黑龙江省西部农田林网区水土流失成因与防治对策

本文针对黑龙江省西部农田林网区水土流失日趋严重状况的调查 ,对水土流失现状进行了论述 ,并对水土流失的成因及危害进行了详细阐述 ,提出了防治水土流失的对策 ,为黑龙江省西部农田林网区水土流失治理工作提供理论参考     

农田林网杨树生物量的研究

目前我国对农田林网的研究多集中在防护效益和粮食产量方面,对农田林网中林木的物质生产、积累与分配以及光能利用等则研究较少。揭示农田林网生态系统中林木的物质生产、积累、分配、循环的规律有助于挖掘土地生产潜力,提高光能利用率,进一步提高农田林网生态系统的生产力。杨树是华北平原农田林网的主要树种,所以我们对杨树生物量进行了初步研究。     

嘉兴市农田林网树种数量化评价

根据嘉兴市农田林网立地条件和自然灾害特点,确定了抗风性、抗寒性、耐湿性、抗病虫性等8个农田林网树种评价指标及其权重,对30种乔木树种,根据评价指标分树种进行调查、数量化评价,得出农田林网树种数量化评价指数。     

台湾地区台中市筏子溪农田林网景观设计研究

筏子溪位于我国台湾地区台中市区城市与乡镇结合的位置,有大面积的农田,常年多风害,农业生产环境不稳定。通过对农田林网的研究梳理及案例研究,归纳出林网的布局、林带的构成、树种的选择和作物的种植方式4个构建农田林网的要素。对筏子溪流域的农地从树种选择、林网构建、时序设计3个方面进行设计实践,完善农田林网景观的设计体系。最后,讨论了农田林网的生态效应、经济效益、文化服务3种景观服务功能。农田林网景观设计是农业生产应对全球气候变化和可持续发展的有效途径。     

建设海防屏障，保障农业稳产

建设海防屏障，保障农业稳产蔡金清（福建省蒲田市林业局）福建省蒲田县在实施沿海防护林体系工程建设以来，连续６ａ被部或省评为沿海防护林体系建设先进单位，特别是农田林网建设取得了历史性进展。７ａ中，全县共营造农田林网面积６０９．９ｈｍ￣２，以年均６６．７ｈ...     

城乡一体化上海农田林网适宜树种调查与规划

快速城市化进程下上海农田林网树种要求发生变化,需要关注其功能的多元化发展。通过调查上海农田林网树种现状,发现存在树种种类不丰富、应用频度低、配置结构失调、季相景观单调等问题。文中以发挥树种的防护、景观、保健和地域特色等多重功能为目标,提出了城乡一体化建设中上海农田林网适宜树种的规划建议。     

林带的胁地及其控制措施

农田林网在防风固土、增温保墒和提高农作物产量等方面的效益，已在生产实践中得到了证实，但农田林网也存在着胁地的不利一面。所谓胁地，就是指在靠近林带的地方在一定范围内的农田部分，由于地上部分树冠遮荫遮光，地下部分树根深入农田与作物夺水肥，致使农作物植株低矮，表现不同程度的晚熟，造成减产。     

基于SBE法的徐淮平原农田林网美景度评价

为探讨平原农田林网景观效益评价技术,以徐州沛县鹿楼镇为示范点,在该区域内有9种不同的植物配置模式,运用SBE美景度评估法对不同配置模式下的农田林网美景度进行分析测算,并对SBE值和6种景观要素进行了回归分析。结果显示,9种配置模式的林分类型中,榉树与高杆红叶石楠混交林景观美学价值最高,影响农田林网美景度高低的景观因子主要是平均树高、彩色树种应用比例,乔、灌木应用比例。在营造城乡农田林网景观生态林时,应采用高大的树种,且加大彩色灌木的比例。     

平原区农田林网营建技术

分析了平原区农田林网的综合效益,阐述了农田林网的建设原则,介绍了农田林网建设中树种选择、林带走向、网格面积、造林密度、抚育管理以及如何减轻林带胁地等技术措施。     

农田林网:防护林体系的重要组成部分

农田林网是青海省湟中县林业资源主要组成部分,该县是青海省的人口大县,农业大县,十分重视农田林网的营造和发展。但由于现有农田林网结构不合理,存在问题较多,影响了农田林网防护效益的发挥和林木经济价值的提高,为此,对全县土地种类、面积、树种组成、林龄结构等诸多方面对农田林网资源进行综合分析及评价。     

桂西南地区黑木相思生长规律、生物量及生产力研究

采用标准地平均木树干解析法对桂西南地区9年生黑木相思人工林的生长规律、生物量、生产力进行研究,结果表明:黑木相思人工林树高、胸径的生长高峰期出现在2~4年生时,树高、胸径连年生长量与平均生长量相交年龄分别是在4、5年生,材积的数量成熟期在8年生以后。9年生时,胸径(带皮)、树高、单株材积、立木蓄积分别为14.9 cm、15.8 m、0.13368 m3、189.15 m3.hm-2;平均木单株各器官的生物量所占比例大小分别为树干枝根干皮叶,干材所占比例达到58.18%;乔木层总生物量为173.32 t.hm-2,净生产力为19.26 t.hm-2.a-1。     

黑龙江省西部柠条的栽培技术及生态价值

根据我省西部的特点,论述了发展和种植柠条是我省西部造林的先锋树种,并介绍了柠条栽培技术的方法和生态及经济价值.     

Correlations and clines in tree growth and wood density of <Emphasis Type="Italic">Balanites aegyptiaca</Emphasis> (L.) Delile provenances in Niger

Balanites aegyptiaca (L.) Delile provides wood and other essential products for farming and pastoralist communities in the West African Sahel. In this region, mean annual rainfall decreases in general from south to north and from west to east, so one might expect clinal variation in fitness-related traits in relation to the rainfall gradients. This paper presents results from a provenance/progeny test of 11 provenances sampled in Niger and established at one relatively dry site in Niger. The objectives were to evaluate phenotypic correlations (Pearson r) between tree growth (height, stem diameter) and basic density of the wood, and clines in growth and density at 13 years. Tree growth and wood density were positively correlated, and the correlations differed among provenances. Mean tree height and stem diameter of provenances increased, in general, from the more humid to the drier parts of the sample region. Results suggest that selection of faster-growing trees could lead to an increase in wood volume and density in the subsequent generation, especially in certain provenances; that provenances from drier areas are better adapted to drought; and that tree improvement and conservation programs should collect seeds from populations in the drier areas for planting and conservation.     

光肩星天牛在黑龙江省的分布及危害特征

对光肩星天牛(Anoplophora glabripennis)在黑龙江省的危害地点、危害树种及危害部位进行了调查研究,结果表明:光肩星天牛在哈尔滨市周围地区形成严重危害,主要危害树种有哈青杨、小黑杨、柳树、家榆、白桦、文冠果、糖槭、茶条槭等;危害部位大多在树干中部区域。     

Hurricane Katrina impacts on forest trees of Louisiana's Pearl River basin

Hurricane disturbance has the potential to markedly affect coastal forest structure and ecosystem processes. This study focused on the impacts of Hurricane Katrina in Louisiana's Pearl River basin, which lies just west of Katrina's final landfall at the Louisiana–Mississippi border. Prior to landfall, composition and structure of bottomland hardwood forests in this region were studied with permanent forest inventory plots sampled in 1989, 1998, 2005 and following the storm in 2006. This enabled a direct comparison of forest structure and dynamics before and after the disturbance, including species-specific tree mortality and damage rates, biomass production, and differences among forest types having varied hydrologic regimes. Background tree mortality rate before Hurricane Katrina was 1.9%, while average annual mortality was 20.5% for the census interval including the disturbance. Change in live tree biomass estimated from allometric models demonstrated a shift from an average annual production of 3.5 Mg ha⁻¹ before the disturbance, to an average loss of 77.6 Mg ha⁻¹ from the storm. Damage associated with Hurricane Katrina varied significantly with tree species but not tree size. Flooded cypress-tupelo swamp forests sustained the least damage and frequently flooded bottomland hardwood forests sustained the highest damage. Hurricane disturbance influenced the structure and composition of these coastal forests through species-specific differences in damage and mortality rates, and varied impacts dependent on forest flooding regime.     

Growth and survival of Prosopis africana provenances tested in Niger and related to rainfall gradients in the West African Sahel

Prosopis africana (Guill., Perrott. and Rich.) Taub. is important for farming and pastoralist communities in the West African Sahel. It provides a range of essential products (wood, fuel, food, fodder and medicines) and services (soil fertility improvement), and is one of many native tree species maintained in the traditional agroforesty system, known as the parkland. However, this and other valuable species are disappearing in many parts of the region due to over-exploitation and, perhaps, due to increasingly drier conditions in the region. A provenance/progeny test (275 families from 28 provenances in Burkina Faso and Niger) was established at one location in Niger to investigate geographic variation in the species. Mean annual rainfall decreases from south to north and from west to east in the seed collection area. Given these gradients, one would expect clinal variation in growth and survival of P. africana and other tree species that occur naturally in the region. Tree growth (height, number of primary branches, stem diameter at 20 cm and 1.3 m) and survival were analyzed at 11 years. Variation due to provenances was significant for growth variables and almost significant for survival. Variation due to families within provenances was not significant for any variable. Provenance means for growth and survival increased from the more humid to the drier parts of the sample region. The clines in growth and survival with regional rainfall patterns suggest that tree improvement and conservation programs should collect seeds from populations in the drier zones for planting and conservation in the West African Sahel. This may be particularly important when one considers the trend in global warming.     

Biomass of fine and small roots in two Japanese black pine stands of different ages

The biomass and the spatial distribution of fine and small roots were studied in two Japanese black pine (Pinus thunbergii Parl.) stands growing on a sandy soil. More biomass of fine and small roots was found in the 17-year-old than in the 40-year-old stand. There were 62 g m⁻² of fine roots and 56 g m⁻² of small roots in the older stand, which represented mean values of 608 g for fine and 552 g for small roots per tree, respectively. In the younger stand, a total of 85 g m⁻² of fine roots and 66 g m⁻² of small roots were determined, representing a mean of 238 g for fine and 186 g for small roots per tree, respectively. Fine and small root biomasses decreased linearly with a soil depth of 0–50 cm in the older stand. In the younger stand, the fine and small roots developed only up to a depth of 30 cm. Horizontal distributions (with regard to distance from a tree) of both root groups were homogeneous. A positive correlation in the amount of biomass of fine and small roots per m² relative to tree size was found. Fine and small root biomasses increased consistently from April to July in both stands. The results also indicated earlier growth activity of the fine roots than small roots at the beginning of the growing season. The seasonal increases in fine and small root biomasses were slightly higher in the younger stand than the older stand.     

土壤调理剂在盐碱地造林实验研究

黑龙江省西部地区是我省农牧业生产的重要基地,盐碱土占该区面积2.1%。由于盐碱土的物理化和化学性质相对比较恶劣,土壤粘重,表层下有碱化层,含盐量和碱化度高,对树木生长影响较大,给该地区林业发展带来了很大难分难解度。为了降低盐碱土对树木生长的危害,研制了一种即能降盐碱土的含盐量和碱化度又能增加土壤怕肥力的调理剂。3年的试验证明调理剂施入土壤后,能够降低盐碱土的含盐量和碱化度,提高了造林成活率和保存率及树木生长率,试验达到了预期效果。     

天然麻栎单木地上生物量模型研究

通过对铜陵叶山林场麻栎样木地上生物量调查,以胸径、树高为自变量,地上总生物量、树干、树枝、树叶生物量为因变量,选择相对生长式、幂函数式和多项式为生物量回归模型,拟合各模型参数、相关指数、回归剩余离差,并计算生物量估测误差。结果表明:麻栎树干、树枝、树叶和地上总生物量与胸径、树高存在显著幂函数关系,其方程分别为:树干W=6.571×10-4D1.8473H2.411、树枝W=1.163×10-4D2.9497H1.3223、树叶W=0.0032D1.5148H0.8821、总生物量W=9.354×10-4D2.0825H2.1154。树干与总生物量的预估精度均达90%以上。     

帽儿山地区次生林椴树单木胸高断面积生长模型的研究

应用帽儿山天然次生林区不同林分条件下选设的20块椴树（Tilia amurensis）固定样地的解析木调查资料,分析多个单木竞争指标与对象木胸高断面积定期生长量的相关关系,在椴树单木胸高断面积生长模型中引入林木自身大小、单木竞争指标和立地因子,应用回归分析法建立帽儿山地区天然次生椴树单木胸高断面积生长模型。研究表明：天然次生林下椴树的胸高断面积定期生长量与对象木相对直径（RD）和竞争压力指数（SCI）等指标存在比较明显的相关关系。应用主分量线性组合的方法构造的综合竞争指标（MCI）包含了各竞争指标与胸高断面积生长量之间的绝大部分的相关信息,可以作为竞争指标应用于单木胸高断面积生长模型。