The impact of carbon trade on the management of short-rotation forest plantations

We extended the Hartman model to examine the optimal rotation, taking into consideration the economic benefits of wood and the dynamics of three carbon pools (aboveground biomass, dead organic matter, and harvested forest products). Chinese fir (Cunninghamia lanceolata) stands in Southern China were taken for a numerical example to analyze the effects of carbon price on the optimal management of short-rotation plantations. The results show that, with the current price of carbon, introducing the effects of harvesting on different carbon pools into the decision model would increase the optimal rotation age on poor (SI = 10) and medium (SI = 17) sites by one year, while it does not have any impact on the optimal rotation for good sites (SI = 21). Irrespective of site condition, the optimal rotation age is not sensitive to carbon price and interest rate. An increase in interest rate by 1% would reduce the optimal rotation age by one year. In conclusion, forest carbon trade could effectively enhance land owners' income from short-rotation forest plantations. However, it does not lead to any significant increase in forest carbon sink.     

Bird community assembly in Bornean industrial tree plantations: Effects of forest age and structure

Plantations of exotic trees for industrial and agricultural purposes are burgeoning in the tropics, and some of them offer the opportunity to study community ecology of animals in a simplified forest setting. We examined bird community assembly in different aged groves of the industrial tree mangium (Acacia mangium) at two plantations in Malaysian Borneo: Sabah Softwoods near Tawau, Sabah, and the Planted Forest Project, near Bintulu, Sarawak. Bird communities were compared among three age-groups of mangium (2-, 5-, and 7-years old) and logged native forest. Mangium rapidly developed into a secondary forest consisting of a wide diversity of understory trees and shrubs. The bird community correspondingly increased in species richness and diversity, and we were able to relate these increases specifically to canopy height, secondary canopy development, and shrub cover. Species of common, small bodied frugivores, nectarivores, and insectivores were diverse in older plantation groves, as were common mid-sized insectivores. However, large, specialized, and normally uncommon taxa (e.g., galliforms, pigeons, hornbills, barbets, midsized woodpeckers, muscicapine flycatchers, and wren babblers) were rare or nonexistent in the plantations. Because we lacked species-specific data on foraging, nesting, and other behaviors of most groups of birds, it was difficult to explain the precise causes of seral diversification in any group except woodpeckers, which have been well studied in Southeast Asia. Thus, in future, particular emphasis needs to be placed on obtaining such data. Industrial plantations, by virtue of their simple structure, variably aged groves, and bird community richness, are good places to gather such data.     

Lichen diversity in temperate montane forests is influenced by forest structure more than climate

Although the effect of forest management on lichens in temperate forests has been widely examined, little is known about the influence of management-related factors on their biodiversity relative to factors that cannot be altered by management. Here we determined whether forest structure or climate determines lichen diversity in the Bavarian Forest National Park in southeastern Germany, taking spatial variables into account. We investigated 517 single tree stems along 4 transects in 113 pre-stratified plots (8 m in diameter) in this montane forest. We grouped environmental variables into three sets: climate (macroclimate, non-manageable), forest structure (manageable), and space. The explanatory powers of these sets of variables for lichen diversity were compared using variance partitioning for the lichen community, species density, and threatened species density. The relationships of single characteristics of forest structure with lichen species diversity were analyzed using generalized linear models (GLM). Lichen diversity was better explained by stand structures than by climate. Spatial effects influenced the number of species per plot. Among the structural features, the availability of dead wood and sycamore maple as well as forest continuity were most important for the enhancement of lichen diversity. Open canopy structures affected the total diversity positively. Although the availability of large trees was not an influential factor in the GLM at the plot level, high diversity levels were generally associated with large stem diameters at the level of single stems. We provide recommendations for sustainable forest-management practices that aim at specifically enhancing lichen diversity in temperate areas experiencing low levels of air pollution.     

Impact of seedling type on early growth of poplar plantations on forest and agricultural land

Today, most poplar plantations in the temperate region are established on abandoned marginal agricultural land, but there is great potential for planting poplars on forest land as the available area is large and does not compete with food production. The objective of this study was to examine how different planting types (un-rooted cuttings, bare-rooted and containerized plants) affect the establishment and early growth of poplar plants on forest and agricultural sites. Our results suggest that on the agricultural site, survival and growth during the first two years are not influenced by plant type. However, at the forest sites, survival of rooted plants was superior compared to un-rooted cuttings. The height and biomass (stem and root) increment of bare-rooted plants was low; greater height and biomass growth was found for containerized plants. Container sizes had no effect on height growth, but leaf and stem biomasses were higher if the largest containers were used. When using the largest containers, concentrations of macronutrients (N, P) were increased compared to bare-rooted plants. Thus, these results suggest that practices for establishing poplar plantations of agricultural land include planting of un-rooted cutting, but on forest land, a plant grown in a container of 470?ml should be used. Together, this can reduce the cost of establishment, increase the available area for poplar plantations and have an impact on poplar plantation economics in Sweden.     

短轮伐期菇木林营造技术研究

银荆、南酸枣、秃瓣杜英、马褂木等8个袋栽香菇试验表明，麻栎、南酸枣每千克干料产鲜香菇为944g和882g，比对照高45．23％和35．69％；桤木、秃辨杜英、银荆、锥栗、马褂木、枫香等产菇量比对照高7．18％～20．92％。造林试验表明，4a生的银荆树高8．93m，胸径8．20cm，生物产量高达189891kg／hm^2；5a生南酸枣、秃辨杜英、马褂木、枫香、锥栗、麻栎生物产量达83790～150228kg／hm^2。研究认为银荆、南酸枣、秃辨社英、马褂木等树种具有早期丰产的特性，采用密植造林4～5a可获得较高的生物产量与经济效益。     

An analysis of potential investment returns and their determinants of poplar plantations in state-owned forest enterprises of China

China’s state-owned forest enterprises have been important national timber production bases and their timber resources have been severely degraded during the past decades. About one-third of the state-owned forestland has been classified as commercial forestland, but no economic mechanisms have been laid out on governing timber plantations under market economy. This paper demonstrates the potential investment returns and analyzes factors that directly influence the returns of fast-growing poplar plantations in a state owned-forest enterprise, China Jilin Forest Industry Group (CJFIG), in northeastern China. We examined practically possible ranges of mean annual increment (MAI), general inflation rate, rate of forest fund, and interest rate in the study area. We then computed net present values (NPV), equivalent annual income (EAI) and internal rate of return (IRR) by using the minimum, medium, and maximum values of the each determinant above. Results showed NPV ranged from $1,024 to $6,925 ha^?1, EAI ranged from $120 to $623 ha^?1 year^?1, and IRR ranged from 13.2 to 29.3 %. We show that growing poplar plantations could be two times more profitable than managing the existing natural forests in CJFIG by referring to EAI values. Improving MAI is the most effective way to increase both NPV and IRR while changes in the one-time tax at timber harvesting or changes in inflation rate have the least effect on NPV and IRR among the determinants studied. Discount rate, which can be easily manipulated by obtaining subsidies and policy-based loans, also has substantial influence on NPV. The state owned forest enterprises in China have special advantages to obtain relatively high economic returns in developing fast-growing plantation forests under market economy.     

吉林省西部杨树人工林病虫害综合防治技术及效益分析

在吉林省西部，杨树人工林面积逐年扩大，森林病虫害的发生种类逐渐增多，威胁着造林成果的巩固。通过对杨树病虫害的科学测报、划分类型、推广森保科技成果等措施，进行综合防治，取得了较好的防治效果和效益。     

发展速生丰产林是贫水地区调整种植结构的重要途径

近年来,全球气候变暖,森林资源的减少,使我国北方地区降水量逐年减少,部分地区出现了严重缺水的现象.2000年春季,京津、河北等地连续发生了13次沙尘暴天气,引起了全国上下的普遍关注.党中央及时提出了加快调整种植结构,退耕还林的战略部署.在水源匮乏地区,大力发展速生丰产林,在提高经济效益的同时,发挥其改善生态环境的作用,意义重大.     

绥宁县用材林林龄结构优化研究

针对绥宁县用材林林龄结构现状,应用系统动力学原理对用材林林龄结构优化进行建模,通过计算预测在不同采伐模式下用材林蓄积保有量和出材量的变化,从而找出最优的采伐模式。结果表明:用材林最优采伐模式即轮伐期为40年,择伐周期为15年,择伐强度为30%,抚育间伐周期为15年,抚育强度为15%。在这种优化模式下,到2025年绥宁县用材林蓄积保有量将达到10 186 848 m3,出材量将达到249 006 m3,使用材林发展达到生态效益和经济效益兼顾的最优状态。     

新沂市农田林网杨树生物量的空间结构

本文采用分层切割法和壕沟全挖法对江苏省新沂市农田林网中，４年生主要的杨树无性系（Ｗ－４６杨，Ｉ－６９杨，ＮＬ－８０１０５杨和ＮＬ－８０２０５杨）的地上部分生物量以及根系生物量进行了测定和分析。结果表明，ＮＬ－８０２０５杨不仅平均单株的生物量最大，而且树干的形质优良。因此，在平原农田林网的经营中，选择ＮＬ－８０２０５杨，既可以提高营林的收益，又能够增强林网的防护效果。     

DRIS-based fertilization efficiency of young hybrid poplar plantations in the boreal region of Canada

In order to maximize early growth and establishment of planted hybrid poplars in the boreal region of Eastern Canada, growth response of four clones to fertilization was tested in two plantations. The first two fertilization treatments were based on Diagnosis and Recommendation Integrated System (DRIS), a method based on nutrient ratios: DRIS I was based on previously established norms from a study that had been conducted in the same area, and DRIS II was based on DRIS norms developed from hybrid poplars in northern Ontario, Canada. Nutrient status and growth of trees under these 2 treatments were compared to unfertilized trees and to trees under standard (STD) fertilization treatment (40 N–20P–20 K). Leaf nutrient concentrations and DRIS indices showed that fertilization treatments, and especially DRIS I corrected N deficiencies but failed to correct P deficiencies. Fertilization increased volume relative growth rate by 7.51, 4.76 and 13.25 % on average at the agricultural site for DRIS I, DRIS II and STD treatments respectively, compared to no fertilizer application. At the forest site, fertilization treatments based on DRIS indices (DRIS I and DRIS II) increased growth rates (6.67 %) slightly more than the standard treatment (5.80 %). Overall, although DRIS-based fertilization treatments generally increased growth rates, they were often equal to or less efficient than the STD treatment, and may not be as practical as using a standard fertilization recipe.     

模拟氮沉降对杨树人工林土壤动物类群结构的影响

氮沉降过量会导致一系列严重的全球性生态问题,研究氮沉降对土壤动物群落结构的影响,对于明晰土壤动物群落受大气氮沉降加剧产生的响应机理有重要意义.通过模拟氮沉降试验,研究了不同氮沉降浓度下土壤动物群落特征的变化规律.试验结果表明：甲螨亚目（Oribatida）,前气门亚目（Prostigmata）,弹尾纲（Collembola）,寡毛纲（Oligocllaeta）,膜翅目（Hymenoptera）及盲蜘目（Opiliones）6个类群在不同龄级,不同氮沉降梯度下所占比例较高,为典型的优势类群;土壤动物类群丰富度及数量在不同氮沉降梯度下呈现先升后降的趋势;幼龄林土壤动物多样性指数普遍较高,且随氮沉降浓度的增加波动明显,老龄林与之相反;土壤甲螨随着氮沉降增加呈现先增后减的趋势,具有环境指示作用.     

杨树林地郁闭前林农间作研究

以郁闭前的杨树人工速生林为研究对象,通过林农间作研究,结果表明：林农间作不仅能获得短期经济效益,对林木生长也有明显的促进作用。     

滩地钉螺种群消长与杨树人工林关系的研究

在南洞庭湖和西洞庭湖的滩地杨树人工林内采取定位观测为主的研究方法，对滩地的地下水位、土壤含水率、螺情的变化规律及其与滩地杨树人工林的相关关系进行了定量研究，揭示了杨树人工林内钉螺种群消长的内在规律和环境因子的偶发效应，显示出滩地杨树人工林生态系统抑螺机制的有效性和持续性，体现了滩地杨树抑螺林的血防安全意义。     

匈牙利丹努波（Danube）河和梯沙（Tisza）河间沙丘洋槐——银白杨混交林林分结构和产量研究

作者采用新的研究方法,研究了不同配比的洋槐(Robinia pseudoacacia L.)/银白杨(Populus alba L)混交林林分结构和产量。通过逐株测量并采用材积表确定了各树种的主林分结构和产量因子。测定了混交林树种以及纯林不同树种的蓄积量。发现林分总蓄积量和和树种混交比例密切相关。与纯林对照组相比,混交林蓄积在16年龄时的相对剩余为1.24-1.55。研究证明,如果2树种都具有初期快速生长率的特点和相同的轮伐年龄,可以进行混交造林,并相互有利。图4表2参15。     

豫东平原杨农间作不同杨树品种生长性状对比研究

杨树是平原地区栽培面积最大、木材产量最高的速生用材树种之一,具有生长快、成材早、产量高的特点,是非常优良的工业用材经营树种。本文通过对民权林场四种速生杨优良性状的对比试验进行比较,得出欧美108杨的优良性状最好,为进一步提高林业经济效益和环境效益提供支持。     

欧美杨细菌性溃疡病发生与危害林间观察

由Lonsdalea quercina subsp.populi引起的欧美杨细菌性溃疡病是2006年菏泽市新发现的一种危害杨树枝干部的毁灭性病害。林间调查发现,该病害在菏泽地区分布广泛,危害严重,病害症状表现溃疡腐烂和肿胀溃疡两种类型,每年4—10月发生,7—8月高温高湿季节是发病盛期。病害发生与林间的生态环境,传媒昆虫的种类、数量,杨树品种等因素关系密切。建议在发病初期采取刮皮涂抹多抗霉素、农用链霉素及杀虫剂,加强抚育管理等综合防控措施。     

浅谈湖区杨树速生丰产林的培育与管理

从2000年3月开始，以培育意杨速生丰产林为目标，并开展科技示范。经对速生丰产林基地示范中心的6．67hm^2林木进行测算，4年生的意杨每667m^2已达到了9．04m^3的蓄积量，年均蓄积增长2、26m^3，667m^2．年均每667m^2林木年收入已达到800元以上。实行林菜间种，菜每667m^2年收入在1000元以上。     

Carbon accumulation in aboveground and belowground biomass and soil of different age native forest plantations in the humid tropical lowlands of Costa Rica

Generic or default values to account for biomass and carbon accumulation in tropical forest ecosystems are generally recognized as a major source of errors, making site and species specific data the best way to achieve precise and reliable estimates. The objective of our study was to determine carbon in various components (leaves, branches, stems, structural roots and soil) of single-species plantations of Vochysia guatemalensis and Hieronyma alchorneoides from 0 to 16 years of age. Carbon fraction in the biomass, mean (±standard deviation), for the different pools varied between 38.5 and 49.7% (±3 and 3.8). Accumulated carbon in the biomass increased with the plantation age, with mean annual increments of 7.1 and 5.3 Mg ha⁻¹ year⁻¹ for forest plantations of V. guatemalensis and H. alchorneoides, respectively. At all ages, 66.3% (±10.6) of total biomass was found within the aboveground tree components, while 18.6% (±20.9) was found in structural roots. The soil (0–30 cm) contained 62.2 (±13) and 71.5% (±17.1) of the total carbon (biomass plus soil) under V. guatemalensis and H. alchorneoides, respectively. Mean annual increment for carbon in the soil was 1.7 and 1.3 Mg ha⁻¹ year⁻¹ in V. guatemalensis and H. alchorneoides. Allometric equations were constructed to estimate total biomass and carbon in the biomass which had an R ²aj (adjusted R square) greater than 94.5%. Finally, we compare our results to those that could have resulted from the use of default values, showing how site and species specific data contribute to the overall goal of improving carbon estimates and providing a more reliable account of the mitigation potential of forestry activities on climate change.