Effect of selective cutting type on the chainsaw productivity in Caspian Forests

Time and motion studies were conducted to evaluate the impact of selective cutting type on Chainsaw productivity in Caspian forests,the selective cutting performed as single and group selection cutting in the region.The selective cutting was performed on a 42-ha tract with an average slope of 30%.The results indicate that felling time for per tree is most affected by diameter at breast height,the distance among harvested trees in single-tree selection method and diameter at breast height in group selection method.The production rate in single and group selection cutting were 21.2 m 3 h-1 and 28.4 m 3 h-1 for one person,respectively.Considering the gross and net production rate in single and group selection cutting,the unit cost was 1.11 USD m-3 and 0.88 USD m-3,respectively.The results indicate that group selection cutting can be more profitable than single-tree selection method.     

Prospect of Evaluation Study on Vegetation Degradation

Vegetation degradation is related to the stability and succession process of ecological systems.This paper combed and screened the recent national and international research on vegetation degradation,and discussed vegetation degradation research in terms of selection of reference ecosystem for evaluation,selection of evaluation index system and the selection of evaluation methods.At last,the direction of vegetation degradation research was predicted and prospected.     

Application of Molecular Marking Technologies in Heredity Breeding of Eucalyptus

Two clonal trial stands of Chinese Fir （Cunninghamia lanceolata） were used in this study, one was 19-year-old stand which included 38 clones, and the other was 17-year-old stand including 102 clones.The statistical analyses showed that there were very significant genetic variations in height, DBH,volume and ratio of heartwood(R_hw),wood basic density（ρ_b ） of the clones in the two stands. The repeatability of clones was in median to high level,and the genetic CV was different over the all five traits.There were very significant phenotypic and genetic correlations among height,DBH and volume,and negative correlations among growth, R_hw andρ_b.The selection method experiment indicated that index selection could improve volume, R_hw andρ_b,showing synthetically superior selection effects compared to any individual trait selection methods.     

Establishment of Efficient Regeneration System of Populus×euramericana cl.‘Bofeng’

Compared with the species of Leuce section,the difficulty in plant regeneration during tissue culture for the species of Aigeiros section is a key limiting factor for their application in genetic engineering of forest trees.In this study,the plant growth regulators combination,copper concentration,light intensity,and the selection pressures of kanamycin were investigated using leaves of Populus×euramericana cl.’Bofeng’ as explants,and a stable and high efficient regeneration system was established.Using this system,both the shoot regeneration rate and rooting rate were up to 100%,and the average number of differentiated shoots in each leaf explant was up to 20,and the survival rate of seedlings reached 98%.The optimal selection pressure of kanamycin in shoot inducement for leaf-explant was 40 mg·L^-1,and the optimal selection pressure of kanamycin in root inducement of adventitious bud was 20 mg·L^-1.The authors also found that differentiation rate of adventitious buds of P.×euramericana cl.’Bofeng’ could be significantly promoted by increased copper concentration,and this is the first report about the key role of copper（Cu） in explant regeneration of Poplars.This regeneration system with high frequency which was established by the authors was as good as that of species of Leuce section,and it provides a good technological platform for genetic engineering of forest tree which uses the species of Aigeiros section as model materials.     

Dependences of longleaf pine （Pinus palustris） natural reproduction on environments above ground

We studied relations between natural seedling reproduction and above ground environment in a longleaf pine ecosystem. Forty-eight 0.05 ha circular plots were sampled under single-tree selection, group-tree selection and control stands in three main longleaf pine areas in south Alabama, USA. We measured six above-ground environment factors, viz. canopy closure, stand density, basal area, average tree height, understory cover and PAR under canopy. We employed forward, back-ward and stepwise selection regression to produce one model. Three main variables：canopy closure, stand density and basal area, were left in the model; light, PAR and understory cover were not incorporated into the model at the 0.10 significance level. Basal area was a positive pa-rameter, while canopy closure and stand density were negative parame-ters. Canopy closure was the main parameter in the model. The model proved to be meaningful, and has potential to provide useful guidance for future work.     

杨树长期育种中遗传测定效率理论分析

The major goal for long-term poplar breeding can be formulated as maximizing annual progress in Group Merit Gain at a given annual budget （GMG/Y＊）. To evaluate different breeding scenarios, a deterministic simulator BREEDING CYCLE ANALYZER covering the most important aspects （gain, cost, time, technique, and gene diversity） of a full breeding cycle was used. The breeding strategies considered was based on pairwise crossing of the selected breeding population and balanced within family selection for the next breeding population. A main scenario and a number of alternative scenarios within these constraints were evaluated using estimates of the best available inputs for poplars. In focus was a comparison between three different testing scenarios for selecting the parents mated to create future breeding generations, thus selecting based on phenotype, clone test or progeny test. For the main scenario, the highest GMG/Y, and the optimal selection age for clone, phenotype and progeny strategies were 0.7480 %, 0.6989% and 0.4675%; 7, 6, and 11 years respectively. Clone test was best except when heritability was high, plant price was high or total budget was low; phenotype strategy was the second except for the case of extremely low narrow-sense heritability, for which the progeny strategy was a little more efficient than phenotype strategy. GMG/Y was markedly affected by narrow-sense heritability, additive variance at mature age, rotation age, plant-dependent cost, total budget and the time needed to produce the test plants, while diversity loss and recombination cost had rather weak effect on GMG/Y. Short rotation age and cheap testing cost favoured all three testing strategies. Comparably short rotation age, low plant-dependent cost and high total budget seem to promote early selection for progeny strategy.     

Options for converting a clone trial of Eucalyptus camaldulensis into a clonal seed orchard considering gain,fertility and effective clone number

We evaluated a clone trial comprised of 20 ramets each of 40 Eucalyptus camaldulensis clones for growth and fertility at 4 years of age. The clones differed significantly in growth with 65–100 % survival in 38 clones while two clones had low survival(40 and 10 %).Fecundity was high and fertility variation low, as indicated by the sibling coefficient value(W = 1.4) with 55 % of clones contributing 80 % of the fruits. Thinning strategies were considered to convert the clone trial to a clonal seed orchard and enhance both gain and diversity in seed crop.When clones were selected based on growth without considering fertility, truncation selection(to retain clones with higher DBH than the trial mean value) would give 8 %gain, but 59 % reduction in effective population size(Ne).Gain and predicted diversity(Ne) was highest when ramets were selected in linear proportion to the breeding value of each clone. Mass selection with the same intercept(for DBH) as truncation selection would give a moderate 3 %gain, but over two times higher predicted Nethan truncation selection. When fertility of retained trees was considered after thinning, mass selection would yield 52 %effective contribution from the orchard trees compared to only 30 % contribution from truncation selection and linear thinning. Higher representation of superior clones in linear thinning and mass selection would lead to greater fertilityvariation and over 30 % reduction in effective clone number(Nc) from that predicted(Ne, assuming equal fertility among ramets) before thinning.     

Black locust (Robinia pseudoacada L.) clonal seed orchards in Hungary

Black locust (Robinia pseudoacacia L.) is one of the most important stand-forming tree species in Hungary and its importance is increasing in many countries. The main aim of the discussed new selection programme is to identify black locust clones with good performance and good form for setting up clonal seed orchards. As a result of selection programme 16 new black locust clones have been improved. In spring 2002 a black locust seed orchard was established with the newly selected clones. About 40% of the plants can be considered to belong to the height growth rate class 1 and 2. Hungary was the first country where micropropagated black locust planting material was used for seed orchard establishment.     

Effects of selection cutting on the forest structure and species diversity of evergreen broa-leaved forest in northern Fujian, southern China

The short-term effects of selection cutting of different intensities on the forest structure and species diversity of evergreen broad-leaved forest in northern Fujian Province were investigated and analyzed. The results showed that selection cutting of low and medium intensities caused little variation in the forest structure. After cutting, the dominant species retained their leading status in the community. However, the community structure changed significantly following selection cutting of high and extra-high intensities; the status of the dominant species of the community declined dramatically. Some tree species began to disappear from the sampling plots. Except for extra-high intensity cutting, the diversity of tree species did not change significantly for the other three cutting intensities. However, the evenness of the stands was very different among the four kinds of cutting plots. For low and medium intensity selection cutting, the evenness declined slightly. For extra-high intensity selection cutting, the evenness increased to some extent, which might be due to a more even distribution of tree species after cutting. Cutting operations resulted in some adverse reactions to development of arborous species diversity of evergreen broad-leaved forest, particularly serious damage to the forest canopy. But the rational selection cuttings, which may benefit the restoration and maintenance of species diversity over a long period and may come about from the variations in environmental factors such as sunlight, temperature and humidity.     

Nest-site selection pattern of Grus japonensis in Zhalong Nature Reserve of northeast China

Nest-site selection patterns of Red-crowned cranes(Grus japonensis) and the effects of environmental variables were studied during the years of 2002-2008 in Zhalong Nature Reserve,Qiqihar city,northeast China.The nest-site selection pattern of Red-crowned cranes included two orders and three choices:the choice of nest-site habitat type within the macro-habitat order,nest zone selection and nest-site micro-habitat selection within the micro-habitat order.Various habitats(such as Carex swamps and reed fire districts) can be selected as the nest sites for Red-crowned cranes,of which reed swamps(93.15%) are given a preference.Factor Analysis reveals that the micro-habitat selection are affected by four main factors:fire,security(concealment /disturbance),incubation(conditions,nest-material),and food.Further analysis reveals that Red-crowned cranes have certain adaptability to the changes of nesting habitat quality in the Zhalong wetlands.In conclusion,fire,reeds,and water were the most important variables for nest-site habitat selection of Red-crowned Cranes in Zhalong Nature Reserve.     

Trend of within-plot selection practiced in two seedling seed orchards ofAcacia mangium in Indonesia

A trend of within-plot selection was examined by applying a retrospective selection index to the results of the selection in two seedling seed orchards ofA. mangium at South Kalimantan in Indonesia. The orchards were established in randomized complete block design with ten replications of four tree row plots. Within-plot selections were conducted twice with around 50% of selection intensity in those orchards: at 22 months and at 51 months after planting, then the results were analyzed with the data on volume, stem form and bole length measured before each selection. Bole length was found to be the highest priority trait throughout the two stages of selection in both orchards. Growth expressed by volume was also an important criterion at the first within-plot selection, while the priority was not obvious at the second selection. Expected gains by within-plot selection were generally small, although predicted gains were positive on all of the three traits at each stage of selection. The seedling seed orchards analyzed in this study were established under a technical cooperation project between JICA (Japan International Cooperation Agency) and Ministry of Forestry in Indonesia in collaboration with Inhutani 3.     

Single-tree and Group Selection in Montane Norway Spruce Stands: Factors Influencing Operational Efficiency

The operational efficiency of single-tree and group selection with a single-grip harvester was studied in uneven-aged spruce forests at high altitudes in southern Norway. Three harvest intensities of single-tree selection and two group sizes were examined in group selection. Single-tree selection included harvest intensities of 25, 45 and 65% of basal area. Group sizes for group selection were 0.063 and 0.250 ha. Normally, single-tree selection is considered less efficient than group selection or clear-cutting. In this study, because time consumption per cubic metre was primarily dependent upon average harvested tree volume, the large harvested tree size for single-tree selection allowed this treatment to be more efficient than group selection. The two blocks in this study were part of a larger design of five blocks with identical treatments under varying stand conditions. The relative operational efficiency of single-tree selection compared with group selection was greatest in stands of low stocking. Other studies have also shown that mechanical damage to the residual stand is lowest under these conditions.     

国内主要针叶树种优树选择技术研究进展

总结了近10 a来国内主要针叶树种优树选择技术研究现状,当前国内优树选择主要应用了优势木对比法、生长量绝对值法和小样地法,对数量指标主要选择的是与材积量相关的因子,如树高年增长量和胸径年增长量。在此基础上对优树选择技术的发展进行了探讨并提出新的观点:①系统调查地理变异,兼顾遗传因素和环境因素,使选择指标定量化,用数理统计的方法进行选择;②对多用途树种应根据不同的育种目标分指标评价和选择,必要时也可再进行综合性选择多用途目标的优树。     

动态数据驱动的林火蔓延模型适宜性选择

基于BP人工神经网络方法设计林火模型适宜性选择技术框架结构,通过神经网络形成林火模型选择知识,实现林火模型的自动化和智能化选择;以火场环境因子为输入变量,以适宜火场环境模拟的林火蔓延模型作为输出变量,构建林火模型选择神经网络模型;研究输入、输出因子数据的获取与计算方式,实现动态数据驱动的林火模型自动选择机制.以北京市为例,选择有详细火场情况记录的72场林火作为试验样本,其中60条记录作为学习样本集,12条记录作为验证样本,对神经网络进行学习和验证,结果表明:模型选择精度可达到80%以上.     

Early selection in eucalypt breeding in Australia – optimum selection age to minimise the total cost of kraft pulp production

Optimum ages for early combined-trait selection were derived for a breeding objective of reducing the total cost of unbleached eucalypt kraft pulp, assuming typical heritabilities and age-age genetic correlations for basic density and growth. The optimum biological selection age, the selection age where average annual gain is maximised, was four years for an assumed rotation age of 15 years. The optimum economic selection age, the selection age where the present value of all future gains is maximised, was three years. These conclusions were relatively robust to changes in assumptions used in analysis.     

基于早期产量的马尾松第1代种子园高产无性系选择

通过对福建省尤溪国有林场马尾松第1代种子园早期产量的研究,进行高产无性系选择。结果表明:即使在种子园初产期,大小年现象明显。以各年度无性系种子均重、出籽率大于建园无性系平均值为标准选择各年度高产无性系,无性系种子均重平均可提高59.94%,出籽率平均可提高41.53%,增产效果选择明显;但各年度入选无性系差别较大,存在产量不稳定型无性系。选择3 a均入选的9个无性系为高产稳产建园无性系,入选率为18.00%,其无性系种子均重可提高75.92%,出籽率可提高54.39%。     

钳嘴鹳迁徙途经西双版纳期间觅食生境选择初探

钳嘴鹤迁徙期觅食生境选择研究在国内还未见报道，2012年5月31日至9月13日多次对迁徙途径西双版纳的钳嘴鹳觅食生境选择情况进行调查。结果发现，钳嘴鹳觅食生境选择的主因子是人为干扰、水、食物、隐蔽物，最适觅食生境是无人类干扰的、植被覆盖率较低的、有相对稳定食物的浅水湿地。     

山地色木槭大苗培育技术

本文介绍了色木槭生物学特征、山地育苗地选择以及栽培技术中苗木选择、起苗、苗木处理、栽植、修剪方法、病虫害防治技术。     

林木育种中的早期选择*

通过对近期国内外所开展的林木早期选择进行综合分析 ,总结了早期选择的主要途径及所取得的主要成果 ,认为对林木进行早晚期相关选择是卓有成效的 ;未来早期选择的发展方向将是常规选择与标记辅助选择相结合。同时对早期选择的开展提出了建议。