The effects of pine mistletoe (Viscum album subsp. austriacum) on the growth of Scots pine and Crimean pine in Turkey

In this study, the effect of pine mistletoe (Viscum album subsp. austriacum) on basal area increment of Crimean pine and Scots pine was investigated. Dendrochronological data were collected from 223 (71 uninfected and 152 infected) Crimean pines and 195 (77 uninfected and 118 infected) Scots pines located in Kastamonu province of Turkey in 2014. Infected sample trees were classified as light, moderate or severe infection levels. Growth trends and basal area increment loses were compared between uninfected and infected trees for the periods of the last 10, 20 and 30 years. In addition, infection status of forest stands was investigated using temporary sample plots; 27 plots in Crimean pine stands and 26 plots in Scots pine. Results demonstrated that basal area increments were negatively affected by pine mistletoe for both species. Mean basal area increment losses of infected trees for the last decade were determined as 24% for Scots pine and 26% for Crimean pine. Basal area increment losses varied by infection levels (light, moderate and severe) as follows: 25%, 20% and 28% for Scots pines and 20%, 32% and 9% for Crimean pines. Scots pine stands were more severely infected by pine mistletoe than Crimean pine stands. There were negative correlations between number of infected trees and stand density for both species, while positive correlation was detected between the number of infected trees and mean diameter for Scots pine. The results of this study indicate that the pine mistletoe infection has negative effect on radial growth of Scots pine and Crimean pine trees. The results can be an important contribution to the forest management and protection activities in mistletoe-infected stands.     

The occurrence and pathogenicity of uni- and binucleate Rhizoctonia and Pythiaceae fungi among conifer seedlings in Finnish forest nurseries

Uni- and binucleate Rhizoctonia and Pythiaceae fungi were isolated from roots of dieback seedlings. Only binucleate Rhizoctonia strains were present in the roots of healthy seedlings. In pathogenicity tests, uninucleate Rhizoctonia sp. were pathogenic and binucleate Rhizoctonia spp. non-pathogenic. Pythium ultimum var. ultimum and Phytophthora undulata were the only Pythiaceae fungi that killed 12-week-old seedlings.     

天然长白松生物量的研究

天然长白松仅见于长白山北坡海拔630～1 400 m之间,是我国特有的松科松属植物,因其特殊的分类地位,被列为国家Ⅲ级珍稀濒危树种,而受到广泛关注。本文利用多元分析方法,对第一代天然长白松的生产结构和生物量进行研究。给出长白松生物量估测的回归模型及估测参数,指出生物量在长白松天然林中的分配规律,为经营长白山这一特有的种群提供理论依据。     

不同林龄樟子松叶片养分含量及其再吸收效率

树木叶片的养分再吸收效率能够反映树木对养分保存、利用以及对养分贫瘠环境的适应能力。以科尔沁沙地东南缘章古台地区樟子松人工林为研究对象,分析了11、20、29、45年生树木叶片的基本特征、养分含量及其再吸收效率。结果表明:叶片衰老后其质量和面积明显减少;叶片凋落前的平均养分含量没有表现出随樟子松年龄增加而出现有规律的变化;凋落叶片中的N、P、K、Mg含量表现出随年龄增加而增加的趋势,而Ca的趋势与之相反;11年生和20年生的樟子松叶片N、P、K的再吸收效率相似,都显著高于29年生和45年生樟子松(P<0.05),而樟子松叶片对Mg的再吸收效率表现出随年龄增大而显著降低,Ca随叶片的衰老而不断累积,再吸收效率表现为负值,20年生的樟子松叶片Ca再吸收效率最大,11年生和45年生最低。樟子松叶片的N、P、K、Mg养分再吸收效率随年龄增加而降低的趋势表明,随年龄增加樟子松对贫瘠养分生境的适应能力逐渐降低,反映了樟子松养分保存方面的衰退特征。     

沙地樟子松天然更新影响因素探讨

根据气象资料和诸多研究结果,从沙地樟子松自然更新过程以及原产地气象因子的特征等方面进一步分析了沙地樟子松天然更新的影响因素,结果表明：沙地樟子松当年4～5月自然落种的种子是实现自然更新的物质基础;降雪日数、积雪日数、5～7月相对湿度、5～7月平均温度等是影响沙地樟子松自然更新的主要因素。其中,5～7月相对湿度、5～7月平均温度变化特征是影响沙地樟子松自然落种的种子萌发及其幼苗生长的关键因素,而降雪日数、积雪日数是影响并决定当年幼苗安全越冬的保证。     

沙区樟子松幼苗培育技术

文章通过对樟子松种子、幼苗生物学特性的大量观测实践和研究,总结出樟子松种子处理、幼苗培育和病虫害防治的育苗技术。     

樟子松栗钙土造林效果初探

以樟子松4 a生容器苗在栗钙土上进行造林,采用每年2、2、2、1、1次连续抚育5 a,结果表明:当年成活率达到95.8%,3 a保存率为86.3%,最终保存率为81.2%,高于国家规定16个百分点;11 a生树高总高度为316.4 cm,未发现有病虫危害,长势良好。     

兴安落叶松、樟子松苗木活力与水势的关系

通过对兴安落叶松、樟子松苗木活力与水势关系的分析，发现苗木活力与其水分状况密切相关，苗木失水首先使根系的水势下降，最终导致造林成活率和生长量的降低， 在苗木贮藏和运输过程中，有用保护剂是提高和保持苗木成活率的有效措施。     

球毛壳菌对樟子松的侵染规律研究

榆林风沙区樟子松枯死主要发生在10—15年生幼龄林上，7月上旬至8月下旬为感病高峰期，翌年4月中旬至5月中旬为死亡高峰期。病菌孢子在整个生长季均能放散与传播，降雨节律及降雨量直接影响孢子的扩散与数量。人工接种发现：病菌的侵入期主要在6月中旬至8月中旬，潜育期半个月，侵入途径是伤口，病株感病部位及枯死枝是病原菌的越冬场所，密度高，植被盖度大的林分感病重。     

沙地樟子松不同林龄树高、胸径等生长指标的关系研究

对沙地樟子松人工林10~60 a林龄样地进行树高、胸径等生长指标调查、观测,使用SPSS20.0进行分析,结果表明:不同林龄树高与胸径、冠幅大小、第一活枝下高高度各生长量两两之间有极显著相关关系,林木树高与胸径、冠幅之间存在正相关关系;树高生长量随胸径变化模型为y=0.405x1.104,树高生长量随冠幅变化模型为y=e2.895-2.836/x。     

大坑换土对毛乌素沙区樟子松生长的影响

毛乌素沙区土壤以风沙土为主,严重地影响樟子松造林的效果。因此栽植坑的大小及其坑内的土壤类型在风沙区樟子松造林中显得尤为重要。该研究进行大坑换土与小坑不换土的对比试验,测定黄绵土和风沙土的理化性质,对比樟子松的保存状况和生长状况。结果表明：黄绵土的理化性质比风沙土的理化性质更好;大坑换土处理的樟子松保存率和生长量比小坑不换土的好。因此,进行大坑栽植和把坑内的风沙土换作黄绵土处理对樟子松的保存率和生长量具有明显的促进作用,大坑换土是毛乌素沙区樟子松造林的一项有效的造林技术。     

毛乌素沙地樟子松套篓造林成效研究

针对毛乌素沙地造林受到风沙危害、干旱缺水、土壤贫瘠、动物干扰等多重环境胁迫问题,在榆林市开展“套篓造林”技术试验,并对其生长量和土壤性状进行测定。结果表明,套篓造林保存率高达96.67％,比不套篓提高30％,树高、地径、冠幅生长量和地上生产力分别提高36.7％、42.37％、48.33％和292.59％,且该技术具有减轻风蚀沙埋、保持土壤水分、改善土壤养分、阻止动物危害等多重功效,从而显著提高了造林成效。