共查询到20条相似文献，搜索用时 203 毫秒
1.
通过对四季竹立竹构件因子和地上生物量的调查,分析了立竹地上现存生物量分配格局及立竹构件因子与构件生物量的关系。结果表明:地上现存生物量分配格局1年生立竹为竹秆>竹叶>竹枝,2年生立竹为竹叶>竹秆>竹枝,2年生立竹竹秆和竹叶生物量分配比例较1年生立竹分别极显著减少和增加,而竹枝生物量分配比例不同年龄立竹间无显著变化。2年生立竹各构件因子与构件生物量间大多呈显著或极显著相关,立竹全高、枝下高、枝盘数是立竹胸径的从属因子,立竹胸径对立竹构件生物量和地上部分总生物量起着决定作用,两者具有极显著的三次曲线函数关系。四季竹在资源分配时对竹叶构件的倾斜有利于种群对已占领生境的巩固和新生境的开拓。 相似文献
2.
指出了细叶龙竹具有速生、高产,成林快,收益高、轮伐期短、抗逆性能和抗痛虫害能力强等特点,探讨了细叶龙竹造林技术,分析了在细叶龙竹营养杯实生苗造林的应用前景. 相似文献
3.
指出了细叶龙竹具有速生、高产，成林快，收益高、轮伐期短、抗逆性能和抗病虫害能力强等特点，探讨了细叶龙竹造林技术，分析了在细叶龙竹营养杯实生苗造林的应用前景。 相似文献
4.
对“伐竹翁”作为日本竹文化象征的考证 总被引：2，自引：1，他引：1
伐竹翁是《竹取物语》主人公之一。本文在揭示小说的日本竹文化背景基础上,通过考证伐竹翁所处的社会背景,探究日本竹编工艺文化,品味伐竹翁竹子般正直的品质,从一个方面揭示了日本竹文化内涵。伐竹翁业已成为日本竹文化的象征。 相似文献
5.
为探索立竹质量及其产量与集约经营的关系,作者对立竹胸径、竹节长度演变、竹壁厚度和节环扭曲程度几个方面进行调查,认为:①留笋养竹是提高立竹质量、促进竹材产量稳步递增的关键;②毛竹单株重的递增,主要依赖于立竹径围的加粗和竹节高度的增加来实现;③扭曲差是一个变值,只要采取调整立竹量、合理改善立竹分布等措施,节环扭曲差是可以不断缩小的。 相似文献
6.
采用Logistic曲线经验式拟合橄榄竹的出笋规律,并对不同时期、立竹年龄、土层的出笋、退笋、成竹情况进行调查分析。研究结果表明：出笋量日进程符合Logistic曲线的“慢一快一慢”规律。由此其出笋期可划分为3个时期。研究结果也表明：不同时期、不同立竹年龄、不同土层的出笋、退笋、成竹存在明显差异。橄榄竹适宜留笋的时期为出笋中期。适宜留笋养竹的立竹年龄以1、2年生为好。橄榄竹不同竹龄发笋能力,与毛竹差别甚大。橄榄竹发笋早,1年生竹连着的鞭可孕笋成竹,竹寿命较短。这就要求在经营管理上要有别于毛竹。橄榄竹适宜留笋养竹的土层深度16～30cm。本研究为橄榄竹制定留笋养竹保育技术提供了可借鉴的理论依据。 相似文献
7.
为了解城市景观绿化红竹林立竹秆形年际变化规律,对高密度全梢竹一次成景栽植,不实施人工干扰,2005年11月营造的红竹林2007-2009年出笋成竹的立竹胸径、枝下高、全高、胸高壁厚和平均节间长进行了调查。结果表明:随着造林年限的延长,立竹胸径逐年显著增大,而相邻年际间立竹胸径增幅趋于降低;立竹枝下高、全高与立竹胸径呈线性增长关系。立竹相对枝下高、相对全高总体上随造林年限的延长而降低,但不同年度立竹间无显著差异;立竹胸高壁厚随立竹胸径的增大而增大,变化幅度较立竹胸径缓慢,不同年度立竹的相对胸高壁厚差异不显著;随造林年限的延长,立竹平均节间长增大,相对平均节间长减小。不同年度立竹的平均节间长与立竹胸径的差异性表现不一致,相对平均节间长不同年度立竹间无显著差异。 相似文献
8.
四方竹是我国特有的珍稀竹种之一,开发利用前景广阔。试验研究了不同施肥方式和不同林分密度对四方竹发笋量的影响。结果表明：施肥能明显提高四方竹的出笋量,以施有机肥并进行覆盖效果最好,笋产量较对照提高56%;最佳施肥方案为,以见效快的复合肥作为先导肥料保证当年的生产量,而以见效慢但持续性长、能改善土壤温度条件的有机肥作为长效肥保证持续生产。竹林密度是影响发笋的重要因子,试验结果显示,立竹量在2 500株/667 m2时,所发笋个体形态明显减小,笋产量明显降低,建议四方竹适宜的立竹量控制在1 500~2 000株/667 m2。 相似文献
9.
对景观红竹林2007-2009年立竹的胸径、枝夹角、枝分角、冠长、冠幅、枝盘数进行了调查分析。结果表明:立竹冠长、冠幅、枝盘数与立竹胸径分别呈3次、2次多项式和线性关系;当立竹密度45023株/hm2以下时,不同年龄立竹不同竹冠部位的枝夹角无显著差异,立竹密度为26713株/hm2时,立竹不同竹冠部位的枝分角差异极显著;试验林立竹密度范围内,立竹密度对枝夹角、相对竹冠长无显著影响,对枝分角、相对冠幅、相对枝盘数有一定的影响。随着立竹密度的增大,竹冠上部枝分角显著下降,竹冠中部、下部枝分角呈先升后降趋势,相对冠幅、相对枝盘数呈下降趋势。当立竹密度为60030株/hm2时,枝分角、相对冠幅、相对枝盘数显著下降,对竹林的更新生长已产生不利影响。 相似文献
10.
【目的】揭示毛竹伐蔸根系养分含量和抗氧化能力的年际变化规律,为毛竹林伐蔸促腐技术研究提供理论参考。【方法】以6年生活立竹的蔸根为对照,分析比较了笋材两用毛竹林伐后2 a、4 a、6 a的伐蔸根系C、N、P、丙二醛(MDA)、可溶性蛋白质含量和根系活力、抗氧化酶活性。【结果】表明随着毛竹立竹伐后年限的增加,伐蔸根系的细胞膜脂过氧化程度提高,渗透调节能力降低,根系活力明显降低,抗氧化能力逐渐下降。但毛竹立竹伐后,甚至伐后6 a时,伐蔸根系仍有较强的生理活性和生长更新能力,具有较高的C、N、P含量,尤其是C含量明显提高,主要养分化学计量比产生适应性调节,N/P相对稳定,C/N、C/P趋于升高。【结论】毛竹伐后6 a,蔸根仍具有较强的养分吸收能力,也能通过与竹鞭的联系从活立竹转运利用有机C,这是毛竹伐蔸难以腐解的重要机制。 相似文献
11.
本文通过对培育杨树工业用材林的立地条件,栽培品种选择,合理密度及最佳轮伐期的确定,以及栽植,林分抚育管理等关键技术措施的论述,为实现定向,速生,丰产,优质,稳定和高效的培育目标,建立了辽宁省的杨树工业用材林基地,提供了可靠的技术保障。 相似文献
12.
Mariusz J. StolarskiStefan Szczukowski Józef TworkowskiAndrzej Klasa 《Forest Ecology and Management》2011,262(8):1558-1566
In this study, the biomass yield and morphological traits of plants were reported from an experiment involving six genotypes of willow in northern Poland. Willow was planted using a pole cutting system, which we designated Eco-Salix, on sites that were unsuitable for food crops. The results presented here are from the first rotation of a four-year cutting cycle. In the field trial, the average willow biomass yield of oven-dry matter was 7.87 Mg ha−1 year−1. Willow plants that were planted as pole cuttings after four growing seasons reached a height of 6.64 m and a stem diameter of 50.5 mm. Clone UWM 043 produced higher yields and more favourable morphological traits when compared to registered Polish cultivars. The willow biomass yield obtained on peaty muck soil was significantly higher than from willow that was grown on heavy textured silt soil. The biomass harvested from plots planted at a density of 5,200 plants ha−1 was 14% lower than plots that had a density of 7,400 plants ha−1. 相似文献
13.
杉木不同密度造林试验，结果表明：造林密度每公顷4995株的林地，每公顷平均村积生长量为9．315m3,每公顷年均产值6408．90元。分另］是林龄27年、造林密度3600株／hm2林地的2．49倍和2．38倍；是林龄13年，造林密度3000株／hm2的1．66倍和1．67倍。试验证明在杉木分布区北缘的低山丘陵区，采用合理密植造林，集约经营的管理方式、缩短轮伐期，来提高林地的经济效益是切实可行的。 相似文献
14.
The spatial and temporal effects of paulownia intercropping: The case of northern China 总被引：3，自引：0，他引：3
We present a financial analysis and further statistical tests of the spatial and temporal effects of intercropped paulownia
(Paulownia elongata) trees on crop yields. The results provide evidence that growing paulownia trees in farm fields can either
increase or decrease crop production, depending on the manipulation of the tree density and rotation length. A 60–100% reduction
of crop yields can result from a higher tree density and/or a later stage of the rotation, but the pattern of reduction is
different for the first (wheat) and second crops (corn, bean or cotton). However, the reduction in crop yield is accompanied
by gains of timber, fuel, fodder, and other goods and services. Thus, although the accumulated net returns from crops decline
as tree density increases, the combined net returns of crops and trees are generally higher than those of the control, ranging
from 50% to 100%.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
15.
This study deals with grazing in kunugi (Quercus acutissima) forests in the Aso district of Kyushu Island in southwest Japan. These forests are managed for production of bed-logs for
shiitake mushrooms and cow-calf farming. One of their characteristics is short-term rotation such as 10–15 years for bed-logs
and a year for calf production. A forest grazing experiment was begun in Minamioguni to look at forest growth, vegetation
change and grazing intensity. Stem densities dropped in a few years. After sprout cutting, they also dropped gradually, then
stabilized. Although grazing caused tree damage and suppressed tree growth, grazing intensity of up to 150 cow-days/ha·year
did not harm forest regeneration. Herbage volume decreased as grazing was repeated and trees grew. Another investigation of
kunugi grazing forests in Minamioguni and Asaji showed the correlation betweenRy (yield index in Stand density diagram) and grazing capacity could be expressed with a regression equation. The results were
also used to design a yield table for kunugi grazing forests. The yield table has items ofRy and grazing capacity in addition to usual yield table items, and can indicate timber yield and grazing capacity at the same
time. The table estimates that proper grazing capacity is 60–80 cow-days/ha·year in wild grass sites. In the light of these
results, an optimal management plan was proposed as a diagram integrating stem density, forest yield, and forest management. 相似文献
16.
Veli-Pekka Ikonen Heli Peltola Lars Wilhelmsson Antti Kilpelinen Hannu Visnen Tuula Nuutinen Seppo Kellomki 《Forest Ecology and Management》2008,256(6):1356-1371
In this work, empirical ring-based models were developed to predict the distribution of early wood percentage, wood density and fibre length along the stems of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) as affected by silvicultural management. The performance of the ring-based models was also compared for Scots pine and Norway spruce with corresponding disc-based (cross-sectional) models. Moreover, both models were integrated with example simulations by a process-based growth and yield model to analyze how management, such as thinning, affects the growth and wood properties of Scots pine trees over a rotation as an average for the tree stem, but also along the stem.The ring-based models built for annual early wood percentage (explained by ring width), air dry wood density (explained by early wood percentage and cambial age) and fibre length (explained by radial growth percentage and cambial age) predicted reasonably well the wood properties both at an intra-ring level, but also at a cross-sectional level. These predictions were also reasonably well in line with corresponding cross-sectional predictions by the disc-based models (which predicted the properties based on the number of annual rings and diameter at breast height and/or the cross-section being considered and temperature sum). The example simulations also demonstrated that both models predicted slightly lower wood density for dominant trees compared to dominated ones grown in thinned and unthinned Scots pine stands over a rotation. Unlike the disc-based model, the ring-based model predicted, on average, higher early wood percentage in dominant trees than in dominated ones. However, fibre length was not significantly affected when the averages of the whole stems were predicted, and this held true for both ring- and disc-based models.In summary, the incorporation of empirical ring-based wood property models into a process-based growth and yield model, offers a means to study in detail how environmental conditions, forest structure and management affect the quantity and properties of stem wood produced over a rotation. The disc-based wood property models used in this work are based on data with large geographical and genetic variation, and therefore may turn out to be more applicable for predicting future wood and fibre resources at a regional and national level. This kind of integrated use of wood property models with a process-based growth and yield model could help us to evaluate the forest resources under current and changing climate. 相似文献
17.
Plantation forests are an important part of the forest estate in many countries. In Ireland, they cover around 9% of the land area and many that are commercially mature are now being felled and reforested. The potential biodiversity value of such second rotation forests has yet to be determined, yet this may be particularly significant in Ireland where cover of semi-natural woodland is only 1%. Invertebrates are a vital component of forest biodiversity, functioning as decomposers and pollinators, herbivores, predators and prey. Spiders and Carabid beetles are often used in biodiversity assessment as they are easily captured using pitfall traps, are taxonomically well known and respond to changes in habitat structure. This study aimed to examine spider and Carabid beetle diversity in second rotation Sitka spruce (Picea sitchensis) plantations at different stages of the forest cycle (5, 8–12, 20–30, 35–50 years), and compare the spiders captured in second rotation forests with those from first rotation. Spider and beetle diversity was influenced by stand structural development in second rotation plantations with numbers of forest-associated species increasing over the forest cycle. Overall, spider richness declined over the forest cycle and this was related to decreasing cover of field layer vegetation and fewer open-associated species. In contrast, total beetle richness increased and became more specialised over the forest cycle which may be related to slower colonisation of disturbed areas by beetles in comparison with spiders, and fewer open specialists at the early stages of second rotation. Spider assemblages were distinguished between rotations. This may be related to differing habitat conditions in second rotation forests including dryer soils with lower pH, differing vegetation complexity and presence of brush piles. Few of the forest species accumulated during first rotation were retained and the early stages of second rotation forest cycle was characterised by a generalist open fauna. Nonetheless, as the forest cycle progressed the spider assemblages between rotations became more similar. Current forest policy supports retaining over-mature trees and creating a mosaic of different aged stands within a plantation. Such measures may provide refuge for forest species after clearfell. In countries where forest fragments exist in a landscape dominated by agriculture, consideration should be given to the capacity of mature forest adjacent to felled stands to support forest species, and to the configuration of over-mature areas retained after felling. 相似文献
18.
19.
大岗山丘陵区杉木中幼林低密度控制及深抚效果 总被引：2，自引：0，他引：2
近年来,国际上由于工资水平的提高和劳动力的缺乏,从而普遍采用低密度控制,即加大造林株行距,加大疏伐强度、减少疏伐次数,以提高林分质量,提前获得收益。杉木(Cunninghamia lanceolata Hook)是我国重要用材树种,生产中通常采用多次下层间伐方式。本文对杉木中幼林一次性间伐的合理保留密度即主伐密度以及深抚的有效性进行了研究。一、试验地概况试验是在江西大岗山山下林场陂元Ⅰ区杉木人工林中进行的。地理坐标为114°36’E、27°42’N,地处中亚热带东部罗霄山北端武功山余脉,海拔130-220m,属丘陵山地。土壤为页岩上发育起来的黄红壤,土层厚度为80-150cm,腐殖质层(A+AB)厚度约为25cm。土壤容重为1.2(g/cm~3)左右,pH值为4.4-4.8,有机质含量约为2.5％。气候属中亚热带湿润型,具有四季分明,气候温和,日照充足,雨量充沛的特点:年均降雨量1590.9mm,降雨量集中分布在4-6月,占全年降雨量的45％,年均蒸发量1503.8mm,相对湿度80％,1月平均最低温度-5.3℃,无霜期270天左右。主要林下植被为:杜茎 相似文献
20.
厚朴林下轮作玄参、大黄种植技术研究 总被引：1，自引：1，他引：0
为更好地指导厚朴规范化种植,充分利用土地资源,大力发展林下经济,增加农民收入。2002年,在龙坪乡开展了厚朴林下轮作玄参、大黄种植模式和厚朴单作种植模式对比试验研究。试验结果表明:在厚朴林下轮作玄参、大黄种植模式下,厚朴各测树因子及皮产量较对照具有明显地增长和增产作用,同时每个轮作期内比对照增产大黄药材520 kg/666.7 m2、玄参药材320 kg/666.7 m2。 相似文献