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Root biomass and root distribution were studied in Entisols derived from the thick deposition of volcanic pumice on Hokkaido
Island, Japan, to examine the effect of soil conditions on tree root development. The soil had a thin (<10 cm) A horizon and
thick coarse pumiceous gravel layers with low levels of available nutrients and water. Two stands were studied: a Picea glehnii–Abies sachalinensis stand (PA stand) and a Larix kaempferi–Betula platyphylla var. japonica stand (LB stand). The allometric relationships between diameter at breast height (DBH) and aboveground and belowground biomass
of these species were obtained to estimate stand biomass. The belowground biomass was small: 30.6 Mg ha−1 for the PA stand and 24.3 Mg ha−1 for the LB stand. The trunk/root ratios of study stands were 4.8 for the PA stand and 4.3 for the LB stand, which were higher
than those from previous studies in boreal and temperate forests. All species developed shallow root systems, and fine roots
were spread densely in the shallow A horizon, suggesting that physical obstruction by the pumiceous layers and their low levels
of available water and nutrients restricted downward root elongation. The high trunk/root ratios of the trees may also have
resulted from the limited available rooting space in the study sites. 相似文献
3.
Lessons Learned on a Wilderness Medicine “Teaching Weekend” 总被引:1,自引:1,他引:0
4.
Jürgen Gross Nina E. Fatouros Seppo Neuvonen Monika Hilker 《Journal of pest science》2007,80(3):139-143
The Palaearctic leaf beetle Chrysomela lapponica usually feeds upon willows in the northern region of its occurrence. However, in Central Europe, some populations are known
that have specialised on birch. In this study, we investigated the significance of other herbivores occurring together on
the same host plants as possible exploitative competitors of C. lapponica. Two populations were studied: a population from Finland specialised on the willow Salix
borealis, and a population from the Czech Republic, specialised on the birch Betula
pubescens. Abundances of folivorous and suctivorous insects on both host plants were recorded at both population sites. The willow
leaf beetle Phratora vitellinae was the most abundant herbivorous insect at both study sites on willow. A field study was conducted to examine the effects
of P. vitellinae on the performance of C. lapponica. The presence of P. vitellinae larvae on the same twig upon which C. lapponica larvae were feeding did not affect increase of body weight in C. lapponica larvae. Thus, the high resource availability of both willows and birches suggest that interspecific competition is unlikely
to be a selection factor driving the evolution of host shift in C. lapponica. 相似文献
5.
We investigated the biomass, vertical distribution, and specific root length (SRL) of fine and small roots in a chronosequence
of Japanese cedar (Cryptomeria japonica D. Don) plantations in Nara Prefecture, central Japan. Roots were collected from soil blocks up to 50 cm in depth in five
plantations of differing age: 4, 15, 30, 41, and 88 years old. Fine-root biomass reached a maximum (639 g m−2) in the 15-year-old stand before canopy closure, decreased in the 30-year-old stand (422 g m−2), and thereafter was stable. Except in the 30-year-old stand, fine-root biomass increased in deeper soil layers as stand
age increased, and the depth at which the cumulative biomass of fine roots reached 90% exhibited a good allometric relationship
with mean stem diameter. Both root-length density (root length per unit soil volume) and SRL decreased with soil depth in
all stands, indicating that plants mainly acquire water and nutrients from shallow soils. The highest SRL was observed in
the 4-year-old stand, but the relationship between SRL and stand age was unclear in older stands. The SRL in surface soils
seemed to decrease with increases in root-length density, suggesting that branching of the fine-root system during development
is related to density-dependent processes rather than age. 相似文献
6.
Demand for goat (Capra hircus) meat in the southeastern USA is steadily increasing as a result of preferences exhibited by ethnic communities. Feeding
systems that include fodder trees can be developed to take advantage of the natural preference of goats for browse. Data were
collected for 2 years on a 5-year old stand of Robinia pseudoacacia L. to evaluate growth characteristics for goat browse and to develop allometric relationships in a randomized complete block
design (intra-row spacing 0.5 or 1 m and coppice height 0.25 or 0.50 m) replicated six times. Allometric equations were derived
from destructive harvests of 68 trees. Main branch size was not affected by intra-row spacing when trees were coppiced at
0.25 m; however, when coppiced at 0.5 m, trees spaced at 1 m had more and larger branches (P < 0.05) than trees spaced at 0.5 m. Intra-row spacing did not influence tree herbage biomass when trees were spaced at 0.5 m
whereas trees coppiced at 0.25 m and spaced at 1 m produced less woody and herbaceous biomass than trees spaced at 0.5 m (P < 0.05). A strong relationship (P < 0.0001) was found between tree herbage biomass and the number of main branches greater than 0.01 m (r
2 = 0.80). The results, based on growth characteristics and tree herbage biomass production, suggest that Robinia pseudoacacia L. would be an excellent candidate as a silvopastoral component in the southeastern USA. 相似文献
7.
To clarify the effects of inundation on the establishment of Salix gracilistyla trees, the relationship between total inundation duration and the distribution and size of trees was examined on a gravel
bar along the Miya River in central Japan. The density of S. gracilistyla was low at both low and high elevations on the gravel bar, but high at middle elevations. The density increased with up to
165 days of inundation and declined gradually with more than 165 days of inundation. Density had a negative effect on crown
area, whereas inundation duration had a positive effect. At lower elevations, growth limitation of S. gracilistyla is mainly caused by inundation stress, whereas at higher elevations it seems to be primarily due to drought stress, although
it depends on the total duration of inundation in a year (TDIY). Consequently, the density is highest at middle elevations
where trees do not become too large. These results suggest that inundation duration is one factor determining the density
of S. gracilistyla trees, which in turn affects the size of each tree. 相似文献
8.
Spatial distribution of sporocarps of Suillus pictus A.H. Smith and Thiers was studied in a plot of 6 × 12 m in size established in a stand of Pinus koraiensis Sieb. et Zucc. in Kyoto, Japan for 4 years, and the biomass of mycorrhizas was examined in the last year. S. pictus was dominant in both sporocarp and ectomycorrhizal community in the study plot. The number of S. pictus sporocarps ranged from 0.94 to 1.26 m−2 (surface area) in the study plot and did not vary very much during the study period. Sporocarps of S. pictus occurred in clumps and the distributions of clumps were generally random. As the spots of sporocarp occurrence changed gradually
from year to year, the distributions of sporocarps that occurred successively in 2-year periods overlapped, especially when
analyzed in 9-m2 unit size using the m
*
–m method. Mycorrhizas of S. pictus were distributed in more subplots than its sporocarps. Distribution of mycorrhizas and sporocarps of S. pictus generally overlapped well. The biomass of mycorrhizas and mycelia in the mycorrhizas of S. pictus was estimated at 15.5 g DW m−2 and 6.2 g DW m−2 (surface area) in this plot, respectively. The biomass of mycorrhizas and mycelia in the mycorrhizas supporting the production
of one sporocarp (average dry weight was 0.86 g) of S. pictus was evaluated as about 16.4 and 7.3 g DW, respectively, in this plot.
Received: December 20, 2001 / Accepted: August 12, 2002
Acknowledgments We thank Dr. T. Furuno, Mr. N. Kato, and Dr. I. Nakai for their help in preparing the study plot and collecting sporocarps,
and Prof. K. Yokoyama for the identification of sporocarps. Thanks are also due to Dr. E. Kuno for his suggestion about analysis.
Correspondence to:J. Kikuchi 相似文献
9.
Given the sequence of Chs gene promoter from Arabidopsis thaliana reported in GenBank (AF248988), a pair of specific 相似文献
10.
D. M. Karadí 《Forest Pathology》1994,24(5):300-303
D. septospora is recorded for the first time on young Serbian spruces. In addition to Serbian spruce, the fungus was also observed on Douglas fir. Based on the length of conidia it was concluded that it was D. septospora var. lineare. 相似文献
11.
The presencs of Arceuthobium minutissimum on Pinus gerardiana in the remperate forests of Dir has been confirmed. It was found in the Zander forests around Anar Killi about 105 km north-east of Dir. This is the first verified report of A, minutissimum on any host other than Pinus wallichiana. 相似文献
12.
Ali Bagherzadeh Rainer Brumme Friedrich Beese 《林业研究》2008,19(1):37-43
It was hypothesized that increasing air and/or soil temperature would increase rates of microbial processes including litter decomposition and net N mineralization, resulting in greater sequestration of carbon and nitrogen in humus, and consequently development in OH horizon (humus horizon). To quantify the effect of temperature on biochemical processes controlling the rate of OH layer development three adjacent forest floors under beech, Norway spruce and mixed species stands were investigated at Soiling forest, Germany by an incubation experiment of OH layer for three months. Comparing the fitted curves for temperature sensitivity of OH layers in relation to net N mineralization revealed positive correlation across all sites. For the whole data set of all stands, a Q10 (temperature sensitivity index) value of 2.35-2.44 dependent on the measured units was found to be adequate for describing the temperature dependency of net N mineralization at experimental site. Species-specific differences of substrate quality did not result in changes in biochemical properties of OH horizon of the forest floors. Temperature elevation increased net N mineralization without significant changes in microbial status in the range of I to 15℃. A low Cmic /Corg (microbial carbon/organic carbon) ratio at 20℃ indicated that the resource availability for decomposers has been restricted as reflected in significant decrease of microbial biomass. 相似文献
13.
An efficient and improved shoot regeneration technique for the micropropagation of Vitex negundo, an aromatic and medicinal shrub through in vitro culture of nodal segments with axillary buds, is described. Thidiazuron
(TDZ) used at 1.0 μM was the most effective in inducing bud break and growth, and also in initiating multiple shoot proliferation
at the rate of 25 microshoots per nodal explant with axillary buds, after 4 weeks of culture. By repeated subculturing of
nodal explants, a high-frequency multiplication rate was established. Optimum shoot multiplication and elongation was achieved
when TDZ exposed explants were subcultured on Murashige and Skoog (MS) media containing a combination of 1.0 μM 6-benzyladenine
(BA) and 0.5 μM α-naphthalene acetic acid (NAA). Efficient rooting was achieved directly in soilrite when basal portion of
the shoots were treated with 500 μM indole-3-butyric acid for 10 min which was the most effective in inducing roots, as 97%
of the microshoots produced roots. Plantlets went through a hardening phase in a controlled plant growth chamber, prior to
ex-vitro transfer. Micropropagated plants grew well, attained maturity and flowered. No phenotypical differences for morphogenesis
were observed among the regenerants. 相似文献
14.
Picea mongolica is an endemic but endangered species in China. The spruce forest is only found in sandy forest-steppe ecotones. In this study, we examined the initial response of the quantity and refilling process of fine roots in an artificial canopy gap with a diameter of 36 m in a P. mongolica forest. Under the canopy, the fine root length densities of trees, shrubs and herbs were 2,622, 864 and 3,086 m·m–2, respectively. The fine root biomass of trees, shrubs and herbs were 148, 62 and 65 g·m–2, respect... 相似文献
15.
H.‐Q. Mou X. Xu R.‐R. Wang Q. Tian Y. Wei S.‐F. Zhu X.‐L. Liao W.‐J. Zhao 《Forest Pathology》2014,44(1):56-61
This article reports Salix tetradenia Hand.‐Mazz as a new host of Candidatus phytoplasma and demonstrates its association with witches' broom disease on S. tetradenia plants. Plants exhibited typical visual symptoms of phytoplasma with virescence, abnormality of flowers and witches' broom, and phytoplasma bodies were observed by transmission electron microscopy. Products of 1.2 kb were amplified by nested PCR using phytoplasma universal primer pairs R16F2n/R16R2, but no amplification products were obtained from symptomless plants. The sequence analysis of three 16S rDNA isolates showed 99.84%, 99.68% and 99.76% identify, respectively, with the homologous gene (nc_005303) of member of ‘Candidatus phytoplasma asteris’ (16SrI) group. Phylogenetic and virtual computer‐simulated restriction fragment length polymorphism analysis of the 16S rRNA, tuf and rp gene sequences confirmed that this phytoplasma clustered in the 16SrI‐B subgroup. These results indicated that the diseased S. tetradenia plants were infected by a phytoplasma of the 16SrI group. This is the first report on the occurrence of phytoplasma disease on S. tetradenia worldwide. 相似文献
16.
To find fungi that are potent for degradation of condensed tannin, a two-step screening was used. This involved measurement
of fungal growth rate on Japanese cedar (Cryptomeria japonica) bark, followed by determination of [14C]-labeled CO2 generated from fungal degradation of synthetic [14C]-labeled condensed tannin model. In the first screening, 75 strains of wood rot fungi were tested, and 19 strains effectively
decreased bark weight and/or the weight of the methanol-soluble fraction. For the second screening, [14C]-labeled condensed tannin model compound was synthesized in 11.8% yield based on radioactivity measurements. Over the incubation
period, Coriolus hirsutus K-2671, Lentinus edodes Is, and Lampteromyces japonicus Nn showed higher cumulative [14C]-labeled CO2 emissions than the other strains and mineralized the [14C]-labeled condensed tannin model compound by 3.7%, 3.0%, and 3.0%, respectively. Fractionation of the methanol extracts from
the medium by gel permeation chromatography after fungal treatment suggested that fungi that can induce the emission of significant
levels of [14C]-labeled CO2 can extensively depolymerize condensed tannins. 相似文献
17.
India is the largest grower of Eucalyptus with an area of 3.943 million hectares under plantations and E. tereticornis is the predominant species in the plains of southern India with an average productivity of 12–25 m3 ha−1 year−1. With the aim to establish seedling seed orchards of the species, seed lots of fifteen provenances were imported from Australia
and a trial was laid. In the present study the genetic diversity existing in the seed orchard was estimated using ISSR–PCR.
Seven ISSR primers amplified 663 amplicons in the size ranging from 255 to 2,711 bp. The total number of polymorphic bands
varied from 59 to 123 with 100% polymorphic banding profiles. The average gene diversity (Hj) of all the provenances ranged from 0.0589 to 0.1109 and the total gene diversity estimated was low (H
T = 0.130) when compared to the earlier reports from other eucalypts species. Analysis of Molecular Variance partitioned the
ISSR variation into inter and intra population components. The inter population component accounted for 55.2% of the variation
and the intra population component accounted for 46.3% (P < 0.001). A neighbour-joining analysis was done using the dissimilarity matrix to determine the aggregation of the individuals
into clusters. Existence of population structure among the populations was revealed in STRUCTURE analysis but geographical
region based clustering was not observed. The assessment of intra and inter genetic variation documented in the present study
suggests that, along with the phenotypic traits, knowledge about genetic diversity measured at the DNA level in individuals
of seed orchards provide an objective guide for selective culling of trees for maintaining optimal diversity for enhanced
genetic gains. 相似文献
18.
Wang Wei-gang Ma Lei Jiang Jian-xin Jiang Li Zhang Zhi-xiang 《中国林学(英文版)》2007,9(2):132-136
Studies were carried out on the transesterification of the Chinese Spicehush (Lindera communis) seed (LCS) oil with methanol for the production of biodiesel. The methyl esters of LCS oil were compared with soybean esters to determine biodiesel fuel performance and properties. The fatty acids content in the seed kernel oil (LKO) and coat oil (LCO) were quantified by gas chromatography and mass spectrometry method (GC-MS). LKO contains 95.1% saturated acids (capric, lauric, myristic and palmitic) and 2.3% unsaturated acids (oleic). LCO contains 24.6% saturated acids (palmitic and stearic) and 73.6% unsaturated acids (oleic, linoleic and palmitoleic). The kinematic viscosity, cold filter plugging point, cloud point, flash point and cetane index were determined. The methyl esters of LKO had a higher kinematic viscosity and a lower cold filter plugging point value, so it has better per- formance in cold weather. The biodiesel of LCS oil has fuel properties within the limits prescribed by American (ASTM D 6751-02) standards, except for a slightly lower flash point of LKO biodiesel than that prescribed by these standards (130°C). Thus, LKO and LCO biodiesel have great potential to be used on a large scale as fuel for diesel engines. 相似文献
19.
[目的]通过研究厄尔尼诺/拉尼娜事件对大兴安岭天气和火天气指数的影响,定量描述厄尔尼诺/拉尼娜事件在火天气指数变化中的作用。[方法]根据研究区及周边气象站日最高气温、日最小相对湿度、平均风速和24 h降水量计算1951—2016年大兴安岭森林火险天气指数,分析超强和强厄尔尼诺年、中等和弱厄尔尼诺年、拉尼娜年和正常年等4种情景下的主要天气因子和火天气指数的差异。[结果]春季火险期,超强和强厄尔尼诺年日均最高气温较正常年偏低0. 21℃,降水量增加6. 78%,拉尼娜年日均最高气温增加0. 44℃,降水量增加2. 77 mm;厄尔尼诺/拉尼娜年的秋季火险期日均最高气温低于正常年。超强和强厄尔尼诺年春季和秋季火险期的细小可燃物湿度码(FFMC)、腐殖质湿度码(DMC)、干旱码(DC)、累积指数(BUI)和火天气指数(FWI)平均值低于正常年份,FWI从西南到东北逐渐降低;中等和弱厄尔尼诺年春季火险期6个指数均低于正常年份,秋季火险期除FFMC外其他火天气指数均低于正常年份;拉尼娜年春季火险期的FFMC、初始蔓延速度(ISI)和FWI低于正常年份,秋季火险期除DC外其他指数均低于正常年份。[结论]大兴安岭地区在超强和强厄尔尼诺年春秋季火险期火天气指数较正常年份低,西部地区火天气指数高于东部地区。拉尼娜年春季火险期东部地区FWI低于正常年份,中西部偏高,秋季火险期西北部地区高于正常年份,东南部偏低。 相似文献
20.
Yasuyuki Ohno Kiyoshi Umeki Kazuhiko Terazawa Michiyasu Yasaka Ichiro Watanabe Mika Takiya 《Journal of Forest Research》2010,15(3):161-168
We analyzed the probability that Betula maximowicziana Regel (monarch birch) would suffer crown dieback (crown-dieback probability) and the basal area growth rate (GB), which was
found to be a predisposing stress factor making birch trees susceptible to crown dieback. First, we analyzed the relationship
between the probability that birch trees would suffer from crown dieback in 1999 and GB from a period prior to the occurrence
of crown dieback (1985–1987), using a data set of repeated measurements on 217 trees. Logistic regression analysis revealed
that monarch birch had a larger crown-dieback probability when GB was low in the preceding period. Hence, there were predisposing
stress factors that reduced GB and continued to affect trees for at least a decade. Next, we analyzed GB in the same period
in relation to symmetrical and asymmetrical competition between trees and found that GB was reduced by symmetrical competition,
suggesting that this was one of the predisposing factors for crown dieback. Based on these results, we used selected models
for crown-dieback probability and GB to calculate crown-dieback probabilities for individuals with different initial basal
areas and experiencing different intensities of symmetrical competition. The predicted crown-dieback probability decreased
with decreasing symmetrical competition between trees. We discuss a possible process of crown dieback to death for monarch
birch and the use of thinning as a method to reduce the risk of crown dieback. 相似文献