceolata (Lamb.) Hook.). However, the influence of this management has not been totally investigated, especially with respect to the changes in the soil microbial community and the relationship to soil properties. This study investigated the physical and chemical properties of the soil, its enzyme activities, and its microbial diversity in three adjoining plantations managed with different successive planting models (long-term continuous growth without harvest, M1; single harvest cutting followed by the construction of a pure plantation, M2; and double harvest cutting followed by the construction of a mixed plantation, M3) to evaluate the impact of these forest management practices. In most soil layers, M1 was observed to have significantly higher content of Na and Al ions, as well as more polyphenol oxidase (PPO) activity, and M2 had a significantly higher field moisture capacity (FMC) and content of Mg ions, while M3 had significantly higher urease (URE) activity. Changes in the totals of N (TN) and C (TC), alongside the availability of P (AP), C/P, N/P, URE, sucrose (SUC), and PPO values, correlated significantly with bacterial diversity, whereas the dynamics of total K (TK), Na, C/P, N/P, and PPO levels were significantly related to fungal diversity. Among the models, soil bacterial genera, including Burkholderia–Caballeronia–Paraburkholderia, Acidothermus, and Paenibacillus, were mostly affected by TN, TC, AP, organic matter (OM), C/N, C/P, N/P, SUC, and the performance of URE. The distribution of fungal genera in different models showed significant differences. Talaromyces, Trichoderma, and Aspergillus were relatively abundant in M1, while Umbelopsis and Saitozyma exhibited more adaptation in M3. These results illustrated better soil properties and higher abundance of microbial diversity in M1 and M3, and furthermore, demonstrated the strategic benefit of both prolonging the rotation period and of creating mixed artificial plantations to maintain diversity. This study improves the understanding of the impact of a successive planting strategy in C. lanceolata plantation sustainability.
TL;DR: Wang et al. as mentioned in this paper used UAV RGB images to monitor the growth of low-growing saplings in an afforestation plot using two key algorithms: divide-and-conquer (DAC) and local maximum (LM).
Abstract: With the rapid development of Unmanned Aerial Vehicle (UAV) technology, more and more UAVs have been used in forest survey. UAV (RGB) images are the most widely used UAV data source in forest resource management. However, there is some uncertainty as to the reliability of these data when monitoring height and growth changes of low-growing saplings in an afforestation plot via UAV RGB images. This study focuses on an artificial Chinese fir (Cunninghamia lancelota, named as Chinese Fir) young forest plot in Fujian, China. Divide-and-conquer (DAC) and the local maximum (LM) method for extracting seedling height are described in the paper, and the possibility of monitoring young forest growth based on low-cost UAV remote sensing images was explored. Two key algorithms were adopted and compared to extract the tree height and how it affects the young forest at single-tree level from multi-temporal UAV RGB images from 2019 to 2021. Compared to field survey data, the R2 of single saplings’ height extracted from digital orthophoto map (DOM) images of tree pits and original DSM information using a divide-and-conquer method reached 0.8577 in 2020 and 0.9968 in 2021, respectively. The RMSE reached 0.2141 in 2020 and 0.1609 in 2021. The R2 of tree height extracted from the canopy height model (CHM) via the LM method was 0.9462. The RMSE was 0.3354 in 2021. The results demonstrated that the survival rates of the young forest in the second year and the third year were 99.9% and 85.6%, respectively. This study shows that UAV RGB images can obtain the height of low sapling trees through a computer algorithm based on using 3D point cloud data derived from high-precision UAV images and can monitor the growth of individual trees combined with multi-stage UAV RGB images after afforestation. This research provides a fully automated method for evaluating the afforestation results provided by UAV RGB images. In the future, the universality of the method should be evaluated in more afforestation plots featuring different tree species and terrain.
TL;DR: Li et al. as discussed by the authors explored the effects of N and P additions on soil CO2 emissions in a P-limited and N-rich Chinese fir plantation (Cunninghamia lanceolata).
Abstract: Nitrogen (N) and phosphorus (P) nutrients have been regularly applied to improve productivity in intensively managed and short-rotation forest plantations in subtropical China. Under the constraint of the national policy of “carbon neutrality”, it is necessary to determine the rational fertilization options by considering both forest productivity and soil CO2 emissions. Past worldwide studies have shown varied responses of forest soil heterotrophic respiration and CO2 emissions to N and P additions. This study designed six treatments with N additions (high level: 15 g N/m2, HN), P (low: 5 g P/m2, LP; high: 15 g P/m2, HP), and their interactions (HNLP and HNHP) to explore the effects of N and P additions on soil CO2 emissions in a P-limited and N-rich Chinese fir plantation (Cunninghamia lanceolata), and we identified the underlying controls using the structural equation model (SEM). The results indicated that LP, HNLP, and HNHP treatments significantly increased soil CO2 emissions in the first four months after treatment and the effects leveled since then. The balance between N and P inputs affected the responses of soil CO2 emissions to P additions. A low P addition significantly increased tree productivity, but the promoting effect gradually declined and was no longer significant after 3 years. Other treatments did not significantly affect tree productivity. The SEM analysis revealed that the promoting effects of P additions on CO2 emission were mainly due to their effects on increasing soil water-soluble organic carbon content and reducing microbial biomass nitrogen content. Considering both soil respiration and tree productivity, this study suggested that LP treatment can effectively balance the N and P nutrients and, in the meantime, maintain relatively low greenhouse gas emissions; thus a low P application level is suggested for N-rich Chinese fir plantations.
20 Mar 2023
TL;DR: In this paper , a carbon-water coupled model (TRIPLEX-CW-Flux) was developed, and an R package (rTRIPleXCWFlux), which integrates vapor pressure deficit and soil moisture into a stomatal conductance submodule to estimate forest carbon and water fluxes.
Abstract: Carbon and water cycles in forest ecosystems are tightly coupled, but global warming-induced soil and atmospheric droughts alter the coupling, thereby greatly increasing uncertainty in predicting carbon and water cycles. Therefore, a carbon–water coupled model (TRIPLEX-CW-Flux) was developed, and an R package (rTRIPLEXCWFlux) was created to facilitate model application. TRIPLEX-CW-Flux integrates vapor pressure deficit and soil moisture into a stomatal conductance submodule to estimate forest carbon and water fluxes. Prediction accuracy of TRIPLEX-CW-Flux and rTRIPLEXCWFlux application were evaluated in a Chinese fir (Cunninghamia lanceolata) plantation. Simulated net ecosystem production (NEP) and evapotranspiration (ET) were in good agreement with flux observations (R2: 0.76 for NEP; 0.71 for ET). Thus, the TRIPLEX-CW-Flux model can be used to predict and quantify effects of global warming-induced droughts on forest carbon and water cycles. The open-access rTRIPLEXCWFlux package facilitates estimations of carbon sequestration and water consumption in forest ecosystems using the observed flux data.
TL;DR: In this article , the authors used a typical sampling to study the impact of four thinning intensities on the tree growth and soil physicochemical properties and their correlation in Cunninghamia lanceolata plantations.
Abstract: Tree growth, along with soil properties, is greatly affected by forest management. We used a typical sampling to study the impact of four thinning intensities (T1: 0%, 2500 stems ha−1; T2: 20%, 2010 stems ha−1; T3: 30%, 1750 stems ha−1; T4: 40%, 1500 stems ha−1) on the tree growth and soil physicochemical properties and their correlation in Cunninghamia lanceolata plantations. The average annual increments in tree height, diameter at breast height (DBH), and volume increased with thinning intensity, and those of T4 differed significantly (P < 0.05) from those of T1. The average annual stand volume increments of T4 were significantly (P < 0.05) lower than that of T1, while the maximum value presented at T3. However, the effect of thinning in promoting the growth of Chinese fir diminished with time. As the thinning intensity increased, the diameter class distribution of the sample stands moved rightwards. Moreover, thinning improved soil physiochemical properties. The effects of thinning on soil properties in 0–20 cm soil layer were greater than those in 20–40 cm soil layer. There was a positive correlation between available nitrogen, available potassium and tree growth. The results of this study showed that thinning had a potential effect on tree growth and soil properties. The heavy thinning intensity (approximately 1500 stems ha−1) was the optimum for maintaining economic and ecological benefits. However, heavy thinning significantly reduced stand volume. From the perspective of improving stand volume and biomass, a moderate thinning intensity (approximately 1750 stems ha−1) could be considered for adoption.
TL;DR: In this article , the morphological characteristics of Chinese fir clonal Pi-efficiency stress were used to evaluate the phenotypic variation in phosphorus conversion and utilization efficiency by tree breeders, and new insights into the molecular mechanisms of Pi-efficient utilization in Chinese fir clones were provided.
Abstract: Cunninghamia lanceolate (Lamb.) Hook. (Chinese fir) is one of the most important wood-producing species, supplying ~20% of commercial timber by plantations in China. However, the genetic potential of the bred variety is limited by soil degrading in the long term and requiring continuous replanting, and especially the shortage and supply of active and efficient phosphorus. Recently, great attention has been paid to the genotypic variation in phosphorus conversion and utilization efficiency by tree breeders. In this study, the morphological characteristics were used to evaluate the Chinese fir clonal Pi-efficiency stress. A Pi-tolerant clone and a Pi-sensitive clone were selected for RNA sequencing, respectively. In addition, gene function annotation and weighted correlation network analysis (WGCNA) were performed. A total of 60 hub genes were selected, combining phosphate accumulation under Pi-deficiency stress. We also used RNA-seq data to analyze the differences in the response of Pi-sensitive clones and Pi-tolerant clones to Pi-deficiency stress, and real-time quantitative polymerase chain reaction (RT-PCR) analyses were used to test the validity of transcriptome data. The present study provided new insights into the molecular mechanisms of Pi-efficient utilization in Chinese fir clones.
01 Jan 2023
TL;DR: In this article , the effects of the 2010 Nanping landslides (China) on soil quality were studied. And the results provided fundamental data for evaluating impacts of natural disasters on soil and rates of natural recovery.
Abstract: Understanding how natural disasters affect soil quality and how it recovers is essential to improve soil management. We studied the effects of the 2010 Nanping landslides (China) on soil quality. We conducted an observational study using three levels of disturbance (‘destroyed’, ‘recovering’, and ‘undisturbed’). The ‘destroyed’ areas were sampled immediately after the landslide and the others were sampled 7 years later. To assess the consistency of landslide-induced effects, we sampled these levels of disturbance in three forest types (Cunninghamia lanceolata conifer forest, Phyllostachys heterocycla bamboo forest, and secondary evergreen broadleaf forest). In total, 81 soil samples were collected and analyzed for 26 soil indicators. A minimum data set (MDS) was identified that represented the physical, chemical, and biological properties of the soils. Indicators in the MDS were then weighted and summed together to calculate a soil quality index (SQI) for each category and a total SQI. The landslide strongly affected all aspects of soil quality. After seven years of natural recovery, most aspects of soil quality were significantly improved but remained lower than in ‘undisturbed’ sites. Recovery was faster for biological than physical or chemical properties. Recovery was slower in bamboo forests than in other forest types, suggesting that human interventions could accelerate post-landslide soil recovery in bamboo forest. Our results provide fundamental data for evaluating impacts of natural disasters on soil and rates of natural recovery.
TL;DR: In this paper , the root removal in Cunninghamia lanceolata and Michelia macclurei plantations was investigated to analyze the changes of soil organic carbon and physical properties and to measure the size and mean weight diameter (MWD) of aggregates.
Abstract: Acid rain is one of most serious environment problems in China. The types of acid rain have gradually transformed from sulfuric acid rain (SAR) to mixed acid rain (MAR) and nitric acid rain (NAR) in recent years. Roots are one source of soil organic carbon and play an important role in the formation of soil aggregates. However, the changes in acid rain type and the effect of root removal on soil organic carbon in forest ecosystems are poorly understood. In this study, we removed roots and simulated acid rain with different types (SO42-:NO3- ratio of 4:1, 1:1, and 1:4) for three years in Cunninghamia lanceolata (CP) and Michelia macclurei (MP) plantations to analyze the changes of soil organic carbon and physical properties and to measure the size and mean weight diameter (MWD) of aggregates. Results showed that root removal in C. lanceolata and M. macclurei remarkably reduced soil organic carbon pool by 16.7 % and 21.5%, and soil recalcitrant carbon by 13.5% and 20.0%, respectively. Root removal substantially decreased the MWD and proportion and organic carbon content of soil macroaggregates in M. macclurei, but not in C. lanceolata. Acid rain did not affect soil organic carbon pool and soil aggregate structures. Our results indicated that roots promote soil organic carbon stabilization and that their contribution to the stability of soil organic carbon varies with forest types. Moreover, soil organic carbon stabilization is not affected by different types of acid rain in the short term.
TL;DR: In this article , Wang et al. presented a new technical support for forest land asset evaluation by enriching the technical system of the traditional forest land expectation value method by considering the actual forest stock volume when assessing the income at the end of the current production cycle in the forest.
Abstract: In order to solve the problem in that the classical forest land expectation value method ignores the actual forest stock volume when assessing the income at the end of the current production cycle in the forest, and fill the research gap in this area, the technical system of the forest land asset evaluation was enriched. The forest land returns were divided into two parts, i.e., the segmented forest land return price from the growth of the actual forest stand to the end of the growth cycle (Bu1), and the segmented forest land return price for an infinite number of growth cycles after the growth of the actual forest stand to the end of the growth cycle (Bu2). Through structure, the forest land gain price expansion model was obtained, and the stand quality including the average diameter at breast height, average height, stock volume, and outturn of stand as dummy variables were used to construct the growth harvest model related to asset evaluation. Taking Cunninghamia lanceolata forest land as an example, the traditional asset evaluation methods were comparatively analyzed. The residual standard deviation (RSD) of the growth model was less than 10%, the total relative error (TRE) and mean system error (MSE) were within ±10%, the mean prediction errors (MPE) were less than 5%, and the mean percentage standard errors (MPSE) were less than 10%, respectively. Combining the forest land net present value expansion model with the traditional evaluation method, the evaluation value of the forest land assets was subsequently calculated, and accordingly, the forest land asset evaluation prime stand factors were predicated. It was found that the valuation results of the forest land net present value expansion model were consistent with the actual situation. The forest land net present value expansion model can therefore be used for asset evaluation of tree forest land (including natural uneven-aged forest land), bamboo forest land, shrub forest land, and economic forest land, and provide new technical support for forest land asset evaluation.
01 Jan 2023
TL;DR: In this article , the authors investigated the response of three species' roots to drought and evaluated the key root architecture traits affecting the drought tolerance of the three species, i.e., root topological index, fractal dimension, and root branching angle.
Abstract: The drought tolerance of plants is significantly influenced by their root architecture traits and root adaptive strategies, but the key root architecture traits that affect drought tolerance and the differences in drought adaptative strategies of species with varying root architectures are not yet clear. This study aimed to investigate the response of three species’ roots to drought and evaluate the key root architecture traits affecting the drought tolerance of the three species. One-year-old potted seedlings of three species [Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.), masson pine (Pinus massoniana (Lamb.)), and moso bamboo (Phyllostachys edulis (Carr.) H. de Lehaie f. edulis)] were planted in a greenhouse under three drought conditions (sufficient water supply, moderate drought, and severe drought) for 90 days. Biomass, root morphology [root surface area (RSA), root length (RL), root diameter (RD)], root architecture [root topological index (TI), fractal dimension (FD), and root branching angle (RBA)] of seedlings were measured monthly. The drought tolerance of species was quantified by studying the response ratio (RR) of root length and biomass in response to drought. We found that: (i) different levels of drought inhibited the biomass accumulation and root growth of the three species, and drought tolerance showed a decreasing order as pine > Chinese fir > bamboo; (ii) drought decreased the RD in bamboo but increased it in pine. Both bamboo and Chinese fir reduced their FD and RBA under drought stress, while pine was relatively stable. All the three species’ roots tended to develop a herringbone branching architecture (increase their TI) under drought stress; (iii) both TI and FD were negatively correlated with the drought tolerance of the seedlings. Our results indicated that plants could adapt to drought by different strategies such as adjusting biomass allocation and root morphology, reducing root branch strength, and branching angles. Roots with narrower branching angles, greater branching complexity, larger TI, and consuming higher cost are more drought-tolerant.