木麻黄人工林地持续利用问题的探讨

木麻黄（CasuarinaequisetifoliacL．）为东南沿海营造防护林的主要树种，现有人工林面积逾100万hm2。建国以来木麻黄培育成效显著．积累了丰富的栽培管理经验，造林技术有所创造发展，有效地发挥了森林防风固沙改善生态环境等多项功能。但因林分结构简单和经营方法不当．导致木麻黄人工林生态系统失调，面临着生长衰退、他力下降、林分更新困难和低效林分增加等局面，广东、福建等地均有类似报导，如何维持和提高木麻黄林土壤肥力，确保人工林地防护效能．已成为沿海防护林体系建设中的迫切问题。l木麻黄连我对林木生长和土壤肥力的影响根…     

前言

<正> 沿海防护林作为我国重要的林业生态工程,主要目标是通过建立具有较高生产力和稳定协调的人工林生态系统,持续地发挥森林改善生态环境和维护生态平衡等多种效益。木麻黄是东南沿海最为重要的防护树种,自50年代营造木麻黄防护林以来,已在7000多公里的海岸带建起了宏伟的绿色屏障,为改善生态环境、抵御自然灾害及发展沿海地区经济和国防建设发挥了重大作用。但由于防护林管理不善等原因,当前木麻黄人工林经营中存在更新困难、生长衰退以及低效林分多和病虫害增加等突出问题,对木麻黄林的持续发     

福建海坛岛主要防护林生态服务功能价值评估

依据平潭县资源调查数据及典型样地的实验分析结果,采用LY/T 1721—2008森林生态系统服务功能评估规范的评估方法以及影子工程法等对福建省平潭县海坛岛主要防护林即木麻黄林、台湾相思树林、湿地松林、黑松林的生态系统服务功能价值进行评估。结果表明:海坛岛4种树种构成的防护林森林生态系统服务功能总价值是157485.39万元,其中木麻黄提供的价值量最大,为70626.12万元,其次分别为台湾相思和黑松,价值分别为49999.52万元、35659.58万元,湿地松提供的价值量最小为1200.17万元。4种树种各项服务功能价值的贡献大小顺序依次为保育土壤固碳释氧森林防护涵养水源。可为沿海防护林生态系统的管理、保护以及为生态补偿提供参考。     

中国东南沿海混交海防林建设研究进展

综述了我国东南沿海混交海防林的现状,目前混交林型海防林主要是木麻黄与湿地松、相思类树种与桉属等树种混交形成的混交林。通过分析比较不同混交林型的生长效果、防护效能和改土效果,提出合理的混交类型。此外还提出采用乡土树种与木麻黄混交,为建设混交林型的海防林体系提供更多的混交树种选择,为我国沿海防护林的管理、低效林的改造以及提高海防林的生态功能提供参考。     

木麻黄防护林持续经营问题初探

木麻黄无性系造林 ,林分密度管理 ,低效林改造 ,抚育间伐技术 ,更新技术等是影响木麻黄防护林持续经营的主要因素。实施生态系统管理 ,采取营造木麻黄混交林、林木施肥等营林技术措施是木麻黄防护林持续经营的主要途径     

木麻黄对加快海南海防林建设的作用与发展建议

充分肯定了先锋树种木麻黄在海防林建设中的作用,进一步分析了当前营造海防林体系建设中面临的挑战和机遇,提出加强木麻黄优良品种选育,不断推进海南沿海防护林体系建设的几点建议。     

沿海木麻黄防护林的主要病虫害及其防治对策

本文综述了我国沿海木麻黄防护林的主要病虫害及其防治对策，着重阐述了生物防治与抗性育种方面的内容，还介绍了近年来国内外木麻黄林几种较为重要的病虫害的概况。     

木麻黄低效防护林形成特点、原因及其改造途径

在研究木麻黄低效防护林生长主要特点、共同特征的基础上,分析了导致大面积木麻黄低效防护林的成因是自然因素和社会经济条件作用下形成的。自然因素包括立地条件较差、林木衰老、灾害天气频繁及病虫害对木麻黄防护林的破坏;社会经济因素主要有立地条件与造林树种选择不当、造林材料遗传性不高、苗木质量低下、林分密度和土壤管理不善以及人为干扰对林分的破坏等。针对木麻黄低效林的形成特点和原因,提出木麻黄低效防护林改造的主要途径。     

福州滨海后沿沙地相思、尾巨桉和木麻黄等树种造林效果初报

对台湾相思、卷荚相思、肯氏相思、尾巨桉、木麻黄(木麻黄501和木麻黄平潭2号)等5个树种在滨海沙地进行造林试验,对造林9个月后不同处理下的苗期生长情况进行对比,认为客土全穴有利于提高苗木的成活率和生长量。生长差异比较结果显示,尾巨桉和肯氏相思可作为长乐滨海沙地防护林造林树种。桉树和相思类树种对增加沿海防护林生态系统的生物多样性和景观多样性,提高防护林的稳定性、抗逆性、防护效能等方面具有重要意义。     

石狮市沿海木麻黄主要有害生物及综合防控措施研究

指出了木麻黄是我国东南沿海防护林的造林先锋树种。石狮市位于福建省东南沿海,市域三面临海,木麻黄防护林有大面积种植。基于现有参考文献和多年从事石狮市林业工作的实践与调查,总结了石狮市沿海木麻黄防护林的主要有害生物种类,并对其的综合防控措施进行了简要阐述。     

木麻黄生长与收获模型系统的研究

利用海南文昌2005年森林资源二类调查的木麻黄工业原料林样地资料,通过参数置换法,构建了以优势高模型为基础,以断面积预估为中心,将蓄积量作为目标变量的生长与收获模型系统。结果表明：组成模型系统的各模型的拟合精度较高,各模型的预估值与观测值差异不显著,适应性较好,能对木麻黄的优势高、断面积和蓄积量生长进行正确预估,可用于研究区木麻黄工业原料林的生长与收获预估。研究方法为一次性调查数据生长模型及类似模型的研建提供了经验和借鉴,并为当前缺少长期定位观测数据和大量解析木数据的森林经营单位编制森林经营方案提供了理论基础。     

基于发展类型理念的多功能人工林经营模式研究

现代森林经营已经从木材导向的单一经营向探索森林多功能可持续经营和实现预期林相技术的转变,但人多地少的林情和不同的功能需求亟待改变长期以来追求木材产量的经营理念,导向社会与生态效益的多功能人工林模式。文中基于发展类型多功能人工林经营理念,探讨了多功能人工林经营模式下的概念框架、目标内容,重点阐述了多功能人工林经营的林分作业法设计,以杉木和木麻黄人工林经营模式为典型应用案例解释了森林发展类型的发展目标、树种比例、混交类型、近期营林措施等设计理念,以期为多功能人工林经营设计提供一种有效可行的思路与技术参考。     

Vegetation status on Nishi-jima Island (Ogasawara) before eradication of alien herbivore mammals: rapid expansion of an invasive alien tree, <Emphasis Type="Italic">Casuarina equisetifolia</Emphasis> (Casuarinaceae)

Insular ecosystems can be dramatically affected by alien species, and records of pre-eradication status are essential to evaluate the effects of eradicating alien species. Nishi-jima Island is a small island of the Ogasawara group on which the first program of complete eradication of alien herbivorous mammals (black rats and feral goats) will be conducted. After eradication, the government plans to conduct ecosystem restoration on the island. This paper reports the angiosperm flora and vegetation of Nishi-jima Island before eradication of the rats and goats, with the objective of aiding ecosystem management after the eradication. Our surveys indicate that vegetation cover by the alien tree, Casuarina equisetifolia has expanded compared with its distribution in a 1974 aerial photograph of the island. The predominant vegetation in 2006 was C. equisetifolia forests and Zoysia tenuifolia grasslands, with fragmented native tree vegetation. The flora of the island comprised 69 angiosperm species (50 indigenous species) of which 30% were endemic, far less than for the Ogasawara Islands as a whole (45%). However, several populations of endangered plants remain. To restore the native ecosystem on Nishi-jima, eradication of C. equisetifolia is important in addition to eradication of alien herbivorous mammals.     

马尾松人工林地力维护研究进展

针对地力衰退与维护这一林业研究热点,文中从林分生产力、土壤理化性质、土壤养分、土壤微生物、土壤酶活性、自毒作用6个方面阐述了马尾松人工林的地力现状。众多研究表明,马尾松人工林尚未出现地力衰退,其产生地力衰退的原因主要是不合理的营林措施。同时从轮作、混交林、发展林下植被、林地施肥、生态系统管理等方面介绍了马尾松人工林地力维护进展,并对马尾松人工林地力维护研究趋势进行了展望。     

Tree microhabitat structures as indicators of biodiversity in Douglas-fir forests of different stand ages and management histories in the Pacific Northwest,U.S.A.

The importance of structural complexity in forest ecosystems for ecosystem diversity has been widely acknowledged. Tree microhabitat structures as indicators of biodiversity, however, have only seldom been the focus of diversity research although their occurrence is highly correlated with the abundance of forest species and ecosystem functions. In this study, microhabitat structures in Douglas-fir (Pseudotsuga menziesii) forests were defined and their frequency and abundance in natural stands and stands of varying active management histories and stand ages was compared. Indicator microhabitat structures for natural forests were determined and the relationship of the abundance of microhabitat structures with tree diameter of Douglas-fir trees was analysed.     

Carbon storage in old-growth and second growth fire-dependent western larch (Larix occidentalis Nutt.) forests of the Inland Northwest,USA

There is limited understanding of the carbon (C) storage capacity and overall ecological structure of old-growth forests of western Montana, leaving little ability to evaluate the role of old-growth forests in regional C cycles and ecosystem level C storage capacity. To investigate the difference in C storage between equivalent stands of contrasting age classes and management histories, we surveyed paired old-growth and second growth western larch (Larix occidentalis Nutt)–Douglas-fir (Pseudostuga menziesii var. glauca) stands in northwestern Montana. The specific objectives of this study were to: (1) estimate ecosystem C of old-growth and second growth western larch stands; (2) compare C storage of paired old-growth–second growth stands; and (3) assess differences in ecosystem function and structure between the two age classes, specifically measuring C associated with mineral soil, forest floor, coarse woody debris (CWD), understory, and overstory, as well as overall structure of vegetation. Stands were surveyed using a modified USFS FIA protocol, focusing on ecological components related to soil, forest floor, and overstory C. All downed wood, forest floor, and soil samples were then analyzed for total C and total nitrogen (N). Total ecosystem C in the old-growth forests was significantly greater than that in second growth forests, storing over 3 times the C. Average total mineral soil C was not significantly different in second growth stands compared to old-growth stands; however, total C of the forest floor was significantly greater in old-growth (23.8 Mg ha⁻¹) compared to second growth stands (4.9 Mg ha⁻¹). Overstory and coarse root biomass held the greatest differences in ecosystem C between the two stand types (old-growth, second growth), with nearly 7 times more C in old-growth trees than trees found on second growth stands (144.2 Mg ha⁻¹ vs. 23.8 Mg ha⁻¹). Total CWD on old-growth stands accounted for almost 19 times more C than CWD found in second growth stands. Soil bulk density was also significantly higher on second growth stands some 30+ years after harvest, demonstrating long-term impacts of harvest on soil. Results suggest ecological components specific to old-growth western larch forests, such as coarse root biomass, large amounts of CWD, and a thick forest floor layer are important contributors to long-term C storage within these ecosystems. This, combined with functional implications of contrasts in C distribution and dynamics, suggest that old-growth western larch/Douglas-fir forests are both functionally and structurally distinctive from their second growth counterparts.     

西藏色季拉山冷杉树冠营养元素的分布特征

2001年10月15日至25日在色季拉山生态系统定位站原始冷杉林,采用标准地调查取样与实验室分析,测定了其优势树种急尖长苞冷杉林冠的养分,结果表明:1年生叶片养分总含量是多年生叶片的1.12倍;叶片在树冠阳面养分总含量高于阴面;林冠的不同高度叶片的养分含量不同;同一枝条不同部位的叶片在养分含量上也有一些差异.枝条与叶片有着相似的养分含量分布规律,这种一致性说明在养分的分配、积累过程中,枝条和叶片对养分的利用是同步的.     

Singular and interactive effects of blowdown, salvage logging, and wildfire in sub-boreal pine systems

The role of disturbance in structuring vegetation is widely recognized; however, we are only beginning to understand the effects of multiple interacting disturbances on ecosystem recovery and development. Of particular interest is the impact of post-disturbance management interventions, particularly in light of the global controversy surrounding the effects of salvage logging on forest ecosystem recovery. Studies of salvage logging impacts have focused on the effects of post-disturbance salvage logging within the context of a single natural disturbance event. There have been no formal evaluations of how these effects may differ when followed in short sequence by a second, high severity natural disturbance. To evaluate the impact of this management practice within the context of multiple disturbances, we examined the structural and woody plant community responses of sub-boreal Pinus banksiana systems to a rapid sequence of disturbances. Specifically, we compared responses to Blowdown (B), Fire (F), Blowdown-Fire, and Blowdown-Salvage-Fire (BSF) and compared these to undisturbed control (C) stands. Comparisons between BF and BSF indicated that the primary effect of salvage logging was a decrease in the abundance of structural legacies, such as downed woody debris and snags. Both of these compound disturbance sequences (BF and BSF), resulted in similar woody plant communities, largely dominated by Populus tremuloides; however, there was greater homogeneity in community composition in salvage logged areas. Areas experiencing solely fire (F stands) were dominated by P. banksiana regeneration, and blowdown areas (B stands) were largely characterized by regeneration from shade tolerant conifer species. Our results suggest that salvage logging impacts on woody plant communities are diminished when followed by a second high severity disturbance; however, impacts on structural legacies persist. Provisions for the retention of snags, downed logs, and surviving trees as part of salvage logging operations will minimize these structural impacts and may allow for greater ecosystem recovery following these disturbance combinations.     

Litter of an alien tree, <Emphasis Type="Italic">Casuarina equisetifolia</Emphasis>, inhibits seed germination and initial growth of a native tree on the Ogasawara Islands (subtropical oceanic islands)

We investigated the effects of the accumulation of litter of an alien tree, Casuarina equisetifolia, on the initial establishment of Schima mertensiana, a tree native to the Ogasawara (Bonin) Islands, in the northwestern Pacific Ocean, in field and greenhouse experiments. The field experiment compared emergence of seedlings in forests dominated by C. equisetifolia with those in native forests, with and without litter removal. The greenhouse experiment compared seedling germination and biomass among 12 treatments that included two soil types (collected from the C. equisetifolia and native forests), two litter types (C. equisetifolia and native litter), and three amounts of litter (5, 15, or 45 g/pot). Significantly fewer S. mertensiana seedlings emerged at sites dominated by C. equisetifolia than at sites of native species in the field experiment. Litter removal tended to increase seedling emergence. Fewer and smaller S. mertensiana seedlings germinated with greater litter cover regardless of soil type or litter type in the greenhouse experiment. Our results demonstrate that C. equisetifolia litter suppresses germination and initial growth of S. mertensiana, and that the main cause of the suppression is the greater amount of litter accumulated under C. equisetifolia forest floor rather than factors such as the nature of the soil or litter between native and alien species.     

Modeling the effects of alternative management strategies on forest carbon in the Nothofagus forests of Tierra del Fuego,Chile

The impact of forest management activities on the ability of forest ecosystems to sequester and store atmospheric carbon is of increasing scientific and social concern. The nature of these impacts varies among forest ecosystems, and spatially and temporally explicit ecosystem models are useful for quantifying the impacts of a number of alternative management regimes for the same forest landscape. The LANDIS-II forest dynamics simulation model is used to quantify changes to the live overstory and coarse woody debris pools under several forest management scenarios in a high-latitude South American forest landscape dominated by two species of southern beech, Nothofagus betuloides and N. pumilio. Both harvest type (clearcutting vs. partial overstory retention) and rotation length (100 years vs. 200 years) were significant predictors of carbon storage in the simulation models. The prompt regeneration of harvest units greatly enhanced carbon storage in clearcutting scenarios. The woody debris pool was particularly sensitive to both harvest type and rotation length, with large decreases noted under short rotation clearcutting. The roles of extended rotations and partial overstory retention are noted for enhancing net carbon storage on the forest landscape.