Agroforestry systems for the temperate zone

Historical development of a permanent agriculture system based on the use of agroforestry in the temperate zone is traced. In general, reasons for a renewed interest in agroforestry include the end of cheap, subsidized fossil fuels; increased concern about soil erosion and marginal land use; an international awakening as to the dangers of indiscriminate use of pesticides, herbicides and other chemicals; and a need to balance food production with other land uses.For the forestry profession in particular, reasons for interest in agroforestry stem from a need to revitalize rural economies, the desire to increase timber exports, and potential resolution to land use conflicts between agriculture and forestry. Through use of agroforestry management systems, an increase in both economic and silvicultural benefits are obtainable.Two agroforestry management systems are reviewed which currently appear feasible for implementation in many industrialized countries of the temperate zone. These two systems include: 1) Animal grazing and intercropping under managed coniferous forests or plantations; and 2) Multicropping of agricultural crops under intensively managed, high value hardwood plantations.Michigan Agricultural Experiment Station Paper No. 12046.     

Agroforestry education and training in Latin America

Regional/Country Report

Agroforestry education and training in Latin America     

Markets and marketing strategies for agroforestry specialty products in North America

Agroforestry Systems - In agroforestry, marketing is unique for several reasons: many products typically lack established marketing institutions, market information, and grade or quality standards....     

Agroforestry: a profitable land use. An overview of the 12th North American Agroforestry Conference

This special issue features papers contributed by presenters at the 12th North American Agroforestry Conference held June 4–9, 2011 in Athens, Georgia, USA. The conference brought together agroforestry researchers, educators, practitioners, and students to highlight agroforestry research, implementation, policy, education, and entrepreneurial opportunities across North America. Eight papers cover topics ranging from adoption of silvopastoral systems across eco-regions and countries; economics of pine straw production; and timber and alley crop production in the Southeastern U.S.; reduction of sublimation of snow with shelterbelts in Canada, carbon offset incentives for agroforestry practices; consumer and market dynamics for chestnut and elderberry specialty crops; and web-based graduate degree and certificate programs in agroforestry.     

Agroforestry training and education in Central America: learning from past experiences

While discussing existing and emerging programs in agroforestry education and training, it is important to review our experience in this field during the past nearly four decades in Central America. During the period, I have trained over 150 graduate students (26 of them completing MS degree with thesis), and offered 19 intensive short courses in several countries of the Latin American region. My experience from these activities shows that adequate library, documentation and research-field facilities, and a critical mass of training personnel are essential for the success of the graduate programs. Additionally, for the short courses, intensive field exercises in data collection and analysis should be given a high priority in the curriculum. Although past short courses have been of a general nature, future courses may focus on specific agroforestry technologies that are common in the region.     

北美:中国市场稳定

2010年是北美针叶锯材生产商不稳定的一年。尽管需求有所增长,但由于产量减少仍导致价格上涨,在春季和夏季暴跌前价格在4月份涨到最高点。针叶锯材价格在下半年有所回升,在2010年年底主要品种价格达到2009年12月份的水平。     

Hardwood silvopasture management in North America

Agroforestry Systems - Hardwood silvopasture management has great potential throughout the Central Hardwood Region in the United States, but has been little utilized due to the lack of available...     

Agroforestry for biomass production and carbon sequestration: an overview

Ever since the Kyoto Protocol, agroforestry has gained increased attention as a strategy to sequester carbon (C) and mitigate global climate change. Agroforestry has been recognized as having the greatest potential for C sequestration of all the land uses analyzed in the Land-Use, Land-Use Change and Forestry report of the IPCC; however, our understanding of C sequestration in specific agroforestry practices from around the world is rudimentary at best. Similarly, while agroforestry is well recognized as a land use practice capable of producing biomass for biopower and biofuels, very little information is available on this topic. This thematic issue is an attempt to bring together a collection of articles on C sequestration and biomass for energy, two topics that are inextricably interlinked and of great importance to the agroforestry community the world over. These papers not only address the aboveground C sequestration, but also the belowground C and the role of decomposition and nutrient cycling in determining the size of soil C pool using specific case studies. In addition to providing allometric methods for quantifying biomass production, the biological and economic realities of producing biomass in agroforestry practices are also discussed.     

Agroforestry for healthy ecosystems: constraints,improvement strategies and extension in Pakistan

Agroforestry Systems - Globally, forest ecosystems are shrinking and their health is declining due to a range of biotic and abiotic factors. Forest ecosystems in Pakistan...     

Agroforestry: working trees for sequestering carbon on agricultural lands

Agroforestry is an appealing option for sequestering carbon on agricultural lands because it can sequester significant amounts of carbon while leaving the bulk of the land in agricultural production. Simultaneously, it can help landowners and society address many other issues facing these lands, such as economic diversification, biodiversity, and water quality. Nonetheless, agroforestry remains under-recognized as a greenhouse gas mitigation option for agriculture in the US. Reasons for this include the limited information-base and number of tools agroforestry can currently offer as compared to that produced from the decades-worth of investment in agriculture and forestry, and agroforestry’s cross-cutting nature that puts it at the interface of agriculture and forestry where it is not strongly supported or promoted by either. Agroforestry research is beginning to establish the scientific foundation required for building carbon accounting and modeling tools, but more progress is needed before it is readily accepted within agricultural greenhouse gas mitigation programs and, further, incorporated into the broader scope of sustainable agricultural management. Agroforestry needs to become part of the agricultural tool box and not viewed as something separate from it. Government policies and programs driving research direction and investment are being formulated with or without data in order to meet pressing needs. Enhanced communication of agroforestry’s carbon co-benefit, as well as the other benefits afforded by these plantings, will help elevate agroforestry awareness within these discussions. This will be especially crucial in deliberations on such broad sweeping natural resource programs as the US Farm Bill.     

北美:加拿大的针叶材锯材产量显著增长

2010年第2及第3季度,北美个别地区针叶材锯材的产量呈显著上升趋势。总的来说,与第2季度相比,第3季度的生产总量有2%的增长。同时,加拿大BC省的针叶锯材产量有2%的增长,美国内陆地区的针叶材产量增幅为6%。所有其它地区的产量在第2季度均呈下降趋势。     

Comparing strategies for modeling individual-tree height and height-to-crown base increment in mixed-species Acadian forests of northeastern North America

Various methods for predicting annual tree height increment (?ht) and height-to-crown base increment (?hcb) were developed and evaluated using remeasured data from permanent sample plots compiled across the Acadian Forest of northeastern North America. Across these plots, 25 species were represented upon which total height (ht) measurements were collected from mixed-species stands displaying both single- and multi-cohort structures. For modeling ?ht, development of a unified equation form was found to result in higher accuracy and less bias compared to a maximum-modifier approach. Incorporating species as a random effect resulted in predictions that were not significantly different compared to predictions from species-specific equations for nine of the ten most abundant species examined. For ?hcb, equations that modeled changes in hcb over two time periods (i.e., an incremental approach) were either not significantly different from or significantly closer to zero compared to predictions that estimated hcb at two time periods (i.e., a static approach). Results highlight the advantages of incorporating species as a random effect in individual-tree models and demonstrate the effectiveness of modeling tree crown recession directly for application in mixed-species forest growth and yield models.     

Harvest impacts on soil carbon storage in temperate forests

Forest soil carbon (C) storage is a significant component of the global C cycle, and is important for sustaining forest productivity. Although forest management may have substantial impacts on soil C storage, experimental data from forest harvesting studies have not been synthesized recently. To quantify the effects of harvesting on soil C, and to identify sources of variation in soil C responses to harvest, we used meta-analysis to test a database of 432 soil C response ratios drawn from temperate forest harvest studies around the world. Harvesting reduced soil C by an average of 8 ± 3% (95% CI), although numerous sources of variation mediated this significant, overall effect. In particular, we found that C concentrations and C pool sizes responded differently to harvesting, and forest floors were more likely to lose C than mineral soils. Harvesting caused forest floor C storage to decline by a remarkably consistent 30 ± 6%, but losses were significantly smaller in coniferous/mixed stands (−20%) than hardwoods (−36%). Mineral soils showed no significant, overall change in C storage due to harvest, and variation among mineral soils was best explained by soil taxonomy. Alfisols and Spodosols exhibited no significant changes, and Inceptisols and Ultisols lost mineral soil C (−13% and −7%, respectively). However, these C losses were neither permanent nor unavoidable. Controls on variation within orders were not consistent, but included species composition, time, and sampling depth. Temporal patterns and soil C budgets suggest that forest floor C losses probably have a lesser impact on total soil C storage on Alfisols, Inceptisols, and Ultisols than on Spodosols, which store proportionately large amounts of C in forest floors with long C recovery times (50–70 years). Mineral soil C losses on Inceptisols and Ultisols indicate that these orders are vulnerable to significant harvest-induced changes in total soil C storage, but alternative residue management and site preparation techniques, and the passage of time, may mitigate or negate these losses. Key findings of this analysis, including the dependence of forest floor and mineral soil C storage changes on species composition and soil taxonomic order, suggest that further primary research may make it possible to create predictive maps of forest harvesting effects on soil C storage.     

北美三种类型公园的考察初探

通过考察北美地区文森特卢戈公园(Vincent Lugo Park)、巴尔波亚公园(Balboa Park)、史丹利公园(Stanley Park)三种不同类型公园,总结了北美社区公园、城市公园和自然公园在建设和管理工作中的特色和亮点;分析比较了三种类型公园在占地规模、受众群体、项目设施和公园管理等方面的差异和特点。     

北美极具特点的两个庭园观赏树种

美之花楸和君王红枫是很有特色的两个北美洲绿化树种,该文对这两个树种的生物学特性和分布区的自然气候状况进行了介绍。美之花楸果大,色彩鲜艳,在树上宿存时间长;君王红枫叶大、形美、颜色独特,可用于观叶和调节绿化造园搭配色彩。这两个树种都有很强的适应性和耐寒力,生长环境很类似中国东北地区,如果条件允许,引进这两个特色树种到中国北部地区搞庭园绿化,会大大改善绿化的冬季景观和生长季节的色彩搭配。