Repellent and stocking guards reduce mammal browsing in eucalypt plantations

Mammalian herbivores regularly browse plantation seedlings. In many areas, seedlings require some form of protection if they are to survive and grow into a productive plantation. Two general approaches for reducing browsing damage to seedlings are to apply chemical repellents and tree guards. Both methods have existed for a long time, and new variations are constantly being developed. Seedling stocking guards, a type of tree guard, are being used operationally in Tasmania, Australia, but there is limited data quantifying their effectiveness and concerns with negative effects on tree performance. Conversely, although proven effective, repellents are not being used, but are potentially cheaper and less problematic. We therefore aimed to determine which is more effective under operational conditions, whether this effectiveness can be improved or extended, and if either treatment has any effects on seedling form or survival. We planted Eucalyptus nitens seedlings with combinations of repellent and stocking guards in six operational plantations to examine and compare their effectiveness. Seedlings were monitored for 12 months to examine treatment longevity. We found that both stocking guards and repellent significantly reduced and delayed browsing severity, with their effects being additive. No negative effects on growth were evident after 12 months, but adverse effects on seedling form warrant further investigation. Both of these methods can be easily and relatively cheaply applied in the nursery before planting, making them appealing options to reduce browsing. However, the ideal method for a given site will depend upon local browsing intensity.     

Seed mass effects on performance of Pinus halepensis Mill. seedlings sown after fire

Pinus halepensis is a widely distributed species in the Mediterranean basin. It is generally well adapted to regenerate after wildfire, except when fire intervals are too short (≤15 years). In these latter situations, direct seeding could be a good alternative for restoring pine woodland after fire. Under dry climate, low seedling growth and survival can greatly limit the use of seeding. Early studies have shown that seedlings grown from large seeds have higher seedling establishment, growth and survival. Seed size grading may however reduce the genetic diversity of a seed lot by eliminating part or all of the families with relatively small seeds. An alternative to improve seed lot quality without losing genetic variability could be collecting and sieving seeds from each family separately. In order to explore the influence of seed mass on P. halepensis seedling performance, seeds from five half-sib families differing in mean seed mass were sown under greenhouse and field conditions. Final seedling emergence was unrelated to seed mass and half-sib family. The time of emergence was also unrelated to seed mass but it varied among families. Seed mass showed a positive effect on seedling height and diameter, both at population level and within family throughout the study period (9 months under greenhouse conditions and 20 months under field conditions). We also observed a negative relationship between seed mass and relative growth rate for seedling diameter, but it was not high enough to fully compensate the initial differences due to seed mass at the end of the 20-month study period. Seedling predation had a considerable impact on seedling survival, and it was not related to seed mass. When seedlings killed by predation were excluded from the survival analysis, larger seedlings, coming from larger seeds, showed slightly better survival, but only during the first growing period. The small advantages obtained from large seed mass in seedling development do not seem to justify the increased operational costs derived from seed mass selection for each family.     

Plant quality assessment: an industrial perspective

The regions of the world using operational seedling testing to any significant extent are Canada, Britain, Sweden, and the Pacific Northwest region of the United States. Testing has been used operationally for batch culling (to ensure quality), as well as for research into improved nursery cultural practices. Savings from testing for seedling survival are substantial. However, growth gains from operational testing are more tenuous. Reduced rotation lengths and lower weeding costs are more likely to be associated with planting larger stock, rather than planting stock with higher physiological quality.Large opportunities for savings exist for regions and organizations that produce poor quality stock, have high planting costs, or both. New tests have been developed and some are becoming operational. New tests might be more effective than existing tests. However, in the regions most involved in seedling testing, plantation survival has increased over the last ten years. Subsequently, additional investments in operational testing will likely achieve diminishing returns.     

Field screening for genetic-based susceptibility to mammalian browsing

Browsing by mammalian herbivores is a major problem in plantation forestry. Seedlings are most vulnerable to browsing during establishment, making protection crucial during this period. Aside from reducing herbivore numbers, browsing can be controlled through the application of tree guards or chemical repellents. These methods are generally short-term options. A promising, potentially longer-term method of reducing browsing damage on plantations is to plant individuals with enhanced natural browse resistance. This requires the development of a rapid, cost-effective means of identifying germplasm with enhanced resistance. Here we present such a screening methodology.We planted Eucalyptus globulus seedlings from 22 different seedlots in randomised blocks along edge rows of six operational plantations. Seedlings were monitored for mammal browsing damage and growth for 2 years. Natural variation between E. globulus seedlots resulted in significant variation in the extent to which they were browsed. Differential browsing was evident just 10 weeks after planting, and caused a significant effect on tree growth after 2 years. Differential browsing was thought to be due to variation in levels of plant secondary metabolites (PSMs). The identification and selective planting of high PSM seedlots in high risk areas could be an effective management tool to reduce browsing in plantation forestry.     

Does forest certification enhance livelihood conditions? Empirical evidence from forest management in Kilwa District,Tanzania

The Forest Stewardship Council (FSC) forest management certification standards have been promoted to contribute to community livelihood conditions. However, little has been done to evaluate it quantitatively. Employing theory of change, this study assesses and compares empirical evidence of the influence of the FSC forest management certification approach to enhance livelihood conditions in Kilwa, Tanzania, by using economic valuation methods and governance indicators. This is achieved through a comparative study of villages with certified community forests (FSC) under community based forest management and those without (non-FSC). Results show that annual average household forest income from FSC-certified forests is significantly higher than that of households in non-FSC-certified forests. With reference to rule compliance as an indicator of good governance, implementation of forest bylaws in villages managing FSC-certified forests is significantly more effective than villages in non-FSC-certified forests. These findings provide an insight into the influence of forest certification in enhancing livelihood conditions and that the incorporation of FSC standards into forest policies may lead to more enhancement of livelihood conditions. These findings serve as a baseline for further research on the effects of forest certification at both spatial and temporal scales.     

Risk rating for mountain pine beetle infestation of lodgepole pine forests over large areas with ordinal regression modelling

The mountain pine beetle Dendroctonus ponderosae Hopkins is endemic to lodgepole pine, Pinus contorta var. latifolia Engelmann, forests in western Canada. However, the current beetle epidemic in this area highlights the challenges faced by forest managers tasked with prioritizing stands for mitigation activities such as salvage harvesting and direct control methods. In western Canada, the operational risk rating system for mountain pine beetle is based on biological knowledge gained from a rich legacy of stand-scale field studies. Due to the large spatial (millions of hectares affected) and temporal (over 10 years) extents of the current epidemic, new research into large-area mountain pine beetle processes has revealed further insights into the landscape-scale characteristics of beetle infested forests. In this paper, we evaluated the potential for this new knowledge to augment an established system for rating the short-term risk of tree mortality in a stand due to mountain pine beetle. New variables explored for utility in risk rating include direct shortwave radiation, site index, diameter at breast height, the temporal trends in local beetle populations, Biogeoclimatic Ecosystem Classification and beetle–host interaction variables. Proportional odds ordinal regression was used to develop a model for the Vanderhoof Forest District in west-central British Columbia. Prediction on independent data was assessed with the area under the receiver operator curve (AUC), indicating good discriminatory power (AUC = 0.84) for predicting levels of mountain pine beetle-caused pine mortality.     

Effect of Garcinia mangostana on inflammation caused by Propionibacterium acnes

The present study was aimed to investigate the activity of Thai medicinal plants on inflammation caused by Propionibacterium acnes in terms of free radical scavenging and cytokine reducing properties. P. acnes have been recognized as pus-forming bacteria triggering an inflammation in acne. Antioxidant activity was determined by DPPH scavenging and NBT reduction assay. The result showed that Garcinia mangostana possessed the most significant antioxidant activity and reduced reactive oxygen species production. Houttuynia cordata, Eupatorium odoratum, and Senna alata had a moderate antioxidant effect. In addition, Garcinia mangostana extracts could reduce the TNF-alpha production as determined by ELISA. Garcinia mangostana was highly effective in scavenging free radicals and was able to suppress the production of pro-inflammatory cytokines. This study has identified the promising source of anti-inflammatory agent which could be useful in treatment of acne vulgaris.     

Effect of an ultrasonic device on the behaviour and the stress hormone corticosterone in feral pigeons

The worldwide presence of feral pigeons Columba livia domestica in urban habitats presents potential public health hazards from pathogens and parasites, and droppings can lead to damage to buildings. A variety of lethal and non-lethal chemical repellents, visual, sonic or mechanic measures are available to deter pigeons, but they are not always applicable or effective. Ultrasonic devices are one of the available possibilities with the advantage of being inaudible to humans and more or less harmless to animals. However, their utility is questionable, because the upper limit of frequencies heard by pigeons reported is well below that of ultrasound. We tested whether a commercially used ultrasound deterrent system has an effect on the behaviour of free-living, as well as caged feral pigeons and assessed whether ultrasound has a physiological effect, i.e. whether it can activate the hypothalamo-pituitary-adrenal-axis (HPA-axis) known to trigger flight behaviour. Our experimental tests did neither show any effect on the behaviour and the HPA-axis of the caged pigeons nor any deterring effect on the free-living pigeons. A habituation effect could not be detected. We therefore, conclude that ultrasound does not deter feral pigeons.     

富氧条件下汽车尾气中NOx净化的研究进展

汽车尾气催化净化技术被证明是最有效的控制汽车排放污染的方法之一。针对在稀薄条件下NOx的催化净化，着重评述各种降解NOx方法的优缺点及国内外相关领域的科研开发与进展，提出开发富氧条件下汽车尾气净化催化剂尚需解决的问题和今后的研究方向。     

Estimation of preservative toxic threshold retention from laboratory decay tests: a new method

Summary This research illustrates a new procedure of analyzing data from soil- or agar-block decay tests using non-linear regression techniques to estimate a toxic threshold retention point for wood preservative chemicals. The model can be used to provide an objective estimate of the level of retention that is fully adequate, and can be applied satisfactorily to decay data from laboratory decay tests. This so-called broken line model procedure analyzes the decay data simultaneously by separating it into two different parts according to the threshold retention point. Such a procedure is preferable to previous methods which suffer from the need of transforming decay data. Our analysis can be performed in any statistical analysis package that includes a non-linear regression procedure, regardless of having a small or large data set, under the assumption that residuals are normally distributed with a homogenous variance. The method of estimating weight loss due to decay and the one due to operational procedure are also described. Received 26 August 1997     

竹材的特性与防腐技术

本文扼要介绍了竹材防腐的研究现状，包括竹材解剖性质与可处理性，竹材防腐处理方法和所使用药剂的研究。展望其发展趋势，为选择高效、低毒、环保的竹材防腐剂以及适当的防腐技术提供可靠的依据。     

世界林业推广发展趋势

本文总结了世界林业推广的发展趋势,介绍了林业推广所包括的内容,认为世界林业推广在概念、推广策略、推广方式和推广教育等诸多方面都发生了很大变化,简要介绍了8种常见的林业推广方式,论述了林业推广对策和林业推广教育,并对如何改进我国的林业推广提出了一些看法。     

Soil productivity,soil conservation and land evaluation

ICRAF's main contributions to research related to soils have been a symposium, Soils Research in Agroforestry; a review of soil productivity aspects of agroforestry; a further review of the potential of agroforestry for soil conservation, covering both erosion control and maintenance of fertility; the construction of a computerized model to predict soil changes under agroforestry systems; and a handbook of practical methods of agroforestry for soil and water conservation in dryland Africa. In research on land evaluation, an environmental data base has been established, leading to a capacity to obtain information, for environmental conditions similar to those of a given site or area, on publications, multipurpose trees, crops, existing agroforestry systems and current experimental work. Land evaluation for agroforestry cannot be achieved merely by synthesis of methods from agriculture and forestry, but will require more data on the performance of agroforestry land utilization types. Recognition of problems of environmental degradation has become an integral part of planning for agroforestry research. By means of a partial synthesis between land evaluation and diagnosis and design, a procedure of site selection for agroforestry research and development has been established.Principal Scientist, ICRAF     

Improved harvesting systems for wet sites

Environmentally acceptable and economical forest operations are needed for sustainable management of forest resources. Improved methods for harvesting and transporting timber are especially needed for wet sites. As the demand for hardwood lumber continues to increase, improved and alternative methods are needed to ensure acceptance of timber harvesting for the wet site conditions that are typical of bottomland hardwoods. Some alternative technological developments include grapple saw feller-bunchers, wide tires, larger forwarders, clambunk skidders, two-stage hauling, mats, cable systems, helicopters and towed vehicles and air-cushioned vehicles. These developments have the potential to improve the performance of the harvesting system and to reduce the negative effects of conventional operations on conventional sites and on difficult sites such as wet areas. Although many of these new alternatives are now operational, others are just concepts or evolving prototypes. More research is still needed to optimize these alternative technologies and to reduce costs associated with their implementation.     

Seeding Herbs to Enhance Cervid Forage and Reforestation in Pacific Northwest Conifer Forests

Forage seeding, seeding grasses and legumes in conifer plantations, has been touted as a method of simultaneously improving elk (Cervus elaphus) and black-tailed deer (Odocoileus hemionus columbianus) nutrition and forest regeneration. When suited to local physiographical and biological conditions forage seeding may (1) increase the nutritional quality and biomass of forage preferred by cervids and (2) reduce the establishment of seral vegetation that competes with conifer seedlings. The effectiveness of forage seeding in reducing conifer browsing by cervids remains questionable. In the past, forage seeding programs have been implemented over wide geographic areas far beyond experimental study sites; many of these have had limited success. In addition, the effects of forage seeding on cervid biology and reforestation have not been rigorously tested. Thus, if forage seeding programs are implemented, it should be done so cautiously with the expectation that the outcome may differ markedly from prior experimental results. We outline criteria for selecting sites for forage seeding programs and prescribe methods for optimizing the seeding of forages. We offer guidelines for designing large-scale forage seeding research to infer treatment differences to a representative population of clearcuts with a specific set of clearly defined site conditions and management objectives. For situations where such large-scale experimentation is prohibitive, we outline research questions we believe are both important and can be answered in small-plot studies.     

Subsidy or stress? Tree structure and growth in wetland forests along a hydrological gradient in Southern Europe

In forested wetlands, hydrology exerts complex and sometimes compensatory influences on tree growth. This is particularly true in semi-arid ecosystems, where water can be both a limiting resource and a stressor. To better understand these relationships, we studied hydrologic and edaphic controls on the density, growth, tree architecture and overall productivity of forested wetlands dominated by the tree species Alnus glutinosa and Salix atrocinerea in Southern Europe. We sampled 49 plots set within 21 stands in the Atlantic coastal zone of the Iberian Peninsula, and quantified woody composition, size structure (diameter and height), and radial growth using dendrochronology. Plots were grouped into three saturation classes to compare tree growth characteristics (tree density, degree of sprouting, live basal area and productivity) across levels of saturation. We used Principal Component Analysis (PCA) to create integrated explanatory factors of hydrology, soil nutrient status and soil texture for use in linear mixed models to predict stand characteristics. Increased site saturation favoured a shift in species dominance from Alnus to Salix and resulted in a higher degree of multi-stemmed tree architecture (‘shrubbiness’), particularly for Alnus. Radial growth was negatively correlated with long-term soil saturation; however, annual productivity on a per-tree basis varied by species. Alnus growth and tree density were negatively correlated with waterlogging and fine-textured soils, possibly due to anaerobiosis in the rooting zone. In contrast, Salix growth was more influenced by nutrient limitation. Overall site productivity as measured by annual basal area increment decreased with prolonged saturation. In summary, soil saturation appears to act as a chronic stressor for tree species in this ecosystem. However, these species persist and maintain a dominant canopy position in the most permanently flooded patches through increased sprouting, albeit at a reduced rate of overall biomass accumulation relative to well-drained sites. The diversity in functional responses among wetland forest species has important implications for the conservation and management of these ecosystems. The sustainable management of these ecosystems is directly tied to their vulnerability to changing hydrological conditions. Non-equilibrium modifications to the hydrologic regime from land use and climate change, which are particularly severe in semi-arid regions, may further decrease productivity, integrity and resilience in these stress-adapted communities.     

提高昆虫病毒杀虫效果的荧光增白剂的研究

荧光增白剂是生物防治研究中最近发现的一类能显著提高昆虫病毒杀虫能力、加快病毒致死昆虫速度、提高昆虫病毒对紫外光的保护作用的化学因子。林间增加效果明显而稳定。荧光增白剂可发展成为有效提高和改善昆虫病毒制剂持续控制农林害虫的重要助剂。虽然荧光增白剂能显著增强昆虫病毒毒力的机理还不清楚，但该机理的阐明可以为生物防治农林害虫提供新的途径甚至理论。本文综述了近10a来国外在应用荧光增白剂提高昆虫病毒毒力和实际应用防治农林害虫的研究进展。并提出了荧光增白剂能扩大病毒的宿主范围，改变昆虫病毒感染宿主的途径和诱发昆虫病毒潜伏侵染的推论。对荧光增白剂应用中的问题也进行了讨论。     

Estimating sap flow from stem heat balances in Quercus robur L. seedlings in relation to light intensity: A comparison of two methods during the establishment phase

? Knowledge of whole tree seedling water fluxes is important in ecological and forestry research, especially under conditions with low transpiration, but no standard method has yet been established that provides reliable in situ measurements.

? The aims were: (1) to assess the performance of two methods for estimating sap-flows in oak seedlings following planting by correlating the data they provided with natural light intensities over a three-week period, and (2) to compare the estimates with transpiration data obtained by weighing pots.

? Estimates of sap flows obtained from data provided by constant power (Dayau-type) heat balance gauges under low light conditions (100–450 μmol m^?2 s^?1) were less variable than estimates from variable power (EMS-type) heat balance gauges. The EMS-type system yielded data with little between-gauge variation, but consistently underestimated transpiration on a daily basis, a systematic error that should be corrected by other methods. The Dayau-type gauges yielded data with substantial variations, and several gauges are probably needed in research to cover these variations. Further, both systems provide rather uncertain estimates of short-time (hour) transpiration rates.

? However, provided that these considerations are taken into account, we conclude that it should be possible to use either system in various research contexts.

     

森林防火隔离带技术的变革与优势

以消减可燃物的方式预防和阻隔森林火灾是林火管理工作的核心。传统阻隔技术向遮荫型防隔火技术的演变已成为近10余年西方多林国家林火管理工作的重要走向。从林火的特点和蔓延基本规律出发, 遮荫型防火隔离带技术通过局部消减可燃物载量和规则化可燃物分布, 显著降低其可能形成的林火强度, 使大多数火灾自行熄灭。该项技术的实施不受区域和气候条件限制; 与传统全光式防火隔离带和生物防火林带相比, 不但工作量较小, 对林分植被和生态环境的干扰也较小。该项技术实现了偶发性林火的防控、森林健康及生态维护的有机结合, 以此替代传统防火隔离带技术效益显著。针对遮荫型防隔火技术的进一步研究工作应包括不同稀化程度林带潜在火行为和其防隔火效能的量化评估、林地局部可燃物稀化的高效作业机具以及伴随该项技术实施产生的大量生物质副产品的有效利用问题。     

不同绿僵菌菌株对筛胸梳爪叩甲幼虫的毒力测定

竹林金针虫是南方竹林笋期最为重要的害虫之一,筛胸梳爪叩甲幼虫是竹林金针虫的优势种群,应用绿僵菌防治具有重要意义。测定了3株绿僵菌对筛胸梳爪叩甲幼虫的毒力,并比较了毒土法和毒饵法两种施菌方式对绿僵菌致病力的影响。结果表明,平沙绿僵菌WP08菌株和金龟子绿僵菌30104菌株对筛胸梳爪叩甲幼虫具有明显的致病效果,在30 d的试验期内,校正累计死亡率分别为90.0%和66.3%,半数致死时间（LT₅₀）分别为15.8 d和25.8 d;毒土法的校正累计死亡率略高于毒饵法,分别为60.1%和52.0%,LT₅₀分别为22.6 d和28.0 d。金龟子绿僵菌LRC112菌株对金针虫无致病力。