Castanopsis Hystrix Research Articles

南亚热带红锥、杉木纯林与混交林碳贮量比较

PDF HTML阅读 XML下载 导出引用 引用提醒 南亚热带红锥、杉木纯林与混交林碳贮量比较 DOI: 10.5846/stxb201405211041 作者: 作者单位: 中国林业科学研究院热带林业实验中心,中国林业科学研究院森林生态环境与保护研究所,中国林业科学研究院热带林业实验中心,中国林业科学研究院热带林业实验中心,中国林业科学研究院热带林业实验中心,中国林业科学研究院热带林业实验中心,中国林业科学研究院热带林业实验中心,中国林业科学研究院热带林业实验中心 作者简介: 通讯作者: 中图分类号: 基金项目: 国家"十二五"农村领域科技计划项目(2012BAD22B0105);中央级公益性科研院所基本科研业务费专项资金(CAFYBB2014QA033);广西自然科学基金项目(2014GXNSFBA118100);中国林业科学研究院热带林业实验中心主任基金项目(RL2011-02) Comparison of carbon storage in pure and mixed stands of Castanopsis hystrix and Cunninghamia lanceolata in subtropical China Author: Affiliation: Experimental Center of Tropical Forestry, Chinese Academy of Forestry,Chinese Academy of Forestry,,,,,, 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:造林再造林作为新增碳汇的一种有效途径,受到国际社会的广泛关注。如何通过改变林分树种组成,优化造林模式提高人工林生态系统碳贮量已成为国内外学者关注的重点。通过样方调查和生物量实测相结合的方法,对南亚热带26年生红锥纯林(PCH)、杉木纯林(PCL)及红锥×杉木混交林(MCC)生态系统各组分碳含量、碳贮量及其分配特征进行了比较研究。结果表明:杉木、红锥各器官平均碳含量分别为492.1-545.7 g/kg和486.7-524.1 g/kg。相同树种不同器官以及不同树种的相同器官间碳含量差异显著(P < 0.05)。红锥各器官碳含量的平均值(521.3 g/kg)高于杉木(504.7 g/kg)。不同林分间地被物碳含量大小顺序为PCH > MCC > PCL;不同树种之间的土壤碳含量差异显著(P < 0.05),0-100 cm土壤平均碳含量为PCL>MCC>PCH。生态系统碳贮量大小顺序为PCL(169.49 t/hm2) > MCC(141.18 t/hm2) > PCL(129.20 t/hm2),相同组分不同林分以及相同林分的不同组分碳贮量均存在显著差异(P < 0.05)。造林模式对人工林碳贮量及其分配规律有显著影响,营建混交林有利于红锥生物量和土壤碳的累积,而营建纯林有利于杉木人工林生物量碳的吸收,也有利于土壤碳的固定。因而,混交林的固碳功能未必高于纯林,在选择碳汇林的造林模式时,应以充分考虑不同树种的固碳特性。 Abstract:The focus has been on afforestation and re-afforestation as new methods for improving carbon sequestration, by optimizing the mode of afforestation and adjusting the forest tree species composition. Carbon content and storage of different components, including tree, shrub, herb, litter, and soil layers and their allocations of a 26-year-old Castanopsis hystrix (PCH), Cunninghamia lanceolata (PCL), and mixed C. hystrix × C. lanceolata (MCC) stands in subtropical China were studied using quadrat sampling combined with biomass measurements. The results showed that the average carbon content of different organs in C. lanceolata and C. hystrix were 492.1-545.7 g/kg and 486.7-524.1 g/kg, respectively. Significant differences were found among different organs in the same tree species(P<0.05). The average carbon content of C. hystrix(539.3 g/kg)was higher than C. lanceolata. Carbon content of the ground cover was PCH>MCC>PCL. Soil content in 0-100 cm showed significant differences among the three stands, which was ranked as PCL > MCC > PCH(P < 0.05). The carbon storage in the total ecosystem was ranked as PCL(169.49 t/hm2)> MCC(141.18 t/hm2)> PCH(129.20 t/hm2. Significant differences were found among different components in the same stand, and among different stands of the same components (P<0.05). Afforestation significantly affected the carbon storage and allocation in plantations, and the mixed stand benefited from increased carbon biomass and soil carbon for C. hystrix; while monoculture stand benefited from the biomass and soil carbon for C. lanceolata Therefore, we should select the afforestation mode based on the carbon acumination characteristics of tree species regarding carbon sequestration forests, because mixed stands do not always fix more carbon compared with pure forests. 参考文献 相似文献 引证文献

Nitrogen and phosphorus productivities of five subtropical tree species in response to elevated CO2 and N addition

The productivities of nitrogen and phosphorus (NP and PP) in plants have been greatly altered by increasing atmospheric carbon dioxide concentrations (CO2) and nitrogen (N) deposition. However, studies on this are quite limited in tropical and subtropical forests. We used open-top chambers to examine the NP and PP of five tree species in response to elevated CO2 and N addition in subtropical forests from 2005 to 2009. The five tree species included the slow-growing species (Acmena acuminatissima and Syzygium hancei) and the fast-growing ones (Castanopsis hystrix, Ormosia pinnata and Schima superba). Elevated CO2 increased the NP and PP of C. hystrix. However, the NP and PP of S. hancei were decreased by elevated CO2, and the PP of A. acuminatissima was lowered by elevated CO2 without N addition. N addition had no significant influence on the NP of all tree species, while it increased the PP of S. superba. The changes in the NP and PP were related to those in plant growth. We concluded that C. hystrix and S. superba would benefit from elevated CO2 and N addition, respectively. The results indicate that plant NP and PP in response to elevated CO2 and N addition are species specific. Our findings could have important implications for better understanding the effects of global change on species composition in subtropical forests.

Soil microbial community composition rather than litter quality is linked with soil organic carbon chemical composition in plantations in subtropical China

Purpose Native broadleaf plantations are increasingly being developed as an alternative to coniferous plantations. This studyexaminedtherelationshipsamonglittercarbon(C)quality, soil microbial community composition, and soil organic C (SOC) chemical properties in plantations and how they were affected by tree species. Materials and methods The solid-state 13 C nuclear magnetic resonance spectroscopy (NMR) technique was used to examine SOC chemical composition, and litter and fine root C quality in four plantations of native tree species (Pinus massoniana, Castanopsis hystrix, Michelia macclurei, and Mytilaria laosensis) in Pingxiang, Guangxi Zhuang AutonomousRegion,insubtropicalChina.Soilmicrobialbiomass C and nitrogen (N) were determined by the chloroform fumigation-extraction method and soil bacterial and fungal biomass were measured with the phospholipid fatty acid (PLFA) technique. Results and discussion The proportions of O-alkyl C, alkyl C, aromatic C, and carbonyl C in SOC and the alkyl/O-alkyl C ratio (A/O-A) in litter and fine root samples, soil microbial C and N, microbial C/N ratios, and the amount of PLFAs were significantly different among the four plantations of different species. SOC in the 0–10-cm layer had 43–49 % O-alkyl C, 24–34 % alkyl C, 14–17 % aromatic C, and 9–11 % carbonyl C in SOC. The microbial C/N ratio, the amount of total PLFAs, and bacterial and Gram-positive bacterial population sizes were linked to the proportion of alkyl C in SOC and the A/O-A ratio in soil. The proportion of alkyl C in SOC was not related to the proportion of alkyl C in litter or fine root samples. Conclusions The microbial community composition rather than plant litter or fine root quality was linked to chemical composition of SOC in the studied subtropical plantations. Future research should place more emphasis on the processes involved in the formation of SOC and their association with the microbial community.

Mineral elements of subtropical tree seedlings in response to elevated carbon dioxide and nitrogen addition.

Mineral elements in plants have been strongly affected by increased atmospheric carbon dioxide (CO2) concentrations and nitrogen (N) deposition due to human activities. However, such understanding is largely limited to N and phosphorus in grassland. Using open-top chambers, we examined the concentrations of potassium (K), calcium (Ca), magnesium (Mg), aluminum (Al), copper (Cu) and manganese (Mn) in the leaves and roots of the seedlings of five subtropical tree species in response to elevated CO2 (ca. 700 μmol CO2 mol-1) and N addition (100 kg N ha-1 yr-1) from 2005 to 2009. These mineral elements in the roots responded more strongly to elevated CO2 and N addition than those in the leaves. Elevated CO2 did not consistently decrease the concentrations of plant mineral elements, with increases in K, Al, Cu and Mn in some tree species. N addition decreased K and had no influence on Cu in the five tree species. Given the shifts in plant mineral elements, Schima superba and Castanopsis hystrix were less responsive to elevated CO2 and N addition alone, respectively. Our results indicate that plant stoichiometry would be altered by increasing CO2 and N deposition, and K would likely become a limiting nutrient under increasing N deposition in subtropics.

Carbon Storage and Allocation Pattern in Plant Biomass among Different Forest Plantation Stands in Guangdong, China

In order to understand how carbon storage and allocation patterns vary among plantation types, we estimated carbon allocation between above- and below-ground compartments in four subtropical plantations and a naturally recovered shrubland (as a control). Results indicated that the carbon storage and allocation pattern varied greatly among forest types and was highly dependent on specific traits of trees and understory vegetation. The fast-growing species, such as Eucalyptus urophylla, accumulated more carbon in plant biomass. The biomass carbon was about 1.9- and 2.2-times greater than the 10-species mixed plantation and Castanopsis hystrix plantations, respectively. Meanwhile, the plantations sequestered 1.5- to 3-times more carbon in biomass than naturally recovered shrubland. The carbon allocation pattern between above- and below-ground compartments also varied with plantation type and stand age. The ratio of tree root carbon to tree aboveground carbon decreased with stand age for Eucalyptus urophylla and the 10-species mixed plantation. In contrast, the ratio increased for Acacia crassicarpa. Our data suggested that planting the fast-growing species in the degraded land of subtropical China was an effective choice in terms of carbon sequestration. The information about carbon allocation patterns was also valuable for decision making in sustainable forest management and climate change mitigation.

Development and characterization of polymorphic microsatellite markers for Castanopsis hystrix (Fagaceae).

Castanopsis hystrix is one of the most important and dominant species in evergreen broad-leaved forests in subtropical China. However, the population of this species undergone severe decline because of deforestation over the past 2 decades. For both conservation and forestry management, it is essential to develop molecular markers for C. hystrix. We identified 11 microsatellite loci in 2 wild populations. The number of alleles ranged from 3-11, with an average of 6.45 alleles per locus. The observed and expected heterozygosities ranged from 0.640-0.960 and from 0.676-0.910, respectively.

南亚热带3种阔叶树种人工幼龄纯林及其混交林碳贮量比较

Enhancement of the carbon storage of plantation ecosystems by optimizing afforestation patterns has beenextensively researched. In the present study,we investigated carbon storage and allocation in an 8-year-old Erythrophleum fordii stand( PE),a Castanopsis hystrix stand( PC),a Mytilaria laosensis stand( PM),and a mixed E. fordii × C. hystrix× M. laosensis stand( MECM) in subtropical China. We showed that the average carbon contents of different organs in E.fordii,C. hystrix,and M. laosensis ranged from 509.0 g / kg to 572.4 g / kg,474.2 g / kg to 553.4 g / kg,and 512.8 g / kg to556.3 g / kg,respectively. We determined significant differences in carbon contents among different organs of the same tree species. Within the same organs,the average carbon contents of different stands were ranked as follows: E. fordii( 539.3 g /kg) M. laosensis( 532. 7 g / kg) C. hystrix( 515. 3 g / kg). In the shrub,herb,and litter layers,the highest carbon contents among the four stands occurred in PM,followed by MECM,PC,and PE. The carbon contents of the 0—10 cm,10—30 cm,30—50 cm,and 50—100 cm soil layers differed significantly among the four stands and were the highest in PM,followed by PC,MECM,and PE. The ecosystem carbon storages were ranked as PM( 308.0 t / hm2) MECM( 182.8t / hm2) PC( 180.2 t /hm2) PE( 135.2 t /hm2). We determined significant differences in average carbon contents within and among stands( P 0.05),but no significant differences in the total ecosystem carbon storage between MECM and PE( P 0. 05). Our results indicate that the mode of afforestation can markedly influence the carbon storage and allocation of plantations. In mixed stands,C. hystrix and E. fordii will benefit from an increase in aboveground biomass carbon,but not from accumulation of soil carbon. On the other hand,in monoculture,M. laosensis will benefit from the sequestration of aboveground biomass carbon and from accumulation of soil carbon. Therefore,the afforestation mode for carbon sequestration forests should be selected according to the carbon accumulation characteristics of the representative tree species.

Water-use efficiency of four native trees under CO2enrichment and N addition in subtropical model forest ecosystems

We aimed to evaluate the changes in water-use efficiency (WUE) in native tree species in forests of subtropical China, and determine how coexisting species would be responding to increases in atmospheric carbon dioxide (CO2) concentrations and nitrogen (N) deposition. We used model forest ecosystems in open-top chambers to study the effects of elevated CO2 (ca. 700 µmol mol−1) alone and together with N addition (NH4NO3 applied at 100kg N ha−1year−1) on WUE of four native tree species (Schima superba, Ormosia pinnata, Castanopsis hystrix and Acmena acuminatissima) from 2006 to 2010. Our result indicated that all species increased their WUE when they were exposed to elevated CO2. Although higher WUE was shown in faster-growing species (S. superba and O. pinnata) than that of slower-growing species (C. hystrix and Acmena acuminatissima), the increased extent of WUE induced by elevated CO2 was higher in the slower-growing species than that of the faster-growing species (P < 0.01). The N treatment decreased WUE of S. superba, while the effects on other species were not significant. The interactions between elevated CO2 and N addition increased intrinsic WUE of S. superba significantly (P < 0.001), however, it did not affect WUE of the other tree species significantly. We conclude that the responses of native tree species to elevated CO2 and N addition are different in subtropical China. The species-specific effects of elevated CO2 and N addition on WUE would have important implications on species composition in China’s subtropics in response to global change.

Carbon storage capacity of monoculture and mixed-species plantations in subtropical China

Mixed-tree plantations can be a good silvicultural alternative to large-scale monoculture coniferous plantations for climate change mitigation, which is facilitated by the sequestration of atmospheric carbon dioxide. To evaluate the impacts of tree species compositions on the carbon storage capacity of plantation ecosystems, we measured the above and belowground biomass, as well as the carbon content, in three 27-year old forest plantations of monoculture Castanopsis hystrix (CH stand), monoculture Pinus massoniana (PM stand), and mixed C. hystrix and P. massoniana (mixed CH/PM stand) stands. We developed an allometric equation to estimate tree carbon storage. The carbon storage levels of understory, litter, and soil components were also estimated. Results show that biomass is positively correlated with carbon storage. The ecosystem carbon storage of the mixed CH/PM stand (327.03Mgha−1) was higher than those of the CH (314.59Mgha−1) and PM (293.60Mgha−1) stands. The majority of carbon storage was found in the soil pool (84.73%, 63.54%, and 75.80% in the CH, PM and mixed CH/PM stands, respectively). Almost 40% of soil carbon at a depth of 0–60cm was stored in the upper 20cm of the soil pool. Except for the vegetation layer, each layer of the CH and mixed CH/PM stands consisted of a higher amount of carbon than did the layers of the PM stand. These findings suggest that mixed CH/PM plantation stands or valuable indigenous CH plantation stands more substantially improve carbon storage in litter, soil, and ecosystems than do monoculture PM plantation stands. The results also imply that developing valuable indigenous tree species is a good silvicultural option for enhancing carbon sequestration and valuable timber cultivation in subtropical China.

Dynamics and speciation of organic carbon during decomposition of leaf litter and fine roots in four subtropical plantations of China

Plant litter and fine roots turnover are important carbon (C) inputs to soil and a direct emission source of CO2 to the atmosphere. C dynamics during litter decomposition provide an insight into C flow in soils. To quantitatively assess how decomposition processes vary with litter types, the solid-state 13C nuclear magnetic resonance spectroscopy with cross-polarization and magic-angle spinning (CPMAS-NMR) technique was applied to analyze the organic C dynamics of conifer (Pinus massoniana) and broadleaf (Castanopsis hystrix, Michelia macclurei and Mytilaria laosensis) leaf litter and fine roots which had degraded during one year litterbag experiment in four subtropical plantations of China. The results were used to estimate decomposition rates of different C types and compositional changes of leaf litter and fine roots during decomposition. The mass loss rates of different C fractions during decomposition varied significantly between litter types. Site environment and initial litter quality played more critical roles in regulating decomposition of fine roots than of leaf litter. The significant changes in the proportion of C forms and degree of humification occurred during leaf litter decomposition, but not during fine roots decomposition. The proportions of alkyl C and carbonyl C and alkyl/O-alkyl C ratio varied with leaf litter types, with an increase for the proportion of alkyl C and alkyl/O-alkyl C ratio in broadleaf leaf litters and an enhanced trend for the proportion of carbonyl C for P. massoniana. The results suggest that the patterns and main controlling factors of litter C compositional change during decomposition differed between above- and belowground, and the dynamics of leaf litter C fractions during decomposition differed between conifer and broadleaf species. The findings of litter C compositional decomposition of the main tree species in this study could contribute to the accurate estimation of soil C sequestration in subtropical plantation ecosystems.

我国南亚热带几种人工林生态系统碳氮储量

Carbon and nitrogen storage in different plantation ecosystems of Erythrophleum fordii,Castanopsis hystrix and Pinus massoniana in subtropical south China were studied.The results showed that the allocation of C in the organs of the different tree species had no significant correlation with their age,while that of N had closer relationship with the age.The N concentration in young organs was higher than that in aged ones and the C/N ratio was higher in aged organs than that in young ones.The N concentration was higher in all components of the nitrogen-fixing species(E.fordii plantation) than that in other species(C.hystrix and P.massoniana plantations).There was an obvious enrichment of C and N in the topsoil of the plantation ecosystems.The total ecosystem carbon storage of E.fordii,C.hystrix and P.massoniana plantations was 236.22 t/hm2,267.84 t/hm2 and 200.57 t/hm2 and nitrogen storage was 17.91 t/hm2,12.38 t/hm2 and 10.59 t/hm2,respectively.Carbon storage of tree layer occupied 42.57%,36.31% and 40.28% while 0—100 cm soil occupied 55.77%,62.52% and 57.83%,respectively.Nitrogen storage of soil occupied 92.00%,93.72% and 95.53%.Our study indicated that most ecosystem carbon and nitrogen storage of the plantations stored in soil.Carbon sequestration ability of C.hystrix plantation is higher compared to other two plantations.

Research and Evaluation on the Machining Properties of &lt;i&gt;Xylia Spp&lt;/i&gt;

In this paper, the machining properties of Xylia spp, compared with Castanopsis hystrix, were tested. Their properties were conducted according to the criteria ASTM D1666-87 and the test on crosscutting is referred to the method established by New Zealand Forest Research Institute. The results show as follow: the machining properties of Xylia spp and Castanopsis hystrix in the planning, sanding, boring, shaping and crosscutting show excellent, but the mortising properties was a bit poor. The properties of Xylia spp were in an all-round way better than Castanopsis hystrix. In the machining performance comprehensive evaluation system for full marks 50 points, its comprehensive marks were separately 45.5 points and 44.4 points.

Research and Evaluation on the Machining Properties of &lt;i&gt;Picea spp.&lt;/i&gt;

In this paper, the machining properties of Picea spp., compared with Castanopsis hystrix, were tested. Their properties were conducted according to the criteria ASTM D1666-87 and the test on crosscutting is referred to the method established by New Zealand Forest Research Institute. The results show as follow: The machining properties of Picea spp. and Castanopsis hystrix show excellent in the planning, sanding, boring, shaping and crosscutting, but in the mortising properties, Picea spp. which was a bit poor shows fair and Castanopsis hystrix shows good. The properties of Picea spp. were in an all-round way better than Castanopsis hystrix. In the machining performance comprehensive evaluation system for full marks 50 points, their comprehensive marks were separately 45.5 points and 44.4 points.

Effects of tree species mixture on soil organic carbon stocks and greenhouse gas fluxes in subtropical plantations in China

Indigenous broadleaf plantations are increasingly being developed as a prospective silvicultural approach for substituting coniferous plantations in subtropical China. Three plantations of monoculture and mixed Pinus massoniana and Castanopsis hystrix were selected to examine soil organic carbon (SOC) stocks and temporal and spatial patterns of the main greenhouse gases fluxes for understanding the effects of mixed forests on soil carbon and nitrogen (N) cycling processes. We found that SOC stock in 0–20cm layer in the mixed plantation was 14.3% higher than that in the P. massoniana, and 8.1% higher than that in the C. hystrix plantations. Differences in SOC stock among the plantations were attributed to soil N stock and leaf litterfall input. Soil CO2 and N2O fluxes in the mixed plantation displayed the seasonal trends, while soil CH4 flux did not show the seasonal trend. The seasonal variations in soil CO2 and N2O emissions were positively related to soil temperature and moisture. Mean soil CO2 and N2O emissions (53.2mgCm−2 h−1 and 5.21μgNm−2h−1, respectively) were significantly higher in the mixed plantation than in the P. massoniana plantation, while they were lower than in the C. hystrix plantation. Mean soil CH4 uptake (38.4μgCm−2h−1) was significantly higher in the mixed plantation than in the C. hystrix plantation, while it is similar to that in the P. massoniana plantation. Variations in soil CO2 flux among the plantations were influenced by fine root biomass, leaf litterfall mass, soil N stock and soil C:N ratio. Differences in soil N2O flux among the plantations could be attributed to the differences in soil N stock, soil NO3−−N content and soil C:N ratio. Soil respiration rate and soil NO3−−N content could account for variations in soil CH4 flux among the plantations. This study confirms that the mixed plantation has a higher SOC stock than the monoculture plantations, and there is an increase in amount of GHG absorbed by the soil of mixed plantations compared to C. hystrix plantations. Therefore, a mixture of C. hystrix versus P. massoniana, could be a better silvicultural approach for SOC sequestration than monoculture C. hystrix plantation for substituting P. massoniana plantations in subtropical China.

Changes in leaf nutrient traits and photosynthesis of four tree species: effects of elevated [CO2], N fertilization and canopy positions

Aims Leaf traits of trees exposed to elevated [CO2] in association with other environmental factors are poorly understood in tropical and subtropical regions. Our goal was to investigate the impacts of elevated [CO2] and N fertilization on leaf traits in southern China. Methods Four tree species, Schima superba Gardn. et Champ. (S. superba), Ormosia pinnata (Lour.) Merr (O. pinnata), Castanopsis hystrix AC. DC. (C. hystrix) and Acmena acuminatissima (Blume) Merr. et Perry (A. acuminatissima) were studied in a factorial combination of atmospheric [CO2] (ambient at ;390 lmol mol 1 and elevated [CO2 ]a t;700 lmol mol 1 ) and N fertilization (ambient and ambient + 100 kg N ha 1 year 1 ) in open-top chambers in southern China for 5 years. Leaf mass per unit leaf area (LMA), leaf nutrient concentration and photosynthesis (Asat) were measured. Important Findings Results indicated that leaf traits and photosynthesis were affected differently by elevated [CO2] and N fertilization among species. Elevated [CO2] decreased LMA in all species, while N fertilization did not affect LMA. Leaf mass-based N concentration (NM) was significantly greater in O. pinnata and C. hystrix grown in elevated [CO2] but was lower in S. superba. Leaf mass-based P concentration (PM) was significantly greater in C. hystrix and A. acuminatissima exposed to elevated [CO2] but was lower in S. superba. N fertilization significantly increased PM in O. pinnata but decreased PM in S. superba. Photosynthetic stimulation in O. pinnata, C. hystrix and A. acuminatissima was sustained after 5 years of CO2 fumigation. N fertilization did not modify the effects of elevated [CO2] on photosynthesis. Leaf traits (NM ,N A ,P M ,P A) and light-saturated photosynthesis were decreased from the upper to lower canopy. Canopy position did not alter the responses of leaf traits and photosynthesis to elevated [CO2]. Results suggest that photosynthetic stimulation by elevated [CO2] in native species in subtropical regions may be sustained in the long term.

Research and Evaluation on the Planning and Sanding Properties of &lt;i&gt;Toona sinensis&lt;/i&gt;

In this paper, the planning and sanding properties of Toona sinensis, compared with Castanopsis hystrix, were tested. The properties were conducted according to the criteria ASTM D1666-87. The results show as follow: in the evaluation system for full marks 5 points, the planning marks of Toona sinensis and Castanopsis hystrix was separately 4.4 points and 4.7 points, and the sanding marks was separately 4.7 points and 4.3 points, slightly different; the planning and sanding properties of Toona sinensis and Castanopsis hystrix all show excellent; feeding speed had remarkable influence on the planning properties of Toona sinensis and Castanopsis hystrix; cutting thickness had different influence on the planning properties of two kinds of woods; the wood quality had important influence on the sanding property.

Research and Evaluation on the Machining Properties of &lt;i&gt;Magnoliaceae glanca Blume&lt;/i&gt;

In this paper, the machining properties (including planning, sanding, drilling, shaping, mortising and crosscutting) of Magnoliaceae glanca Blume, compared with Castanopsis hystrix, were tested. Their properties were conducted according to the criteria ASTM D1666-87 and the test on crosscutting was referred to the method established by New Zealand Forest Research Institute. The results show as follow: The machining properties of Magnoliaceae glanca Blume and Castanopsis hystrix in the planning, sanding, boring, shaping and crosscutting all show excellent, but the mortising property, a bit poor, shows good. The comprehensive properties of Magnoliaceae glanca Blume are better than Castanopsis hystrix.

Research and Evaluation on the Planning and Sanding Properties of&lt;i&gt; Magnoliaceae glanca&lt;/i&gt; Blume Plantation Wood

In this paper, the planning and sanding properties of Magnoliaceae glanca Blume, compared with Castanopsis hystrix, were tested. The properties were conducted according to the criteria ASTM D1666-87. The results were shown as follow: the planning and sanding properties of both Magnoliaceae glanca Blume and Castanopsis hystrix showed excellent; in the evaluation system for full marks 5 points, the planning marks of both two kinds of wood were 4.7 points, and the sanding marks were separately 5 points and 4.3 points; feeding speed had remarkable influence on the planning properties of both two kinds of wood; cutting thickness had a little influence on the planning property of Magnoliaceae glanca Blume even when planning at a higher feeding speed of 9m/min; the wood quality had important influence on the sanding properties.

Research and Evaluation on the Planning and Sanding Properties of &lt;i&gt;Mytilaria laosensis&lt;/i&gt;

In this paper, the planning and sanding properties of Mytilaria laosensis, compared with Castanopsis hystrix, were tested. The properties were conducted according to the criteria ASTM D1666-87. The results show as follow: the planning and sanding properties of Mytilaria laosensis and Castanopsis hystrix all show excellent; in the evaluation system for full marks 5 points, the planning marks of Mytilaria laosensis and Castanopsis hystrix was separately 4.8 points and 4.7 points, and the sanding marks was separately 4.47 points and 4.3 points, so the planning and sanding properties of Mytilaria laosensis were slightly better than Castanopsis hystrix; feeding speed had remarkable influence on the planning properties of Mytilaria laosensis and Castanopsis hystrix; The wood quality had important influence on the sanding properties.

Soil organic carbon stock and chemical composition in four plantations of indigenous tree species in subtropical China

AbstractSubtropical China has more than 60% of the total plantation area in China and over 70% of these subtropical plantations are composed of pure coniferous species. In view of low ecosystem services and ecological instability of pure coniferous plantations, indigenous broadleaf plantations are being advocated as a prospective silvicultural management for substituting in place of large coniferous plantations in subtropical China. However, little information is known about the effects of tree species conversion on stock and stability of soil organic carbon (SOC). The four adjacent monospecific plantations were selected to examine the effects of tree species on the stock and chemical composition of SOC using elemental analysis and solid‐state 13C nuclear magnetic resonance (NMR) spectroscopy. One coniferous plantation was composed of Pinus massoniana (PM), and the three broadleaf plantations were Castanopsis hystrix (CH), Michelia macclurei (MM), and Mytilaria laosensis (ML). We found that SOC stock differed significantly among the four plantations in the upper (0–10 cm) layer, but not in the underneath (10–30 cm) layer. SOC stocks in the upper (0–10 cm) layer were 11, 19, and 18% higher in the CH, MM, and ML plantations than in the PM plantation. The differences in SOC stock among the four plantations were largely attributed to fine root rather than aboveground litterfall input. However, the soils in the broadleaf plantations contained more decomposable C proportion, indicated by lower percentage of alkyl C, higher percentage of O‐alkyl C and lower alkyl C/O‐alkyl C ratio compared to those in the PM plantation. Our findings highlight that future strategy of tree species selection for substituting in place of large coniferous plantations in subtropical China needs to consider the potential effects of tree species on the chemical composition in addition to the quantity of SOC stock.