Farmlink: promoting conservation buffers farmer-to-farmer

Farmer-to-farmer outreach was used within a targeted watershed to promote the installation of conservation buffers. In this program called “FarmLink”, four farmers/landowners were employed part-time as “advisors” and trained by University of Nebraska-Lincoln Extension, Natural Resources Conservation Service, and Natural Resources District personnel. Topics included basic buffer design and benefits, availability of incentive programs, and sales techniques. These individuals then contacted their neighbors to explain the need for and benefits of buffers and other conservation practices. In early 2003, 42 landowners were contacted, leading to contracts for the establishment of 16 separate conservation practices on 24.8 ha (61.3 acres) of farmland. These included just over 8 ha (20 acres) of grassed waterways or similar plantings and 14 ha (35 acres) of streamside buffers. In addition, because of information received in the training sessions, one of the advisors installed 1.7 ha (4.3 acres) of streamside buffers, 0.45 ha (1.1 acres) of grassed waterways, and 2.0 ha (5.0 acres) of grasses and forbs on his own land. During these contacts, it became apparent that: (1) many farmers and landowners were not familiar with the multitude of programs available to assist with the installation and maintenance of conservation practices; and (2) landowners generally appreciated the personal touch of someone coming out to talk directly to them, pointing out specific areas on their land where conservation practices could best be implemented, discussing available compensation programs, and describing management needed to help ensure practice success. Although one-to-one contacts cannot be used in all cases, it was demonstrated to be effective in this watershed.     

Biological consequences of clear-cut logging around streams—Moderating effects of management

Effects of riparian harvesting on in-stream biota were monitored in five streams in exotic conifer plantations that differed in how logs were extracted, patterns in deposition of woody debris, and the degree to which riparian buffers were retained. Streams were sampled on three occasions in summer, once prior to harvesting and twice afterwards. Consistent effects of harvesting included an increase in the amount of woody debris in the channel, increased fine sediment and a trend towards higher algal productivity. Invertebrate communities changed dramatically in some streams. General patterns included an increase in small sized taxa and taxa with generalist diets in the first year after harvest, then a trend towards a greater representation of grazers and larger taxa the following year. Responses in particular taxa were highly variable between streams. Some of this variability was related to forestry management, the least dramatic changes occurring where a narrow riparian buffer strip was retained. Reduced impacts were also observed in streams where woody debris was piled over the channel. We suggest that management practices that maintain shading of the stream channel will moderate forestry effects, and that practices such as channel cleaning are likely to be detrimental.     

Stream size influences stream temperature impacts and recovery rates after clearfell logging

Water temperature has profound effects on stream ecosystems. We studied effects of clear-fell logging Pinus radiata plantations on mid-summer water temperatures and recovery times in streams with 2–12 m wide channels. Post-logging increases were 2–3.8 °C for summer daily means and 4–7.3 °C for summer daily maxima. Rates of recovery of thermal regimes after logging were strongly negatively correlated with stream size, as indexed by catchment area, channel width or baseflow (r² = 0.80–0.93). Summer daily mean and maximum temperatures declined during the riparian vegetation regrowth phase by 0.18 and 0.47 °C year⁻¹, respectively, for the largest stream and 1.4 and 1.9 °C year⁻¹ in the smallest stream. Thermal regimes were restored in small streams (2–4 m wide channels) about 6–8 years after clearfelling. In medium-sized streams (6–12 m wide channels), we predict this recovery will take 12–16 years.     

Riparian forest and instream large wood characteristics,West Branch Sheepscot River,Maine, USA

This study examined riparian forest and instream large wood characteristics in a 2.7 km reach of the West Branch of the Sheepscot River in Maine in order to increase our basic knowledge of these components in a system that is known to have undergone multiple land conversion. The West Branch is approximately 40 km long, drains a 132 km² watershed and is vitally important to the remnant population of Atlantic salmon (Salmo salar) and other native species. The riparian forest is comprised of relatively small trees with a mean DBH of 21 cm (SD ± 10.92) with 56% of the trees having a DBH <20 cm. Balsam fir (Abies balsamea) and red maple (Acer rubrum) are the most common species (54%), and 75% of all trees are short-lived, small diameter species. These data suggest the riparian forest in the West Branch Sheepscot River is dominated by young forest stands, a legacy of land use. During a survey conducted in 2005, 210 pieces of large woody debris (LWD) were identified in the study reach; an average of 78 pieces km⁻¹. The total volume of pieces was 8.5 m³ or 3.2 m³ km⁻¹ (LWD in this study is defined as pieces ≥10 cm in diameter and >2 m in length). The mean diameter of LWD was 17 cm with 75% of all pieces having a diameter <20 cm. Most pieces were oriented parallel or nearly parallel to the channel and did not appear to influence channel morphology. In contrast, larger pieces were more often in perpendicular or nearly perpendicular orientations, and were more likely to have a pool-forming function. Overall, the reach has low levels of stable large wood, which do not have a major influence on stream habitats.     

Soil quality relationships with tree growth in exotic forests in New Zealand

Quantitative information on the relationships between site quality and plantation productivity (dominated by the exotic species Pinus radiata) is required to achieve goals for sustainable forest production. Soil quality is a key component of site quality. A nationwide study of soil quality measurements is reported for 35 representative forest sites, covering a wide range of climatic and edaphic conditions found throughout New Zealand's plantation forest estate, representing most of the soils used for plantation forestry in New Zealand. The objectives of the study were to find the most important soil properties that discriminated among eight New Zealand Soil Orders and determine relationships between Soil Orders and early tree growth rates for P. radiata and Cupressus lusitanica. Soil physical and chemical properties were measured to identify key soil indicators of soil quality related to tree productivity. Tree growth was measured after four years on small plots planted at very high stand density (40 000 stems ha⁻¹). A factorial design was used to examine the influence of three factors on tree productivity: two species, P. radiata D. Don (ectomycorrhizal) and C. lusitanica Miller (endomycorrhizal); with and without fertilizer; and low or high disturbance (soil compaction and/or topsoil scalping by machinery). Carbon content, Phosphorus (P) retention, and soil physical properties that index the degree of soil compactness were strongly correlated to Soil Order. These properties are similar to soil quality factors that correlated with tree growth. Discriminant analyses of soil quality parameters by Soil Order clustered soils based on P retention (phosphate absorption capacity), subsoil Carbon (C), and subsoil air capacity (volume % of voids at 10 kPa matric potential). Allophanic Soils and Podzols clustered (from plots of first versus second canonical variates) separately from the other Soil Orders, which were somewhat clustered on the second variate within a broad clustering on the first variate. Soil Orders were ranked for tree growth rates for both species: pumice Andisols > Inceptisols > tephric Andisols > Entisols > Ultisols > Spodosols (NZ classification: for P. radiata is Pumice > Brown > Pallic > Allophanic > Recent > Raw > Ultic > Podzol and for C. lusitanica Pumice > Pallic > Allophanic > Brown > Raw > Ultic > Recent > Podzol).     

河岸带落叶松林土壤氮素空间格局研究

通过对庞泉沟河岸带落叶松林的土壤氮素空间格局进行分析,了解河岸带全氮、铵态氮、硝态氮的储量以及氮素的空间格局,为河岸带对河流氮素的净化研究提供基础数据。结果表明：1）土壤表层氮素含量较高,土壤中全氮、铵态氮、硝态氮空间异质性明显,并且氮素在土壤层之间、高地连续体上存在不规则的垂直格局和水平格局。2）在高地连续体上,河岸带土壤全氮与硝态氮呈显著正相关（r=0.613）,全氮与铵态氮呈正相关（r=0.114）,全氮与与河岸带宽度呈负相关（r=-0.075）,铵态氮与硝态氮呈负相关（r=-0.004）。土壤氮素格局受多因素影响,氮素的形态与含量主要受地形、林分、降水以及土壤理化性质等因素的综合影响。     

西藏天然林资源保护与可持续经营

探讨了西藏天然林资源的现状、特点、问题,提出了天然林资源的可持续经营措施。     

谈在实施"天保"工程中保护永翠河的对策

本文从分析永翠河流域的现状入手，提出该河存在的问题，用森林生态学观点，提出在实施“天保”工程中保护永翠河流域的对策，为带岭局林业可持续发展提供重要参考。     

Methods to prioritize placement of riparian buffers for improved water quality

Agroforestry buffers in riparian zones can improve stream water quality, provided they intercept and remove contaminants from surface runoff and/or shallow groundwater. Soils, topography, surficial geology, and hydrology determine the capability of forest buffers to intercept and treat these flows. This paper describes two landscape analysis techniques for identifying and mapping locations where agroforestry buffers can effectively improve water quality. One technique employs soil survey information to rank soil map units for how effectively a buffer, when sited on them, would trap sediment from adjacent cropped fields. Results allow soil map units to be compared for relative effectiveness of buffers for improving water quality and, thereby, to prioritize locations for buffer establishment. A second technique uses topographic and streamflow information to help identify locations where buffers are most likely to intercept water moving towards streams. For example, the topographic wetness index, an indicator of potential soil saturation on given terrain, identifies where buffers can readily intercept surface runoff and/or shallow groundwater flows. Maps based on this index can be useful for site-specific buffer placement at farm and small-watershed scales. A case study utilizing this technique shows that riparian forests likely have the greatest potential to improve water quality along first-order streams, rather than larger streams. The two methods are complementary and could be combined, pending the outcome of future research. Both approaches also use data that are publicly available in the US. The information can guide projects and programs at scales ranging from farm-scale planning to regional policy implementation.     

Red alder leaf decomposition and nutrient release in alder and conifer riparian patches in western Washington,USA

Current management practices encourage conversion of red alder (Alnus rubra) riparian forests to conifers in the Pacific Northwest U.S. Patches of young naturally regenerated conifers are commonly present in alder dominated riparian areas and an understanding of the soil processes in these patches will be helpful in guiding future riparian management. Study objectives were to: (1) determine decomposition rates of red alder leaves in riparian alder and conifer patches, (2) relate decomposition rates to environmental factors and litter chemistry, and (3) determine nutrient release from decomposing alder leaves in these patches. Study sites were riparian areas adjacent to Brown and Le Bar creeks in the Skokomish River basin, Olympic National Forest, Washington. Red alder leaves were placed in litterbags in red alder and conifer riparian patches along each stream in November 2000 and collected after 1 and 3 years. There was rapid mass loss of alder leaves in the first year in both patch types, but decomposition was significantly faster (p < 0.05) in alder patches (43.2% mass remaining, k = 0.855 year⁻¹) than in conifer patches (48.4% mass remaining, k = 0.734 year⁻¹). There was little mass loss after the first year and no significant difference in decomposition rates. After 3 years mass remaining was 44.2% (k = 0.283 year⁻¹) and 47.8% (k = 0.48 year⁻¹) in alder and conifer patches, respectively. Decomposition rate differences were attributed more to the effects of the different litters in each patch and the influence on soil microbial and faunal communities than differences in soil temperature and moisture. The forest floor was deeper in conifer patches (3.7 cm) than alder (1.8 cm) patches. This was ascribed to slower decomposition rates in conifer patches, greater litterfall in conifer patches, and/or removal of alder surface litter by flooding. Alder patches were lower in elevation (0.8 m above bankfull width) than conifer patches (2.2 m). Forest floor and soil C and N concentrations and pHs were not significantly different in alder and conifer patches. Nutrient release from decomposing alder leaves was not significantly different in conifer and alder patches, although there was a trend for C, N, P, K, and Ca to be lost faster from leaves in alder patches than conifer patches in the first year. Red alder litter input to riparian conifer patches will initially decompose rapidly and provide nutrients, particularly N and P to conifers, as well as enhancing soil C since long-term decomposition rates are slow.     

城市森林研究中的几个问题

作者从植被生态学角度讨论了城市森林若干基本问题,如城市森林概念、城市森林分类、城市森林与生物多样性保护以及城市森林评价指标体系等,所阐述的观点希望对城市林业研究和管理有所启迪。       

台州市沿海围涂果园防护林效益调查研究

沿海围涂果园，采用“窄带小网型”防护林营建技术，能降低风速３６．８％－７０．％，减少落果３８．２％－６０．５％，提高空气湿度１％－３％，减少蒸发量１３．７％〉改善果园生态环境，促进果树生长，从而提高产量，该技术宜于南方滨海果园推广。     

印度北部丘陵地区水土保持措施

印度西北丘陵山区是人类和动物干扰非常敏感的地区。为了满足当地居民粮食、饲料、纤维和能源的需要．在脆弱的丘陵坡地进行农业生产是不可避免的。因此,为了确保土地资源的可持续利用,经过30多年在北部丘陵地区的实践证明,农林业技术措施不仅能实现农业高产而且能够促进水土保持。介绍了印度北部丘陵山区水土保持的主要措施。     

桉农间作系统土壤养分特征

主要对桉树大宽行条带方式种植的三年生桉农间作试验地土壤进行取样分析。对土壤养分研究表明:间作甘蔗、木薯和牧草在提高土壤有机质方面差异不大,但是在提高土壤全量N、P、K以及速效N、P、K上,间作甘蔗和牧草要优于间作木薯。其中,间作甘蔗和间作牧草全P和全N差异明显,而全K则和对照林地基本持平,速效N、P、K与对照林地相比,都有明显提高。间作木薯以提高全P为主,速效N和速效P也有一定幅度提高。     

滨水植被缓冲带水质净化研究

滨水植被缓冲带兼具生态、社会和经济价值。对其研究以生态学和水文学为基础,涉及多种学科和技术。我国滨水植被缓冲带的理论与实践研究均较为薄弱。文中从滨水植被缓冲带的结构特征及作用、滨水植被缓冲带水质净化机理和滨水植被缓冲带水质净化的影响因素3个方面进行论述,同时探讨总结了滨水植被缓冲带在水质净化方面需要进一步研究的突出问题。随着人们对水污染关注的增加,滨水植被缓冲带的生态净水方式将备受重视。     

次生林带状改造更新效果的研究

在次生林带状改造中 ,经过方差分析表明 :选择 6m、 4m采伐带宽度对落叶松更新成活率效果较好 ;不同树种更新效果有所差别 ,落叶松成活率最高 ,生长情况也好于其它更新树种 ,各更新树种保存率差异并不显著。