江西省薄壳山核桃产业及苗木生产现状分析

薄壳山核桃树形挺拔、树冠优美,果仁营养丰富,木材质地优良,是一种极具市场竞争力的高效生态经济型木本油料树种;但在江西省还处于初始发展阶段,科研基础薄弱,产业发展相对滞后;本文通过分析江西薄壳山核桃产业发展与苗木生产现状及存在问题,总结提出了今后科研开展的方向及促进产业发展的对策。     

湖北省薄壳山核桃引种栽培及发展对策分析

简述了国内薄壳山核桃引种栽培概况,对湖北省近年来有关薄壳山核桃引种栽培情况进行了总结,并在分析薄壳山核桃引种栽培效果和存在问题的基础上,提出了发展对策建议。     

云南省薄壳山核桃产业发展现状与低效林改造技术

在对云南省薄壳山核桃产业发展和低效林改造现状深入调查的基础上,分析了云南省薄壳山核桃低效林成因,提出抚育管理、高接换种、接后管理、修剪、病虫害防治等改造措施,加大薄壳山核桃低效林改造技术成果推广应用,促进云南省薄壳山核桃产业健康发展。     

我国薄壳山核桃生产现状与产业化发展策略

在对薄壳山核桃在美国的栽培现状及我国引种栽培历史进行全面分析的基础上,针对目前薄壳山核桃产业发展过程中存在的主要问题,从充分利用现有种质资源,加快新品种培育进程;加强科学研究,提升薄壳山核桃产业发展的科技含量;实行定向培育,完善配套栽培技术体系等方面提出了我国薄壳山核桃产业发展的策略与建议,旨在为薄壳山核桃引种和开发利用提供理论依据。     

几个适合山东栽培的薄壳山核桃优良品种介绍

通过实地考察,观察介绍了适合山东地区栽培的薄壳山核桃品种,并对其生长结果性状进行了观测,同时结合薄壳山核桃产业发展需求提出了山东省薄壳山核桃发展的几点建议。     

万亩薄壳山核桃在丽江落地生根

"随着今年12000亩薄壳山核桃在丽江成功落地生根,我们对10年内完成50万亩基地建设更加信心十足了。"丽江市市林业局种苗站站长李宏,说起薄壳山核桃这项新兴的特色生态产业的发展时如数家珍,激情昂扬。薄壳山核桃原称美国山核桃,为胡桃科、山核桃属落叶乔木。薄壳山核桃原产美国和墨西哥,是世界上重要的干果之一。薄壳山核桃为阳性树     

江苏丘陵地区薄壳山核桃适宜栽培模式及其产业发展对策

根据薄壳山核桃发展现状和江苏省丘陵地区实际情况,提出丘陵地区薄壳山核桃适宜栽培模式:人工纯林栽培模式、粮-林复合栽培模式、茶-林复合栽培模式、林相复合栽培模式和庭院经济栽培模式,并提出丘陵地区发展薄壳山核桃产业的对策和建议,以期为薄壳山核桃在江苏丘陵地区的栽培推广提供参考。     

云南省薄壳山核桃种植现状及发展策略

在总结云南省薄壳山核桃种植历史的基础上,分析了薄壳山核桃发展的制约因素,并结合近年研究结果,提出了云南省薄壳山核桃发展的策略。     

江苏薄壳山核桃和油用牡丹发展现状与对策

薄壳山核桃和油用牡丹是近年来江苏推广栽培的主要木本油料树种。至2017年4月,江苏薄壳山核桃和油用牡丹的栽培面积已达6 400 hm~2,其中油用牡丹1 800 hm~2,薄壳山核桃4 600 hm~2,但在发展过程中还存在思想认识不到位、农民直接参与度不高,产业基础薄弱、技术人才缺乏等问题。为促进江苏薄壳山核桃和油用牡丹产业健康发展,提出了科学规划布局、加强种苗管理、强化技术培训、优化推广模式、加大扶持力度,夯实产业基础等对策措施。     

江苏薄壳山核桃发展态势分析与策略

根据江苏薄壳山核桃种植现状及存在的问题,分析了当前全省薄壳山核桃发展的有利因素和发展潜力,并从宏观层面上提出今后的发展思路及对策。     

Below-ground root yield and distribution in natural and replanted mangrove forests at Gazi bay, Kenya

Estimation of total biomass in woody ecosystems is important because of its relevance to nutrient turnover and the potential to store carbon. Most work on mangrove biomass, particularly in the Western Indian Ocean Region, has concentrated on the above-ground component; comparatively little is known on below-ground biomass. The current study was conducted at Gazi bay on the southern coast of Kenya. The objective was to determine the below-ground biomass of three species of mangrove, Rhizophora mucronata Lamarck, Avicennia marina (Forsk.) Vierh and Sonneratia alba J. Smith, in natural and replanted stands. The effects of distance from the tree base and of soil depth on root biomass and size distributions were also studied using coring. Live below-ground biomass (mean ± S.E.) ranged from 7.5 ± 0.4 t/ha to 35.8 ± 1.1 t/ha, 48.4 ± 0.7 t/ha to 75.5 ± 2.0 t/ha and 39.1 ± 0.7 t/ha to 43.7 ± 1.7 t/ha for R. mucronata, S. alba and A. marina, respectively, depending on the age of the stand. Including dead roots produced total biomass values of 34.9 ± 1.8–111.5 ± 5.6 t/ha, 78.9 ± 3.3–121.5 ± 7.3 t/ha and 49.4 ± 1.1–84.7 ± 5.4 t/ha for R. mucronata, S. alba and A. marina. These values imply carbon contents of live roots ranging between 3.8 ± 0.2 C t/ha and 17.9 ± 0.6 C t/ha, 24.2 ± 0.4 C t/ha and 37.7 ± 1.0 C t/ha and 19.5 ± 0.4 C t/ha and 21.9 ± 0.9 C t/ha for R. mucronata, S. alba and A. marina stands, respectively, and 17.4 ± 0.9 C t/ha and 55.7 ± 2.8 C t/ha, 39.4 ± 1.7 C t/ha and 60.7 ± 3.6 C t/ha and 24.7 ± 0.6 C t/ha and 42.4 ± 2.9 C t/ha for R. mucronata, S. alba and A. marina stands, respectively if dead roots are included. Stand densities were 4650 ± 177 stems/ha, 3800 ± 212 stems/ha and 3567 ± 398 stems/ha for R. mucronata 6-year old, 12-year-old and natural stands respectively. Mean stem diameter, and basal area were highest in the 12-year-old plantation while below-ground root biomass increased with age. Stand density for S. alba, was highest in the 12-year-old plantation (7900 ± 141 stems/ha) while the 9-year-old stand had trees with the largest diameter (7.7 ± 0.9 cm). Below-ground biomass was highest in the 12-year old (75.5 ± 2.0 t/ha) and lowest in the natural stand (48.4 ± 0.7 t/ha). Stand density for A. marina was highest in the 12-year-old plantation (4300 ± 919 stems/ha) while mean stem diameter (7.9 ± 0.7 cm) and basal area (16.2 ± 2.1 m²/ha) were highest in the natural stand. Below-ground biomass in the 12-year-old (43.7 ± 1.7 t/ha) and natural stands (39.1 ± 0.7 t/ha) was similar. Root densities decreased with soil depth and with distance from the base of trees for all species and stands. Fine roots (diameter <5 mm) constituted between 24% and 45% of the total stand live root biomass. The information generated is important in establishing the total biomass and thus the potential amount of carbon sequestered by mangroves in the study area.     

Gas exchange responses of <Emphasis Type="Italic">Eucalyptus</Emphasis>, <Emphasis Type="Italic">C. africana</Emphasis> and <Emphasis Type="Italic">G. robusta</Emphasis> to varying soil moisture content in semi-arid (Thika) Kenya

A dramatic decline in forest cover in eastern Africa along with a growing population means that timber and poles for building and fuelwood are in short supply. To overcome this shortage, the region is increasingly turning to eucalyptus. But eucalyptus raises environmental concerns of its own. Fears that it will deplete water supply, affect wildlife and reduce associated crop yields have caused many countries in the region to discourage farmers from planting this exotic. This paper is part of a series of investigations on the growth and water use efficiency of faster growing eucalyptus hybrids, which was introduced from South Africa to Kenya. The hypothesis is that the new hybrids are more efficient in using water and more suitable for the semi-arid tropics than existing eucalyptus and two popular agroforestry species. Gas exchange characteristics of juvenile Eucalyptus grandis (W. Hill ex Maiden), two eucalyptus hybrids (E. grandis × Eucalyptus camaldulensis Dehnh.), Grevillea robusta (A. Cunn) and Cordia africana (Lam) was studied under field and pot conditions using an infrared gas analyzer was used to measure photosynthetic active radiation (PAR), net photosynthetic rate (A), stomatal conductance (g _s) and transpiration rate (E) at CO₂ concentrations of 360 μmol mol⁻¹ and ambient humidity and temperature. A, E and g _s varied between species, being highest in eucalyptus hybrid GC 15 (24.6 μmol m⁻² s⁻¹) compared to eucalyptus hybrid GC 584 (21.0 μmol m⁻² s⁻¹), E. grandis (19.2 μmol m⁻² s⁻¹), C. africana (17.7 μmol m⁻² s⁻¹) and G. robusta (11.1 μmol m⁻² s⁻¹). C. africana exhibited high E values (7.0 mmol m⁻² s⁻¹) at optimal soil moisture contents than G. robusta (3.9 mmol m⁻² s⁻¹) and eucalyptus (5.3 mmol m⁻² s⁻¹) in field experiment and G. robusta (3.2 mmol m⁻² s⁻¹) and eucalyptus (4.2 mmol m⁻² s⁻¹) in pot-grown trees. At very low soil moisture content, extremely small g _s values were recorded in GC 15 and E. grandis (8 mmol m⁻² s⁻¹) and G. robusta (14 mmol m⁻² s⁻¹) compared to GC 584 (46.9 mmol m⁻² s⁻¹) and C. africana (90.0 mmol m⁻² s⁻¹) indicating strong stomatal control by the species. Instantaneous water use efficiency ranged between 3 and 5 μmol mmol⁻¹ and generally decreased with decline in soil moisture in pot-grown trees but increased with declining soil moisture in field-grown trees.     

黄河小浪底库区山地栓皮栎人工林土壤呼吸的季节动态

[目的]分离并量化土壤自养呼吸和异养呼吸,探讨各自贡献率及其随季节变化的动态特征。[方法]采用壕沟法和气体红外分析法,研究黄河小浪底库区山地栓皮栎人工林土壤总呼吸、自养呼吸和异养呼吸速率的季节动态变化、贡献率和环境影响因子。[结果]表明:栓皮栎人工林总土壤呼吸、自养呼吸和异养呼吸均呈夏季速率高、冬季速率低。栓皮栎土壤总呼吸、自养呼吸及异养呼吸速率与5 cm土壤温度均呈极显著指数相关,温度敏感性系数Q_(10)值大小为自养呼吸(3.40)异养呼吸(2.90)土壤总呼吸(2.45);栓皮栎土壤总呼吸、自养呼吸、异养呼吸速率与0 10 cm土壤体积含水量均显著线性相关;土壤总呼吸、自养呼吸速率与0 10 cm土壤电导率显著相关。土壤总呼吸和异养呼吸的温度敏感系数Q_(10)值均在冬季最大,夏秋季最小;而自养呼吸的Q_(10)值则呈相反的变化趋势。栓皮栎人工林自养呼吸和异养呼吸对土壤总呼吸的月贡献率为13.23%37.33%和62.67%86.76%,且自养呼吸的贡献率与土壤温度的季节变化规律相似。土壤总呼吸、异养呼吸与自养呼吸的CO2年通量分别为1 616.41、1 199.39、417.02 g·m~(-2)·a~(-1)。[结论]经过区分与定量化土壤总呼吸及其组分,确定异养呼吸为本研究区栓皮栎人工林土壤总呼吸的主要组分,作用于异养呼吸的生物与非生物因子均能显著影响整个森林生态系统表层CO_2总排放通量的大小,进一步为该研究区森林生态系统碳循环与能量流动的进一步量化研究提供参考。     

重庆酸雨区缙云山典型林分冠层酸雨淋洗特征

选取重庆缙云山的针阔混交林、常绿阔叶林、毛竹林、灌木林4种典型林分,观测酸性降水过程中林外雨、穿透雨及干流等林内水分转换分量中的主要离子含量变化,分析林分冠层对雨水化学组成的影响,结果表明:(1)降雨中的离子当量浓度大小依次是SO42-＞Ca2+＞ NH4+＞Mg2+＞K+＞Na+＞NO3-;(2)降雨经过林冠层后pH值降低,干流的酸化程度增加最大;(3)降雨经林冠层后离子浓度明显增加(除灌木林),穿透雨中通量增加最大的阴离子和阳离子分别为SO42-(2.19×103～6.47×103 eq·hm-2)和Ca2+(1.41×103～3.39×103 eq-hm-2),离子来源主要为大气沉降和植物分泌物或淋出;(4)同一离子在不同林分的干流和穿透雨中的通量变化不同,反映出不同林分冠层的离子交换性差异.在针阔混交林中,林下降雨净淋溶量大小顺序为SO42-＞Ca2+＞ NO3-＞K+＞NH4+＞Mg2+＞ Na+;常绿阔叶林为SO42-＞ Ca2+＞ K+＞NO3-＞ NH4+＞ Mg2+ ＞Na+;毛竹林为Ca2+＞ SO42-＞ K+＞NO3-＞ NH4+＞Na+＞Mg2+;灌木林为Ca2+＞ NO3-＞ K+＞ Na+＞Mg2+＞ NH4+＞ SO42-.     

Carbon dioxide exchange of a larch forest after a typhoon disturbance

A typhoon event catastrophically destroyed a 45-year-old Japanese larch plantation in southern Hokkaido, northern Japan in September 2004, and about 90% of trees were blown down. Vegetation was measured to investigate its regeneration process and CO₂ flux, or net ecosystem production (NEP), was measured in 2006–2008 using an automated chamber system to investigate the effects of typhoon disturbance on the ecosystem carbon balance. Annual maximum aboveground biomass (AGB) increased from 2.7 Mg ha⁻¹ in 2006 to 4.0 Mg ha⁻¹ in 2007, whereas no change occurred in annual maximum leaf area index (LAI), which was 3.7 m² m⁻² in 2006 and 3.9 m² m⁻² in 2007. Red raspberry (Rubus idaeus) had become dominant within 2 years after the typhoon disturbance, and came to account for about 60% and 50% of AGB and LAI, respectively. In comparison with CO₂ fluxes measured by the eddy covariance technique in 2001–2003, for 4.5 months during the growing season, the sum of gross primary production (GPP) decreased on average by 739 gC m⁻² (64%) after the disturbance, whereas ecosystem respiration (RE) decreased by 501 gC m⁻² (51%). As a result, NEP decreased from 159 ± 57 gC m⁻² to −80 ± 30 gC m⁻², which shows that the ecosystem shifted from a carbon sink to a source. Seasonal variation in RE was strongly correlated to soil temperature. The interannual variation in the seasonal trend of RE was small. Light-saturated GPP (P_max) decreased from 30–45 μmol m⁻² s⁻¹ to 8–12 μmol m⁻² s⁻¹ during the summer season through the disturbance because of large reduction in LAI.     

Nitrogen leaching in response to increased nitrogen inputs in subtropical monsoon forests in southern China

Dissolved inorganic nitrogen (DIN) (as ammonium nitrate) was applied monthly onto the forest floor of one old-growth forest (>400 years old, at levels of 50, 100 and 150 kg N ha⁻¹ yr⁻¹) and two young forests (both about 70 years old, at levels of 50 and 100 kg N ha⁻¹ yr⁻¹) over 3 years (2004–2006), to investigate how nitrogen (N) input influenced N leaching output, and if there were differences in N retention between the old-growth and the young forests in the subtropical monsoon region of southern China. The ambient throughfall inputs were 23–27 kg N ha⁻¹ yr⁻¹ in the young forests and 29–35 kg N ha⁻¹ yr⁻¹ in the old-growth forest. In the control plots without experimental N addition, a net N retention was observed in the young forests (on average 6–11 kg N ha⁻¹ yr⁻¹), but a net N loss occurred in the old-growth forest (−13 kg N ha⁻¹ yr⁻¹). Experimental N addition immediately increased DIN leaching in all three forests, with 25–66% of added N leached over the 3-year experiment. At the lowest level of N addition (50 kg N ha⁻¹ yr⁻¹), the percentage N loss was higher in the old-growth forest (66% of added N) than in the two young forests (38% and 26%). However, at higher levels of N addition (100 and 150 kg N ha⁻¹ yr⁻¹), the old-growth forest exhibited similar N losses (25–43%) to those in the young forests (28–43%). These results indicate that N retention is largely determined by the forest successional stages and the levels of N addition. Compared to most temperate forests studied in Europe and North America, N leaching loss in these seasonal monsoon subtropical forests occurred mainly in the rainy growing season, with measured N loss in leaching substantially higher under both ambient deposition and experimental N additions.     

Growth analysis of the competition–density effect in non-self-thinning Populus deltoides and Populus?×?euramericana plantations

The competition–density (C–D) effect for non-self-thinning Populus deltoides and Populus × euramericana plantations from 3 to 9 years was analyzed using the reciprocal equation of the C–D effect. The C–D effect was well described by the reciprocal equation, and with the progress of time the C–D curve, on logarithmic coordinates, of the P. × euramericana plantations shifted upward faster than that of the P. deltoides plantations. With increasing physical time t, the biological time τ, i.e. the integral from zero to t of the coefficient of growth λ(t) in the general logistic curve with respect to t, increased rapidly during early growth stages and the increases in τ gradually became slow during later growth stages. This trend was more evident in the P. deltoides plantations than in the P. × euramericana plantations. The coefficients A and B included in the reciprocal equation were calculated at each growth stage. With increasing τ, the coefficient A, the reciprocal of which means the asymptote of yield (=wρ) at a given growth stage, increased abruptly to a maximum value and then tended to decrease gradually to a constant level. On the other hand, the coefficient B, the reciprocal of which means the asymptote of mean stem volume at a given growth stage, decreased exponentially and tended to be close to zero with increasing τ. The λ(t) decreased with increasing stand age, whereas the final yield Y(t) defined as W(t) ρ, where W(t) is the asymptote of w in the general logistic growth curve, increased gradually with increasing stand age. The differences in coefficients A, B, and λ(t) between the two species were reported.     

Influences of forest tending works on carbon distribution and cycling in a Pinus densiflora S. et Z. stand in Korea

This study was conducted to determine carbon (C) dynamics following forest tending works (FTW) which are one of the most important forest management activities conducted by Korean forest police and managers. We measured organic C storage (above- and below-ground biomass C, forest floor C, and soil C at 50 cm depth), soil environmental factors (soil CO₂ efflux, soil temperature, soil water content, soil pH, and soil organic C concentration), and organic C input and output (litterfall and litter decomposition rates) for one year in FTW and non-FTW (control) stands of approximately 40-year-old red pine (Pinus densiflora S. et Z.) forests in the Hwangmaesan Soopkakkugi model forest in Sancheonggun, Gyeongsangnam-do, Korea. This forest was thinned in 2005 as a representative FTW practice. The total C stored in tree biomass was significantly lower (P < 0.05) in the FTW stand (40.17 Mg C ha⁻¹) than in the control stand (64.52 Mg C ha⁻¹). However, C storage of forest floor and soil layers measured at four different depths was not changed by FTW, except for that at the surface soil depth (0–10 cm). The organic C input due to litterfall and output due to needle litter decomposition were both significantly lower in the FTW stand than in the control stand (2.02 Mg C ha⁻¹ year⁻¹ vs. 2.80 Mg C ha⁻¹ year⁻¹ and 308 g C kg⁻¹ year⁻¹ vs. 364 g C kg⁻¹ year⁻¹, respectively, both P < 0.05). Soil environmental factors were significantly affected (P < 0.05) by FTW, except for soil CO₂ efflux rates and organic C concentration at soil depth of 0–20 cm. The mean annual soil CO₂ efflux rates were the same in the FTW (0.24 g CO₂ m⁻² h⁻¹) and control (0.24 g CO₂ m⁻² h⁻¹) stands despite monthly variations of soil CO₂ efflux over the one-year study period. The mean soil organic C concentration at a soil depth of 0–20 cm was lower in the FTW stand (81.3 g kg⁻¹) than in the control stand (86.4 g kg⁻¹) but the difference was not significant (P > 0.05). In contrast, the mean soil temperature was significantly higher, the mean soil water content was significantly lower, and the soil pH was significantly higher in the FTW stand than in the control stand (10.34 °C vs. 8.98 °C, 48.2% vs. 56.4%, and pH 4.83 vs. pH 4.60, respectively, all P < 0.05). These results indicated that FTW can influence tree biomass C dynamics, organic C input and output, and soil environmental factors such as soil temperature, soil water content and soil pH, while soil C dynamics such as soil CO₂ efflux rates and soil organic C concentration were little affected by FTW in a red pine stand.     

Methane and nitrous oxide emissions from mature forest stands in the boreal forest, Saskatchewan, Canada

Despite the spatial significance of Canada's boreal forest, there is very little known about CH₄ and N₂O emissions from non-peatlands within it. The primary objective of this project was to study the atmosphere–soil exchange of CH₄ and N₂O at three sites in the boreal forest of central Saskatchewan. In the summers of 2006 and 2007, CH₄ and N₂O emissions were measured along transects in three different mature forest stands (aspen, black spruce and jack pine) using a sealed chamber method. At the aspen site, the gross rates of mineralization and nitrification, and the relative contribution of nitrification and denitrification to N₂O emissions, were also measured using the ¹⁵N isotope dilution technique. Results indicated that the jack pine and black spruce sites were slight sinks of CH₄ (−0.123 g CH₄–C m⁻² yr⁻¹and −0.017 g CH₄–C m⁻² yr⁻¹ respectively in 2006 and −0.095 g CH₄–C m⁻² yr⁻¹and 0.045 g CH₄–C m⁻² yr⁻¹ respectively in 2007), whereas the aspen site was a net source (4.40 g CH₄–C m⁻² yr⁻¹ in 2006 and 19.60 g CH₄–C m⁻² yr⁻¹ in 2007). The high CH₄ emissions at the aspen site occurred at depressions that were water-filled due to above-average precipitation levels in 2005–2007. All three sites had very low cumulative N₂O emissions, ranging from −0.002 to 0.014 g N₂O–N m⁻² yr⁻¹ in both years. The ¹⁵N results indicated that N cycling at the aspen site was very conservative, allowing little N to escape the system as N₂O; the emissions that did occur were due primarily to a nitrification-related process.     

The pharmacokinetical study of plant alkaloid tetrandrine with a simple HPLC method in rabbits

A simple HPLC method was developed to quantify rabbit plasma tetrandrine (Tet) with propranolol (Pro) as internal standard. Based on the established method Tet and Pro were eluted at 7.1 and 12.0 min, respectively. It was shown that the concentration-time data of Tet fit the classical two-compartment model, no matter the drug was administered intravenously or orally to rabbits. The values of AUC_0 → ∞, clearance (Cl_0 → ∞), volume of distribution (Vd), and elimination half-life (t_1/2β) of Tet were 59861.149 ± 26962.196 μg/L ? min, 0.503 ± 0.173 L/min/kg, 179 ± 76.185 L/kg, and 283.808 ± 162.937 min for intravenous injection of 5 mg/kg, or 18986.217 ± 7462.308 μg/L ? min, 0.805 ± 0.267 L/min/kg, 110.284 ± 94.176 L/kg, and 732.919 ± 847.32 min for gavage administration of 10 mg/kg , respectively. The results indicate that Tet displays a limited absorption in intestinal tract, even though it has a favorable pharmacokinetic profile after oral or intravenous administration.