Fire and retention island remnants have similar deadwood carbon stock a decade after disturbances in boreal forests of Alberta

In an attempt to reconcile wood extraction and forest biodiversity in managed boreal forests,ecosystem-based forest management(EBM)has become the de facto management approach.Retention forestry represents one prominent way that EBM is implemented in many parts of the world.Retention patches commonly left after harvesting serve as analogues of fire island remnants,which are patches of unburned forests in the burned forest matrix.Although the persistence of retention patches has been questioned,few studies have attempted to quantitatively compare forest attributes in both burned and harvested forests.As part of a larger program examining multiple aspects of ecosystem function in fire and harvest island remnants,we investigated the impact of disturbance type(fire/harvest)and forest edges on C stock in snags and coarse woody debris(CWD)found in island remnants in mixedwood boreal forests of Alberta,Canada.Total C stock(in snags and CWD)was similar between the two disturbance types and edge plots had similar total deadwood C stocks to interiors.The edges of island remnants had about two-fold more snag C stock than their interiors in both disturbance types,but C stock in CWD was unaffected by edge effects and disturbance type.Our results suggest that deadwood C dynamics in island remnants in fire and harvest disturbed boreal forests were similar,thus lending support for the continued implementation of retention forestry in Alberta.

Disentangling the effects of management and climate change on habitat suitability for saproxylic species in boreal forests

Forest degradation induced by intensive forest management and temperature increase by climate change are resulting in biodiversity decline in boreal forests.Intensive forest management and high-end climate emission scenarios can further reduce the amount and diversity of deadwood,the limiting factor for habitats for saproxylic species in European boreal forests.The magnitude of their combined effects and how changes in forest management can affect deadwood diversity under a range of climate change scenarios are poorly understood.We used forest growth simulations to evaluate how forest management and climate change will individually and jointly affect habitats of red-listed saproxylic species in Finland.We simulated seven forest management regimes and three climate scenarios(reference,RCP4.5 and RCP8.5)over 100 years.Management regimes included set aside,continuous cover forestry,business-as-usual(BAU)and four modifications of BAU.Habitat suitability was assessed using a speciesspecific habitat suitability index,including 21 fungal and invertebrate species groups.“Winner”and“loser”species were identified based on the modelled impacts of forest management and climate change on their habitat suitability.We found that forest management had a major impact on habitat suitability of saproxylic species compared to climate change.Habitat suitability index varied by over 250%among management regimes,while overall change in habitat suitability index caused by climate change was on average only 2%.More species groups were identified as winners than losers from impacts of climate change(52%–95%were winners,depending on the climate change scenario and management regime).The largest increase in habitat suitability index was achieved under set aside(254%)and the climate scenario RCP8.5(>2%),while continuous cover forestry was the most suitable regime to increase habitat suitability of saproxylic species(up to+11%)across all climate change scenarios.Our results show that close-to-nature management regimes(e.g.,continuous cover forestry and set aside)can increase the habitat suitability of many saproxylic boreal species more than the basic business-as-usual regime.This suggests that biodiversity loss of many saproxylic species in boreal forests can be mitigated through improved forest management practices,even as climate change progresses.

Dieback of managed spruce stands in western Germany promotes beetle diversity

Biodiversity loss is a significant problem at a global scale and may be amplified by climate change.In recent years,coniferous forests have had substantial die-back across Europe due to drought and subsequent bark-beetle outbreaks.As many studies on the consequences of disturbance and subsequent management have focused on natural stands,management implications for managed spruce stands are not well understood,even though such stands are widespread throughout Europe.In this study,beetle taxonomy,conservation value,and community com-position are compared among spruce plantations and four post-disturbance management approaches:standing dead-wood,lying deadwood,clear cuts,and long-term succession.Diversity and community composition differed significantly among management categories,while different beetle fami-lies responded similarly.Intact spruce stands harbored the lowest beetle diversity while the highest taxonomic diver-sity and conservation value was on clear cuts and stands with lying or standing deadwood.The proportion of forest specialists was highest in successional forests.In summary,different forest management categories harbored distinct beetle communities at the family-,species-,and ecological guild levels.Therefore,post-disturbance management should consider the landscape scale and include different management types.This enhances landscape heterogeneity and thus overall biodiversity but could also mitigate negative impacts of natural disturbances on ecosystem services.

The diameter of beech snags is an important factor for saproxylic beetle richness: Implications for forest management and conservation

Snags are an important component of beech forests that promote biodiversity.However,their occurrence is completely marginal in managed stands.Creating snags in these stands would greatly enhance biodiversity.We investigated whether snag dimensions were important for saproxylic beetle richness since they were easily transferable parameters to forest management and assessed the presence of other snag microhabitats affecting beetle communities.Data collection was performed using passive flight traps placed on thirty snags in a recent beech reserve.A total of 6706 adults belonging to 231 saproxylic species(53 Red List species,23%)were captured.The results showed that the most important snag parameters were the diameter(thickness)and canopy openness of the surrounding stands.The occurrence of Fomes fomentarius,the volume of snag and decay class 3 were marginally significant in terms of the preference of all saproxylic species.Alpha diversity was reduced by an advanced degree of decay and a surprisingly deep stem cavity.After dividing snag thickness into categories(<35 cm;35–70 cm and>70 cm DBH),we found that categories with snag diameter greater than 35 cm showed little differences in all saproxylic and Red List species richness and diversity indices and exhibited the highest similarity in beetle communities.Regarding recommendations to forest managers in terms of optimization and simplification of practical procedures,we suggest actively creating high stumps to act as snags greater than 35 cm in DBH diameter to promote biodiversity in beech management stands.

华山松朽木阴燃特性的初步研究

用自行设计的燃烧试验床对华山松Pinus armandii朽木进行阴燃试验,采集阴燃过程中的温度数据,通过分析朽木的物理性质、阴燃过程中的温度变化数据和现象,研究了朽木阴燃的引燃特性、持火力和蔓延特性.结果表明,华山松朽木具有易引燃、蔓延速度慢、高温维持时间长的特点,朽木具有保存火种作用.根据朽木阴燃特性提出了相应的森林消防措施.

华北地区古树主要形态特征变异分析

【目的】通过对古树形态特征变异分析研究,了解古树表型性状的生态地理变异,以期为华北地区古树名木的资源保护和健康维护提供参考。【方法】以6个区域5种不同类型的古树为研究对象,选取7个不同的形态特征指标,采用ANOVA方差分析和LSD最小显著差异法,对测定的性状特征数据进行数学统计分析。【结果】5种古树7个性状指标间存在一定程度的变异,树洞在不同树种中的变异程度最大,而树高、胸径和树叶稀疏情况的变异程度最小,性状最为稳定;古树的形态差异与生境异质性关系密切,具有相似生境的古树通常具有相似的表型特征;树高、树叶稀疏状况和枯枝比等表型性状特征值与土壤营养元素多呈负相关关系。【结论】华北地区古树的形态特征具有多型性,且受生境异质性影响较大,具有较好的生态适应性。

不同土壤处理对东北连翘生长影响的研究

以东北连翘盆栽苗为试验材料,研究樟子松、红皮云杉纯林下土、枯枝落叶覆盖园土处理对东北连翘生长的影响。旨在从园林景观建设的角度考虑,尝试研究筛选出适合樟子松、红皮云杉林下生长的灌木,为丰富松科植物林下园林景观配置提供参考。研究结果表明:樟子松林下土、枯枝落叶覆盖园土对东北连翘的生长都无明显的促进作用或抑制作用,对有机物的积累和叶绿素的合成有促进作用;红皮云杉林下土对新梢的加粗生长有促进作用,促进叶绿素b和总叶绿素的合成;红皮云杉枯枝落叶覆盖园土对东北连翘的生长无明显的促进作用或抑制作用。

Effect of wind damage on the habitat suitability of saproxylic species in a boreal forest landscape

Many forest-dwelling species are dependent on deadwood. Sources of deadwood include competition- and senescence-related mortality of trees, and various damages. This study described a methodology for predicting the effect of wind damage on the amount of deadwood and suitability of the forest for saproxylic species. The methodology was used in a forested boreal landscape of 360 ha to analyze the effects of wind damage on the habitat quality for 27 groups of saproxylic species differing in their requirements for the species, size and decay stage of deadwood objects. A reference plan maximized net present value (MaxNPV) while others either minimized or maximized height differences between adjacent stands. Maximization of height differences resulted in high amount of wind damage and deadwood while minimizing height differences minimized wind damage and the amount of damage-related deadwood. The fourth plan maximized the average habitat suitability index (HSI) of the 27 groups of saproxylic species. The plans were compiled with and without even-flow harvesting constraints for three 10-year periods. Maximization of height differences between adjacent stands resulted in higher HSI values than obtained in the MaxNPV plan or in the plan than minimized height differences between adjacent stands. The average HSI of shade-demanding species correlated negatively with the amount of harvested timber. No strong correlations were found for light-demanding and indifferent species.

林中枯立木对大斑啄木鸟生存繁衍的影响

文章以内蒙古乌拉特前旗一个啄木鸟观察地为研究对象,从大斑啄木鸟的取食、营巢、活动空间、传递信息等角度进行观察。结果表明林内枯立木是大斑啄木鸟生存繁衍的重要因子。

Forest structure of a maple old-growth stand: a case study on the Apennines mountains(Southern Italy)

In Europe, very small forest areas can be considered to be old-growth, and they are mainly located in Eastern Europe. The typical structures of old growth forests infrequently occur in Mediterranean mountainous environments, since they have been affected by human activities for centuries. This study focused on a remote and almost pure Italian maple stand located in southern Italy, which has not been managed for long time due to its inaccessibility. The effects of natural evolution on the forest stand were evaluated through the analysis of the spatial and chronological structure and the regeneration patterns, then estimating the amounts and quality of deadwood occurrence. Across the whole stand, all the trees with DBH （diameter at breast height） larger than 50 cm （LLT, large living trees） were measured （DBH and height） and age was also determined through a dendrochronological approach. The diameters observed ranged between 50 and 145 cm with ages of 12o to ~5o years. The Latham index calculated for trees within the sample plot highlighted a multilayered canopy with a dominant layer of largeliving trees （age 〉 120 years）. The size-class distribution of stems had a reverse-J shape, and basal area was 52 m2 ha-1. Deadwood was exclusively constituted by standing dead trees and CWD and its volume was on average 31 m3 ha-1. Pure Italian maple forests are generally rare in Europe, and it was unexpected to find a forest stand characterized by a so complex structure with old growth attributes. The study of complex forest stand, even if small, could give precious information on the forest evolution, clarifying also diverse auto-ecological traits of tree species that usually are not common in our forests.

试论枯艺盆景

该文比较系统地阐述了舍利文化及其与枯艺盆景的关系 ,并首次提出枯艺盆景的概念。在初步探讨枯艺盆景的起源和美学原则的基础上 ,对枯艺盆景创作技法。

Diversity of plants and mammals as indicators of the effects of land management types in woodlands

Background:The ecological indicators are useful tools to determine the effects of human disturbances on woodland biodiversity.Nevertheless,ecological indicators not always responded in the same way to disturbances,and the responses can differ among taxa.In arid and semiarid woodlands,the use of deadwood associated with cattle raising can affect biodiversity and Nature’s contributions to people.Methods:Our study aimed to assess changes in taxonomic and functional diversity of two assemblages,plants and mammals,in Prosopis woodlands under different land management types:grazed woodlands and a protected area.For plants,changes in structural diversity were also analyzed.Prosopis trees under different land management types were selected and their deadwood characteristics were registered.Through live traps and camera traps,we obtained data on the presence-absence of mammals per tree to estimate diversity indices.For plants,we measured the abundance of vegetation by species and by cover type through the Line-Intercept Method to estimated diversity.Finally,we built generalized linear models to assess the responses of diversity of each assemblage to covariables concerning deadwood and different land management types.Results:We found that all diversity indeces for plants were either negatively affected by the presence of deadwood on the ground,or favored by its extraction.For mammals,removal of deadwood increased taxonomic diversity,while functional diversity increased with deadwood on the trees.Both structural diversity of plants and functional diversity of mammals were greater in grazed woodlands.Conclusions:The sustainable use of woodland resources is essential for the activities of rural communities.Our study results indicated that land management of grazed woodlands promoted the structural diversity of plant assemblages and the functional diversity of mammals.The presence of deadwood negatively affected plant diversity but it increased mammal functional diversity.It is advisable to maintain trees that preserve their wooden structure within the managed areas to promote the functional diversity of mammals,while trees with extraction from standing wood will favor the functional diversity of the plant assemblage.Understanding the effects of human disturbances can contribute to management for the conservation of woodlands diversity and Nature’s contributions to people.

郑州郊区枯枝上的3种暗色丝孢菌研究

[目的]了解郑州郊区生存在枯枝上的暗色丝孢菌种类。[方法]采用形态描述、绘图和显微摄影相结合的方式对采集自郑州郊区的40余份枯枝标本进行了暗色丝孢菌调查。[结果]从标本样品中分离鉴定出3种暗色丝孢菌,分别是膨梗头束霉、禾色串孢、黄槐棒孢。[结论]为了解中原地区枯枝上的暗色丝孢菌资源奠定了基础。

某耙吸挖泥船呆木设计

对于耙吸挖泥船而言,快速性和操纵性直接关系到其航行和疏浚作业的安全性和经济性。呆木作为改善船舶航向稳定性常用的附体,广泛应用于肥大型船上。以某耙吸挖泥船为例,分析呆木对其快速性和操纵性的影响,并介绍呆木的2种线型设计。通过开展阻力和自航模型试验,比较2种呆木线型设计的优劣,供后续同类型船舶的呆木设计参考。

大型公务船尾部墩木布置研究

文章研究了在船台上轴系对中时,某大型公务船尾部分水踵下墩木布置方案。采用有限元法,对比分析了不同边界条件下计算结果的差异性,讨论了尾部墩木布置的数目以及材料特性对墩木强度和船体尾部变形的影响。计算结果表明:在合适的位置适当增加尾部墩木数量有利于支反力的均匀分布;而提高尾部墩木的刚度有利于船体尾部的变形控制。根据计算结果提出优化的墩木布置原则,以保证建造过程中船体结构和墩木的安全。

13000m^3大型耙吸挖泥船的结构设计

通过13000 m3大型耙吸挖泥船的设计,阐明了挖泥船结构设计的重点。经过研究与反复比较,选择了比较有利的结构——强框架结构,从而保证了结构强度,而且也便于施工。

广东省森林死木碳库特征

基于广东省第8次国家森林资源清查的固定样地调查数据和2016年典型抽样的死木调查数据,利用分树种、分腐朽程度的各个组分相兼容的生物量模型以及相对应的地上、地下部分含碳系数,对广东省森林死木碳库动态进行估算,分析死木种类、林分类型和龄组对死木碳库的影响,量化林分生长特性和自然灾害对死木碳库的贡献。结果表明:2007—2012年间广东省乔木林死木碳库新增碳储量5811.86 Pg,占同期乔木林活立木碳库的2.94%,其中枯倒木多于枯立木;阔叶混交林和马尾松林贡献了近70%的死木碳储量;马尾松、其他软阔、湿地松、阔叶混交林和其他硬阔的死木碳储量占同类森林总活立木碳储量的比例较大,均超过4.00%,桉树和杉木比例最小,均不足1.00%;从龄组看,发生在中龄林的死木碳储量占总死木碳储量比例最大,过熟林最小。与同龄组林分的现存碳储量相比,从幼龄林(2.03%)到过熟林(4.56%)基本呈上升趋势。全省新增死木库碳密度为(0.7612±3.3988)Mg/hm^2。竞争和衰老引起的枯死在林分中普遍存在,占发生死木林分面积的60%以上,但增加到死木碳库的储量不足总量的四分之一,而自然灾害只占发生死木林分面积的10%,对死木碳库的贡献却超过40%。到2016年,2007—2012年间增加到死木库的碳储量下降到785.57 Pg,减少约85%,枯倒木的腐朽程度重于枯立木,不同树种间腐朽程度不一,杉木腐朽程度最低。清林等人为经营活动和死木的腐朽是存量减少的主要原因。

基于CFD的带呆木船舶尾部流场分析

为了研究船舶呆木附近流场特性,本文采用计算流体力学方法研究了一艘带呆木的船舶尾部流场。数值仿真首先分析了直航状态下的尾部呆木压力分布和呆木泄出涡形态,然后分析了回转状态下的泄出涡特征。研究表明呆木末端是全船压力最低点,在高速直航时有明显的泄出涡产生,而回转状态下泄出涡大幅减弱或消失。船舶直航时呆木泄出涡存在空化的可能,在船舶设计中不能忽略。

呆木对供应船线性水动力导数影响的研究

以供应船为研究对象,采用CFD商用软件FLUENT,结合动网格技术对平面运动机构(PMM)试验进行了数值模拟,得到不同呆木面积所对应的船舶水动力,进而获得相应的线性水动力导数,并分析了数值计算结果的合理性,得出水动力导数随呆木面积变化的趋势图。该结论可以为供应船舶操纵性能预报以及呆木设计的研究提供一定的参考。

攀西地区橡皮树两种真菌病害的鉴定

1990～2001年,对攀西地区橡皮树真菌病害进行了系统的调查和鉴定,认为其主要病害为:炭疽病和枯枝病。