广西天峨县引种岩桂试验效果初报

叙述了我国岩桂栽培的历史，以及在广西天峨县石灰岩地区引种岩桂的育种和造林技术。研究结果表明：岩桂成活率高、生长较快，即使在石旮旯地也能正常生长，是石漠化地区绿化造林进行生态治理的理想树种。同时通过对岩桂枝叶的加工利用，可增加石漠化地区农民的收入，加快山区农民脱贫致富的步伐。     

岩桂人工林水土流失监测及效益评估

通过连续2年对岩桂人工林主要生长区降雨、地表径流、泥沙含量的观测和3种栽培模式水土流失的对比分析,得出了以下2个重要结论:①3年生林分与2年生林分比较,水土流失大为减少,岩桂纯林模式水土流失减少了91.81%,岩桂 白犀草模式减少水土流失为88.97%;②林草栽培模式较农耕地模式水土流失减少,岩桂纯林和岩桂 白犀草混交林模式水土流失均比未停耕农耕地有较大程度减少,2年生岩桂纯林水土流失减少35.3%,岩桂 白犀草混交林水土流失减少34%,3年生岩桂纯林水土流失减少88.11%,岩桂 白犀草混交林水土流失减少83.67%.     

岩桂开发利用价值及栽培技术

本文通过对筠连县岩桂自然资源的调查,根据岩桂的生物学特性和生产实践,提出了岩桂的开发利用价值和栽培技术。     

昭平举办森林防火培训班展

日前,广西壮族自治区昭平县举办森林防火专业、半专业队灭火知识培训班。自治区直属高峰林场、黄冕林场、大桂山林场等6个国有林场对外造林驻昭平负责人和造林大户华劲公司、欣荣星公司、瑞发公司,以及昭平县森林防火指挥部、县国有林场防火负责人．县专业森林消防队员等共110多人参加了培训。     

岩桂优良类型选择研究

通过对筠连县岩桂产区进行全面调查，根据岩桂叶型、叶色及分枝习性等特征，将岩桂分为三种类型即长叶岩桂、园叶岩桂和中间型。在立地条件、栽植密度、年龄、管理措施、采叶强度等相同的情况下，对三种类型的采叶量、鲜叶出油率和黄樟油素含量进行调查测定。对数据进行Bartlett检验F检验和q检验，分析得出三种类型的采叶量无明显差异，长叶岩桂的鲜叶出油率明显高于其它类型0．3—0．6个百分点，长叶岩桂的黄樟油素含量明显高于其它类型2—3个百分点。根据试验表明长叶岩桂的出油率和黄樟油素含量高，为选出的优良类型，适合全县大面积推广。     

岩桂果实油脂脂肪酸组成分析

采用油脂制备方法,从岩桂果实中得到45～55％的油脂;分析岩桂果实油脂中含有棕榈酸、硬脂酸、油酸、亚油酸等多种脂肪酸,其中油酸、亚油酸等不饱和脂肪酸质量分数达70％以上.     

大桂山林场场外造林管理问题及对策

指出了国有林场场外造林是林场租用本单位以外的集体林地、农民承包地、县(市)区国有林(农)场林地进行造林,以及收购企业、林场、村集体、造林公司、个人等的树兜、中幼林、成熟林等相关业务活动。目前,大桂山林场是面积、规模都较大的广西林业局直属林场之一,林场利用资金、技术以及管理方面的优势,加大对外租地造林力度,历经十多年的经营管理,林场场外造林租地面积已扩大到约40000hm2,造林面积约31000hm2,同时,林场在场外造林经营管理过程中的问题也不断出现。对大桂山林场场外造林管理存在的问题进行了分析,提出了提升管理成效的具体对策,以期为林场森林经营管理提供参考。     

不同生境对踏郎生长及土壤养分空间差异的影响

踏郎(Hedysarum fruticosum),又称羊柴、山花子、山竹子、油葫芦稍,豆科岩黄芪属.踏郎是一种优良的保土固沙灌木,具有很强的根蘖能力,常"一株成林",是优良的固沙造林植物种,大部分分布在我国内蒙和西北地区的固定、半固定沙丘上,而在内蒙古大面积的半流动沙地上和流动沙地的附近也有分布,用其固定沙丘(柏玉珍,1989).     

石漠化地区岩桂优良类型的选育及其丰产栽培技术探讨

针对石漠化地区自然条件,探讨岩桂优良类型选育技术及其在石漠化地区的丰产栽培技术。     

岩桂叶精油蒸馏出油率及化学成分变化的研究

对岩桂叶精油在蒸馏过程中的出油率及化学成分变化情况进行了研究。在常压水上蒸馏情况下，岩桂叶的蒸馏出油率达到３．９２％，其出油量的８７．７６％集中在蒸馏前期的６０ｍｉｎ内，以后随蒸馏时间的进行逐渐下降。岩桂叶精油的主要化学成分为１１个，以黄樟油素为主，其含量达到９５％以上。各化学成分在蒸馏过程中的变化规律是：黄樟油素和芳樟醇的含量随蒸馏时间的进行逐渐减少；其它化学成分的含量均随蒸馏时间的进行而逐渐增     

Relationships between growing-season soil water-deficit, mineralizable soil nitrogen and site index of coastal Douglas fir

Relationships between measures of soil water availability, available soil macronutrients and site index of coastal Douglas fir were examined in 53 stands. Growing-season water-deficit was able to explain the most variation in site index of all soil water-balance measures examined (R² = 0.42). Of all soil chemical properties examined, mineralizable N in the surface 30 cm of the mineral soil and in the forest floor accounted for the most variation in site index (R² = 0.54). Multiple regression of the natural log of mineralizable N, and growing-season water-deficit on site index gave an R² of 0.63. Use of mineralizable N as a measure of N availability is supported, and interactions between water-use efficiency and stand N status are suggested.     

慈竹无性系种群生长与立地条件关系

根据调查资料,对昆明地区慈竹生长与立地条件的关系进行了研究.结果表明:无性系株高与坡度、胸径与海拔呈负相关;无性系胸径、株高与土层厚度和湿度呈正相关.通过回归分析,建立无性系株高、胸径与坡度、海拔、土层厚度、湿度之间的方程,为慈竹造林地选择和立地质量提供理论依据.     

Predicting depth translocation of base cations after forest liming: results from long-term experiments

Forest liming is a common measure to counteract soil acidification. In forest practice, lime is applied to the forest floor where it changes the chemical properties. However, little is known about the depth impact of liming and the depth translocation of lime components. To investigate the long-term impact of forest liming, several study plots have been established in the 1980s in Germany in stands with different site conditions. We analysed soil chemical data obtained during the last 28?years from 45 of the study plots. We examined the depth impact of liming and predicted the main factors responsible for the increase in Calcium (Ca) and Magnesium (Mg) stocks after liming in the mineral soil using multiple linear regression analyses (MLR). Stocks of Ca and Mg as well as base saturation (BS) showed a strong depth gradient with significant differences between limed and control plots down to 40?cm of the mineral soil. About 65–70?% of applied Ca and Mg were recovered in the forest floor and the upper 40?cm of the mineral soil. BS in 0–40?cm increased by a mean of 11?%. MLR models could explain 48–74?% of the variation in mean changes of Ca and Mg in 0–10, 10–20 and 20–40?cm soil depth when soil and climate variables, amount of applied lime and years after liming are included in the model. After testing the model robustness with a cross-validating procedure, we concluded that these models might be applied to many regions in Central Europe with comparable soil and climate conditions and thus, have widespread application.     

地形因子对思茅松人工林土壤有机碳储量的影响

[目的]以思茅松人工中龄林为研究对象,探讨不同坡向、坡度和坡位对思茅松人工林SOC储量的影响,为精确评估思茅松人工林碳储量提供科学依据。[方法]对不同坡向、坡度和坡位不同土壤层次的SOC含量、全氮、土壤密度、C:N和SOC储量进行T检验和单因素方差分析,对不同土层的SOC储量和全氮、土壤密度、C:N之间进行Pearson相关分析。[结果]思茅松人工中龄林,SOC含量、全氮和C:N随着土层加深而减少,土壤密度随着土层加深而增加。不同的坡向和坡度显著影响SOC储量大小,阳坡的SOC储量要显著高于阴坡,坡度为20 30°的SOC储量要显著低于10 20°和0 10°,坡位对SOC储量大小无显著影响。在0 100 cm土层中,随着土层深度的增加,不同立地条件的思茅松人工中龄林的SOC储量呈减小趋势,不同坡向、坡位和坡度0 20 cm土层SOC储量均显著高于其它土层。坡向和坡度显著影响0 20 cm土层的SOC储量(P0.05);坡位对各层SOC储量均无显著影响(P0.05)。0 20 cm土层中SOC储量和土壤密度呈极显著负相关,和坡向、坡度呈显著负相关关系;除2040 cm土层外,其它土层的SOC储量与全氮之间呈极显著正相关;SOC储量和坡位与C:N在任一土层均无显著相关关系。[结论]立地条件差异影响SOC储量的大小与分布,尤其是坡向和坡度的不同会造成思茅松人工中龄林SOC储量的差异。     

八角林地土壤酶活性和养分的分布特点及其相关分析

研究了广西高峰林场和大明山自然保护区八角林地土壤酶活性(包括过氧化氢酶、转化酶、脲酶、蛋白酶和酸性磷酸酶)和养分的分布特点及土壤酶活性与土壤养分的关系。结果表明:(1)土壤养分含量和酶活性以表层土壤的最大,随土壤深度的增加逐渐下降;(2)坡位不同,土壤养分含量和主要酶活性也不同,呈现下坡>上坡的趋势;(3)土壤酶活性与土壤有机质、全氮、全磷、水解氮、速效磷和速效钾密切相关,不同的土壤酶活性之间存在极显著的相关性。因此,土壤酶活性可作为八角林地土壤肥力的指标之一。     

贵州湄潭县狭叶方竹林群落类型划分与应用评价

为保护与利用狭叶方竹资源,采取作业设计调查法对贵州湄潭县狭叶方竹资源进行普查。根据普查结果,将影响狭叶方竹生长的立地环境因子筛选归类作为划分其群落类型的依据。普查结果显示,狭叶方竹在相似气候条件和中偏碱性土壤上,影响其生长的主导因子为海拔、坡位、坡向、土层厚度和林分上层郁闭度。按有明显影响的海拔、坡位和土层厚度因子将狭叶方竹林区划为6个群落类型区、36个适宜立地类型。在适宜立地类型基础上,结合狭叶方竹对林分上层林木郁闭度的适应性,将狭叶方竹林划分为144个群落类型。对区划的6个群落类型区的狭叶方竹资源现状、经营与利用方式进行了综合评价。     

Factors influencing the availability of nitrogen in thinned and unthinned Douglas-fir stands in the central Oregon Cascades

Soil N mineralized during 7-day anaerobic incubation at 40°C (‘available’ N) was compared at two soil depths and correlated to soil and site factors in Douglas-fir stands with different combinations of thinning and multinutrient fertilization. Available N expressed either on an area basis (kg ha⁻¹) or on a concentration basis (mg kg⁻¹) at the two depths did not vary significantly by stocking density, treatment, or density-treatment interaction. There was a significant difference between the soil depths, averaging 39 mg kg⁻¹ at 0–20 cm depth, and 20 mg kg⁻¹ at 20–40 cm depth. Available N was positively correlated with total soil N, exchangeable Ca, and adjusted aspect (the former two factors accounting for 46% of the total variation), and negatively with rock content and slope steepness. Stand density had no effect.     

Soil thermal and moisture regimes on forested slopes of an appalachian watershed

Soil thermal and moisture regimes were studied at four sites of contrasting slope positions and aspects within a forested Appalachian watershed (39° 41′N, 79° 45′W, elevation from 567 m to 796 m). The overall mean temperature for the 0–50 cm soil layer was 12.3°C in 1981; mean annual temperatures ranged from 13.3°C at 2 cm depth on a south-facing lower site to 11.0°C at 50 cm depth on a north-facing lower site. During the growing season soil temperatures of the south-facing lower site exceeded those of other sites by 1°C or less for soils less than 20 cm in depth. Maximum temperature differences between sites were reached in November, and the minimum temperature differences between sites were observed in January.The soil moisture content on the north-facing site exceeded that of all other sites. The south-facing lower site was the driest, while the south-facing upper site and the ridge top were intermediate and had similar moisture regimes. It was concluded that the moisture regime of the south-facing lower site was a joined effect of aspect and relatively high stoniness.     

Spatial distribution of soil carbon and nitrogen storage and forest productivity in a watershed planted to Japanese cedar (Cryptomeria japonica D. Don)

Digital terrain modeling was used to evaluate landscape-level spatial variation of soil C and N storage and site productivity in Japanese cedar (Cryptomeria japonica D. Don) stands. Soil C and N storage were measured in samples from surface soils (0–25 cm depth) of 29 Japanese cedar stands in the 205-ha Myougodani watershed, Toyama Prefecture. The site index (C. japonica tree height at age 40 years) was used as a measure of forest productivity. Seven terrain attributes (elevation, slope gradient, aspect, profile curvature, plan curvature, openness, and wetness index) were calculated from a digital elevation model. Soil C and N storage were negatively correlated with slope gradient and positively correlated with openness. Variation in the site index was closely related to the wetness index. The prediction models using terrain attributes as explanatory variables explained 50% of the variability in soil C storage, 53% of the variability in soil N storage, and 75% of the variability in site index. This result demonstrated that this technique is useful for estimating the spatial distribution of soil properties and productivity in forest landscapes. On the other hand, there was no correlation between site index and soil C and N storage. Use of the prediction models in a geographic information system revealed that the spatial distribution of forest productivity differed considerably from those of soil C and N storage.