Predicting field performance using seedling quality assessment

Seedling quality is defined as fitness for purpose. Attributes for assessing seedling quality are grouped in material attributes that can be rapidly assessed by any number of direct or indirect methods, and performance attributes that are assessed by subjecting whole seedlings to certain environmental regimes and evaluating their growth response. Material attributes comprising morphology, bud dormancy, water relations and nutrition and performance attributes comprising frost hardiness, vigour and root growth potential are discussed with regard to relevance for predicting field performance. Measurement techniques and relevance in assessing seedling quality are presented for different physiological attributes: electrolyte leakage, enzymatic activity, water potential, water conductance, mineral nutrition, food reserves, mitotic index, gas exchange, chlorophyll content, plant growth regulators, stress-induced volatile emission, and nuclear magnetic resonance. Methods with future potential in improving the prediction of field performance are identified and discussed. The methods presented in this respect are chlorophyll fluorescence, infrared thermography, machine vision systems, integrated approaches and ecophysiological evaluations.     

高脂马尾松实生苗与扦插苗的早期生长比较

对2～5年生马尾松实生苗、扦插苗2种苗木进行造林对比试验,试验结果显示,这2种苗木造林的保存率都超过95%。扦插苗和实生苗2年生时5个测量性状（树高、胸径、冠幅、活枝轮盘数、侧枝总数）均差异不显著;3年生时树高、胸径差异显著,其它不显著;4年生时5个性状差异均显著。即从3年生开始扦插苗早期生长量才显著高于实生苗。说明扦插林早期较实生林速生。在种子短缺的情况下,利用优良的无性系繁殖苗木,是十分有效的。     

Mechanical shock during transportation: effects on seedling performance

A study was carried out to monitor shocks to seedling planting stock during transport from nursery to the planting site in normal commercial reforestation operations. Size and exact time of mechanical shocks were measured by a recorder placed inside seedling boxes. Seedling shipments by refrigerated semi-trailer, 5-ton truck, pickup truck, small trailer and all-terrain vehicles were monitored in Alberta and British Columbia. Number of shocks, peak acceleration and average drop height were tabulated for travel on both paved and gravel roads.Twenty-two trials involving seven species were established at nurseries and field locations covering several ecological zones in both provinces. Frozen-stored, cool-stored, and freshly lifted seedlings were used in the trials. Seedlings were given two mechanical stress treatments by dropping them 30 times from 0.5-m and 30 times from 1.0-m, respectively. Control seedlings were not dropped. Treatments were applied to nursery-trial seedlings not exposed to normal handling and transport, and to field-trial seedlings after transport to the planting site. Six root growth potential tests were made with treated and control seedlings in conjunction with the nursery trials.Seedling survival and volume growth were recorded for two growing seasons and the results statistically analysed.     

苗龄对华木莲苗木质量及其造林成效的影响

为更好提高华木莲造林质量,以1年生(S1-0)、2年生(S2-0)、3年生(S3-0)实生苗进行造林试验,分析了不同苗龄苗木的质量及其造林效果的差异.结果表明:1)华木莲苗期生长指标与苗龄显著正相关,苗木在第2年的各生长指标的相对生长率显著高于第3年;2)采用S2-0、S3-0苗营造的人工林第1年的成活率分别为93％、90％,显著高于S1-0林分的成活率;S2-0林分第2、3年保存率分别为89％、84％,显著高于S3-0、S1-0林分;3)生长指标来看,S1-0、S2-0、S3-0"同年造林"时,造林后第2年、第3年,S2-0林分的树高生长量、地径生长量均显著高于S1-0、S3-0林分;苗木"逐年造林"时,在树龄为6 a时,S1-0、S2-0、S3-03种苗型所造林分的树高无显著差异,S2-0、S1-0所造林分的地径均显著高于S3-0林分.4)叶绿素含量来看,S1-0与S2-0所造人工林在第3年时SPAD值分别为60.05、47.12,高于S3-0所造3 a人工林的SPAD;5)相关性分析表明,仅有苗龄与1 a林分的树高、地径、保存率等指标相关系数在0.75以上,为显著正相关.综合保存率、生长量、叶绿素含量等指标,S2-0苗适应性强,所造林分质量稳定,效果更佳.在同等条件下,华木莲苗龄显著地影响造林效果,造林时选用合格的S2-0苗能提高华木莲造林成效.     

播种时期对蒙古栎不同类型苗木出苗和生长的影响

以蒙古栎种子为材料,研究播种时期对蒙古栎不同类型苗木出苗和生长的影响,结果表明:蒙古栎在秋季不同时间播种的出苗率均在60%以上,但以早期(9月下旬)播种的出苗率最高(大于80%),早期播种的苗木在苗高、地径、侧根数、根体积和根生物量等指标上都明显要高于其它播种时期,蒙古栎在秋播裸根育苗时应适时早播;秋季播种的容器苗在所有观测的形态指标上均好于春季播种的容器苗,秋季容器育苗质量更高。     

桉树无性系扦插育苗试验初报

无性系指一株树木用无性繁殖的方法培育出来的所有植株总称。无性系林业包括了无性系选育和无性系繁殖,并大规模地采用无性系苗造林。无性系林遵循了有性育种、无性利用的策略,保持了母本优良遗传品质,具有单位面积产量高、林相整齐、便于管理等特点,是获得最大林业生态经济效益的手段。同时还具有遗传改良快、选育周期短、能加快良种化进程等优点,是林业发展的总趋势。2002年我省农业育种攻关项目“三板材”新品种引进和选育子专题开始了四川桉树无性系林业试验研究,经过选优、幼化、引进等工作程序,建立了16个无性系的采穗圃和多个无性系…     

Predicting field performance of five irrigated tree species using seedling quality assessment in Burkina Faso,West Africa

Five exotic tree species (Acacia angustissima (Mil.) Kuntze, A. mangium Wild, Gliricidia sepium (Jacq.) Alp., Leucaena hybrid (L×L), and Leucaena leucocephala (Lam.) de Wit) were investigated to determine whether parameters of nursery seedling stock quality could be used to predict their field performance in a plantation irrigated with treated waste-water to produce fodder and wood. Plants were grown in the nursery in two contrasting rooting substrates (ordinary nursery soil and sand), predicted to have different effects on resource allocation. Three categories of morphological indicators were measured, i.e., plant dimensions (height, diameter, root length), plant weights (shoot, root and whole plant weights) and indices (sturdiness quotient ‘SQ’, shoot:root dry weight ratio ‘SRR’ and Dickson’s quality index ‘DQI’). In the nursery, all species performed better in the ordinary nursery soil for all growth parameters except root length. Thus ordinary nursery substrate appeared superior to sand in terms of plant quality. However, a follow up at plantation phase revealed that only some morphological attributes or ratios were suitable to predict field performance for the five tested species in irrigated plantation. In addition, the effect of the substrate observed at the nursery stage had disappeared 12 months after out planting due to the availability of water and nutrients provided by the treated waste water used for the irrigation. The results showed that root collar diameter and DQI appeared to be the most appropriate indicators to predict the outplanting performance of the five tested species in a short-rotation irrigated plantation in semi-arid Burkina Faso. The former measure is simpler and non-destructive.     

云南西双版纳大果紫檀种源苗期试验

在云南西双版纳对8个大果紫檀种源的苗期生长表现进行了研究,结果表明:大果紫檀种源间地径、苗高和径高比差异均极显著,越南种源的地径生长与绝大多数的泰国种源(MT5种源除外)差异不显著,但其苗高生长显著低于泰国种源,其径高比显著高于泰国种源;大果紫檀各种源的生长表现与其产地的经纬度呈现明显的相关性;以MT2和MT3泰国种源生长最快,可初步视为优良种源;大果紫檀各种源苗高生长均在2～5月份缓慢加快,6月份则生长迅速加快,与当地月最低气温有关。大果紫檀是一个典型的热带树种,在我国宜选择春季月最低气温较高的地区引种。     

轻基质网袋容器培育杉木苗的技术要点

介绍了应用轻基质网袋容器培育杉木壮苗的新技术,其主要内容为:5—6月份播种,苗床由粗砂、黄心土(或火烧土)依次铺成;当嫩苗高3~4 cm时移入轻基质网袋容器,基质由50%木屑+30%泥炭土+20%炭化谷壳组成。翌年2—3月,超过85%的苗木地径大于0.3 cm、苗高20 cm即可出圃造林。     

Effects of Douglas-fir 2+0 seedling morphology on field performance

The relationships between field performance of Douglas-fir (Pseudotsuga menziesii) 2+0 seedlings and their initial diameter and root mass were evaluated on five sites in Oregon in the early 1980s to identify opportunities for improving seedling grading prior to planting. Survival and height 3–5 years after planting were positively related to seedling size at the time of planting. On all sites, survival nearly doubled from the smallest to largest diameter classes. Root mass had a similar relationship to survival on sites with environmental stress. Increasing root size class increased survival more for the small diameter classes than for the larger diameter clases. On the other hand, increasing root size class increased total height more for the large diameter class than the smaller ones. Although height was not as strongly affected as survival on several sites, height differences among initial seedling diameter classes were still significant and increasing after five years. Root class effects on height were less important than diameter class effects.     

Planting frozen conifer seedlings: Warming trends and effects on seedling performance

In temperate climates, conifer seedlings are often held in frozen storage (–2 °C) for extended periods and then placed in cool storage (+2 °C) so the root plug can thaw prior to outplanting. Two plug temperature treatments were used to test the hypothesis that thawing seedlings prior to outplanting may be unnecessary: seedlings were planted with frozen root plugs (frozen seedlings) and with thawed root plugs (thawed seedlings). The experiment was conducted under two watering regimes (irregular, regular) and with three conifer species (lodgepole pine [Pinus contorta var. latifolia], western larch [Larix occidentalis], interior spruce [Picea glauca × engelmannii]) to increase the generality of the results. The warming of root plugs after planting was examined. Thawed root plugs warmed to soil temperature rapidly (about 30 min) while frozen root plugs took longer (to 2 h) because ice in the plug had to melt before temperatures rose. Larger root plugs took longer to warm to soil temperature. Several aspects of seedling field performance were also assessed. For all species, variable fluorescence did not differ between frozen and thawed seedlings. Bud break was faster for thawed than frozen western larch seedlings but did not differ between frozen and thawed seedlings for either lodgepole pine or interior spruce. Height increment differed significantly between frozen and thawed seedlings that received the irregular watering regime; this effect was likely a response to the positioning of irrigation nozzles, which resulted in sporadic and non-uniform irrigation patterns. Height increment did not differ between frozen and thawed seedlings that received the regular watering regime. Root collar diameter and volume increments were not significantly affected by plug temperature treatment under either watering regime. Planting seedlings with frozen root plugs did not hinder field performance over one growing season under these watering regimes.     

A method for trapping hylobius abietis (L.) with a standardized bait and its potential for forecasting seedling damage

A method for trapping walking Hylobius abietis (L.) (Coleoptera: Curculionidae) was developed and evaluated. Synergism between α‐pinene and ethanol in attracting H. abietis was confirmed. The effects of varying release rates of these substances and of adding other host terpenes were studied. A simple bait was developed containing α‐pinene and ethanol released from separate vials. The correlation between trap catch and seedling damage was estimated during May, June, and August on 1‐, 2‐, and 3‐year‐old clear‐cuttings. In May and June, population levels were relatively high on all clear‐cuttings and no significant correlations were found. The August experiment showed a strong positive correlation between catch and damage. The percentage damaged seedlings per captured weevil was considerably higher in August than in May or June. Possibilities for developing a system for forecasting seedling damage using this trapping method are discussed.     

A multivariate statistical approach to predicting mature tree performance based on seedling characteristics

A common objective in commercial reforestation is to plant seedlings that will produce superior adult trees. Long forest management planning horizons and life spans of most forest trees complicate the prediction of growth and performance of adult trees originating from planted seedlings of unknown genetic origin. We used multivariate statistics to identify and rank a set of seedlings characteristics that could predict the performance of mature trees in Pinus ponderosa. Results indicated that metabolic heat rate (q), a measure of total metabolism, of one-year-old foliage during the peak growth in May, was the most important seedling characteristic that predicted mature-tree performance. Increased metabolic heat rate in seedlings corresponded with greater vigor of mature trees. Additionally, seedling basal stem diameter (D), height (H), and needle length (NL), measured in November, were, in order of importance, other variables that defined the vigor class of the mature clones. However, these seedling morphological characteristics correlated negatively with vigor classification of the mature clones, contradicting the notion that greater D and/or H during the seedling stage may indicate a greater vigor at maturity.     

低碳建筑的新标准

澳大利亚绿色建筑委员会(Green Building Council of Australia)在对绿星评级(Green Star)的最新变化中引入了低碳零碳建筑的新标准.五星级和六星级的绿星级(Green Star)建筑现在必须达到最低的温室气体排放标准,同时也提出了提高气密性测试行业能力并鼓励使用可持续来源的建筑用木材的措施.目前,有一个有五星级绿星(Green Star)认证的项目需要在“温室气体排放(Greenhouse Gas Emissions)”信用中获得绿星(Green Star)3分,比基准建筑高效25％.六星级绿星(Green Star)建筑必须达到至少6分,显示比基准高效近40％.     

Influence of cavity size, seedling growing density and fungicide applications on Keithia blight of western redcedar seedling growth and field performance

To determine the influence of cavity size, seedling density and fungicide application on severity of Keithia blight caused by the fungus Didymascella thujina (Durand) Maire, western redcedar (Thuja plicata Donn) seedlings were grown in styroblocks of 3 cavity sizes, thinned to 3 growing densities and sprayed several times monthly with mancozeb fungicide. After two growing seasons cavity size, seedling growing density and number of fungicide applications all significantly (p0.05) affected blight severity. Blight severity was inversely related to the number of mancozeb fungicide applications. The only significant two-way interaction was for cavity size and seedling growing density.Eighteen seedlings from each of the nine cavity sizes and seedling densities combinations were assessed for shoot height, root collar diameter and blight severity, prior to planting at both Holt Creek and Salmon Creek on Vancouver Island, British Columbia in March 1994. Growth was reassessed during October 1994. Seedling height and root collar diameter increased significantly (p0.05) with certain cavity size and seedling density combinations. Blight severity increased significantly (p0.05) for all nine treatments at both sites, however, between sites blight severity increased significantly (p0.05) only at the wetter, Salmon Creek site.     

西伯利亚花楸引种实生苗在辽宁4个地区的生长表现

利用西伯利亚花楸1年生实生苗在沈阳、大连、清原、新宾4个地区进行了栽培试验。观测了西伯利亚花楸物候期,分析了树木的生长量等指标,结果表明,西伯利亚花楸最适宜地区为沈阳,其次为清原和新宾,大连地区表现较差,可为辽宁地区引种作借鉴。     

黄榆优树种子性状变异及其子代苗期生长表现

为选育黄榆优良遗传资源,以不同黄榆优树所采种子及其当年生播种苗为材料,研究了不同优树种子性状变异及其子代苗期生长表现。结果表明:不同黄榆优树种子在宽度、质量、发芽能力等性状上均存在变异,其子代苗期在地径生长上也存在变异,可以综合这些性状来对初选的优树进行再选择。4号优树在种子播种品质指标和子代苗期生长上均表现较好,可以作为优良的遗传资源加以利用。     

Research versus operational correlations between seedling survival and root growth potential of shortleaf pine

Relationships between root growth potential (RGP) and plantation survival were evaluated for 12 families of shortleaf pine (Pinus echinata Mill.) from Oklahoma and Arkansas in 2 consecutive years. Bare-root, 1+0 seedlings were either planted one day after lifting (nonstored) or were stored at 1° to 3°C for 4 weeks. Correlations were obtained using the traditional research method where seedlings are planted in the field prior to obtaining results from the RGP test. In addition, operational correlations were derived by planting seedlings after obtaining RGP test data.For nonstored seedlings, research correlations were generally higher (r values were larger in 18 of 24 cases) than operational correlations. The predictive ability of operational correlations may not be high enough with 28-day pot tests to warrant batch culling of freshly lifted shortleaf pine. However, results were mixed for stored seedlings. In one year, operational correlations were generally higher than research correlations.     

利用优良无性系培育马尾松容器嫁接苗技术研究

为提高城步县在20世纪90年代营建的1.5代马尾松种子园遗传品质和种子产量,以当代种子产量、子代材积增益均高为标准,选择出16号、58号、80号等22个优良无性系,用于培育容器嫁接苗补植到间伐后的种子园进行提质改造。结果表明:以直径20 cm、高度18 cm规格的塑料容器,按70%泥炭土、25%松林表土、5%珍珠岩体积比配置的混合基质培育砧木苗,采用离地23~27 cm的切接法或舌接法嫁接,2年生容器嫁接苗高度达84 cm、成活率达81%以上。