共查询到20条相似文献，搜索用时 135 毫秒
1.
2.
3.
杜仲利用传统上采取砍树肃皮，对资源和生态环境破坏严重。采用剥皮再生利用技术，可避免砍树的弊端，既可采剥高质量的干皮，又能使剥皮植株正常生长，每隔４－５年，可再度剥皮青山常在，永续利用。 相似文献
4.
为适应生产需要，对杜仲进行大面积剥皮试验。结果可看出，随气温升高，杜仲剥皮后再生效果明显增加；从单株看，阴面的再生皮愈合较好，残留尚未愈合的多系是午后受阳光直射的部位；剥充后，如遇连续２天下雨，则将影响再生皮的形成。 相似文献
5.
6.
7.
土壤水分对杜仲剥皮再生的影响 总被引：2，自引：1，他引：2
分别对12和25年生杜仲进行Ⅰ、Ⅱ、Ⅲ、Ⅳ级供水处理,研究不同水分条件对杜仲愈伤组织和再生皮生长的影响.结果表明:供水改善了林地水分条件,土壤平均含水量和贮水量增大,25年生杜仲消耗土壤水分较多,土壤含水量较12年生杜仲林地的低.杜仲剥皮后,供水能加快愈伤组织的形成,剥皮后第5 d,处理Ⅰ、Ⅱ、Ⅲ均有微绿色的愈伤组织出现,较对照提前5 d左右;剥皮后25 d,12和25年生的愈伤组织厚度分别达到1.00和0.94mm,生长速度分别为0.040和0.037 mm·d-1,分别较对照增加47.1%和80.8%.供水能显著促进杜仲再生皮的生长,剥皮后5个月,12和25年生杜仲Ⅰ、Ⅱ、Ⅲ、Ⅳ级供水处理的再生皮厚度分别较对照增加5.0%、22.5%、75.8%、71.7%和18.5%、29.3%、80.7%、95.0%.6月份是杜仲再生皮生长的关键期,供水对再生皮生长最有利.杜仲水分利用效率在Ⅲ级供水处理时最大,12和25年生分别较对照提高39.3%和37.4%.生长季中,土壤含水量应保持在160～170 g·kg-1. 相似文献
8.
9.
<正> 杜仲、黄柏等树种,其皮为贵重药材。但历来取皮都是用“杀鸡取卵”的办法,一棵树生长几十年只能采剥一次,造成资源不足,供求矛盾。如果能使一些树木剥皮后不致死亡,且可以再生新皮,达到源源不断地采剥,在经济上将有重要意义;同时,有些危害树皮的病虫害像腐烂病、吉丁虫等等,剥皮治疗后,再使其复壮,也很有实际意义。为了探索这种可能性,本人从1974年开始,对花曲柳、李树、 相似文献
10.
11.
Terminalia arjuna (“Arjuna”) in the family Combretaceae is a well-known medicinal tree whose bark is extensively used in Ayurvedic medicine, particularly as a cardiac tonic. Demand for Arjuna bark, both in India and abroad, has been growing rapidly for over a decade. Litsea glutinosa (“Maida”) in the family Lauraceae is a medium size tree. Its bark is used to treat joint pain, fracture, sprain, arthritis, back pain, and indigestion. Presently the bark of Arjuna and Maida is being extracted through unscientific and destructive harvesting practices. This is the first study on development of sustainable harvesting practices of Arjuna and Maida bark. The stages of bark recovery varied from tree to tree. Age of tree, harvesting method, and season of harvest influenced bark regeneration. This study recommends that for sustainable harvest, mature bark from only one fourth to one third of the total girth of the tree should be stripped by removing only outer and middle bark, leaving the inner bark for regeneration. However, strip harvesting was found to be the best method in younger trees having a girth at breast height (GBH) of less than 60 cm. Sustainable bark harvesting can be done after every 2 yr for Arjuna and 1 yr for Maida by removing opposite quarters of trunk bark. 相似文献
12.
《林业研究》2020,31(4)
The management of deer impacts on forested lands requires quantification of the negative factors(e.g.,bark stripping) on tree survival in relation to other ecological variables(e.g.,competition from neighboring trees).This study measured the effects of bark stripping by sika deer,Cervus nippon,and competition among trees on the survival of Abies veitchii in a subalpine coniferous forest in central Japan over 12 years.Most of the trees subjected to bark stripping by deer were small(10 cm in diameter at breast height);however,some trees were stripped repeatedly.Although light bark stripping did not strongly influence tree survival after 12 years,heavily stripped stems(i.e., 65% of the stem circumference stripped) were severely affected.The effect on longevity for each tree after bark stripping was explained by maximum bark stripping intensity during the study period,rather than initial bark stripping intensity.When 85% of the stem circumference had been stripped,survival rates decreased.Bark stripping influenced survival rates much more than competition from neighboring trees.Because bark stripping occurred repeatedly,frequent measurements are important to grasp the full effects caused by this action.Heavy bark stripping of a stem enhances tree mortality.Thus,management of bark stripping is an essential element of stand maintenance and species composition in subalpine coniferous forests in Japan. 相似文献
13.
Ph. M. Wargo 《Forest Pathology》1988,18(5):279-290
Concentrations of amino acids, total amino nitrogen, and phenols, ratio of phenol to amino nitrogen, and pH in the bark of American beech, Fagus grandifolia, were determined to see if these chemical constituents were correlated with susceptibility of trees to infestation by the beech scale, Cryptococcus fagisuga. The relationship of these bark constituents with scale infestation levels (none, light, and moderate), tree size (large vs. small trees), and bark shading was determined. Levels of some individual amino acids and total amino acid content in moderately infested trees were significantly higher than in uninfested trees. Large uninfested beech trees, which tend to be more readily infested by scale, had significantly higher concentrations of aspartic acid. Concentrations of phenol in the outer bark of both infested and uninfested trees were significantly higher than in the inner bark. However in bark infected by Nectria, phenol levels in the inner bark were significantly higher than in the outer bark. 相似文献
14.
This paper presents the results of a research project concerning bark beetle populations in Norway spruce stands managed under a nature protection regime in national parks in Tatra Mountains in Poland and Slovakia. The preliminary data on bark beetle occurrence and related selected stand characteristics are presented. The dynamics of a bark beetle outbreak that occurred from 1994–97 in the stands localized on both sides of the state border and in various nature protection regimes is analyzed retrospectively. The data concerning the tree/stand characteristics, i.e. DBH and increment of trees are discussed in relation to its potential role in the mechanism for the spread of bark beetle populations. The patterns of the spatial distribution of trees attacked during the research period (1999–2001) are described. 相似文献
15.
Masaki Ando Akemi Itaya Shin-Ichi Yamamoto Ei'ichi Shibata 《Journal of Forest Research》2006,11(1):51-55
The long-term changes of the area of Sasa nipponica grassland, bark stripping damage to trees by sika deer, Cervus nippon, and sika deer densities on Mt. Ohdaigahara were assessed with aerial photographs, information from previous studies, and
field experiments. The grasslands expanded year after year. The expansion rate was highest from 1982 to 1992, and lowest from
1992 to 1997. Bark-stripping damage on coniferous trees was heavier than that on broadleaf trees in both the early 1980s and
1998. The deer density in the eastern part of the area had been high (14.4–64.3 km−2) from 1984 until 1998. We presume that rich growth of S. nipponica and heavy feeding pressure by sika deer over the long term caused expansion of S. nipponica grasslands by killing canopy trees by bark stripping and preventing forest regeneration. 相似文献
16.
《Scandinavian Journal of Forest Research》2012,27(2):194-201
Hylobius abietis (L.) (Coleoptera:Curculionidae) is the major insect pest of forest regeneration in Europe, where adult weevils kill conifer seedlings by feeding on the bark. This study demonstrates that pine weevils also feed extensively in the crowns of mature coniferous trees. Crown feeding primarily took place during a limited period immediately after the migration to new breeding sites (roots of freshly cut coniferous trees). The weevils reached the crowns mainly by flight and tended to concentrate on trees in freshly cut-over areas. The proportion of sexually mature females successively increased during the crown-feeding period, indicating that they require a certain period of maturation feeding. The pine weevils fed on twigs of 3-20 mm thickness, and they consumed about 0.2-0.3% (200 cm2) of the total bark surface in the crowns of mature Scots pine trees. Calculations suggested that the amount of food consumed in the trees surrounding a fresh clear-cutting should have met the nutrient requirements of the weevil population in the area during the maturation feeding period. In the crowns of shelterwood trees, about 50 cm2 of the bark was consumed per tree (0.63 m2 ha-1). This level of consumption is not believed to be high enough to relieve the feeding pressure on seedlings and thereby explain the low level of damage usually found under shelterwoods. 相似文献
17.
Filipe Xavier Catry Francisco Moreira Inês Duarte Vanda Acácio 《European Journal of Forest Research》2009,128(3):231-240
Cork oak (Quercus suber) forests are acknowledged for their biodiversity and economic (mainly cork production) values. Wildfires are one of the main
threats contributing to cork oak decline in the Mediterranean Basin, and one major question that managers face after fire
in cork oak stands is whether the burned trees should be coppiced or not. This decision can be based on the degree of expected
crown regeneration assessed immediately after fire. In this study we carried out a post-fire assessment of the degree of crown
recovery in 858 trees being exploited for cork production in southern Portugal, 1.5 years after a wildfire. Using logistic
regression, we modelled good or poor crown recovery probability as a function of tree and stand variables. The main variables
influencing the likelihood of good or poor crown regeneration were bark thickness, charring height, aspect and tree diameter.
We also developed management models, including simpler but easier to measure variables, which had a lower predictive power
but can be used to help managers to identify, immediately after fire, trees that will likely show good crown regeneration,
and trees that will likely die or show poor regeneration (and thus, potential candidates for trunk coppicing). 相似文献
18.
The consumption of the pine needles and the stripping of bark by sheep grazing annual pastures in three open stands of P. radiata and one of P. pinaster were measured. The P. radiata were four years old and the densities were 250, 500 and 750 trees ha-1. The P. pinaster included two, three and four year-old trees and the density was 440 trees ha–1.Needles were eaten immediately after the sheep were admitted and this continued throughout the year. Within ten weeks of the start of winter grazing, sheep stocked at 7–10 ha–1 had eaten about half of the accessible needles on both species where densities were less than500 trees ha–1. The estimated consumption was about 260 g sheep–1 day–1 for the P. radiata. Bark stripping then commenced and continued throughout spring and summer on most plots. In some plots at low tree density, bark was stripped from more than 35% of the trees. In denser stands, needle consumption per tree was less and bark was stripped from less than 5% of the trees.Bark damage was most common on the smaller trees, and severity of stripping was negatively correlated with tree size. Of all the trees with bark damage, 22% of the P. pinaster and 14% of the P. radiata had more than half of the stem circumference stripped. A number of these will probably suffer both stem distortion and growth retardation, and some may die.Methods of reducing the incidence of bark damage are discussed. 相似文献
19.
林木体细胞胚胎发生的研究进展 总被引：2，自引：0，他引：2
本文概述了近年国内外林木体细胞胚胎发生研究的进展,针对存在的问题提出相应的对策,以期推动我国林木体细胞胚胎发生研究在理论上的深入和生产上的进一步应用。今后在林木体细胞胚胎发生研究方面应加强以下五方面工作:1)珍稀优异种质规模化体细胞胚胎发生植株再生体系的研究和应用;2)林木成年优树的复壮及体细胞胚胎发生植株再生系统建立;3)进一步加强体细胞胚胎发生机理和应用技术研究;4)进一步扩大林木体细胞胚胎发生再生植株体系建立的树种数量;5)加强体细胞胚胎发生植株再生系统在林木转基因方面的应用技术相关研究。 相似文献
20.
The amount of total extractable phenols was determined for bark sections obtained from behind cankers naturally induced by Nectria coccinea var. faginata and from behind mechanically inflicted wounds on stems of American beech. Healthy bark from susceptible trees was found to contain a similar level of phenolics as bark from trees determined to be resistant to the beech bark disease. Six months after wounding, wound-altered bark from susceptible trees was found to be lower in phenols than woundaltered bark from resistant trees. Inoculation of wounds with N. coccinea var. faginata resulted in decreased phenolic levels in bark sections nearest the wound surface, and increased phenolic levels in sections nearest the vascular cambium, several mm distant. Phenolic levels in injured or infected bark appear to follow similar patterns as those resulting from injury or infection of xylem tissues. 相似文献