杉木优良无性苗木造林效果初步研究

通过对不同来源无性苗木、无性苗木在不同立地条件下的生长表现以及与实生林对比试验 ,分析了无性造林效果。试验结果表明 :经选择的优良无性苗木具有较高的生产力。

Effect of Acorn Burying Depth on Germination, Seedling Emergence and Development of Quercus aliena var. acuteserrata

Acorns of Quercus aliena var. acuteserrata Maxim. are often predated by small mammals and birds in natural forests. These animals not only eat the acorns during the acorn ripening season, but also cache and hoard most of the remaining acorns on the forest floor in the soil for their future use. These buried acorns form the main seed resource for regeneration. Burying depth is potentially important for germination and for seedling development. The effects of burying depth on germination and seedling development in relation to acorn size were studied in an experiment, in which acorns were planted at 6 cm-, 12 cm- and 18 cm-depth. The experimental results showed that fewer acorns germinated as burying depth increased. From the deeply buried acorns fewer seedlings emerged at later time than from those acorns buried less deeply. They appeared to have more difficulties to emerge above-ground than die seedlings from shallowly buried acorns. The deeply buried acorns and their seedlings also appeared to be more susceptible to rot. Acorn size did not significantly affect germination and emergence of the seedlings. As early emerged seedlings had longer developmental periods in their first growing season, and therefore grew better than die late emerged seedlings, seedlings from die shallowly buried acorns took the advantage.

林业工程苗木培育及病虫害防治技术

随着生态环保理念的广泛普及,人们对林业工程建设的重要性认识越来越深刻,对林业工程的关注度也不断提高。建设林业工程时,苗木培育及病虫害防治,是重点环节。培养苗木时,必须注意提升苗木的整体质量,在对病虫害进行防治的过程中,必须注意防治方法的运用,确保防治方法科学合理,能够为苗木实现健康生长起到重要的保障作用。本文对林业工程苗木培育及病虫害防治技术进行深入分析,并结合实际情况提出科学合理的建议,为提高我国林业工程建设水平,推动我国林业工程实现可持续发展,提供支持和帮助。

An environmental gradient change of Picea mongolica seedling from the center of a forest canopy gap in forest-steppe ecotone in Inner Mongolia Autonomous Region of China

In sandy forest with a forest canopy gap for a period of over 30 years, the spruce（Picea mongolica） seedlings were monitored on two 5-m- wide transects from the center of a large gap into the surrounding forest. The farther they were to the far center, the taller grew the seedling and the more is the number of seedling. There were many seedlings under the canopy but almost all seedlings died before they grow up. Along the forest edge, growth of seedlings was temporarily enhanced by lateral penetration of light from the gap. The implications for natural forest regeneration dynamics are discussed. Our results prove that in P mongolica forest a gap disturbance creates a non-uniform environment for regeneration of the species, and determines that the forest was a non-even aged forest.

The fate of ^(15)N-labeled nitrogen inputs to pot cultured beech seedlings

The partitioning of nitrogen deposition among forest soil （including forest floor）, leachate and above- and belowground biomass of pot cultured beech seedlings in comparison to non-cultured treatments were investigated by adding 1.92 g.m^-2 ^15N tracer in throughfall for two successive growing seasons at a greenhouse experiment. Ammonium and nitrate depositions were simulated on four treatments （cultured and non-cultured） and each treatment was labeled with either ^15N-NH4^＋ or ^15N-NO3^-. Total recovery rates of the applied ^15N in the whole system accounted for 74.9% to 67.3% after ^15N-NH4^＋ and 85.3% to 88.1% after ^15N-NO3^-in cultured and non-cultured treatments, respectively. The main sink for both ^15N tracers was the forest soil （including forest floor）, where 34.6% to 33.7% of ^15N-NH4^＋ and 13.1% to 9.0% of ^15N-NO3^-were found in cultured and non-cultured treatments, respectively, suggesting strong immobilization of both N forms by hetero- trophic microorganisms. Nitrogen immobilization by microorganisms in the forest soil （including forest floor） was three times higher when ^15N-NH4^＋ was applied compared to ^15N-NO3^-. The preferential heterotrophic use of ammonium resulted in a two times higher retention of deposited ^15N-NH4^＋ in the forest soil as compared to plants. In contrast, nitrate immobilization in the forest soil was lower compared to plants, although statistically it was not significantly different. In total the immobilization of ammonium in the plant-soil system was about 60% higher than nitrate, indicating the importance of the N-forms deposition for retention in forest ecosystems.

Effects of Disturbance Intensities on Vegetation Patterns in Oak Forests of Kumaun,West Himalaya

In order to realize the significance of oak forests for ecology and economy of the Himalayan region,the present study attempts to objectively characterize disturbance intensities and their impacts on compositional features of identified Oak forests, i.e.Banj-oak(Quercus leucotrichophora A.Camus), Tilonj-oak(Q.floribunda Lindley)and Kharsu-oak(Q. semecarpifolia J.E.Smith)in west Himalaya. Amongst studied forests,Q.leucotrichophora and Q. semecarpifolia forests exhibited high sensitivity towards disturbance intensities.In both forests, increasing level of disturbance significantly lowered tree density,dominance and natural recruitment (seedling and sapling density).Q.floribunda forests, however,appeared relatively more resilient to anthropogenic disturbances.Amongst studied oak forests,Q.semecarpifolia forests with overall poor natural regeneration are in a most critically endangered demographic state.However,a slightly improved regeneration(i.e.,seedling density)in moderately disturbed plots is indicative that such plots may be utilized most suitably for in situ revival of these forests.Effect of disturbance intensities on tree population is an important subject for forest ecology and management and the present study highlights a need for adopting different management strategies across disturbance intensities in diverse oak forests of west Himalaya.

Effects of Trichoderma harzianum YC_(459) and soil types on seed germination and seedling growth in rock slope restoration

We carried out experiments with various concentrations of Trichoderma harzianum YC459 in different soil types(forest soil, mixed soil,merchantable soil, and leaf mold soil) to evaluate its effect on seed germination and seedling establishment of four species(Festuca arundinacea Schreb., Dianthus barbatus var. asiaticus Nakai,Lespedeza cyrtobotrya Miq., and Parthenocissus tricuspidata Planch) for rock slope restoration. We also investigated the use of drilled slanted holes on the rock slopes for seedling establishment. The results showed that T. harzianum concentration had significant effects on seed germination, seedling growth, and seedling survival for all the species with different soil types. Seed germination and survival rates peaked at 5% T. harzianum concentration with leaf mold soil and decreased as T. harzianum concentration increased from 5% to 10%. Seedling survival rates of all four species were generally lowest at 0% T. harzianum concentration in all soil types.The height of F. arundinacea and L. cyrtobotrya peaked at 5% T. harzianum concentration whereas that of D. barbatus and P. tricuspidata peaked at 10%T. harzianum concentration. We concluded that 5% T. harzianum concentration with leaf mold soil is appropriate for seed germination and seedling survival rates of most species, thus enhancing seedling establishment. Practical application of the findings of this study will contribute in the vegetation restoration of steep rocks in mountain environments.

Design and Development of a Forest Nursery, for the Enhancement of Multi-Functional Agriculture and for a Didactical Purpose

The experimental idea of the present project was elaborated in order to create a structure where different categories and institutions could collaborate, with the common aim to develop a sustainable and profitable agriculture in mountain and marginal areas. The target was the recovering of an abandoned agricultural site, throughout its re-organisation, re-qualification and auto-sustainability, involving local citizens. This approach was based on three further broad functions such as environmental, economic and social purposes. This cooperation, that allows the capitalization of local knowledge and the forging of relationships between local and external sources of expertise, information and advice, is fundamental to the future of existing rural communities, in particular in mountain areas. The model proposed, with the elaboration of a management software and technical agronomic sheets, could be an incentive for the activities already present in that region and to stimulate new ones. The enhancing of the native ecological system, the biodiversity tutelage and the valorization of the knowledge of the territory is the basic requirement for the successful of any land management.