Canopy interception is a significant proportion of incident rainfall and evapotranspiration of forest ecosystems. Hence, identifying its magnitude is vital for studies of eco-hydrological processes and hydrological im...Canopy interception is a significant proportion of incident rainfall and evapotranspiration of forest ecosystems. Hence, identifying its magnitude is vital for studies of eco-hydrological processes and hydrological impact evaluation. In this study, throughfall, stemflow and interception were measured in a pure Larix principis-rupprechtii Mayr.（larch） plantation in the Liupan Mountains of northwestern China during the growing season（May–October） of 2015, and simulated using a revised Gash model. During the study period, the total precipitation was 499.0 mm; corresponding total throughfall, stemflow and canopy interception were 410.3, 2.0 and 86.7 mm,accounting for 82.2, 0.4 and 17.4% of the total precipitation, respectively. With increasing rainfall, the canopy interception ratio of individual rainfall events decreased initially and then tended to stabilize. Within the study period, the simulated total canopy interception, throughfall and stemflow were 2.2 mm lower, 2.5 mm higher and 0.3 mm lower than their measured values, with a relative error of 2.5, 0.6 and 15.0%, respectively. As quantified by the model, canopy interception loss（79%） mainly consisted of interception caused by canopy adsorption, while the proportions of additional interception and trunk interception were small. The revised Gash model was highly sensitive to the parameter of canopy storage capacity,followed by the parameters of canopy density and mean rainfall intensity, but less sensitive to the parameters of mean evaporation rate, trunk storage capacity, and stemflow ratio. The revised Gash model satisfactorily simulated the total canopy interception of the larch plantation within the growing season but was less accurate for some individual rainfall events, indicating that some flaws exist in the model structure. Further measures to improve the model’s ability in simulating the interception of individual rainfall events were suggested.展开更多
Plantations of Rupprecht's larch(Larix principis-rupprechtii)have been widely established in the drylands of northwest and north China under traditional fastgrowing plantation management strategies.These strategie...Plantations of Rupprecht's larch(Larix principis-rupprechtii)have been widely established in the drylands of northwest and north China under traditional fastgrowing plantation management strategies.These strategies and the long-term logging ban have led to over-populated stands with lower structural and functional stability,less economic benefit and higher water consumption.To guide the sustainable management of larch plantations,field surveys and historical data compilation were undertaken in the Liupan Mountains of northwest China.The main influencing factors(stand structure and site condition)and their effects on mean tree height,mean DBH and timber volumes were determined based on up-boundary line analysis.Tree growth models coupling the effects of tree age,stand density,and elevation were established.Both height and DBH markedly increased initially and then slowly with tree age,decreased with stand density,and showed unimodal change with elevation.The coupled growth models accounted for72-78%of the variations in tree height,DBH and timber growth.Recommendations for future plantation management are:(1)prolong the rotation to at least 60 years to produce large-diameter,high-quality timber and maintain greater carbon stocks;(2)zone the target functions of stands by elevation;and,(3)reduce stand density for balanced supply of multiple ecosystem services.The growth models developed can predict growth response of larch plantations to density alteration under given ages and elevations,and assist the transformation from traditional management for maximum timber production to site-specific and multifunctional management with longer rotations and moderate tree density.展开更多
A newly recorded genus Joelminetia Speidel Witt, 2007 in the family Pyralidae and the newly recorded species Joelminetia kostjuki Speidel Witt, 2007 are reported from South China. Morphological descriptions and illust...A newly recorded genus Joelminetia Speidel Witt, 2007 in the family Pyralidae and the newly recorded species Joelminetia kostjuki Speidel Witt, 2007 are reported from South China. Morphological descriptions and illustrations of the genus and species are given.展开更多
目的比较慢性鼻-鼻窦炎伴鼻息肉(chronic rhinosinusitis with nasal polyps,CRSwNP)与不伴鼻息肉(chronic rhinosinusitis without nasal polyps,CRSsNP)的临床特征,为制定合理治疗策略提供依据.方法回顾性分析2018年11月~2019年12月...目的比较慢性鼻-鼻窦炎伴鼻息肉(chronic rhinosinusitis with nasal polyps,CRSwNP)与不伴鼻息肉(chronic rhinosinusitis without nasal polyps,CRSsNP)的临床特征,为制定合理治疗策略提供依据.方法回顾性分析2018年11月~2019年12月住院手术的苏皖地区225例慢性鼻-鼻窦炎(CRS)患者术前血常规、血生化、血清总IgE(total IgE,tIgE)、特异性IgE(specific IgE,sIgE)、鼻窦CT及术后病理检查等临床资料,进行统计学分析.结果225例中,CRSwNP组148例(65.8%),CRSsNP组77例(34.2%).患者的性别、年龄、住院时间、外周血白细胞及分类、血生化指标在两组间差异无统计学意义(P>0.05).CRSwNP和CRSsNP患者中至少1种变应原阳性分别占34.5%和40.3%,其中尘螨过敏最多见,阳性率分别为23.0%和26.0%,两组间差异均无统计学意义(P>0.05).血清tIgE阳性率、20种变应原slgE浓度等级和阳性率、吸入性及食物性变应原阳性率在两组间差异也均无统计学意义(P>0.05).鼻窦CT扫描Lund-Mackay评分中,两组各鼻窦、窦口鼻道复合体及CT总分CRSwNP组都高于CRSsNP组,差异均有统计学意义(P<0.05).在病理组织中,两组患者淋巴细胞及浆细胞浸润均为60%以上,但嗜酸性粒细胞(Eos)在CRSwNP组的阳性率为43.2%,显著高于CRSsNP组的阳性率22.1%,差异有统计学意义(P<0.05).结论本地区CRS患者目前仍以淋巴细胞/浆细胞性炎症为主,但CRSwNP息肉组织中Eos阳性率达43.2%,需引起重视并进一步关注.CRSwNP和CRSsNP患者变应原阳性率分别为34.5%和40.3%,两者无明显差异,尘螨为主要致敏原.展开更多
基金supported by the National Key Research and Development Program of China(2016YFC0501603)the National Natural Science Foundation of China(Nos.41671025+2 种基金413904614123085241471029)
文摘Canopy interception is a significant proportion of incident rainfall and evapotranspiration of forest ecosystems. Hence, identifying its magnitude is vital for studies of eco-hydrological processes and hydrological impact evaluation. In this study, throughfall, stemflow and interception were measured in a pure Larix principis-rupprechtii Mayr.（larch） plantation in the Liupan Mountains of northwestern China during the growing season（May–October） of 2015, and simulated using a revised Gash model. During the study period, the total precipitation was 499.0 mm; corresponding total throughfall, stemflow and canopy interception were 410.3, 2.0 and 86.7 mm,accounting for 82.2, 0.4 and 17.4% of the total precipitation, respectively. With increasing rainfall, the canopy interception ratio of individual rainfall events decreased initially and then tended to stabilize. Within the study period, the simulated total canopy interception, throughfall and stemflow were 2.2 mm lower, 2.5 mm higher and 0.3 mm lower than their measured values, with a relative error of 2.5, 0.6 and 15.0%, respectively. As quantified by the model, canopy interception loss（79%） mainly consisted of interception caused by canopy adsorption, while the proportions of additional interception and trunk interception were small. The revised Gash model was highly sensitive to the parameter of canopy storage capacity,followed by the parameters of canopy density and mean rainfall intensity, but less sensitive to the parameters of mean evaporation rate, trunk storage capacity, and stemflow ratio. The revised Gash model satisfactorily simulated the total canopy interception of the larch plantation within the growing season but was less accurate for some individual rainfall events, indicating that some flaws exist in the model structure. Further measures to improve the model’s ability in simulating the interception of individual rainfall events were suggested.
基金funded by the National Natural Science Foundation of China (U20A2085,U21A2005,41971038)the Central Public-Interest Scientifi c Institution Basal Research Fund of Chinese Academy of Forestry (CAFYBB2021ZW002,CAFYBB2020QB004)。
文摘Plantations of Rupprecht's larch(Larix principis-rupprechtii)have been widely established in the drylands of northwest and north China under traditional fastgrowing plantation management strategies.These strategies and the long-term logging ban have led to over-populated stands with lower structural and functional stability,less economic benefit and higher water consumption.To guide the sustainable management of larch plantations,field surveys and historical data compilation were undertaken in the Liupan Mountains of northwest China.The main influencing factors(stand structure and site condition)and their effects on mean tree height,mean DBH and timber volumes were determined based on up-boundary line analysis.Tree growth models coupling the effects of tree age,stand density,and elevation were established.Both height and DBH markedly increased initially and then slowly with tree age,decreased with stand density,and showed unimodal change with elevation.The coupled growth models accounted for72-78%of the variations in tree height,DBH and timber growth.Recommendations for future plantation management are:(1)prolong the rotation to at least 60 years to produce large-diameter,high-quality timber and maintain greater carbon stocks;(2)zone the target functions of stands by elevation;and,(3)reduce stand density for balanced supply of multiple ecosystem services.The growth models developed can predict growth response of larch plantations to density alteration under given ages and elevations,and assist the transformation from traditional management for maximum timber production to site-specific and multifunctional management with longer rotations and moderate tree density.
基金supported in part by the National Natural Science Foundation of China (41101051)
文摘A newly recorded genus Joelminetia Speidel Witt, 2007 in the family Pyralidae and the newly recorded species Joelminetia kostjuki Speidel Witt, 2007 are reported from South China. Morphological descriptions and illustrations of the genus and species are given.
