干旱阳坡人工直播造林配套技术研究

2008年秋季在内蒙古呼和浩特市和林格尔县、清水河县山地、丘陵区的干旱阳坡进行人工直播山杏、山桃造林试验。在播前播后实施工程性鼠害治理措施,鼠口密度共下降了85．3％～87．6％;直播造林从整地到抚育管理采用抗旱保苗技术措施,造林平均出苗率达到90％,平均保存率在85％左右。该项直播配套技术可用于半干旱区荒山丘陵的人工造林。     

Direct seeding of Quercus robur L. for reforestation: The influence of mechanical site preparation and sowing date on early growth of seedlings

Compared with conventional planting, direct seeding of Quercus spp. is a method that can reduce the costs of reforestation considerably. However, interference from natural vegetation and predation on acorns contribute to regeneration failures. Mechanical site preparation has the potential to reduce both these problems. To study the influence of sowing date and of different mechanical site preparation treatments on early seedling growth, an experiment was carried out in storm-felled areas, formerly Norway spruce forests, in southern Sweden from May 2006 to September 2008. Five treatments were applied and acorns were planted in May and July 2006. The treatments were: disc trenching, patch scarification, topsoil removal, mounding and an undisturbed control. A delay of less than two months in seeding resulted in the equivalent of one year's growth reduction with respect to oak seedling's height and biomass. This could be explained by delayed emergence of seedlings, and by the dry conditions during summer seeding. The seedlings only exhibited a weak positive biomass growth response following disc trenching, patch scarification and top soil removal. In the latter case this might be explained by increased soil compaction and extensive removal of the humus layer. Site preparation by mounding resulted in good vegetation control, an increased biomass growth response and deeper seedling roots. In this treatment, we found high relative light levels near seedlings, reduced soil moisture and dry bulk density of the soil and higher soil temperatures. One or more of these environmental factors could have influenced the growth response. Whether this increased early growth rate persists throughout young stand development is, however, uncertain.     

四川省黑水县花楸繁育技术研究

通过不同处理措施的苗床育苗和营养钵育苗观测试验,研究了花楸播种繁殖的出苗和生长情况。结果表明:(1)利用营养钵播种育苗,播种深度4 cm,出苗率最高,可达到90%,当年保存率为75%,大大高于土壤作床播种出苗率,(2)从生长量来看,用腐殖土、河沙及松针作为基质,苗床播种深度为5 cm的播种方式,出苗后1a内生长最高可达44.5 cm,最低11.5 cm,整体平均生长高度为29.3 cm,生长量较其它播种方式优势明显,(3)在高山峡谷地区进行花楸育苗,幼苗期间主要病虫害为立枯病和红蜘蛛,通过科学施用多菌灵和敌杀死,可有效控制。     

Improvement of direct tree seeding with cover crops in afforestation: Microclimate and resource availability induced by vegetation composition

The low cost of direct tree seeding makes it increasingly useful for afforestation. However, the success of the technique is often unpredictable due to a series of different adverse biotic and abiotic factors. A plant cover with low competitive ability towards resources could offer a natural alternative to the herbicides currently used to control weeds. The effects of cover plants on availability of resources and microclimate were studied in a field experiment in the central France during three years. An experiment design crossing three mixtures of tree seeds with four vegetation compositions (a bare soil, flora of the meadow, and two mixtures of cover plants) was established and repeated randomly in three blocks in a meadow. Vegetation composition, tree seedling emergence, light availability, soil water content, and temperatures under each treatment were measured. The vegetation composition of the meadow stayed stable, with grass species dominating. The cover plants sown disappeared rapidly after one or two years. Outcome of direct seeding of trees depended on the vegetation treatment. Bare soil gave the highest emergence rate while meadow vegetation gave the lowest, with the mixture of cover plants being intermediate. Light availability and soil water content were very low under the meadow vegetation but were very high on the bare soil, again with cover plant mixtures being intermediate. This study confirms that a bare soil obtained by herbicide is a secure way to ensure tree seedling establishment in afforestation by direct seeding. However, with the onus currently on reducing herbicide use, the results suggest that sowing a mixture of cover plants could be an acceptable alternative to herbicides. The cover plants could offer protection against frost, scorching temperatures, or the water run-off encountered on bare soil. However, there are also a number of unresolved issues that need be addressed before the cover plants technique can be recommended.     

Effects of Seed Invigoration and Microsite Preparation on Seedling Emergence and Establishment After Direct Sowing of Pinus sylvestris L. at Different Dates

Seed properties and seedbed conditions influence forest regeneration following direct seeding. It might therefore be possible to improve result by improving seed quality and seedbed conditions. In a direct seeding experiment designed to determine the effects of seed invigoration (incubation at 30% moisture content for 7 days) and microsite preparation (2-cm-deep pyramidal indentations) on the regeneration, sowing was repeated on eight different occasions, and seedling emergence, survival and height growth were recorded. Seedling emergence, mainly after early sowing, was improved by invigoration when used in combination with microsite preparation. Both survival and growth were impaired by delaying sowing until later in the growing season, but were not significantly affected by invigoration or microsite preparation. It is concluded that an improved and less varying regeneration result after direct sowing may be achieved by using invigorated seeds in combination with microsite preparation.     

Effects of post-fire management practices and slope-aspect on medium-term Spanish black pine regeneration: implications of using a direct seeding strategy in burnt areas

The natural regeneration of non-serotinous Spanish black pine (Pinus nigra Arn. ssp. salzmannii) is known to be null or limited after severe wildfires. However, it remains challenging to define efficient management strategies within the burnt area, which can help to increase the post-fire resilience of this species. We conducted a direct seeding experiment during 2011–2015 to assess the effect of different post-fire management treatments (control, soil ripping, woodchips, and soil ripping?+?woodchips) performed in opposite slope-aspects (north- and south-facing) on pine emergence, seed predation, survival, growth, and biomass allocation during the early stages of seedling development (1–5 years) after a severe wildfire. Our results showed that the slope-aspect did not have an important effect in both the seedling emergence and seed predation rates. In contrast, the influence of slope-aspect was significant as both survival and growth of pine seedlings were reduced at the south-facing slope-aspect compared to the north-facing slope-aspect due to harsher environmental conditions. A variable and reduced impact on seedling emergence and seed predation rates was induced by both soil ripping and woodchips treatments. Overall, post-fire management treatments helped to enhance survival rates during early growth stages, although this effect was short-lasting. This knowledge can be used to define post-fire seeding management strategies oriented to enhance the resilience of severely burnt pine forest stands; therefore, while both the soil ripping and woodchips treatments might not be practices leading to increase their post-fire regeneration, direct seeding at north-facing slope-aspects could be a more appropriate management strategy.     

宁镇丘陵山地农膜覆穴营造杉木林效益试验

采用农膜覆穴营造杉木林，有利于增加地温，保持土壤湿度，并具防寒，抗旱作用，能提高造林成活率和促进苗木生长，造林时如用土球苗，地膜全部覆在土下５ｃｍ深处，效果则更好。     

油松种子包衣山地直播造林及效果分析

结合北票气候特点,进行了油松种子包衣山地直播造林试验,结果表明,油松种子包衣直播造林后,保证了山地造林的出苗率,多效复合剂包衣比对照出苗率提高5.4倍以上,同时提高了苗木生长量,防止了鸟、鼠、兔等野生动物和松苗立枯病危害,提高了山地造林的成效。     

四照花和狭叶四照花种子的萌发试验

对四照花和狭叶四照花种子进行不同处理的萌发试验。结果表明四照花种子的发芽率显著高于狭叶四照花种子；干藏1年的狭叶四照花种子的生活力已完全丧失。经用0．05％赤霉素预处理后沙播的四照花种子，其发芽率极显著高于未使用赤霉素处理的沙播和土播的种子，且种子出苗整齐，发芽快，发芽时间比其提前4～7天；用0．05％赤霉素处理后沙播的种子和未用赤霉素处理直接土播的种子，其发芽率显著高于未经赤霉素处理而沙播的种子。狭叶四照花仅土播种子与沙播种子间存在差异。试验结果还表明四照花和狭叶四照花种子的萌发需要经过一个低温阶段。     

青钱柳种子赤霉素处理育苗研究

为了研究青钱柳种子破除休眠,提前播种出苗的方法。采用赤霉素不同浓度溶液对青钱柳种子进行"浸泡后直接播种"、"浸泡并沙藏后播种"2组种子处理育苗试验。结果表明:浸泡后直接播种没有打破种子休眠,播种当年出苗率为0,第2年才出苗;浸泡并沙藏后播种能打破种子休眠,播种第1、2年均出苗,总出苗率13.54%~28.13%,第1年出苗率2.08%~5.21%,占总出苗率的9.1%~27.8%。其中,赤霉素500、750 mg/L浓度溶液浸泡及沙藏处理后,破除种子休眠效果明显,当年出苗率为5.21%,依次占总出苗率的23.8%、27.8%,是适宜的种子处理溶液浓度。     

Seed Biology,Stand Characteristics,and Regeneration of Fraxinus rhynchophylla Hance

Fruit size and seed moisture content were measured and seed production and dispersal were monitored to understand the seed biology of the Korean ash (Fraxinus rhynchophylla Hance) in two Korean ash forests. A combination of four ground treatments and four crown closure levels were created in a natural forest to understand the site conditions needed for seedling emergence in natural stands and to determine practical regeneration methods for direct seeding. The seed size of Korean ash increased until late May and its moisture content decreased rapidly in early November. Prolific seed bearing occurred every 3 yr. The distance of seed dispersal by wind was about 30 m, but more than 90% of the seeds dispersed within 10 m from the seed trees. Twenty-five seed trees per hectare provided for successful natural regeneration. The seedling emergence in the natural stands was best with scarification treatment and 25～50% of crown closure.     

七叶一枝花种子育苗技术研究

采用种子冷藏和沙藏后控温催芽的方法,研究七叶一枝花种子育苗技术。结果表明:种子的出苗率达到了70%~80%。冷藏的种子育苗,其苗床育苗和种植地直播育苗的发芽率和出苗率均高于沙藏的;种植地直播育苗的发芽率和出苗率大小为核桃林杉木林金银花林;苗床育苗1年后移栽于不同林分下,其成活率冷藏的也高于沙藏的,其大小为核桃林杉木林金银花林,与不同林分下种子直播的结果基本一致,但移栽的成活率比种子直播的成活率要低。     

Effects of soil organic matter,moisture, shading and ash on white pine (Pinus strobus L.) seedling emergence

The effects of soil organic matter, soil moisture, shading and ash on white pine (Pinus strobus L.) emergence were investigated using soil monoliths in greenhouse experiments. White pine seedling emergence increased with soil organic matter removal, and levelled with the elimination of the litter and fermentation layers, where seedling emergence did not significantly increase further. Increased shade and soil moisture levels also improved seedling emergence whereas ash had no or little impact on white pine seedling emergence. The silvicultural implications of these findings are discussed with regard to white pine management.     

Factors influencing establishment by direct seeding of indigenous tree species in typical plantations and shrubland in South China

Seed limitation of desired indigenous species has constrained the succession of established plantations from an early successional stage, to more natural forests in South China. Because of its low cost and time-saving advantages, direct seeding has been considered a useful method in forest regeneration. To improve our understanding of whether and how direct seeding can lead to the establishment of indigenous tree species, we carried out an experiment in four typical plantations (eucalyptus, mixed-native, mixed-legume, mixed-conifer) and a shrubland in South China. We also tested the effect of understory vegetation and litter removal on seedling establishment and growth. Seeds of three indigenous tree species (Castanopsis chinensis, Cryptocarya chinensis, and Psychotria rubra) were sown with understory vegetation and litter either retained or removed. Seedling emergence, survival, and growth were recorded for 21 months. We found that conditions that favored seedling emergence often differed from those that favored seedling survival. While the removal of understory vegetation and litter did not influence the final seedling establishments for all the three introduced species, growth of Psychotria rubra was influenced at several sites. Seed mass was positively correlated with seedling emergence and subsequent growth. The large-seeded Castanopsis chinensis showed higher emergence and growth than the intermediate-seeded Cryptocarya chinensis or the small-seeded Psychotria rubra. Seedlings of Castanopsis chinensis grew better in plant communities with high understory light penetration and high soil exchangeable potassium. Growth of P. rubra seedlings decreased significantly with soil hydrolyzed nitrogen. In conclusion, direct seeding can be useful for the establishment of indigenous tree species into plantations and shrubland. Optimizing early seedling establishment and growth will require the selection of suitable native species for improving seedling establishment in different plantations. Additionally, understory vegetation and litter and fertilizer should be properly managed to enhance the establishment of certain indigenous tree species.     

农作物及果园地面覆盖研究综述

地面覆盖能起到增肥、保墒、防热、预防根系冻害和改善土壤理化性状的作用,促进土壤有机质和营养物质的积累、分解和转化,从而复壮树势,提高果品的产量和质量。为给有关地面覆盖对经济林木的影响的研究提供参考和依据,综述了有关地面覆盖对农作物及果园土壤中水、肥、气、热及微生物等肥力因子的影响方面的研究成果和研究进展。     

Effects of seed traits on the success of direct seeding for restoring southern Thailand’s lowland evergreen forest ecosystem

The success of direct seeding, as a low-cost approach to forest restoration, varies with tree species and seed characteristics. A system to predict which tree species are likely to be suitable for direct seeding would therefore be useful for improving forest restoration projects. Therefore, this study aimed to determine the effects of seed traits on the success of direct seeding to restore tropical forest in southern Thailand. Seeds of 19 indigenous lowland tropical forest tree species were collected, from both the east and west sides of the Thailand peninsular and the following parameters measured: seed size, shape, coat thickness and moisture content. Field trials were established to determine seed germination rates and to calculate a “direct seeding suitability score” for each species, which combined seedling establishment and growth rates. Seed size, shape and moisture content were associated with germination percentage. Species with higher seedling survival tended to have large or intermediate-sized seeds, round or oval seeds and seeds with low or medium moisture content. Only seed coat thickness was significantly correlated with the suitability score (r = 0.65, p < 0.01). Seed coat thickness >0.4 mm coincided with higher rank suitability score. These conditions successfully predicted the success or failure of direct seeding for 15 out of 19 species tested. Eight tree species are recommended as suitable for restoring lowland evergreen forest ecosystems in southern Thailand, by direct seeding.     

封禁条件下沙地飞播植被与生境的变化研究

通过对飞播林地封育后5a来的植被状况、土壤水分、土壤有机质及养分（N、P、K）含量等的调查研究,得出流动沙地经飞播造林种草封育5a后,使沙地得到了固定和半固定,地表风蚀减弱,沙物质得到固定,结皮层形成,土壤有机质和肥力提高,小气候得到了改善,但土壤水分含量有所下降,各个种在群落中的地位也发生了变化。     

壳斗科3树种直播造林试验研究初报

对丝栗栲、青冈和毛果青冈直播造林的试验研究表明:直播造林能有效提高造林成活率,但树种间差异显著,青冈达94 00%,毛果青冈为83 92%,丝栗栲仅63 59%;壳斗科树种种子的含水量较高,种子发芽基本上不需外加水分;防止啮齿类动物挖食是直播造林成功的关键,预防方法有:行为信息应用、选择种子丰年播种、清除造林地灌草等。     

干旱沙区沙地云杉育苗技术及幼苗生长节律

以沙地云杉种子和1年生种子播种幼苗为试验材料,研究遮阴与否和不同覆沙厚度对沙地云杉幼苗保苗率和出苗率的影响。结果表明:从出苗到越冬,遮阴处理和不遮阴处理幼苗保存率为69.04%、17.35%,干旱荒漠区播种育苗覆沙适宜厚度0.5 cm。幼苗年生长规律研究表明:苗木地径和苗高的年生长规律基本相似,高生长从6月进入快速生长期,而地径生长从6月20日进入快速生长期,到7月苗高生长和地径生长趋于平缓,8月苗高生长和地径生长基本停止。在生长期幼苗地下部分干质量百分率和地上部分干质量百分率在生长季内持续上升,经回归分析,地下部分和地上部分干物质积累回归方程分别为:Y=0.000 2x-8.5223、Y=-1-0.6x2+0.092 9x-1 877.4。通过相关分析表明,影响地径和苗木生长的主要环境因子为最低气温、20 cm土壤温度、15 cm土壤温度和10 cm土壤温度。     

种植深度对栓皮栎种子萌发及幼苗生长发育的影响

为了了解林木种子直播过程中,播种深度对林木种子出苗率及幼苗生长发育的影响,在济源王屋山地区次生栓皮栎林内,设置4 cm和12 cm两种播种深度,种植100枚健康栓皮栎种子,定期观察记录其发芽和成长状况。结果显示:①4 cm条件下,栓皮栎的发芽率为92%,而12 cm条件下,发芽率仅为62%,二者差异显著;②在2种种植深度下,栓皮栎幼苗的地上茎长度分别为11.79±0.55 cm和11.41±0.65 cm,差异不显著,而叶片数分别为10.33±0.68和9.54±1.13,亦无显著差异。由此可见,在一定范围内,种植深度对林木种子的发芽和出苗率有直接影响,但对出苗后幼苗的生长发育并无明显影响。