陕西秋季飞播造林研究

飞播造林是陕西造林绿化的主要手段之一。本文以播期为中心，对陕西秋季飞播造林的主要相关技术进行了较为的研究，阐明了陕西秋季飞播造林的特点和规律，为陕西乃至毗邻省同类自然条件地区大面积开展秋季飞播造林提供了科学依据。     

豫北太行山区飞播造林成效喜人

我省太行山区飞播造林试验始于1982年,针对太行山区的立地类型和气候条件,飞播工作人员在造林地选择、树种选择、播期确定、播区规划设计、成效调查和播后管理等方面进行了深入系统的研究,根据不同地自然条件和飞播造林要求,将豫北飞播宜林地划分为二个造林类型区,即豫北太行中山油松区、豫北太行低山丘陵侧柏油松区。在飞播宜林地造林类型区划的基础上,制定了不同的造     

陕西蜜蜂飞机播种造林试验

本文通过蜜蜂3型和4型飞机在陕西省渭南市2009年秋季进行飞播造林试验,总结出蜜蜂3型和4型飞机性能和飞播造林经验,为今后飞播造林提供技术依据。     

太行山区飞播造林减少播种量试验初探

飞播造林中,在适当减少播种量的情况下,通过与对照区落种、出苗等情况对比,以及不同植被盖度、不同坡度、坡位等因素对出苗影响的调查,认为适当减少播种量,出苗量能够达到飞播造林的规程要求,且可降低飞播造林成本。     

榆林沙区飞播造林成效评定标准探析

根据榆林沙区历年来飞播造林沙地出苗、成苗调查数据分析,确定流动沙地飞播造林治沙成效评定时间及标准,并且针对不同立地条件类型的播区,提出相对应的评定标准,指导半干旱沙区飞播造林治沙的生产实践。     

人工点撒播造林在飞播造林中重要性的探讨

在四川省飞播造林中,占用飞播造林计划,开展辅助人工点撒播造林,在经济不发达,群众经济收入低的贫困县,为加速造林步伐,采取占用飞播造林计划开展人工点撒造林的优越性,已为人们所认识.本文对在什么条件下开展飞播,什么条件下适宜人工点撒播进行了调查研究,提出以下看法,供商榷.一、占用飞播造林计划,开展人工点撒播造林的重要性和作用1.人工点撒播造林适应性强,与飞机播种造林比较,最大的优点是在划定的飞播区周围较近的地方人口稠密,采用人工点撒播能在作业时提供足够劳动力.在达不到飞播造林规     

油松飞播造林效果调查

通过对太行山中段土石山的飞播造林试验,对油松飞播造林的播区选择、播期的确定以及不同坡向、坡度,不同土层厚度和植被状况应采取的技术措施进行了调查总结。油松飞播造林有苗面积占到有效面积的66.8%超过部颁优级飞播造林40%的标准,亩均保存幼苗186.8%株。每造成1亩林,较直播造林和植苗造林成本降低1.72元和8.87元,取得造林速度快、效率高、成本低、省工省力的好效果。     

晋西黄土丘陵区飞播造林成效调查

对岚县、五寨在不同年度、不同立地条件下飞播造林的成效进行了调查，分析了飞播造林成效差的原因，以便为今后这一地区的生态环境建设提供科学依据。     

基于气象因子的咸阳市飞播造林播期确定

通过对咸阳市1996—2005年飞播造林播区(以旬邑、淳化、礼泉为代表)开展飞播成效调查,并收集与飞播造林同期气象实况资料,对飞播造林成效与气象因子进行了回归分析,找出影响飞播造林成效的主导气象因子,给出咸阳市飞播造林最佳播期。     

气象因子对马尾松飞播造林成效的影响

在对安徽省岳西、金寨、责池等11个县（市、区）1991—1992年马尾松飞播造林播区，开展飞播当年出苗调查和飞播3a后成效调查的基础上，通过收集飞播造林当年至成效调查前气象实况数据，就飞播造林成效与气象因子进行逐步回归分析，找出影响飞播造林成效的主导因子，并进行了进一步分析。     

Influence of nursery culture on western red cedar

Western red cedar (Thuja plicata Donn) seedlings were grown in a greenhouse and subjected to six nursery cultural treatments (long-day wet (LDW), long-day moderate (LDM), long-day dry (LDD), short-day wet (SDW), short-day moderate (SDM), and short-day dry (SDD)) during mid-summer. Seedling attributes were measured before fall and spring planting.Short-day and moisture stress treatments reduced shoot but not root growth, resulting in reduced shoot to root ratios. Fall tested LDW seedlings had a higher osmotic potential at saturation and turgor loss point than other treatments. Fall tested short-day seedlings had lower resistance to plant water movement. The LDW seedlings had the greatest new root growth in fall testing, while one of the lowest in spring testing. In the fall, LDW seedlings had the greatest net photosynthesis (P_n) at 25 °C root temperature, with all treatments having a similar decline in P_n as root temperatures decreased to 1 °C. In the spring, all treatments had a similar decline in P_n with decreasing predawn shoot water potential. Moisture stress and short-day nursery cultural treatments applied in mid-summer will not harden western red cedar seedlings for all potential field conditions.Spring, compared to fall, tested seedlings had two times the shoot and three times the root dry weight. Spring tested seedlings had a lower osmotic potential, maximum modulus of elasticity, relative water content at turgor loss point and greater dry weight fraction. Fall, compared to spring, tested seedlings had lower resistance to plant water movement and greater cuticular transpiration. In general, fall tested seedlings had more root growth than spring tested seedlings. Spring, compared to fall, tested seedlings generally had greater stress resistance.     

对刺五加播种当年出苗率和保存率的初步研究

在春季,科学播种已层积催芽成功的刺五加种子,13天出苗,至35天出苗结束;其中裂口露白种子出苗52.3%,未裂口露白优良种子出苗15%;至9月上旬保苗率44.92%。通过实验提出了种苗损失系数值和播种当年提高出苗率、保苗率的措施要点。     

Afforestation trials with Prosopis chilensis (Mol.) Stuntz and Prosopis flexuosa D.C. in the Dry Chaco, Argentina

In implantation trials carried out with Prosopis chilensis and Prosopis flexuosa, the following variables were considered: implantation time (December and March), implantation technique (direct seeding and seedling transplantation) and age of the seedlings at the time of transplantation (60, 105 and 150 days). Survival was evaluated for more than 9 months after implantation and trials were repeated in 3 consecutive years.

Results from both species were similar and they show that survival after transplantation was higher (60–80%) than from direct seeding (35–45%). Survival from transplantation was independent of the size and age of the seedlings and it was less affected by climatic conditions than direct field sowing. Survival from direct seeding was higher in March than in December. The best time for either implantation alternative would be the end of the summer or beginning of fall, when climatic conditions increase the probability of seedling survival.     

蒙古栎播种育苗试验初报

以蒙古栎为材料进行育苗技术研究,结果表明：秋播育苗效果优于春播育苗,可提前出土7～10 d,发芽率提高10%,成苗率提高12%;苗高、地径较春播分别提高了5～15 cm和0.15 cm。最佳播种量为0.5～0.7 kg.m-2,最佳保留密度为130～170株.m-2。     

NATURAL ADJUSTMENT OF POPULATION DENSITY OF LARCH CASEBEARER (COLEOPHORA DAHURICA)

Population increase of Larch casebearer(C. dahurica)were controlled by compre-hensive factors.Spring wind caused 27％ of larvae on crown to fa11 down.Early and late frosts,larch catempillar,sawfly and needle cast of larch could reduce the food quality and quantity of larchcasebearer and had indrect effects on population density. Birds,ants and spites were the mainpredators of C.dahurica. The parasite complex comprised Piermalebae,Eulophidae,Ichneumonidaeand Braconidae."Self--adjustment",of population caused by"self--population density",only runseffectively at a high larval density.     

Soil organic matter in a ponderosa pine forest with varying seasons and intervals of prescribed burn

Prescribed burning is used to reduce fuel loads and return ponderosa pine forests of the Western U.S. to their historical structure and function. The impact of prescribed burning on soil is dependent on fire severity which is largely managed by burning in the fall or the spring; frequency of fire will also regulate long-term fire impacts. The objective of this study was to determine if soils and soil organic matter (SOM) were affected by prescribed burning in the fall or the spring using singular or multiple prescribed burns. Prescribed burning was initiated in the spring of 1997 and fall of 1997 at 5-year intervals and once during a 15-year period on a study site located within the Malheur National Forest of the southern Blue Mountains of eastern Oregon. Soils were sampled by major genetic horizon in 2004. The 5-year interval plots had burned twice with 1–2 years of recovery while the 15-year interval plots had burned only once with 6–7 years of recovery. Samples were analyzed for pH, carbon (C), nitrogen (N), C/N ratio, cation exchange capacity, base saturation, water repellency, and humic substance composition by alkali extraction. Fall burning decreased C and N capital of the soil (O horizon +30 cm depth mineral soil) by 22–25%. Prescribed burning did not have an effect on fulvic or humic acid C concentration (FA and HA, respectively) of the mineral soil and only a minor effect on FA and HA concentration of the O horizon. One or two fall burns decreased humin and the alkali non-soluble C (NS) content of O horizon by 15 and 30%, respectively. Initiating fall burning in fire-suppressed stands may not preserve soil C, N, humin, and NS content, but may replicate the natural fire regime. Spring burning using a return interval of 5 or more years reduces the fuel load while having little impact on soil C, N, and SOM composition and may be used to prepare a site for subsequent fall burns.     

Natural adjustment of population density of Larch casebearer (Coleophora dahurica)

Population increase of Larch casebcarer (C. dahurica) were controlled by comprehensive factors. Spring wind caused 27% of larvae on crown to fall down. Early and late frosts, larch caterpillar, sawfly and needle cast of larch could reduce the food quality and quantity of larch casebcarer and had indirect effects on population density. Birds, ants and spites were the main predators ofC. dahurica. The parasite complex comprisedPtermalidae, Eulophidae, Ichneumonidae andBraconidae. “Self-adjustment”, of population caused by “self-population density”, only runs effectively at a high larval density.     

A silviculture-oriented spatio-temporal model for germination in Pinus pinea L. in the Spanish Northern Plateau based on a direct seeding experiment

Natural regeneration in Pinus pinea stands commonly fails throughout the Spanish Northern Plateau under current intensive regeneration treatments. As a result, extensive direct seeding is commonly conducted to guarantee regeneration occurrence. In a period of rationalization of the resources devoted to forest management, this kind of techniques may become unaffordable. Given that the climatic and stand factors driving germination remain unknown, tools are required to understand the process and temper the use of direct seeding. In this study, the spatio-temporal pattern of germination of P. pinea was modelled with those purposes. The resulting findings will allow us to (1) determine the main ecological variables involved in germination in the species and (2) infer adequate silvicultural alternatives. The modelling approach focuses on covariates which are readily available to forest managers. A two-step nonlinear mixed model was fitted to predict germination occurrence and abundance in P. pinea under varying climatic, environmental and stand conditions, based on a germination data set covering a 5-year period. The results obtained reveal that the process is primarily driven by climate variables. Favourable conditions for germination commonly occur in fall although the optimum window is often narrow and may not occur at all in some years. At spatial level, it would appear that germination is facilitated by high stand densities, suggesting that current felling intensity should be reduced. In accordance with other studies on P. pinea dispersal, it seems that denser stands during the regeneration period will reduce the present dependence on direct seeding.     

云南省飞播造林回顾

云南省飞播造林始于1960年，至2000年，经过了试验阶段、推广阶段、发展阶段、高科技阶段等4个阶段，共在大理、楚雄、昆明、丽江、红河、玉溪、曲请、昭通、文山、保山、临沧、思茅等12个地州市85个县市设置播区980个累计作业面积289346hm^2，设计宜播面积2230320hm^2，保存面积1028821hm^2，保存率为46.13%，相当于增加森林覆盖率2.61个百分点。分析了飞播中存在的问题，提出了今后的保障措施。     

乌兰察布市兴和县山区春季雨季造林与管理措施的浅析

文章针对乌兰察布市兴和县山区利用春季雨季的有利时机,搞好造林,提高造林成活率,春季雨季造林技术及管理粗浅的想法。