Biomass and net primary productivity (NPP) are important factors for studying terrestrial carbon storage and the carbon cycle. Using data from existing literature, this study synthesized and analyzed a comprehensive database of direct field observations of forest biomass and NPP for Southwestern China. The biomass of mature natural forests and mature planted forests range from 81.2 Mg·ha−1 to 692.6 Mg·ha−1 (mean = 288.1 Mg·ha−1) and from 76.8 Mg·ha−1 to 670.1 Mg·ha−1 (mean = 181.5 Mg·ha−1), respectively. Mature natural forests have higher biomass than mature planted ones. The NPP values of natural and planted forests range from 1.4 Mg·ha−1·year−1 to 29.6 Mg·ha−1·year−1 (mean = 13.6 Mg·ha−1·year−1) and from 0.6 Mg·ha−1·year−1 to 26.5 Mg·ha−1·year−1 (mean = 9.9 Mg·ha−1·year−1), respectively. Correlations among biomass, NPP, and environmental factors show that NPP significantly decreases with latitude and increases with mean annual temperature, mean annual precipitation, growing degree-days on a 0 °C base, and mean annual drought index, whereas biomass positively correlates with stand age and leaf area index strongly. Karst forests exhibit almost the same NPP as non-karst forests, but the former have significantly lower biomass compared to the latter. Comprehensive regional data synthesis and analysis based on direct field observations of forest biomass and NPP are important for benchmarking global and regional vegetation and carbon models, estimating regional carbon content, restoring vegetation, and mitigating climate change.

https://www.mdpi.com/1999-4907/7/8/173/pdf

Forest Biomass and Net Primary Productivity in Southwestern China: A Meta-Analysis Focusing on Environmental Driving Factors

Recent sediments from Lake Chenghai, China, were investigated at high temporal resolution to trace both natural and anthropogenic effects on the lake using total organic carbon (TOC), total nitrogen (TN), total phosphorus (TP), organic phosphorus (Po), inorganic phosphorus (Pi) and organic carbon and nitrogen stable isotopes (δ13Corg and δ15N) in a 137Cs-dated sediment core. The results indicated that the sedimentary record covers the last 60 years, during which the lake had undergone apparent changes in nutrient sources and productivity in response to nutrient loading. Prior to the late 1980s, the nutrient contents in sediments mainly originated from algae and lake productivity was relatively stable. Since the late 1980s, increasing TOC, TN and TP concentrations together with the change of δ13Corg and δ15N suggested anthropogenic perturbations in nutrient loading and lake productivity. Endogenic nutrients derived from algae and anthropogenic inputs were two important sources of sedimentary nutrients. The anthropogenic nutrients mainly originated from the discharge of industrial wastewater and artificial cultivation of Spirulina after the middle 1980s, and domestic wastewater discharged from Yongsheng County since 1993.

A 60-year sedimentary record of natural and anthropogenic impacts on Lake Chenghai, China.

Aims Tropical seasonal rain forest in Xishuangbanna is one of the most species-rich forest ecosystems in China.This area is also one of the biodiversity hotspots for conservation priorities of the world.For the purpose of monitoring long-term dynamics of tree populations,a 20-hm2 plot was established in a dipterocarp forest in Mengla Nature Reserve in 2007 by Xishuangbanna Tropical Botanical Garden,Chinese Academy of Sciences and Xishuangbanna Administration of Nature Reserves,in collaboration with Alberta University,Canada and Tunghai University(Taiwan,China).Methods The construction technology and field protocol followed those applied in the establishment of the 50 hm2 plot in the tropical forest of Barro Colorado Island in Panama,developed by Center for Tropical Forest Science,Smithsonian Tropical Research Institute in 1980.All free-standing trees with diameter at breast height(DBH)≥ 1 cm were tagged,mapped,measured(girth)and identified to species in the plot.Spatial distribution patterns of four dominant canopy tree species(among different tree size classes)and 12 rare species were analyzed by using a point pattern analysis Ripley's L-function.Important findings A total of 95 834 free-standing individuals with DBH ≥ 1 cm were recorded in the 20 hm2 plot.Of which,95 498 individuals were identified to species level.This plot included 468 species belonging to 213 genera and 70 families,except for another 336 individuals that could not be identified yet.The flora of plot was mainly composed of species in tropical families.Shorea wantianshuea that dominates the forest canopy was ranked the second in terms of importance value,although it had the largest basal area.Pittosporopsis kerrii,an understory tree species showed the highest abundance(20 918 individuals).The four canopy species had a large number of juveniles and exhibited size structures with reverse-J shape associated with continuously regenerating populations.Young trees(saplings and poles)revealed a clumped spatial distribution,but adults tended to have a random distribution.Most of the 12 rare tree species in the plot also showed aggregated distribution pattern.

Establishment of xishuangbanna tropical forest dynamics plot:species compositions and spatial distribution patterns

Both biodiversity and biomass are important variables in forest ecosystems, and the relationship between them is critical for ecosystem functioning and management. The primary Pinus kesiya forest is increasingly threatened by human disturbance in Yunnan Province. We observed that species richness had a positive impact on aboveground biomass across all forest vegetation layers, and this relationship was strongest in the herb layer. The asymptotic relationship between cumulative species number and aboveground biomass suggested that individual of Pinus kesiya trees with relatively large diameters contributed the majority of the aboveground biomass in the tall tree strata due to their strong competitive advantage over other tree species. Although aboveground biomass increased with stand age in the tall tree strata, climate factors and the soil nutrient regime affected the magnitude of the diversity-productivity relationship. Stand age had no significant effect on species richness and aboveground biomass in the forest understory. The effect of the positive diversity-productivity relationship of the tall trees on the shrub layer was negligible; the diversity-productivity relationship in the forest understory was significantly affected by the tall tree aboveground biomass. The tall trees have increased the strength of the positive diversity-productivity relationship in the forest understory.

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Positive relationship between species richness and aboveground biomass across forest strata in a primary Pinus kesiya forest.

Vacuum pyrolysis method for reclamation of rare earth elements from hyperaccumulator Dicranopteris dichotoma grown in contaminated soil

A study of the Alnus cremastogyne plantation showed that it was characterized by fast-growing , flourishing root system , quick undergrowth restoration , higher biodiversity , soil improving and water holding capacity .The biomass of tree organs were in order trunk root branch bark leaf .The roots in the soil layer of 0 -40cm accounted for 96.14 %of the total roots .The biomass in the arbor layerwas the largest , accounting for 84.93 % of the total biomass of the plantation .The biomass of leaf litter layer , herbage layer and shrub layer were less than the arbor layer .Finally regression models of the biomass of different Alnus cremastogyne organs were established to provide the reference for the management of the Alnus cremastogyne plantation . [ Ch , 5 tab .16 ref .]

Characteristics of Alnus cremastogyne plantation community and its biomass in central Yunnan Plateau

We censused all free-standing trees with diameter at breast height (dbh) ≥ 1 cm in a four-ha plot in a mid-montane humid evergreen broad-leaved forest in Gaoligong Mountains, Southwest China. A total of 10,546 freestanding trees with dbh ≥ 1 cm were recorded, and all individuals, including 95 species from 64 genera and 35 families were identified. Nine of 95 species had more than 300 individuals, with 4,472 in total. Eleven species had only one individual in the four-ha plot. Symplocos ramosissima (Symplocaceae), the most abundant species (837 stems), and Gordonia longicarpa (Theaceae), the species with the largest basal area (13.05 m 2 ), were most dominant in the plot. Compared with other dynamic plots in China, the plot had intermediate levels of species richness, stem density, and basal area, but the proportion of rare species and the maximum importance value were lowest. The species abundance pattern models changed from a logarithmic series model (for the trees with dhb ≥ 1 cm) to a logarithmic normal model (for the trees with dbh ≥ 10 cm), and to both geometric series model and logarithmic normal model (for the trees with dbh ≥ 20 cm), reflecting the differences in community characteristics among trees with different size.

Tree species richness and abundance in a four-ha plot in a mid-montane humid evergreen broad-leaved forest in Gaoligong Mountains of Yunnan province, China

(1) Remediation of soil contaminated by heavy metals has become a hot topic in the world, and phytoremediation technology is the most widely used. (2) In addition to traditional economic benefits, ecological benefits of artificial forest have been more and more important, which are very helpful to soil polluted with heavy metals in the environment. (3) The characteristics of heavy metal pollution of soil and plantations of repair mechanism have been reviewed, and the current mining areas, wetlands, urban plantations on heavy metal elements have enriched the research results. The purpose is to find a new path for governance of heavy metal soil pollution.

https://iopscience.iop.org/article/10.1088/1742-6596/51/1/012003/pdf

Research Progress of Artificial Forest in the Remediation of Heavy Metal Contaminated Soils

Flora of seed plants in Wuding County, Yunnan.

Through analyzing the soil conditions of lakesides of Chenghai Lake,aiming at the difficulty in forestation,some technical measures were proposed on the basis of experimental study.The results of analysis indicated that the sides of Chenghai Lake were mostly covered with loose sediment,the percentage of stone and gravel was high as 79.31 % or above,the soil water penetrability was big,not good for both water and fertilizer preservation.In forestation experiments,using quality big size container seedling,soil replacement,big planting pit,seep-hose irrigation system in dry season,good forestation effect was achieved.

Meng Guang-tao

Papers

Characteristics of Alnus cremastogyne plantation community and its biomass in central Yunnan Plateau

Tree species richness and abundance in a four-ha plot in a mid-montane humid evergreen broad-leaved forest in Gaoligong Mountains of Yunnan province, China

Research Progress of Artificial Forest in the Remediation of Heavy Metal Contaminated Soils

Flora of seed plants in Wuding County, Yunnan.

Soil Condition Analysis and Application Technology of Forestation at Sides of Chenghai Lake