美国红枫苗木修剪技巧

美国红枫苗木种植前应对苗木根系、树冠进行修剪,必须将劈裂、病虫、过长根系剪除,确保美国红枫苗木原有的自然姿态;剪口（或锯口）大于2CM的,必须进行防腐处理。行道树定干高度宜在3m,美国红枫可定在2．5m以上,第一分枝点以下侧枝全部剪除,分枝点以上枝条酌情疏剪或短截。修建时应保留原有树形,适当疏剪,保留的主侧枝应在健壮芽上短截,     

美国红枫苗木修剪技巧

正美国红枫苗木种植前应对苗木根系、树冠进行修剪,必须将劈裂、病虫、过长根系剪除,确保美国红枫苗木原有的自然姿态;剪口(或锯口)大于2CM的,必须进行防腐处理。行道树定干高度宜在3m,美国红枫可定在2.5m以上,第一分枝点以下侧枝全部剪除,分枝点以上枝条酌情疏剪或短截。修建时应保留原有树形,适当疏剪,保留的主侧枝应在健壮芽上短截,剪去1/5-1/3     

适度修剪对成熟和过熟天然云南红豆杉复壮影响初步研究

研究结果表明：木里天然生长之云南红豆杉以成熟和过熟林分为主,主梢枯死率平均在78．5％左右,在自然状态下天然更新不良,但该树种在主干或主枝受损后具有较强的萌蘖更新能力;对云南红豆杉成熟和过熟母树进行适度修枝,不仅能有效刺激母树主干萌蘖更新芽的形成和生长,而且能极大地增加一级以上各级侧枝的数量和提高枝条生长量,使成熟和过熟树体焕发生机。其修剪强度以母树一级侧枝上枝径在1．5cm左右的次级侧枝总量的40％-50％为宜;复壮修剪必须经林业相关部门批准和在严格监管的条件下进行,且复壮修剪只能采用短截回缩的方式均匀地在一级侧枝上部枝径1．5cm左右处短截和修剪一级侧枝上的次级侧枝,同时应切除母树原已枯死的枯梢和枯枝,严禁直接在母树主干上剪切一级侧枝。     

杉木采穗圃的营建及管理技术研究

通过试验研究杉木采穗圃母株不同定植株行距、母株距根茎处不同截干促萌高度及圃地施用不同种类的基肥对母株产穗量的影响,结果表明:杉木母株定植株行距20 cm×20 cm+母株距根茎部位15 cm处截干+施用1 050 kg.hm-2硫酸钾复合肥作基肥(A3B3C2)组合产穗量最高,母株嫩枝单株年平均产穗量18.8穗,母株硬枝单株年平均产穗量15.9穗。     

思茅松采穗圃营建技术研究

用已认定的良种(景谷思茅松无性系种子园种子)建立采穗圃,做了不同的营建环境、定植密度、修剪技术、施肥种类、喷施药剂等的试验,探索了这些技术对采穗母株穗条产量影响。结果表明,采穗圃在自然环境下的穗条产量与大棚环境下的穗条产量之间存在极显著差异,自然环境更适宜采穗圃的建立;采穗圃不同定植密度之间存在显著差异,以采用40cm×40cm株行距较好;侧枝修剪长度和定杆高度两因素对采穗母株穗条产量影响不显著;采穗母株定植时每株施普钙100g促萌效果最好;喷施不同药剂实验中,高锰酸钾的施用能明显提高采穗母株穗条产量,而喷施赤霉素则使穗条产量降低。     

浅谈春季树木的修剪

1春季树木修剪的原则春季树木修剪的目的是为了树形美观,开花植物花繁叶茂,通过修剪使树冠保持一定形状和大小,使树体结构合理、枝条疏密得当,便于管理。2修剪方法2.1树木短截(又称短剪)只剪去1年生枝条的一部分。2.1.1目的是为了增加枝条,控制枝条长度,扩大树冠,利用剪口芽改变枝条生长方向,使树形更加圆满。2.1.2短截分为轻短剪(剪去枝条的1/5~1/4)、中短剪(剪去枝条的1/3~1/2)、重短剪(剪去枝条的2/3~3/4)和极重短剪。2.1.3注意事项:剪口部位应在预留芽上方1 cm左右,剪口要平滑,截粗枝剪口应涂防腐剂。2.2疏枝(疏剪)指枝条从基部去除的修…     

不同密度、截干高和基肥对桉树采穗圃插穗产量的影响

通过正交试验设计研究了采穗圃母株定植密度、截干促萌高度及基肥种类对桉树采穗圃嫩枝插穗和硬枝插穗产穗量的影响。试验结果表明：母株以20cm×20cm定植株行距（A3）＋母株距根茎部位20cm处的截干促萌高度（B3）＋施用1125kg.hm-2发酵牛粪（C2）组合即（A3B3C2）为最佳处理组合,单株嫩枝产穗量达23.3条·年-1,单株硬枝产穗量达16.6条·年-1。     

不同培育周期米老排苗木造林效果分析

通过铺设培育周期为6 和12 个月的两种米老排（Mytilaria laosensis）实生苗( 简称I 和II 类 苗) 对比试验和调查造林保存率、母株和萌条生长指标,初步评价造林后8 个月米老排幼龄林的生长 表现,为确定适宜的苗木培育周期和选择合适的苗木规格提供参考。研究结果表明： I 类苗的造林保存 率、母株地径和高度均显著大于II 类苗,两者间的保存率、母株地径和高度的差值分别为13.8 个百分 点、0.60 cm 和0.41 m;不同培育周期的苗木对造林后萌条生长无显著影响,优势萌条地径和高度以及萌 条平均地径和高度分别约为1.0 cm、1.0 m、0.8 cm、0.8 m,而萌蘖率和萌蘖数均分别超过93% 和2.5 株 穴-1;I 类苗造林后80% 以上的母株生长高于优势萌条,而II 类苗造林后母株生长高于优势萌条的比例约 占一半;母株地径与萌条生长指标相关性均不显著,而母株高度与优势萌条高度和萌条平均高度的相关 性达到显著水平;总体上,采用培育6 个月的实生苗造林,有利于促进新造米老排幼龄林的生长。     

阔叶箬竹分株容器苗培育技术Ⅱ.母株的选择与处理

以阔叶箬竹为研究对象,开展了母株筛选、截秆和密度处理、生长调节剂鞭根处理综合试验,旨在为阔叶箬竹容器苗培育提供技术支撑。结果表明：(1)分株扩繁母株地径对新叶数、新竹数和鞭径有极显著正向影响,较母株高度和节数影响更显著;对地径分级的分析表明,新叶数、新竹数和鞭径在径级间差异显著或极显著。(2)截秆高度(A)和种植密度(B)的处理组合间新竹数、新叶数、萌鞭数和最大叶宽均有显著或极显著差异;极差分析表明,母株密度为主要影响因素,且两因素间有明显的交互作用,以A₂B₂为最佳理论处理组合,即2株母株截秆高度50 cm的箬竹容器苗综合生长性状最佳,此时新叶数量为9.42片·株^-1、最大叶宽为4.06 cm、新竹数为1.30株·盆^-1、新鞭数为1.40鞭·盆^-1。(3)生长调节剂处理结果表明,不同浓度萘乙酸处理对萌鞭数、鞭长、萌鞭率和鞭根生物量均有显著或极显著影响,但对鞭径的影响不显著,其中50 ppm处理的新鞭鞭径、鞭长和生物量最大,100 ppm处理的萌鞭数和萌鞭率最大。综上认为,母株...     

修剪方式对油松嫁接红松幼树生长的影响

采用不同修剪方式对油松嫁接红松后母株侧枝修剪进行了研究,结果表明:修剪方式对嫁接幼树生长量有明显的影响,除嫁接后第1年差异较小外,随着树龄的增长,适度修枝后嫁接幼树的树高和直径连年生长量显著高于未修剪和全部修剪;适度修剪可比未修剪的树高和直径5 a定期生长量分别提高63%和56%,比全部修剪的树高和直径5 a定期生长量分别提高122%和97.5%。     

马尾松开花结实规律的初步研究

马尾松开花结实习性及球果丰歉规律,是良种生产的主要研究内容之一。例如幼林期初始开花结果年龄、雌雄球花的比例;成林期的结实数量、年度之间的差异以及球果在树冠层的分布情况;立地条件对林木开花结实的影响等问题,无论是实生种子园还是无性系种子园甚或采种母树林,都应当有所了解,掌握规律以指导园地管理与种子采收。探明这些问题不仅对于良种生产,同时在杂交育种等科研工作方面也是必不可少的。为此,我们对实生马尾松开花结实规律进行了初步研究,现总结如后。     

Effects of Seed Weight and Seed Type on Early Seedling Growth of Pinus sylvestris under Harsh and Optimal Conditions

The effects of seed weight and seed type on seedling growth of Pinus sylvestris (L.) were studied by seeding individually weighed orchard and stand seed in different mixtures under harsh (direct seeding in field) and optimal (seeding in nursery) conditions. In the nursery experiment an increase in the seed weight from 3 to 7 mg increased the seedling height by 10-27% and total weight by 27-113%, and decreased the height/diameter ratio by 5-6% after 2 yrs. With elimination of seed weight effects, orchard seedlings were 2% taller than stand seedlings in year 2. Without elimination of seed weight effects, orchard seedlings were 7-13% taller. In the field experiment an increase in the seed weight from 3 to 7 mg increased seedling height by 18-65%, stem volume by 81-274% and the number of top-buds by 23-34% in year 5. After elimination of seed weight effects, orchard seedlings were 7-13% taller than stand seedlings and without elimination of seed weight effects 20-21% taller after 5 yrs. Even after elimination of both seed weight and genetic effects orchard seedlings were 3-9% larger than stand seedlings in the field experiment. In conclusion, the influence of seed weight and seed type on growth traits and slenderness is highly significant and the influence seems to be greater in harsh conditions.     

云南松天然优良林分疏伐营建母树林的研究

10余年来对滇西和滇中的云南松天然优良林分疏伐营建母树林及遗传增益的研究结果表明疏伐是优良林分营建母树林的重要技术措施。改建16年生左右的云南松天然优良林分为母树林,以选择0．3(郁闭度)疏伐强度为好,母树林经2次疏伐后即可定型,其疏伐间隔期不超过4年。1993～1995年,母树林平均单株结球果达60个,每公顷结10329个,结实株率达95．65％,分别是对照的5．08倍、1．26倍和1．15倍。母树的结实性状较为稳定,单株结实量的频率分布呈对数正态分布,一般以4年为1个结实周期。云南松天然优良林分和母树林子代均具有干型通直、木纹理扭转度小、生长量大的特点。云南松诸性状间较多地受基因连锁或共效基因的作用,而受环境的影响相对较小,大多数性状具有较高的遗传稳定性。在云南松种子的调拨中应注意不同种源的适生区域。云南松优良林分和母树林子代林6～10年生的树高、胸(地)径、材积和木纹理扭转度的遗传增益分别为5．74％～20．14％、8．61％～40．46％、27．88％～107．11％和17．42％～59．79％。     

Effects of Light Intensity and Regeneration Mode on Stem Form and Growth of Cunninghamia lanceolata Saplings

ABSTRACT

Regeneration plays an essential role in the restructuring of plant communities, with seedlings and sprouts representing two different regeneration strategies. As an important timber species, Cunninghamia lanceolata is widely distributed throughout southern and eastern China. However, the morphology and growth of its sprouts and seedlings under natural environments have not been examined in detail. Our study quantified the morphology and growth of Cunninghamia lanceolata during its early regeneration phase. We selected a secondary mixed coniferous forest in the Huangshan region of China as the research location, and examined sapling height, basal stem diameter, lateral branch length, as well as the relationships between main stem and lateral branch elongation, and between sapling basal stem diameter and height. The results showed that high light intensity promoted the extension growth of main stems and the elongation of lateral branches of seedlings. Meanwhile, sprouts generally had shorter height growth than seedlings with the same basal stem diameter, and the growth allocation of seedlings was generally more dependent on light intensity. Our findings suggest that the morphology and growth of C. lanceolata might vary depending on the interaction of regeneration mode (plants originating from sprouts or seedlings) and light intensity.     

榆树杂交与苗期选择初步试验

以春榆、裂叶榆、大果榆和白榆作为母本,以欧洲白榆为父本采用切枝室内水培法进行杂交试验。在试验中对杂交得到种子的难易程度、杂交种子发芽率、苗期地径和苗高生长量进行了比较,结果显示各个杂交组合杂交较易取得成功,就苗期数据来看,杂交优势明显。     

印度阿鲁纳恰尔邦温带阔叶混交林树桩周长和高度对受干扰的树形杜鹃再发芽的影响

Sprout contribution to natural regeneration of Rhododendron arboreum following the tree felling for fuel wood and other purposes was studied in two disturbed sites (Paipraw and Falockchar) of Rhododendron forest in Arunachal Pradesh, northeast India. Cut stumps were categorized into seven girth and height classes to evaluate the effect of stump girth and height on production of sprouts. Effect of stump girth on survival of sprouts was also investigated. Results show that highest number of cut stumps is recorded in medium girth classes (50–80, 80–110, and 110–140 cm) in both Paipraw and Falockchar stands. However, density of cut stumps is higher in Paipraw (1 210 stumps·ha⁻¹) than Falockchar (1 154 stumps·ha⁻¹). Nevertheless, a little higher percentage of sprouting is recorded in Falockchar (18%) than that of Paipraw (15%). Similarly, maximum number of cut stumps is observed in the medium height classes (50–80, 80–110 and 110–140 cm) in both the sites. Cut stumps with lower girths show greater ability of sprouting than that of larger girth classes. Significant correlations are observed between stump girth and sprout number and between stump height and number of sprouts. Survival of sprouts also depends on stump girth. Survival of sprout shows significant variations between different sampling times in both the sites. Though overall sprout regeneration of R. arboreum is very poor, sprouts arising from lower girth classes survive well than those of higher girth classes. The findings of this investigation signify that stump sprouting is not playing much role in the natural regeneration of R. arboreum though it has the ability to sprout. Sprout survival is not adequate to restore a stand where indiscriminate tree felling is continued and the species may be considered as a poor coppicer. Therefore, regeneration through seeds and seedlings should be preferred over regeneration through sprouting.     

Thinning alters crown dynamics and biomass increment within aboveground tissues in young stands of Chamaecyparis obtusa

The stand density of a forest affects the vertical distribution of foliage. Understanding the dynamics of this response is important for the study of crown structure and function, carbon-budget estimation, and forest management. We investigated the effect of tree density on the vertical distribution of foliage, branch, and stem growth, and ratio of biomass increment in aboveground tissues; by monitoring all first-order branches of five trees each from thinned and unthinned control stands of 10-year-old Chamaecyparis obtusa for four consecutive years. In the control stand, the foliage crown shifted upward with height growth but the foliage quantity of the whole crown did not increase. In addition, the vertical distribution of leaf mass shifted from lower-crown skewed to upper-crown skewed. In the thinned stand in contrast, the foliage quantity of individual crowns increased two-fold within 4 years, while the vertical distribution of leaf mass remained lower-crown skewed. The two stands had similar production rates, numbers of first-order branches per unit of tree height, and total lengths of first-order branches. However, the mortality rate of first-order branches and self-pruning within a first-order branch were significantly higher in the control stand than in the thinned stand, which resulted in a higher ratio of biomass increment in branch. Thinning induced a higher ratio of biomass increment in foliage and lower in branch. The increased foliage quantity and variation in ratio of biomass increment after thinning stimulated stem growth of residual trees. These results provide information that will be useful when considering thinning regimes and stand management.     

Patterns of Stem Damage by Moose (Alces alces) in Young Pinus sylvestris Stands in Sweden

The incidence of recent moose browsing of the main stem on young Scots pine (Pinus sylvestris L.) trees, and correlations with tree or stand characteristics, were examined using data from a large-scale survey in Sweden. On average, 10% of all Scots pine main stems showed one or more types of recent damage, with browsing of the apical leader accounting for about 75% of all damage recorded. Stripping of bark off the main stem occurred most frequently in the southern area, where site productivity is highest. Apical leader browsing was negatively correlated with height of the main stems, length of the apical leader and incidence of pre-commercial thinning, whereas bark stripping and stem breaking were positively correlated with the same variables. All types of recent stem damage correlated positively with the extent of previous stem damage and also with the extent of recent browsing of lateral shoots.