Modeling landowner participation in a proposed reforestation loan program

The absence of available credit to finance reforestation investments among NIPF landowners has been one of the contributing reasons why landowners do not reforest after harvest. Financial assistance programs are therefore a solution to initiating reforestation investments. However, previous studies indicate many landowners are not actively participating in existing government assistance programs. This paper examines reforestation loans as an alternative financial assistance program. Landowner participation in a proposed reforestation loan program is modeled using logistic regression. Results indicate that landowner participation in the program is influenced by ownership size, socio-demographic characteristics, and availability of other forestry incentive and assistance programs.     

黄土丘陵区退耕还林模式与生态农业建设新思路

通过调查，总出七种适用于黄土丘陵区退耕还林（草）的模式：乔、灌结合式、林草结合式、林粮结合式、集流高效经济林、集流高效经济林、集流速生用材林、集流灌、药、草经济林以及半退半耕式，同时提出生态农业建设的新思路；一必须坚持林体结构全面发展、土地资源全面绿化、林业资源综合利用的“两全一综”的林业发展战略；二必须实现用乔、灌、草覆盖“四荒”、用干鲜果覆盖农田的“两个覆盖”的奋斗目标，只有这样方能达到退耕还林和山区整体脱贫之目的。     

Long-term effect of different planting proportions on forest landscape in Great Xing’an Mountains, Northeast China after the catastrophic fire in 1987

A landscape model (LANDIS) was used to study the long-term forest dynamics under five planting types (100% larch (P₁); 70% larch and 30% Mongolian Scotch pine (Pinus sylvestris var. mongolica) (P₂); 50% larch and 50% Mongolian Scotch pine (P₃); 30% larch and 70% Mongolian Scotch pine (P₄); 100% Mongolian Scotch pine (P₅)), which were also employed in severely burned area under current planting intensity, and under natural regeneration (as a comparison) in Tuqiang Forest Bureau in the northern slopes of Great Xing’an Mountains after the catastrophic fire in 1987. Results showed that different planting types had a significant influence on the abundance of larch, Mongolian Scotch pine and white birch. The abundance of larch increased with time, whereas the abundance of Mongolian Scotch pine was in a converse way. The abundance of larch and Mongolian Scotch pine under these planting scenarios was higher than that under natural regeneration. Under these planting scenarios, the abundance of larch increased with the increasing proportion of larch, and the abundance of Mongolian Scotch pine was in a similar way. Contrary to larch and Mongolian Scotch pine, white birch had higher abundance under natural regeneration than that under these planting scenarios. Also, the different proportions of larch and Mongolian Scotch pine had an influence on the abundance of white birch. White birch had higher abundance with the increasing proportion of Mongolian Scotch pine. As for the total abundance of larch and Mongolian Scotch pine, the difference was not significant under P₂, P₃ and P₄ scenarios, but was higher than that under P1 and P5 scenarios, which indicated that individual-species planting should not be used in the forest landscape. __________ Translated from Chinese Journal of Applied Ecology, 2006, 17(5): 855–861 [译自: 应用生态学报]     

Site preparation alters biomass, root and ectomycorrhizal development of outplanted western white pine and Douglas-fir

This report documents impacts from manipulations of native forest soils and competing vegetation on development and ectomycorrhizal formation of outplanted western white pine and Douglas-fir in the Inland Northwest. Treatments were: 1) mounding surface horizons with competition left in place, 2) mounding surface horizons with subsequent physical or chemical control of competing vegetation, 3) scalping for control of competing vegetation, and 4) a control, or no postharvest disturbance. Treatments were applied on a low-altitude, relatively harsh site and on a higher altitude, more moderate site. Wich established seedlings, mounding with no competition control generally produced small seedlings (5–15g; both species) with low numbers of ectomycorrhizal short roots (21). Mounding with competition control produced large seedlings (20–48g) with moderate numbers of short roots (25). Scalping produced small seedlings (8–16g) with high numbers of short roots (41). The control also produced small seedlings (8–13g) but with a moderate number of short roots (27). Douglas-fir produced more short roots on the harsh than the moderate site. Western white pine produced high root to shoot ratios (above 0.60) in the mound with competition on the harsh site. Douglas-fir produced very high root to shoot ratios (above 1.0) in both the mound with no competition of the harsh site and in the mound with competition of the moderate site. Throughout, western white pine produced more ectomycorrhizae more rapidly than Douglas-fir. Ectomycorrhizal development and root and shoot weight of both conifers were adversely affected by competing vegetation.     

志丹县退耕还林视角下农业可持续发展的思考

90年代以来,得益于退耕还林的优惠政策及石油征占补偿,志丹县农业有了巨大的发展。在分析了农户收入结构及农业增长方式之后,认为,这是一种以要素密集投入为代价的资源消耗型的粗放式增长模式,有限的政策资源及自然资源不会带来长久的繁荣。探讨应如何根据资源消耗状况,来实现农业的可持续发展,为发展志丹县农业可持续发展提出几点建议。     

Linking Land Cover Changes in the Sub‐Alpine and Montane Belts to Changes in a Torrential River

Channel changes are the consequence of changes in sediment yield from the slopes and in the connectivity between slopes and channels because of distinct land use and climate impacts. In this study, we investigated the characteristics and evolution of a short reach in the headwater of the Ijuez River, central–southern Pyrenees. Assessment of a series of sedimentary and geomorphic structures confirmed major changes to the valley bottom, mainly related to changes in the intensity of human activity. The oldest sedimentary structure is a terrace level located 3 to 4 m above the current alluvial plain. General deforestation, overgrazing and recurring fires in the montane belt (1100–1600 m a.s.l.) have led to increased soil erosion and connectivity, and to the triggering of debris flows that have been deposited on the fluvial terrace. Woody fragments from within the debris flows were dated using accelerator mass spectrometry ¹⁴C radiocarbon techniques (AMS), yielding ages between 100 and 115 cal years bp , which coincides with the period of maximum deforestation and human density in the Pyrenees. Depopulation and farmland abandonment since the beginning of the 20th century has resulted in generalized natural and artificial reforestation, a shrinkage of the eroded areas and a decline in connectivity between slopes and the channel. The most important consequence has been channel incision and narrowing, and the development of a sediment armour layer. Active sediment transport is continuing, although there has been a decrease in sediment yield from the slopes. Copyright © 2014 John Wiley & Sons, Ltd.     

多情景退耕还林对林地生物多样性保护价值的潜在影响

退耕还林对生物多样性保护具有显著的正向影响,评估其生物多样性保护生态服务价值意义重大。现有研究多采用当量法计算生物多样性保护的生态服务价值,但该方法未考虑不同林地类型的差异化生物多样性价值,因而难以实现空间精细化评估。该研究从生态连通视角切入,以云南省保山市施甸县为例,根据坡度和相关政策设定1种现状情景(情景I)与3种退耕情景(情景Ⅱ、情景Ⅲ与情景Ⅳ),采用形态空间模式识别生态源地、指数法分析生态连通性和斑块重要性,进而计算各情景下的生物多样性保护的生态服务价值。在此框架中,该研究通过空间精细化手段修正各类林地的当量因子系数。结果表明：随着物种扩散距离的增加,生态连通性增加,情景Ⅱ、Ⅲ和Ⅳ的森林的生物多样性保护的生态服务价值均呈现增加趋势,依次增加了3.02×10⁷、4.7×10⁶和1.57×10⁷元,更有助于增加生物多样性保护生态服务价值的退耕方式是情景Ⅱ;从修正当量角度看,情景Ⅱ、Ⅲ和Ⅳ的修正当量系数分别为1.51、1.46和1.47,最有利的退耕情景为退耕程度最小的情景Ⅱ,而退耕程度最大的情景Ⅲ却没有取得相应的成效...     

Sustainable management of planted forests: some comparisons between Central Europe and the United States

Following the introduction of planned forestry and the regular high forest system more than 250 years ago, forests in Central Europe became increasingly shaped by plantation silviculture. Many natural woodlands were replaced by planted forests, and forest plantations are still being established through afforestation of extensive land areas. Nowadays, forests are managed for many different purposes, including wood production, recreation, ecological, cultural, and amenity values, biodiversity, and soil and groundwater protection. This brings new challenges to forest management and silviculture. To reach a sustainable forestry, in the sense of Brundtland (WCED 1987), we are now reshaping European forestry toward a more nature oriented silviculture. Maybe forestry in the United States and elsewhere can benefit from the mistakes made in Europe during the last two centuries and take a shortcut toward sustainable forestry.     

麻疯树的研究、利用现状及面临问题

麻疯树有很高的经济价值,是世界公认的生物能源树。文章介绍麻疯树育苗与造林技术的同时,分析国内外对麻疯树研究及开发生物柴油现状、面临的问题,并提出相应对策。     

Planting cost,survival, and growth one to three years after establishing loblolly pine seedlings with straight,deformed, or pruned taproots

To provide an objective approach for comparing various planting methods likely to differ in cost, seedling performance, and cost efficiency, loblolly pine (Pinus taeda L.) seedlings were dug-hole or slit planted with either straight, deformed, or pruned taproots, and planting rate (seconds per seedling) and three-year survival and growth of seedlings were measured. The per-hectare cost of dug-hole planting seedlings to ensure straight taproots ($273) was over five times that of slit planting seedlings with intentionally deformed or pruned taproots ($50). Although third-year pine survival did not differ significantly among treatments (74% to 87%), yield index was 58% higher for seedlings dug-hole planted with straight taproots (1152 dm³ stem volume/ha) versus that for seedlings slit planted with deformed or pruned taproots (730 dm³/ha). Third-year cost efficiency (yield index ÷ planting cost) of slit planted seedlings with deformed or pruned taproots (11.7 dm³/$) was over three times that of dug-hole planted seedlings with straight taproots (3.5 dm³/$). These short-term results suggest that the higher values of yield index resulting from straight-root planting do not justify its considerably greater cost.