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51.
In Finland, recycling of wood-ash as a fertilizer has been widely studied in recent decades in peatlands drained for forestry. Wood-ash is reported to promote tree growth without any significant negative impacts on the environment and could, therefore, be a suitable option on cut-away peatlands, which are estimated to increase by 30,000 ha over the next ten years. However, the environmental effects of ash-fertilization on cut-away peatlands or on ground vegetation are not well known. We studied the effects of wood- and peat-ash application on the nutrient content in soil and plants and on the heavy metal content in the vegetation of a cut-away peatland. Six treatments of different quantities and mixtures of wood-ash, peat-ash, biotite, or Forest PK-fertilizer were replicated in three plots. Both wood- and peat-ash fertilization ensured an adequate level of nutrients for the early establishment and growth of ground vegetation and birch seedlings in a cut-away peatland. Dense pioneer moss cover was important in trapping the heavy metals, such as cadmium, which are present in the ash. Ground vegetation of mosses and herbaceous plants also had a major role in the retention of the nutrients that could otherwise have leached from the open cut-away peatland area during the early stages of afforestation. Both wood- and peat-ash proved to be suitable for the initial fertilization of afforested cut-away peatlands, but in order to guarantee a sufficient long-term potassium supply for tree growth, an application of biotite with the peat-ash is recommended.  相似文献   
52.
在福建三明市梅列区陈大镇棕南进行山乌桕等24个乡土阔叶树种山地造林对比试验,4年生结果显示,24个树种间的造林成活率、树高、胸径、冠幅生长量均存在极显著差异,表明山地造林成功的关键技术之一是树种选择。24种乡土阔叶树种的高生长与胸径(地径)生长均表现出极显著的正相关(P〈0.0001)。根据各树种的造林成活率与生长量的综合表现,山乌桕、枫香、山杜英、拟赤杨、石栎、木荷、杨梅在山地造林表现较优,可作为当地营造水土保持林、水源涵养林等生态公益林的首选树种。  相似文献   
53.
在10余年的观察研究基础上,通过对实验地的专业调查,评价桉树对漳州林业发展的贡献及存在问题,剖析桉树与杉木复层混交立体经营、不同世代复合经营培育复层林、不炼山造林近自然经营、生态采伐不炼山更新、生态经营培育中大径材等5种有利于桉树可持续发展新模式的营造技术及经营效果,为林业决策管理部门和营林实体提供借鉴和参考。  相似文献   
54.
We assessed the successional development of above- and belowground ecosystem biomass and carbon (C) pools in an age-sequence of four White pine (Pinus strobus L.) plantation stands (2-, 15-, 30-, and 65-years-old) in Southern Ontario, Canada. Biomass and C stocks of above- and belowground live and dead tree biomass, understorey and forest ground vegetation, forest floor C (LFH-layer), and woody debris were determined from plot-level inventories and destructive tree sampling. Small root biomass (<5 mm) and mineral soil C stocks were estimated from soil cores. Aboveground tree biomass became the major ecosystem C pool with increasing age, reaching 0.5, 66, 92, and 176 t ha−1 in the 2-, 15-, 30-, and 65-year-old stands, respectively. Tree root biomass increased from 0.1 to 10, 18, 38 t ha−1 in the 2-, 15-, 30-, and 65-year-old stands, respectively, contributing considerably to the total ecosystem C in the three older stands. Forest floor C was 0.8, 7.5, 5.4, and 12.1 t C ha−1 in the 2-, 15-, 30-, and 65-year-old stands, respectively, indicating an increase during the first two decades, but no further age-effect during the later growth phase. Mineral soil C was age-independent with 37.2, 33.9, 39.1, and 36.7 t C ha−1 in the 2-, 15-, 30-, and 65-year-old stands, respectively. Aboveground ecosystem C increased with age from 3 to 40, 52, and 100 t C ha−1 in the 2-, 15-, 30-, and 65-year-old stands, respectively, due to an increase in aboveground tree biomass. Belowground ecosystem C remained similiar in the early decades after establishment with 37, 39, and 39 t C ha−1 in the 2-, 15-, and 30-year-old stands, but increased to 56 t C ha−1 in the 65-year-old stand due to an increase in root biomass. The difference in total ecosystem C between the 2- and 65-year-old stand was 116 t C ha−1. Our results highlight the importance of considering the successional development of forest ecosystem C pools, when estimating C sink potentials over their complete life cycle.  相似文献   
55.
In south-western Australia, plantations of Eucalyptus globulus are being established on land that has previously been used for conventional agriculture. Sustaining the productivity of these tree plantations in second and subsequent rotations will depend partly on maintenance of soil fertility, especially soil nitrogen (N) supply rates. We compared soil N status and supply rates between adjacent pasture and 6-11 year old first-rotation eucalypt plantations at 31 paired sites in south-western Australia. Total soil N varied widely among sites (0.07-0.68% in the fraction <2 mm of the 0-10 cm soil layer), but concentrations averaged over all sites did not differ between land-use types. However, measurements of the indices of mineralization (mineral N produced during incubation of intact cores), potentially available N (from short-term anaerobic incubation) and model-predicted mineralization rates during 28-day aerobic incubations were generally lower in afforested soils than in pasture soils. This finding was supported by in situ field estimates of N mineralization over a full year at two contrasting paired pasture-plantation sites. At each site there was a marked reduction (2-3-fold) in net annual mineral N flux rates in soils under eucalypt plantations. Reduced N mineralization associated with tree plantations was due to both changes in soil organic matter quality and the generally lower soil moisture content under trees in comparison with pasture. These results suggest that N supply rates of pasture soils are likely to decline when the land is planted to successive crops of eucalypts. Eucalypt plantation managers will need to take account of this and implement management strategies to maintain adequate N nutrition to sustain tree growth in future rotations.  相似文献   
56.
在干旱或荒漠地区造林,降雨稀少,风多且风大,加之人力、物力的贫乏等原因,导致造林成活率低。采用保水剂、保水剂 地膜、保水剂 地膜 生根粉等几种抗旱技术,对臭椿的土壤含水量、生长情况、叶含水量及成活率进行了比较试验。结果表明,干旱地区造林中应用这些抗旱技术,与对照相比,均可以提高土壤含水量、叶含水量以及促进臭椿的生长,其中保水剂 地膜 生根粉综合技术处理的效果最好,保水剂 地膜处理的次之,最后是保水剂处理。干旱或荒漠地区采取有效的抗旱栽植技术,可以有效地解决造林绿化中的难题。  相似文献   
57.
以北京红坨山采石场为例,采用植生基质喷射技术、生态袋挡墙、"V"型种植槽垂直壁面绿化、客土造林等措施进行坡面的绿化防护设计与施工,为北京市矿山废弃地的生态恢复起到了示范作用。  相似文献   
58.
根据杨树光合营养器官的形态解剖特征、应用数学方法,推导出杨树扦插理论模型,再换算求解出造林密度模型。应用实例表明,两模型既有严格的理论基础、又容易取得模型参数,且计算简便,易于生产采纳。  相似文献   
59.
张尔  钱小香 《热带林业》2011,39(4):34-35
利用木麻黄营造沿海沙地防护林,不仅符合适地适树的造林原则,而且也是保护和恢复全省海防林带生态工程的有效途径之一.因此持续性发展木麻黄沿海防护林、苗木品种和造林技术至关重要.文章介绍了木麻黄沿海防护林造林技术,并对以后的造林工作提出了一些建议.  相似文献   
60.
This study describes the changes in height and diameter in Quercus ilex trees grown on agricultural land in a semi-arid Mediterranean climate, in response to different soil management practices: mechanical weeding (MW), chemical weeding (CHW) and no treatment (NT); and compares trees grown from 1-year-old saplings and from acorns. After 6 years, trees that had been mechanically weeded were largest; for trees grown from saplings the average height was 120 cm and diameter was 3.83 cm, for trees grown from acorns average height was 100 cm and diameter was 2.56 cm. Soil organic matter increased in all managed plots while phosphorus, nitrate, and water content oscillated between years. The no treatment plot had the highest values for nitrate and organic matter while the chemical weeding plot had the highest level of phosphorus. Annual mean on C/N ratios were higher in the mechanical weeding (12.6 ± 3.3) followed by the chemical weeding (12.0 ± 1.6). Also mechanical weeding treatment showed the lowest soil water content throughout the study. An old tillage-induced compaction zone appeared in all plots at a depth of 12.5–17.5 cm with mechanical weeding causing the greatest compaction. However, no relationships were found with tree heights, neither with spatial compaction zoning. All trees showed the same growth pattern, whether raised from saplings or acorns and irrespective of soil management system. The height and diameter of trees were linked to the sum of height and diameter ratios from previous years. Our study shows that soil management does influence tree growth rate. Mechanical weeding should be considered for afforestation of agricultural lands with Q. ilex in semiarid Mediterranean lands.  相似文献   
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