Fir Plantations In China Research Articles

Effects of biochar and litter on carbon and nitrogen mineralization and soil microbial community structure in a China fir plantation

To investigate the effects of biochar addition (1 or 3%) to the soil of a China fir plantation with or without litter, we conducted a 90-day incubation experiment. We also studied the C and N dynamics and the microbial community structure of the soil. In soil without litter, the application of biochar at a rate of 3% significantly decreased CO2 emissions, while addition of 1% biochar had no effect. Biochar application did not affect the net N mineralization rate but significantly reduced the NH4+ concentration after 90 days. In litter-enriched soil, biochar application had no significant effect on total CO2 emissions; however, application of 3% biochar significantly reduced the net N mineralization rate. Biochar application to soil with or without litter immediately reduced the dissolved organic carbon (DOC) concentration independent of the application rate, which was primarily due to sorption of DOC by the biochar. Phospholipid fatty acid analysis demonstrated that both concentrations of added biochar to soil (with or without litter) altered the soil microbial community structure at the end of incubation, although the effect of biochar was not as strong as the effect of time or litter application. The effect of biochar addition alone on microbial community structure was inconsistent over time. Litter added to soil significantly increased fungi and reduced Gram-positive bacteria. In the presence of litter, biochar applied at both 1% and 3% significantly increased (p < 0.05) the proportion of actinomycete only at day 90. Our results indicate biochar as a potentially effective measure for C sequestration in the test soil of a China fir plantation, even in the presence of litter.

Large Ecosystem Service Benefits of Assisted Natural Regeneration

AbstractChina manages the largest monoculture plantations in the world, with 24% being Chinese fir plantations. Maximizing the ecosystem services of Chinese fir plantations has important implications in global carbon cycle and biodiversity protection. Assisted natural regeneration (ANR) is a practice to convert degraded lands into more productive forests with great ecosystems services. However, the quantitative understanding of ANR ecosystem service benefits is very limited. We conducted a comprehensive field manipulation experiment to evaluate the ANR potentials. We quantified and compared key ecosystem services including surface runoff, sediment yield, dissolved organic carbon export, plant diversity, and aboveground carbon accumulation of ANR of secondary forests dominated by Castanopsis carlesii to that of Chinese fir and C. carlesii plantations. Our results showed that ANR of C. carlesii forest reduced surface runoff and sediment yield up to 50% compared with other young plantations in the first 3 years and substantially increased plant diversity. ANR also reduced the export of dissolved organic carbon by 60–90% in the first 2 years. Aboveground biomass of the young ANR forest was approximately 3–4 times of that of other young plantations, while aboveground biomass of mature ANR forests was approximately 1.4 times of that of mature Chinese fir plantations of the same age. If all Chinese fir plantations in China were replaced by ANR forests, potentially 0.7 Pg more carbon will be stored in aboveground in one rotation (25 years). The results indicate that ANR triggers positive feedbacks among soil and water conservation, biodiversity protection, and biomass accumulation and thereby enhances ecosystem services.

Effects of ageing and successive slash-and-burn practice on the chemical composition of charcoal and yields of stable carbon

Chinese fir (Cunninghamia lanceolata) plantations cover over 12Mha in the southeast provinces of China. The traditional conditioning of fields of this conifer involves the slash-and-burn practice. As a result of this practice, pyrogenic carbon (PyC) is produced by the incomplete combustion of organic matter; this includes a continuum of materials ranging from partially charred biomass and charcoal to soot. Owing to the structure and composition of PyC, it has traditionally been considered to have high chemical recalcitrance and resistance to degradation. Thus, PyC produced during slash-and-burn cultivation practices may profoundly alter the terrestrial carbon (C) cycle and soil chemical composition. Hence, this study aims to investigate the quantitative and qualitative composition of charcoal from the oldest Chinese fir plantation in China. Charcoal was sampled in soils from plots of different stand ages after one to four slash-and-burn rotations. This approach permitted an assessment of the effects of ageing and consecutive slash-and-burn rotations on the chemical composition of charcoal and the estimation of the stocks of stable C. The chemical composition of the PyC fraction was examined via elemental (CHN) and 13C nuclear magnetic resonance spectroscopy (13C NMR) analyses. These revealed some signs of degradation, such as a decrease in relative abundance of aryl-C and an increase in H/Cat values over time. The stocks of charcoal and yield of stable C in soil slightly increased with the number of fires, reaching a maximum of 1164kg of PyC per hectare after four prescribed burns. Nevertheless, charcoal stocks decreased sharply with increasing stand age after each slash-and-burn event. In fact, over 25% of the charcoal stock was lost during the period from 12- to 21-years after the first slash-and-burn, and 85% was lost in the 97-year old stand. Our results together indicate that there has been a substantial loss of charcoal in soils following slash-and-burn rotations, on a time scale of decades associated with gentler slopes. Our results question the long-term persistence of charcoal in soils and highlight the necessity for periodic slash-and-burn rotation to maintain PyC stocks.

Linear mixed-effects models to describe individual tree crown width for China-fir in Fujian Province, southeast China.

A multiple linear model was developed for individual tree crown width of Cunninghamia lanceolata (Lamb.) Hook in Fujian province, southeast China. Data were obtained from 55 sample plots of pure China-fir plantation stands. An Ordinary Linear Least Squares (OLS) regression was used to establish the crown width model. To adjust for correlations between observations from the same sample plots, we developed one level linear mixed-effects (LME) models based on the multiple linear model, which take into account the random effects of plots. The best random effects combinations for the LME models were determined by the Akaike’s information criterion, the Bayesian information criterion and the -2logarithm likelihood. Heteroscedasticity was reduced by three residual variance functions: the power function, the exponential function and the constant plus power function. The spatial correlation was modeled by three correlation structures: the first-order autoregressive structure [AR(1)], a combination of first-order autoregressive and moving average structures [ARMA(1,1)], and the compound symmetry structure (CS). Then, the LME model was compared to the multiple linear model using the absolute mean residual (AMR), the root mean square error (RMSE), and the adjusted coefficient of determination (adj-R 2). For individual tree crown width models, the one level LME model showed the best performance. An independent dataset was used to test the performance of the models and to demonstrate the advantage of calibrating LME models.

会同和朱亭11年生杉木林能量积累与分配

PDF HTML阅读 XML下载 导出引用 引用提醒 会同和朱亭11年生杉木林能量积累与分配 DOI: 10.5846/stxb201110081464 作者: 作者单位: 中南林业科技大学 长沙,中南林业科技大学 长沙,中南林业科技大学 长沙 作者简介: 通讯作者: 中图分类号: 基金项目: 国家重点野外台站资助项目(2000-076); 国家林业局重点科研资助项目(2001-07) The energy storage and its distribution in 11-year-old chinese fir plantations in Huitong and Zhuting Author: Affiliation: Central South University of Forestry & Technology,, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:利用我国杉木中心产区会同和杉木扩大栽培区朱亭测定的杉木林生物量和干物质热值资料的基础上,对会同和朱亭11年生杉木人工林能量积累和分配规律进行研究。结果表明:杉木人工林群落林分能量现存量与立地和气候条件关系密切,朱亭11年生杉木人工林群落林分能量现存量 (9294×108-10894×108J/hm2)显著低于会同(12406×108-14733 ×108J/hm2);同龄林分中,现存能量的数值在一定的林分密度范围内,随密度增加而减少。随密度增加而减少的能量现存量,主要是减少了树干的能量现存量,而枝、叶的能量现存量则保持一定稳定状态;能量在林分各组分的分配比大小依次是干＞根＞叶＞枝,林分各组分能量的分配比大小也与立地和气候条件有关,树干中能量分配比会同(56.8%-61.2%)大于朱亭(47.0%-53.5%),枝叶中能量分配比朱亭(28.3%-34.2%)大于会同(22.2%-25.9%);林分能量现存量的空间分布与林分功能作用层面及对水分和养分交换作用密切相关,林分的地表平面和林冠2/3高度处分配的能量最多。 Abstract:The energy storage and distribution were studied in the 11-year-old Chinese fir plantations in Huitong, the central production area and Zhuting, the expanded cultivation area based on the biomass and thermal value of try matter. The result showed that the the amount of existing energy in Chinese fir plantation of Huitong area (12406×108-14733×108J/hm2) was significantly higher than that in Zhuting (9294×108-10894×108J/hm2), suggesting the stand condition and climate play a critical role on the energy accumulation in Chinese fir plantations. Besides, the amount of existing energy in both Chinese fir plantation areas decreased with increasing density in a certain range of stand density, mainly due to the reduced existing energy of the trunk capacity, whereas the amount of existing energy of branches and leaves maintains at a stable state. The allocation of the energy to the different componentsof the tree was different, ranked with decreasing order: stem, roots, leaves, and branches. The energy distribution ratio in Huitong is different from that in Zhuting, e.g. the for both planations, for energy allocated into stem was 56.8%-61.2% in Huitong plantation, which was higher than that of 47.0%-53.5% in Zhuting, while in leaves, the allocation ratio is much lower in Huitong (22.2%-25.9%) than that in Zhuting (28.3%-34.2%). For the spatial distribution of the amount of existing energy at the stand level, most of existing energy was distributed at the soil surface and 2/3 height of the canopy above the ground, where was regarded the most important places for the exchange of substances and energy including water, light, gas and heat in the surrounding environment in forest. Results indicated that: (1) where there is the most urgency in supply of water and nutrients, there is the largest gathering of energy flows at the ecosystem level, and (2) for the 11a stand, there were some factors not suited to the growth of Chinese fir plantation in Zhuting area, in terms of micrometeorologic factors and stand conditions compared with Huitong area, the central area of China fir plantation. 参考文献 相似文献 引证文献

Simulations of runoff and evapotranspiration in Chinese fir plantation ecosystems using artificial neural networks

Runoff and evapotranspiration are two key variables of water budget in forest ecosystems. Modeling runoff and evapotranspiration dynamics play a vital role in assessing the hydrology cycle and function of forest ecosystems. Based on the hydrological and meteorological data collected over 20 years from January of 1988 to December of 2007 at Huitong National Forest Ecosystem Research Station, we used back propagation neural network (BPNN) and genetic neural network (GNN) models to simulate runoff and evapotranspiration of Chinese fir plantations for two watersheds located in Huitong county of Hunan Province, China. The purpose of this study was to accurately simulate runoff and evapotranspiration dynamics using both BPNN and GNN models. The model simulations of the runoff and evapotranspiration indicated that the GNN model concurrently possesses efficiency, effectiveness, and robustness. Moreover, the simulated results of GNN and BPNN model were compared with a multivariate statistics (M-slat) model. We found that the GNN model performed better than M-slat and BPNN models for modeling both runoff and evapotranspiration of Chinese fir plantations in China.

Comparison of Seasonal Variations in Carbon Dioxide Concentrations between a Natural Hardwood Stand and a Fir Plantation at the Guandaushi Subtropical Forest, Taiwan

The purpose of this study was to understand variations in carbon dioxide concentrations at different canopy heights in a natural hardwood stand and a China-fir (Cunninghamia lanceolata) plantation at the Guandaushi subtropical forest. The measurements began in September 2004 and continued to the end of June 2005. There were 4 sampling heights, including 0.5, 4, and 12 m above ground level (agl) and 3~4 m above the canopy at the 2 stands. Results showed that the highest concentration of carbon dioxide was near the forest floor, and the lowest ones were at 12 m agl and 3~4 m above the canopy for both the natural hardwood stand and fir plantation. Seasonal and yearly variations of sampling heights between 12 m agl and 3~4 m above the canopy were not significant. The carbon dioxide concentrations of the 4 sampling heights were higher in spring and summer than in winter. Variations in carbon dioxide concentrations of the sampling height at 12 m in the natural hardwood forest were influenced by light intensity, regardless of daily or yearly variations. We concluded that the forest floor soil of the natural hardwood stand had a higher respiration rate, and there was a lower photosynthetic rate at the 12m level of the canopy. Therefore, at all sampling points, the concentrations of carbon dioxide were higher than these in the China-fir plantation. This concentration gradient was more significant in the higher-temperature season (June) than in the lower-temperature season (December to January).

Typhoon impacts on stream water chemistry in a plantation and an adjacent natural forest in central Taiwan

Summary We studied the hydro-chemical responses to a category 3 typhoon of two forested watersheds at Lienhuachi Experimental Forest: a 24 year old China-fir plantation (WS4) and a natural hardwood forest (WS5). One hundred and nineteen millimeters of precipitation fell in 26 h resulting in a peak stream flow of 80 l s −1 ha −1 in WS4 and 11 l s −1 ha −1 in WS5 despite a much lower base flow at WS4: 0.012 l s −1 ha −1 as compared to 0.38 l s −1 ha −1 at WS5. Stream water conductivity, an indicator of overall ionic strength, decreased by approximately 50% in WS4 and 30% in WS5. The observation that the China-fir plantation had a higher stream flow and ion fluctuation than the natural forest during typhoon Talim was the opposite of that observed during non-storm periods. The output of suspended solids in stream water was two orders of magnitudes higher in the plantation than in the natural forest during the storm period (8.8 vs. 0.06 kg ha −1 net export of suspended solids). The plantation exhibited lower resistance than the natural forest to the stream water chemistry impacts of a category 3 typhoon with a return interval of six years. Among the 11 ions analyzed, nitrogen, phosphorus, and potassium were the only elements that had higher concentrations in the natural forest than in the plantation, a pattern consistent with the aggradation of biomass and the concomitantly high demand on the macro-essential elements in the plantation. Conversion of a native broad leaf forest to a conifer plantation has persistent and large effects on hydro-chemical cycling, changes that are still evident after two decades of growth.

Characterization of organic matter in rainfall, throughfall, stemflow, and streamwater from three subtropical forest ecosystems

Little is known about the characteristics of dissolved organic matter derived from precipitation, throughfall, stemflow, and streamwater in subtropical forest ecosystems. Water samples were, thus, collected from rainfall, throughfall and stemflow of a China-fir plantation, a secondary hardwood and a natural hardwood, and streams in forest ecosystems in the central part of subtropical Taiwan on March 31 and May 8, 1999. We examined pH, electrical conductivity, dissolved organic carbon, and acid-neutralizing capacity (ANC) in the samples. Furthermore, the humic polymers (MW>1000) and fulvic acids (FAs; MW>1000) were isolated from the water samples and characterized by elemental analyses and Fourier transform infrared (FTIR) spectroscopy. Results showed that the contents of carboxylic acid of both humic polymers (MW>1000) and FAs (MW>1000) contributed to the water sample ANC, ranging from 8.7 to 61.2% and 0.2 to 38.1%, respectively. FTIR and elemental analyses of isolated humic polymers (MW>1000) and FAs (MW>1000) from throughfall and stemflow had characteristics previously reported for humic substances. The study showed that throughfall and stemflow, not affected by soils, may be additional sources of humic substances.