Diversity of naturally-regenerated native woody species in forest plantations in the Ethiopian highlands

Woody species diversity and ground layervegetation cover were studied in plantations ofPinus patula, Cupressus lusitanica,Grevillea robusta, and Juniperusprocera, and in surrounding natural forests inWondo Genet, Ethiopia. In the understory of theplantations, a total of 53 naturallyregenerated tree and shrub species belonging to31 families were recorded. Important indigenoustimber species were also represented. Treesaccounted for 72% of all naturally-regeneratedwoody plant species. On the average, 78% ofthe woody species found in plantations werealso found in the natural forest. There was nosignificant variation in understory woodyspecies richness among plantations. C.lusitanica plantations had a significantlyhigher abundance of woody species than those ofP. patula, but the difference wasnot significant in relation to J. procera,G. robusta and the adjacent natural forest.The herbaceous ground cover percentage in G. robusta and P. patula stands wasconsiderably higher than in C. lusitanicaand J. procera stands. Relative toplantations of other species, plantations ofthe native tree species J. procera hadhigher understory species richness, mediumwoody species abundance and low ground cover.Although there was a marked variation inoverstory plantation density, its effect onunderstory species richness and abundance wasnot significant. The density ofnaturally-regenerated woody species inplantations was over three times the usualplanting density in Ethiopia, indicating a highpotential of forest plantations for restoringthe natural forest ecosystems on degraded landsat a comparatively low cost.     

扦插时期和基质种类对榛子嫩枝扦插生根的影响

试验以5 a树龄杂交榛(85-134)和欧榛(巴塞罗纳)当年生嫩枝为试材。结果表明:(1)杂交榛(85-134)和欧榛(巴塞罗纳)嫩枝扦插均可生根,以欧榛生根效果略好;(2)杂交榛(85-134)和欧榛(巴塞罗纳)枝条长生长动态呈"慢-快-慢"的"S"型曲线,在供试的三个时期中以枝条长生长速生期结束即7月初扦插效果最佳,两品种的生根率最高,分别达到71.1%和81.1%;(3)以珍珠岩和蛭石(体积比为2∶1)为扦插基质,其气、液、固三相比最理想,最有利于插穗生根。     

Eucalyptus plantations in Israel: an assessment of economic and environmental viability

This paper discusses a plantation management approach involving a combination of “short” and “long” rotations designed to allow farmers to receive income from trees as soon as possible after establishment. We present results from two plots that represent extreme conditions: (a) a seasonally waterlogged, non-saline site (Nahalal), and (b) a saline site (Ginnegar) located in the Yizre’el Valley, Israel. Six improved seed sources, four of Eucalyptus camaldulensis and two of E. occidentalis, were examined. The local Israeli seed source of E. camaldulensis (HA) performed best at both sites. In Nahalal, the short rotation thinning of the slower growing (50%) plantation trees could provide economic returns approximately five years after establishment. The calculated mean annual increment (MAI) of these trees reached 12.2 t ha⁻¹ year⁻¹. The long rotation, or better performing half of the plantation trees, could be used as a source of sawn timber, providing higher-value products. By nine years after establishment, the average DBH of the various seed sources reached 25.8 ± 1.9 cm. The calculated MAI of the combined cutting rotations reached 48.3 t ha⁻¹ year⁻¹. Eucalyptus grown under the combined (short- and long-term) management approach at Nahalal was more profitable than many other non-irrigated local crops. Eucalyptus production in Ginnegar would be less profitable than in Nahalal. However, an additional ecological benefit was provided by the crop’s ability to lower the water table. When this contribution to regional drainage is taken into account, trees become economically competitive with other non-irrigated field crops under saline conditions. Jim Morris–Deceased.     

玫瑰新品种‘红灯’、‘串珠’嫩枝扦插繁殖技术研究

以玫瑰的嫩枝为试材,采用L9（34）正交试验设计,分析激素种类、基质种类、激素浓度和处理时间对玫瑰扦插生根的影响。结果表明：激素浓度对生根影响最大,其次是基质和激素种类,处理时间对生根的影响最小。最佳组合为：100mg/LIBA处理插穗5min,蛭石做基质。     

冀北地区华北落叶松人工林提前主伐利用的探讨

通过对冀北地区围场县落叶松人工林的调查,从落叶松的林龄结构、落叶松采伐的经济效益、落叶松适生的立地条件及提前主伐利用对非公有制林业的激励等方面,论述了冀北地区华北落叶松提前主伐利用在促进林业发展、发挥生态作用的可行性和重要意义。     

林隙微环境异质性及物种更新响应研究进展

林隙作为森林循环和演替的重要场所,其内小环境特征随着时间和空间而改变,林隙内资源及其空间分布的不均匀性,为物种的共存和更新提供了环境条件,而物种分布的复杂性又进一步促进了森林小环境的异质性分化。本文从小气候状况、土壤及微地形方面对林隙小环境异质性问题进行了论述,并就林隙内微生境因子的异质性分布格局与物种拓殖策略的关系以及边缘效应对物种多样性形成和维持机制的作用等方面进行了阐述。     

Seed rain and natural regeneration in <Emphasis Type="Italic">Lophostemon confertus</Emphasis> plantations in Hong Kong,China

Natural forests have been increasingly replaced by artificial plantations around the world. Some research results suggest that artificial plantations can promote natural regeneration. The efforts in establishing protective forests in Hong Kong over the last 50 years after the Second World War have resulted in many exotic tree plantations which are ideal sites for the study of natural regeneration. This study looked at the seed rain and understorey woody plant diversity in three Lophostemon confertus plantations (25–40 years old) in Hong Kong. All the plantations were > 1 km from the nearest seed sources. Two of the plantations had a seed rain comparable in density and diversity to unplanted grasslands, and the understorey plant diversity was also low and dominated by shrubs. The other site had a higher and more diverse seed rain, as well as higher understorey stem density, but both the seed rain and the understorey were dominated by the shrub Psychotria asiatica. The poor seed rain at two sites and the rarity of potential canopy tree species in both the seed rain and understory regeneration at all sites suggest that planting exotic monocultures does not promote succession. Enrichment planting will be needed to restore forest diversity.     

充分利用伐区剩余物进行木片生产是提高经济效益的有效途径

随着我国“天保”工程的实施,人造板需求量的大幅度增加,使生产人造板的原料木片市场显 得非常紧俏。本文从木片生产的内外部条件和木片生产效益的有效途径两方面阐述了如何开拓市场,开发原 材料,提高木片质量,建立木片生产基地等问题;并对有关部门提出了切实可行的管理扶持方面的建议。     

Distribution of carabid beetles among 40-year-old regenerating plantations and 100-year-old naturally regenerated forests in Southwestern China

Effects of reforestation by native tree species on species assemblages of carabid beetles were studied between 40-year-old regenerating plantations and 100-year naturally regenerated forests in Southwestern China. Two old naturally regenerated forest types (ca.100 years old) were chosen: hemlock-spruce forests (Tsuga chinensis and Picea brachytyla) and birch forests (Betula albo-sinensis). Three young regenerating forest types (ca. 40 years old), including spruce plantations (P. brachytyla), larch plantations (Larix kaempferi and Larix mastersian), and natural broad-leaved forests, were established after the logging of the old naturally regenerated forests. Using pitfall traps, we compared the distribution of carabid beetles in the five forest types. Three replicated plots for each forest type were chosen, and each plot was investigated with four trap sites twice each month during the growing season (May to October) in 2004. Our results showed that species richness and abundance were significantly higher in the young regenerating forests than in the old naturally regenerated forests. Analysis of complementarity in carabid species lists across the forest ages and types showed that the old naturally regenerated birch forests had the lowest similarity with the young regenerating larch plantations, and the highest similarity was shown between the two young regenerating plantations. Although PCoA ordination grouped the carabid assemblages according to forest type and forest age, the overall similarity among all forest types was high. Moreover, quantitative character species analysis did not detect significant species associated with forest types and ages. Based on the specificity and fidelity, most carabid species were abundant in all habitats, and only a few species were restricted in one or two forest types. Multiple linear regression between the species richness, abundance and Shannon diversity of carabids and of five environmental variables showed that the cover of canopy and herbaceous layer, and the depth of leaf litter had significant effects in determining richness, abundance and diversity of carabid beetles. Thus, the young regenerating forests at the mature stage could provide an appropriate habitat for most forest species of carabids survived in adjacent old naturally regenerated forests and might replace the role in part of the old-growth forests in sustaining the diversity of carabid assemblages. But some species are still restricted in old naturally regenerated forests, so in order to protect the diversity of carabid assemblages, it is necessary to sustain the intact old naturally regenerated forests when reforesting with some native tree species following natural succession.     

Effects of age and frequency of cutting on productivity of Mediterranean deciduous fodder tree and shrub plantations

Deciduous fodder trees and shrubs are important feed resources for the critical summer period in semi-arid and sub-humid Mediterranean environments. Eleven such species were established in central Macedonia, Greece as 1-year old seedlings in 1987 and studied through 1994. Height and biomass were statistically different among species and tended to increase with the age of plants. Common Robinia pseudoacacia was the tallest and the most productive species, reaching more than 3 m height and 4 kg DM/plant 8 years since planting; it was followed by Ostrya carpinifolia, the variety monophylla of Robinia, Colutea arborescens and Amorpha fruticosa. Grazeable proportion of total biomass was about 50% and decreased as the age of plants increased. Repeated annual cutting resulted in significant reduction of both height and total biomass by 51% and 88%, respectively as compared with uncut plants at the end of the eighth year while frequent cutting tended to increase the grazeable proportion of biomass after the fourth year. To attain an optimum combination of quantity and quality of biomass in deciduous fodder tree and shrub plantations cutting or grazing should not start earlier than the third year since establishment.     

伞伐更新法对赫卡尼亚(Hyrcanian)森林系统中森林再生和林分结构的影响

研究伞伐更新法对赫卡尼亚森林系统中森林再生和林分结构的影响。在伊朗北部优势种为山毛榉（Fagus orientalisLipsky）的硬木林,采取伞伐更新法和非伞伐更新法方法设计实验区。结果表明,在山毛榉（F orientalis Lipsky）林中采用伞伐更新法处理,明显影响林下草本植物种的频度和密度。伞伐更新法处理后,林堇菜（Viola silvestris Lam.）、车叶草（Asperula odorata L.）、苔草（Carex spp.）和悬钩子（Rubushyrcanus Juz）的种频度明显增加。在对照区,树种的胸高直径（57.50&#177;2.15cm）大于被处理区（50.67&#177;1.88cm）的树种的胸高直径（50.67&#177;1.88 cm）,但对照区和处理区的树种的高度值相似。在1995-2005年间,波斯铁木（Parrotia persica）苗木数量增加到13.2%,而山毛榉（F orientalis）和欧洲鹅耳枥（Carpinus betulus）的苗木数量却明显减少。总之,应该利用其它育林方法,如,带状择伐作业,而不是伞伐更新法培育赫卡尼亚森林中山毛榉林。     

The sustainability of selection cutting in a late successional broadleaved community forest in Bhutan

This study assessed the sustainability of selection cutting in a community forest (CF) in Bhutan. The harvesting approach differed from cable crane logging operations in an adjacent commercially managed forest by creating much smaller canopy openings. This had many implications for natural regeneration of preferred species. The study was conducted in a late successional broadleaved CF containing 32 genera of tree species dominated by Quercus and Castanopsis and managed for timber, firewood, non-wood forest products and forest grazing. The study was based on a comparison of two forest inventories to assess forest structure and regeneration, a study of stumps to quantify harvesting intensities, and a household survey to quantify livestock holdings and grazing patterns. The study examined different intensities of selection cutting in three blocks of the CF and found that higher intensities of selection cutting did not have a negative impact on: (a) natural regeneration of seedlings and saplings of preferred timber species; (b) the diameter distribution of all species and use categories except for Quercus; (c) the diversity of tree genera; and (d) the percentage of remaining trees with favorable bole shape and form. These results contrasted with findings in the adjacent commercially managed forest. Community management of broadleaved forests with selection cutting appeared to be sustainable and avoid some of the unresolved silvicultural problems associated with commercially managed forests in Bhutan. However more research is needed on the sustainable management of Quercus spp.     

林窗和林下环境对红栲种子出苗的影响研究

红栲种子具有休眠特性,林下环境中红栲种子比林窗环境中早出苗。林窗中红栲种子成苗率显著高于林下红栲种子成苗率,同样是无盖网埋藏深度2 cm的处理,林窗红栲种子成苗率为7.2%,林下为1.6%。在林下,无盖网埋藏深度0cm、2 cm5、cm 3种处理,红栲种子成苗率分别是4.0%、1.6%和0.8%,红栲种子的埋藏深度与成苗率之间呈负相关。     

吉林省农安县农田防护林更新采伐年龄的研究

通过对农田防护林分生长过程和林况变化过程的分析,得到了林分后期经济效益和防护效益的变化过程,然后根据农田防护林经营的目的,提出其合适的更新采伐时间,这种通过林况反映效益变化的方法在实践中具有一定的可行性。     

抚育间伐对长白落叶松人工林生长及效益的影响

对九台市上河湾林场1997年营造的长白落叶松人工林进行抚育间伐试验,结果表明:间伐3 a后,间伐和未间伐的林分密度分别为2 150株·hm-2和3 150株·hm-2,平均胸径分别为11.0 cm和9.3 cm,总蓄积分别为119.6 m3·hm-2和89.0 m3·hm-2。对长白落叶松人工林进行合理抚育间伐,可显著提高林分质量和生长量及经济效益。     

湿地松多效益经营模式林分采伐技术研究

文中在利用 Richards函数对湿地松生长进行拟合和利用动态规划方法在计算机上直接模拟抚育间伐的基础上 ,初步确定了江西省丘陵区湿地松多效益经营模式林分的采伐技术。研究结果表明 :湿地松多效益经营模式林分始伐年龄为 81 0年 ,主伐年龄为 2 5年 ,最优抚育间伐方案为间伐 3次 (含始伐 ) ,时间分别为第 8、1 2及 1 6年 ,间伐强度分别为 95 0、70 0、30 0株·hm2 ,最后保留株数为 5 5 0株·hm2 。     

抚顺地区落叶松人工林有害生物种类发生状态及防控技术

大面积发展的落叶松人工纯林已占抚顺市森林面积的29.4%,为落叶松有害生物提供了丰富的营养源。林内生物多样性单一,造成落叶松有害生物灾害频发,严重影响了落叶松的健康生长和森林环境的稳定。据调查,抚顺地区落叶松有害生物多达34种,其中虫害19种、病害10种、鼠害3种、鸟害2种。该文总结了抚顺地区落叶松有害生物的发生情况和危害特点,并提出了有效防控措施及今后治理方向。     

Estimation and economic evaluation of aboveground carbon storage of <Emphasis Type="Italic">Tectona grandis</Emphasis> plantations in Western Panama

Tropical tree plantations may play an important role in mitigating CO₂ emissions through their potential to capture and sequester carbon from the atmosphere. The Clean Development Mechanism (CDM) as well as voluntary initiatives provide economic incentives for afforestation and reforestation efforts through the generation and sale of carbon credits. The objectives of our study were to measure the carbon (C) storage potential of 1, 2 and 10-years old Tectona grandis plantations in the province of Chiriquí, Western Panama and to calculate the monetary value of aboveground C storage if sold as Certified Emission Reduction (CER) carbon credits. The average aboveground C storage ranged from 2.9 Mg C ha⁻¹ in the 1-year-old plantations to 40.7 Mg C ha⁻¹ in the 10-year-old plantations. Using regression analysis we estimated the potential aboveground C storage of the teak plantation over a 20 year rotation period. The CO₂-storage over this period amounted to 191.1 Mg CO₂ ha⁻¹. The discounted revenues that could be obtained by issuance of carbon credits during a 20 year rotation period were about US$460 for temporary CER and US$560 for long-term CER, and thus, contribute to a minor extent (1%) to overall revenues, only.     

不同类型沙松人工林产量及生长预测

文章对1963∽1964年在白石砬子自然保护区营造的沙松纯林、沙松-落叶松-阔叶混交林及沙松-阔叶混交林等不同林型人工林的固定标准地进行了产量观测，通过计算机拟合运算优化出指数函数Y=ae^bx，对各种类型沙松人工林进行了生长预测。结果表明，各类沙松人工林均有良好的发展前途，到55年生主伐时可获得可观的木材产量；除沙松-落叶松混交林外，其他几种混交林型材积生长量差异不显著；结合生态群落结构和生物多样性因素分析得出：在东部山区的适宜地区应大力推广培育沙松-落叶松-阔叶混交林等针阔混交林模式。     

A synthesis on the impact of non-native conifer plantations on ant and beetle diversity in north-western Patagonia

Softwood forestry with non-native tree species is increasing worldwide and especially in many developing countries of the Southern Hemisphere. Tree plantations are beneficial in environmental and socioeconomic aspects, but at the same time there are recognised costs associated with afforestation. Our aim was to revise the existing information on the impact of exotic conifer plantations in north-western Patagonia on insect biodiversity. A total of five studies were selected and, in these, not every insect group responded in a similar manner to the habitat replacement. There was a tendency towards a reduction in abundance and species richness of several insects inside pine plantations. This change in abundance and richness was especially evident for ant assemblages and when pine plantations were dense. Beetle assemblages, in turn, showed diverse responses to the replacement of native vegetation with forests depending on the native habitat matrix. Our findings confirm that practices that reduce tree density (via thinning or during plantation) should be recommended to minimise their impact on insect biodiversity in north-western Patagonia. The consistent behaviour of ant assemblages, coupled with their abundance, ease to sample and unambiguous taxonomy make them reliable candidates for long-term monitoring of the impact conifer forestation in north-western Patagonia, as well as probably in other regions of the world in which non-native pines replace natural environments.