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1.
白藤丛栽试验初报*   总被引：5，自引：1，他引：5       下载免费PDF全文
  相似文献   

2.
尾叶桉纸浆林造林密度控制技术的研究   总被引：7，自引：0，他引：7       下载免费PDF全文
对 5 9年生尾叶桉纸浆林生长分析表明 :(1)密度与树高、胸径呈反比。 3种密度的树高、胸径大小均为密度B >C >D。两配置树高、胸径也以配置B >A。 (2 )密度对单株材积的影响与对胸径影响的规律一致。 5 9年生时单株材积生长量以密度B最高 ,达到 0 0 85 33m3·株 - 1,是最低单株材积密度D的 2 0 4倍。两配置单株材积以配置B >A。 (3) 4 7年生时单位面积蓄积量大小为密度B >C>D ,密度B达到 94 185m3·hm- 2 ,是最低D处理蓄积量的 1 15倍 ;5 9年生时蓄积量最大者为密度C ,达到 12 7 6 0m3·hm- 2 ,是最低蓄积密度D的 1 17倍。随着时间的变化 ,密度控制尤为重要。 4 7、5 9年生时单位面积蓄积均以配置B >A ,配置B分别比配置A高 2 4 82 %、2 3 5 3%。 (4)对胸径D和冠幅CW 值用方程进行回归拟合 ,结果以乘幂CW=a×Db 拟合最好。方程表达式为CW=0 4 72 4×D0 6 715。 (5 )编制的经营密度表反映出 ,随着胸径D的递增 ,基本经营密度N0 逐渐下降 ;当D≥ 18cm时 ,N0 的下降趋势渐趋平缓  相似文献   

3.
The biology and host plant range of Lixus nordmanni Hochhuth were studied in the eastern part of Turkey. This weevil feeds and grows on Heracleum trachyloma Fisch. et C.A. Mey, Heracleum sosnowskyi Manden, Heracleum pastinacifolium C. Koch, H. platytaenium Boiss., Angelica sylvestris L. and Falcaria sp. of the family Apiaceae (=Umbellifera). In the early spring, adults emerged from overwintering places and started feeding on host plants. After feeding for several days on leaves, they mated and laid eggs on the main stem of a host. After emergence, larvae fed in stems up to late summer and pupated in the same places. Pupae were found at the beginning of autumn and then adults of the new generation emerged from the stem. Most of adults overwinter under dry plants at rootneck and under stones. L. nordmanni have one generation per year in eastern Anatolia. This Caucasian weevil species is recorded for the first time for Turkish fauna. The biology and host plant records are presented.  相似文献   

4.
Eight trails with randomized block design with 4–8 rape varieties and 4–6 repetitions were performed from 1988–93 at two locations (Zurich-Reckenholz and Zollikofen). From each plot 10 plants were removed at one or two dates and the number of eggs and larvae of the stem weevilCeutorhynchus napi were counted in the laboratory. In addition in 1991 and 1993 the number of splitted stems were recorded. The results show thatC. napi neither prefers O-varieties nor OO-varieties for egg deposition. But there is a clear preference for a distinct developmental stage of the rape plants. The stem weevil prefers plants up to 22 cm hight for egg laying. On the average early vvarieties were significantly less infested by the stem weevil than moderately-early to late flowering varieties. The O-varieties Bienenu and Jet Neuf had fewer splitted stems than the OO-varieties and among them Idol and Eurol had fewer than Arabella and Libravo. The risk for splitted stems is increasing with higher infestation.  相似文献   

5.
Stem deformation has often been observed in young black spruce (Picea mariana (Mill.) B.S.P.) and jack pine (Pinus banksiana Lamb.) plantations. Whenever important stem deformations are observed at the time of harvesting, timber value is negatively affected especially during the wood transformation process. The present work was undertaken to quantify and qualify the importance of stem deformation of black spruce and jack pine in the boreal forest of central Quebec at the stand and tree levels. In 30 black spruce and jack pine plantations, approximately 22% of spruce trees and 27% of pine trees exhibited stem deformation. The proportion of deformed trees was higher in the youngest plantations and decreased with the age of the plantations. Stem deformation caused the formation of compression wood which is another factor that can reduce the value of wood products. Thirty-nine black spruces and 34 jack pines were analysed at the tree level. On average, compression wood represented 14% and 20% of stem volume in 7- and 10-year old black spruce plantations, respectively. These proportions ranged from 18% in the youngest jack pine plantation to 26% in the oldest one. Stems of both species classified as normal contained a lower volume of compression wood than stems classified as deformed or very deformed. Annual percentages of compression wood and annual shoot length increased significantly with tree age (p < 0.0001 for both variables). Statistically significant correlations were also found between the range of displacement of the stem and the percentage of compression wood. The fewer number of trees with deformed stems in older plantations combined with high compression wood formation suggests that, over time, a deformed tree can become normal and straight in appearance.  相似文献   

6.
The wood boring weevil, Pentarthrum huttoni Wollaston, is reported for the first time from Austria. It was recorded from coffins in the crypt of St. Michael’s church in the centre of Vienna. Extensive tunnelling of the larvae and surface damage by the adults caused disintegration of the historically significant wooden 18th century coffins. Beetles were also detected in rotten cardboard on the loamy soil of the crypt. Infestation by this Cossonine weevil is promoted by the very damp conditions in the crypt, a consequence of the closure of ventilation funnels in the 1940s.  相似文献   

7.
《Southern Forests》2013,75(4):239-246
Due to the labour challenges in South Africa, mechanised forestry equipment has increasingly been required to operate in complex forest conditions – such as coppiced Eucalyptus compartments – where they have not operated before. For this reason, harvesters are either used in certain coppiced compartments with uncertain productivity expectations, or harvesters are not used in these compartments due to a lack of productivity knowledge. This research aimed to determine the influence of tree volume and tree form on the productivity of an excavator-based harvester in coppiced regrowth – with either double or single stems, or planted single stems – in Eucalyptus grandis pulpwood compartments. In addition, the stem felled first and the distance between stems were investigated for coppiced double stems. The stem felled first is whichever stem between the two coppiced double stems the harvester grabbed, felled and processed first. The tree volume was determined; thereafter the trees were classified into different form classes. The tree volume and the cycle time were used to determine productivity. The research results showed that planted trees had the highest productivity across all tree sizes, followed by coppiced single stems and then coppiced double stems. When harvesting a 0.2 m3 tree, the mean harvester productivity was 8.7 m3 per productive machine hour (PMH0) in coppiced double stems, 13.8 m3 per PMH0 in coppiced single stems and 16.1 m3 per PMH0 in planted trees. In coppiced double stems the productivity was significantly influenced by the size of the stem felled first. In coppiced double stems the productivity was not significantly influenced by the distance between stems. The productivity for both coppiced single stems and coppiced double stems was significantly influenced by stem form. The poorly formed trees had lower productivity compared to the trees with good form.  相似文献   

8.
The aim of this study was to assess the effect and importance of the feeding of the pine top weevil (Pissodes piniphilus) on the germination of Endocronartium pini (syn. Peridermium pini) in Scots pine (Pinus sylvestris), and thus to establish the possibility of the E. pini infection via insect woundings. Germination tests were therefore carried out on current and previous year needle and phloem extracts. Elucidation of the importance of pathogen infection for the insect's feeding preference was also required; for this purpose feeding preference tests were carried out with healthy and infected pine branches using the pine top weevil as a test insect. Weevil feeding increased the germination of E. pini aeciospores on pine extracts. Germination on previous year annual-shoot extracts was lower than that on current year annual-shoot extracts. The advance of the growing season increased this trend, but weevil feeding increased germination on extracts from older annual shoots to the levels found on extracts from current annual shoots. Spores germinated equally well on needle extracts and on phloem extracts. The weevils ate more often on infected branches than on healthy branches. E. pini infections may occur via woundings on branches and weevil feeding may facilitate this.  相似文献   

9.
Red clover (Trifolium pratense L.) is becoming increasingly important in grassland systems because of its high productivity, protein content and nitrogen-fixing ability, but its use has been constrained by losses due to pests and diseases, and this contributed to the decline of red clover usage allowing white clover (T. repens L.) to become the dominant legume of UK grasslands. One of the major pests of red clover is the clover root weevil (Sitona lepidus Gyllenhal, Coleoptera, Curculionidae) which attacks both the shoots and roots, particularly the N-fixing root nodules, of clover plants. This current work investigates the feeding preferences of S. lepidus with respect to 11 varieties (Pawera, Kuhn, Astra, Norseman, Norseman low, Norseman high, Marcom, Merviot, Milvus, Britta, Sabtoron) and 5 lines (AA30, AA31, AA4493, AA4494 and AA4495) of red clover in order to identify relationships between the variation in attractiveness of different red clover varieties for both adult and larval stages of the weevil. Of those tested Norseman high showed potential resistance, being less favoured by both adults and larvae of the weevil. This may be attributed to the potentially high phyto-oestrogen levels in this variety.  相似文献   

10.
Based on farmers’ knowledge and laboratory studies, the nutrient accumulation in the topsoil (0–20 cm) under Cordia africana Lam (Cordia), Millettia ferruginea Hochst (Millettia) and Eucalyptus camaldulensis Dehnhardt (Red gum) managed under two agroforestry practices on different farms at three sites was evaluated. The number of these trees on individual farms has increased during the last two decades. The number of stems ha−1 of Red gum was higher on farms of wealthier households than on farms of poor and medium households at two of the sites, but, at one site the number of stems ha−1 on farms of poor households was higher than on farms of wealthier households. Apart from the concentration of Na in the topsoil, there were significant variations in the analysed soil nutrients between the tree species. At all study sites, significantly higher concentration of P was observed under Millettia and Cordia than under Red gum. At one site, concentrations of available P under Cordia were nearly two-fold, and four and half-fold greater than under Millettia and Red gum, respectively. At one site, total N under Red gum was 14% and 24% lower than under Cordia and Millettia, respectively. In contrast, organic C content under Red gum was 11.6% greater than under Millettia and 23.8% greater than under Cordia. The pH under Millettia and Cordia were significantly higher than concentrations under Red gum at one site. Topsoil under Millettia and Cordia also had significantly higher levels of exchangeable Ca and Mg than Red gum.  相似文献   

11.
Teratosphaeria gauchensis and T. zuluensis both cause a stem canker of eucalypts that leads to serious damage in various parts of the world. Until recently, this disease was unknown in Portugal. Nevertheless, severe damage to Eucalyptus globulus has been observed in Portugal since 2006 when symptoms appeared as necrotic spots on young green stems and leaves, twig lesions, and dark oval‐shaped lesions on stems and trunks. The isolates from affected E. globulus tree plantations were identified using sequence data of the ITS1‐5.8S‐ITS2 and EF‐1α clusters, together with morphological characteristics. Based on these results, the causal organism was identified as T. gauchensis, which represents the first report of this pathogen from Portugal.  相似文献   

12.

• Introduction   

The Eucalyptus Weevil (Gonipterus “scutellatus” Gyllenhal) is a notorious pest of eucalypt plantations around the world, but its host range differs across its area of introduction, which may be due to it being a complex of several cryptic species.  相似文献   

13.
In Honghuaerji region,Scambus sp. is an effective natural enemy of the mongolian scotch pine cone weevil (Pissodes validiirostriis Gyll). The percentage of parasitism on larvae of the mongolian scotch pine cone weevil amounts to 20 to 30% commonly, sometimes as high as 45% or more, thus significantly regulating the weevil population. But the high mortality of larvae ofScambus in winter, which according to the surveys (conducted in 1986, 1987, and 1988) were 24.00%, 51.03% and 47.70% respectively, seriously influenced the natural suppression effect. In order to reveal the cause of winter death of this natural enemy, from 1990 authors studied the winter physiological indices, cold hardiness and overwintering protection ofScambus larvae, in the purpose of providing scientific basis of usingScambus in biological control.  相似文献   

14.
Naturally regenerated paper birch (Betula papyrifera Marsh.) is commonly removed from juvenile interior Douglas-fir (Pseudotsuga menziesii var. glauca [Beissn.] Franco) plantations in southern interior British Columbia, Canada, to increase conifer productivity and create a free-growing stand; however, this practice is expensive and contentious because of possible negative ecological impacts. One solution is to retain an optimal density of birch where growth gains of understory Douglas-fir are balanced against losses to Armillaria ostoyae (Romagn.) Herink and understory plant species diversity. We sought to find this optimal density by comparing four evenly applied birch density reduction treatments (0, 400, 1111, and 4444 retained birch stems ha?1) and an unthinned control (>7300 retained birch stems ha?1). The mortality rate of Douglas-fir due to Armillaria root disease increased non-significantly with thinning intensity. Mean diameter increment of surviving Douglas-fir improved the most where birch was completely removed, with little variation among intermediate thinning treatments. Height growth was unaffected by the thinning treatments. Diversity of cryptogams was significantly greater in the control than where all birch was removed. We suggest that the treatment with 4444 retained birch stems ha?1 provides the best balance for improving Douglas-fir growth while minimizing risk of increased Armillaria root disease and reduced understory plant diversity in young mixed stands.  相似文献   

15.
The effect of Thidiazuron （TDZ）, basal media and light quality on adventitious shoot regeneration from in vitro cultured stem of Populus albaxP berolinensis were determined to establish a high efficiency shoot regeneration system from stem explants of P. alba~P berolinensis. Stems ofPopulus alba~P berolinensis were collected from cultured shoots in vitro derived from dormancy buds of 3-year-old seedlings. The stem explants were cultured on MS medium containing 0.02-mg·L-1NAA （naphthaleneacetic acid）, and 0.1, 0.3, 0.5 and 1.0 mg·L-1 concentrations of TDZ to determine the effect of TDZ on shoot regeneration. Three basal media, i.e. MS, woody plant medium （WPM） and B5, were used to test their influences of different media on adventitious shoot regeneration. Green, red, blue and yellow plastic films in comparison with florescent light as control were used to observe their effects on shoot regeneration. The results showed that differ- ent concentrations of TDZ had an evident influence on shoot regeneration. Lower concentration of TDZ （0.1 mg·L-1） resulted in more ad- ventitious shoot regeneration and higher concentration of TDZ （〉0.1 mg·L-1） inhibited shoot regeneration. Among different media, MS medium exhibited a high efficiency for shoot regeneration, followed by WPM medium, while B5 medium inhibited shoot regeneration. Normal light and yellow light exhibited better effects on shoot regeneration, compared with other light.  相似文献   

16.
Abstract

The pine weevil Hylobius abietis L. is major threat to forest regeneration in the Nordic countries. The persistence of the deltamethrin insecticide used against pine weevil on Norway spruce seedlings was studied after the seedlings were dipped or sprayed. Insecticide application was timed to occur either before or after frozen storage. Bioassays with the stems of Norway spruce seedlings were used to determine the effect of the insecticide against feeding by the pine weevil. The measures of the control effect were reduction in area of gnawed bark and the state of health of the pine weevils. The concentration of deltamethrin decreased rapidly in seedlings, especially after spraying treatment, which did not efficiently protect seedlings against the pine weevil 6 weeks after planting. There were no signs of degradation of deltamethrin or of an effect on seedling height after frozen storage. In bioassay, the amount of deltamethrin that efficiently prevented feeding by the pine weevil was 5.5 µg g?1 fresh weight. After one growing season in the field, about 1.76–2.24 µg g?1 (13–15% of the initial level) of dipped deltamethrin remained in the seedlings. In seedlings treated by spraying, 0.93–0.98 µg g?1 (7–8% of the initial level) of the deltamethrin remained. According to bioassays, these amounts were no longer sufficient to protect seedlings from feeding by the pine weevil. Therefore, in the first summer, dipping was a significantly more efficient method of application for control of pine weevils.  相似文献   

17.
The population fluctuation of the red palm weevil, Rhynchophorus ferrugineus was studied, using the aggregation pheromone traps, during 2000 and 2001 in the United Arab Emirates. The insect population increased gradually from January to reach its peak in March, April, or May. The populations in three date palm plantations were much less in 2001 compared to 2000 with reductions of 29.7–51.7%. An evaluation of the performance of the pheromone traps showed that they could capture 4.4 to 20.7% of the resident populations of R. ferrugineus in the three different date palm plantations. No significant differences could be found in rates of capture between males and females. Individuals of marked weevils released in date palm plantations migrated 1–7 km from the plantations in which they were released. The released marked weevils were recaptured, mostly, within 3–5 days post release.  相似文献   

18.
During 1993 progressive, severe shoot blight and canker disease in crowns of mature, merchantable red pines (Pinus resinosa) in central Wisconsin was noted in plantations in which paper mill waste sludge previously had been applied. For eight treated plantations and six non‐treated plantations, incidence of shoot blight attributed to the pathogenic fungus Sphaeropsis sapinea (syn. Diplodia pinea) was quantified during 1993 or 1994. Foliage and soil samples also were collected for analyses. Sphaeropsis shoot blight was more frequent in treated plantations than in the non‐treated stands (means of 81% of trees and 10.2% of shoots compared with 7% of trees and 0.1% of shoots, respectively). Consistent with other reports of damage caused by some diseases of conifers in situations of altered host nutrition, mean foliar N concentrations were higher in treated plantations (1.61%) than non‐treated plantations (1.31%) (p < 0.001). Mean foliar Zn, Mn, Cu, and Al concentrations were lower in treated plantations than non‐treated plantations, and mean soil P, Ca, and Mg concentrations were higher in treated plantations than non‐treated plantations.  相似文献   

19.
Dalbergia sissoo Roxb. is one of the promising multipurpose tree species of South Asia. Most of the plantations of D. sissoo from seeds are facing severe threats due to the die-back disease, which ultimately causes death of this potential tree-species within a few months. Vegetative propagation could avoid the die-back disease. Thirty mother trees of different age-groups of D. sissoo were selected for evaluating the rooting behaviour of branch cuttings from D. sissoo as influenced by auxins (IAA or IBA at 100, 200, 500 mg·L−1), ages of mother trees (10, 4 and 2 years old) and different environment conditions, i.e., different mediums (soil and sand) or light conditions (in shade and open condition). The results show that application of IAA and IBA induced more numbers of cuttings (collected from 10-year-old mother trees) to root compared to control. Branch cuttings of D. sissoo collected from 10-year-old mother trees and planted in soil bed in open conditions had 100.0% of cuttings to root in IAA (100 mg·L−1) and IBA (200 mg·L−1) treatments. Both rooting medium (Soil and sand) influenced significantly (p<0.05) on rooting response of branch cuttings. Soil medium was found to achieve maximum no. of branch cuttings to root, compared to sand medium.  相似文献   

20.
The present study deals with effects of flooding depth on growth, morphology and photosynthesis in Alnus japonica species thorough one field study and two controlled experiments. In the field study performed in Kushiro Mire, Hokkaido Island, Japan, tree heights and stem diameters decreased with an increase in water depth accompanied with the reduction of soil redox potential. In contrast, the rate of multiple stems per individual tree increased. In the controlled experiments for seedlings flooding suppressed the shoot elongation and biomass increment in roots. However, diameter increment around water levels, epicormic shoot development and adventitious root formation were enhanced in flooded seedlings. The photosynthetic rate and stomatal conductance of flooded seedlings also were lowered with an increase in flooding depth. The recovery of the reduced photosynthetic rate and stomatal conductance occurred simultaneously with the advancement of adventitious root formation in the flooded seedlings. These results indicate the importance of a series of morphological changes occurring on stems around water levels in flood tolerance in A. japonica species.  相似文献   

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