Establishing royal paulownia on the Virginia Piedmont

A study was established in the Virginia Piedmont to investigate theeffects of site preparation treatments (subsoiling and trenching) and the useofweed mats on royal paulownia survival and growth. Seedlings were monitored inthree study blocks for seven years. Following the seventh growing season,survival was low, ranging from 11% in the control plots to 27% in the trenchedplots. Plot volume index averaged 28,633 for the subsoil plots, while controlplots had an average plot volume index of 12,685. Weed mats significantlyincreased soil moisture from 18.7 to 20.4%. Likewise, weed mats significantlyimproved seedling survival after seven years, from 9% to 30%.     

杨树补植造林调查

针对“三北”地区退耕还林地杨树造林成活率高低不一的问题．在集安市财源镇马蹄村选择了3块低成活率的样地予以补植，收到良好的效果。     

吉林省主要杨树造林品种介绍

本文介绍了适合吉林省栽培的主要杨树品种的特性及生长指标。     

Propagation of trembling aspen and hybrid poplar for agroforestry: potential benefits of elevated CO2 in the greenhouse

We examined the usefulness of elevated CO₂ in the greenhouse to aid in early selection of genotypes and in the propagation of Populus tremuloides Michaux (aspen) and hybrid poplars for agroforestry, afforestation, or reclamation. Growth in elevated (800 ppm) vs ambient (375 ppm) CO₂ for 95 days resulted in greater height (14%), stem caliper (16%), overall biomass, and proportional allocation of biomass to roots as well as elevated net assimilation and water-use-efficiency. Aspen clones selected for superior growth (based on phenotypic selection) broke bud significantly earlier than unselected clones under both CO₂ levels; superior clones were also taller with greater stem caliper under both CO₂ treatments (but not significant). Under ambient CO₂ male aspen were taller than females while under elevated CO₂ female aspen were taller than males and also had greater caliper (but not significant). Hybrid poplar grown under elevated (vs ambient) CO₂ broke bud significantly earlier and had significantly greater net assimilation and water-use efficiency; they were also taller with greater caliper (but not significant). Differences in performance among the eight hybrid clones were enhanced by growth under elevated CO₂. Under ambient CO₂, P38P38 was the clone that broke bud earliest, was tallest with greater caliper and had a lower shoot:root biomass ratio. Sargentii, on the other hand, was the shortest with the smallest caliper. The implications of these results need to be considered in the context of using aspen and hybrid poplar for large-scale agroforestry, afforestation and reclamation across Canada. This revised version was published online in August 2006 with corrections to the Cover Date.     

适宜平原栽植的白杨派杨树良种选择

从1994年开始,对引进的15个白杨派优良无性系,以易县雌株作为对照进行对比筛选试验,经过11 a试验研究,筛选出窄冠1号、窄冠3号、毛新80(三倍体毛白杨的无性系)和1414杨4个优良无性系,经多重比较,在材积、树高、胸径生长量及根系、冠幅等方面都明显优于对照易县雌株(CK)和其它无性系,可作为华北平原地区速生丰产林、农林复合经营、农田林网和城镇及道路绿化的推广新无性系。     

春季杨树大苗抗旱造林技术

在干旱地区进行春季杨树大苗造林时，应采用随整地随造林的方法。整地后，用机械进行拉沟，在沟底挖植树坑，规格为50cm×50cm×50cm。栽植前利用甲基托布津溶液对苗木整株进行杀菌处理，栽植时浇三遍水，即底水、苗口水、催芽水。在夏季和秋季干旱时要对杨树幼林进行灌水，每次每公顷灌水量为450—750m^3。浇水后及时松土保墒，提高灌溉效果。     

杨树埋干造林的试验研究及应用

易受洪水冲袭的河滩地采用杨树埋干造林方法,抗水袭性强,具有很强的生命力,成林后通过科学经营管理,同样可达到速生丰产标准,在特殊的立地条件下,采取杨树埋干造林方法仍是一种最佳选择。     

Growth and photosynthetic responses of four Virginia Piedmont tree species to shade

To determine the effects of shade on biomass, carbon allocation patterns and photosynthetic response, seedlings of loblolly pine (Pinus taeda L.), white pine (Pinus strobus L.), red maple (Acer rubrum L.), and yellow-poplar (Liriodendron tulipifera L.) were grown without shade or in shade treatments providing a 79 or 89% reduction of full sunlight for two growing seasons. The shade treatments resulted in less total biomass for all species, with loblolly pine showing the greatest shade-induced growth reduction. Yellow-poplar was the only species to show increased stem height growth in the 89% shade treatment. The shade treatments increased specific leaf area of all species. Quantum efficiency, dark respiration and light compensation point were generally not affected by the shade treatments. Quantum efficiency, dark respiration, maximum photosynthesis and light compensation point did not change consistently between the first and second growing seasons. We conclude that differences in shade tolerance among these species are not the result of changes in the photosynthetic mechanism in response to shade.     

Application of for the identification and management of hybrid poplar accessions

Molecular markers are a powerful tool with many potential applications in agriculture and forestry. In particular, can provide information on the relatedness of various clones or varieties that are difficult to distinguish morphologically, thus helping in the management of plant accessions and in breeding programs. The goal of this study is to genotype 15 clones used in the Prairie Farm Rehabilitation Administration (PFRA) breeding programs. Simple Sequence Repeat (SSR, or microsatellite markers) were selected for genotyping using the polymerase chain reaction (PCR). This type of marker is considered the method of choice due to their abundance, polymorphism and reliability compared to other types of . Sixteen previously isolated and characterized in aspen (Populus tremuloides) and other poplar species (Populus spp.) were initially tested. Nine markers were selected based on the “informativeness” and the quality of the amplification products. The nine markers were combined in groups of three to improve the efficiency of the genotyping technique. Using the nine markers, the average number of alleles per locus was 5.1. The expected and observed heterozygosity ranges were 0.32 to 0.80 and 0.13 to 0.92 respectively. The results also show that it is possible to produce a unique “DNA fingerprint” specific to each of the 15 hybrid poplar clones with the nine . In this study it was possible to show that two clones, P. ‘Melville’ and P. x ‘Walker’ used in Saskatchewan have similar DNA profiles with nine markers and a combined probability of identity of 2.23×10⁻⁶ suggesting that these clones are identical. This observation will prevent unnecessary duplication of the two accessions in breeding programs. This revised version was published online in August 2006 with corrections to the Cover Date.     

半干旱沙地杨树机械造林的最佳栽植深度

在半干旱沙地利用新型植树机进行造林，最好采用苗根造林方式，最佳栽植深度为45cm。     

科尔沁沙地杨树钻孔造林技术的研究

杨树钻孔深栽造林试验,在干旱的年份,造林成活率达90%以上,在钻孔深达1.3m时,胸径和生长速度比传统造林方式提高8%和3.6%。深栽的杨树插干下切口直接吸收地下水分,秋季造的杨树,随第2年土壤温度的逐渐升高,地下端吸收了足够的水分并形成了许多幼根,先生根后放叶,为幼苗的成活和生长提供了有利的条件,因此,在干旱的科尔沁沙地,钻孔深栽技术比传统造林技术显示出更大的优越性。     

沙区营造杨树速生林的关键栽培措施

通过多年实践，总结出一套适于沙区杨树速生丰产的栽培技术，明确培育方向，选择适宜的造林地和良种壮苗，设计合理的造林密度，为沙区营造杨树速生林提供一系列抚育措施。主要概括为造林地的选择、良种壮苗、选择适宜的栽植密度、整地方法、注意苗木质量、造林季节选择、造林方法、实行林农问作、加强抚育管理、合理修枝、病虫害防治等11项措施。     

朝阳地区速生杨造林效果初报

对朝阳地区近年来杨树造林品种间的生长与保存率情况做了对比调查,从中选出了几种适合该地区生长的树种,为该地区杨树造林提供参考。     

阜新地区杨树用材林栽培品种综合评价

杨树是阜新地区主要造林树种，针对阜新地区栽种的现有杨树品种生长适应性进行了调查分析，并对杨树生长主要因子与本身的生物特性的关系进行评价。37个杨树品系生长适应性差异显，乡土树种小美旱、彰武小钻杨表现为最佳，生产中应大力推广，其他表现较好的树种应继续观察。该对阜新地区杨树的发展提出了具体建议。     

Growth and stem quality responses to fertilizer application by 21 loblolly pine clones in the Virginia Piedmont

Clonal forestry offers the opportunity to increase yields, enhance uniformity and improve wood characteristics. Intensive silvicultural practices, including fertilization, will be required to capture the full growth potential of clonal plantations. However, variation in nutrient use efficiency that exists among clones could affect growth responses. Our research objective was to determine the range of growth response and stem form quality due to fertilization in clones of Pinus taeda. A split-plot experimental design was used, with the whole plots being two levels of fertilizer application (fertilizer versus control) and the split plot factor being 25 clones. Whole plot treatments were blocked and replicated four times. Six years after planting and five years after fertilizer application, a repeated measures analysis showed fertilizer-by-time and clone-by-time interactions affected volume (p < 0.10). Clone-by-fertilizer interactions were observed for tree height, branch traits, and a metric of foliar display. These interactions were primarily due to scale-effect phenomena rather than rank shifts. The magnitude of fertilizer responses observed in a small number of genotypes suggests that knowledge of fertilizer responses in widely deployed genotypes, if developed prior to mid-rotation, may better optimize management of single-clone blocks. Our results further indicate that a range of possibilities exist for the design and application of clone-specific precision silvicultural systems.     

长江中下游洲滩杨树栽植初探

长江中下游洲滩栽植杨树已经发展成为洲滩开发的重要模式之一。通过对长江洲滩特殊地理环境的分析,总结出洲滩杨树栽植的经验和教训,并针对洲滩地势条件、汛期洪水、大风及沙质土壤等不利因素提出应对方案,以提高洲滩杨树栽植水平,促进洲滩杨树产业发展。     

提高风沙干旱区杨树造林成效的几点经验

在风沙干旱区进行杨树造林，通过细致整地、适地适树、良种壮苗及一次浇水或二次浇水等技术措施，可有效保证造林成活率。     

The effect of weed control and fertilization on survival and growth of four pine species in the Virginia Piedmont

The growth response of loblolly pine (Pinus taeda L.), shortleaf pine (Pinus echinata Mill.), Virginia pine (Pinus virginiana Mill.), and white pine (Pinus strobus L.) to weed control and fertilization in the Piedmont of Virginia was assessed. Four different silvicultural treatments were evaluated: (1) check (no treatment); (2) weed control; (3) fertilization; (4) weed control plus fertilization. The weed control treatment included a series of herbicide and mechanical treatments to eliminate competing hardwoods. The fertilizer treatments added N, P, K, and S. Survival and growth was measured annually through age 5. There were significant differences in survival and growth among species. Survival was greatest for loblolly pine, lower in shortleaf and Virginia pine, and lowest in white pine. Fertilization without controlling the competing hardwoods decreased survival in all planted pines due to the increased hardwood competition. Loblolly pine was tallest through the 5-year period, shortleaf and Virginia pine were shorter and white pine was shortest. Silvicultural treatments had no impact on tree height but significantly affected DBH. Weed control increased DBH while fertilization did not. When applied in combination with weed control, there was no additional increase in growth of the pines due to fertilization beyond that from weed control only. Fertilization stimulated the growth of the competing hardwoods which were significantly taller in the fertilized plots.     

杨树大苗造林地膜覆盖技术

结合常规造林方法应用地膜覆盖技术,提高了杨树大苗造林成活率,加快了工程造林步伐,解决了东北地区春季大风、干旱、无雨的干燥恶劣天气条件下进行大规模工程造林成活率低的问题,达到一季造林、一次成活、一次成林。同时节省了造林资金。