Effects site conditions on industrial fiber plantations of Lar/x olgensis

Plot sampling was conducted in the second cultivation areas ofLarix olgensis in Heilongjiang Province, China. By analyzing plot investigation data, wood properties, and kraft pulps of 840 plots and 248 sample trees in industrial plantations of L. olgensis on different sites, we examined the growth process of L. olgensis industrial plantation with suitable structure, the wood fiber feature, chemical composition, physical performance and pulp characteristics. It is suggested that site conditions have major effects on plantation growth, fiber contains, fiber length, rate between fiber length and fiber width, pulping rate and pulp physics intensity. The best site for L. olgensis industrial plantation growth is site class Ⅰ and site class Ⅱ, which are on lower locations. Site condition has an obvious influence on the wood characteristics. Within the range of site conditions and stand densities studied, the worse the site condition, the less the fiber contains, the shorter the fiber length, and the more the 1% NaOH extraction. This kind of relationship becomes more obvious as stand age increases. However, the influence of site condition on pulping rate and pulp physics intensity is not obvious. The result provides theoretical base for cultivation of industrial fiber plantation of L. olgensis.     

Length of cuttings in establishment and production of short-rotation plantations of Salix ‘Aquatica’

The effect of length of cuttings, 10 to 50 cm long, on establishment and productivity of short-rotation plantations was investigated in five trials, for periods of 2 to 9 years. The trials were established on abandoned agricultural fields planted with unrooted Salix Aquatica cuttings. The effect of cutting length was very similar in all five trials: the longer the cuttings (up to 30–50 cm), the better the survival and growth. In most trials the greatest difference in survival was between cutting lengths of 10 and 20 cm, especially in unfavorable growing conditions. In an annually harvested trial during the 9-year test period, a cutting length up to 30 cm affected biomass production per stool positively. In two trials grown with 5-year rotation, the longest cuttings produced 7 times the above-ground biomass of the shortest ones. Results of these trials also emphasize the importance of establishment for the future success of willow plantations.     

Effects of environmental factors on seedling growth and anthocyanin content in Betula ‘Royal Frost’ leaves

Determining the influences of environmental factors on seedling growth and leaf color may improve our understanding of the chromogenic mechanisms in leaves and the biosynthesis of anthocyanin. To determine the optimum conditions for Betula ‘Royal Frost' seedling cultivation, we assessed seedling growth and anthocyanin content under natural conditions. The temperature had a significant influence on height but not on radial growth.Between June and September, the anthocyanin content was significantly positively correlated with light intensity and air moisture and significantly negatively correlated with temperature. In single-factor experiments to determine the variation in anthocyanin content in the greenhouse, anthocyanin content increased with increasing soil water content and at first increased, then decreased with increasing p H of the irrigation water and temperature, but decreased with increasing light intensity. K_2SO_4 can increase the anthocyanin content. So to maintain leaf color, seedlings should be cultivated with 200 lmol m~(-2) s~(-1) light intensity at 20 °C and soil moisture content between 60 and 90%, and the irrigation water should be neutral or alkaline. Additionally, spraying with K_2SO_4 can be beneficial.     

Effects of Cold Acclimation on Several Enzyme Activities in Euonymus radicans ‘Emorald & Gold’and Its Relation to Semi-lethal Temperature

The changes in activities of superoxide dismutase (SOD), peroxidase (POD) and ATPase in the leaves of Euonymus radicans were studied when seedlings were cold-acclimated (at 4 ℃) for 1 week, 2 weeks, 3 weeks and then treated for 1 d under low temperature stress (at 5 ℃). The semi-lethal temperatures of acclimated and unacclimated seedlings were also investigated. The results indicated that the activities of the three enzymes in the leaves of the seedlings treated at 4 ℃ for 1, 2 and 3 weeks were all higher than those of unacclimated seedings (treated at 22 ℃ as controls). The activities of SOD and POD increased continuously with the prolongation of the time of cold acclimation, but stepped up to summits then down to the levels of the controls. The activities of SOD culminated at the first week, and the activities of POD at the second week. When acclimated and unacclimated seedlings were both treated at 5 ℃ for 1 d, the activities of the three enzymes in the leaves of acclimated seedlings were a little lower than those before stress, but higher than those of the controls. Moreover, the decrease rate of enzyme activities was greatly lower than that of the controls. The results showed that cold acclimation could enhance the stability of the three enzymes in the leaves of seedlings under low temperature stress; the semi-lethal temperature was 19.1 ℃ when the seedlings were treated at 4 ℃ for 3 weeks, but it was 5.4 ℃ when the seedlings were treated at 22 ℃. The decline of the semi-lethal temperature caused by the adaptive changes of enzyme activities was one of the foundations of enhancing the cold tolerance.     

Effects of ethylene and (Z)-hexen-3-al on production of volatiles in Populus simonii × P. pyramidalis ‘Opera 8277’ cuttings

We studied the effects of ethylene, (Z)-hexen-3-al, combinations of ethylene and (Z)-hexen-3-al, methyl jasmonate on the release of terpenoids and green leaf volatiles (GLVs) of Populus simonii × P. pyramidalis ‘Opera 8277’ by fumigation. The results show that exposure to ethylene alone did not induce volatiles. However, it was induced by exposure to combinations of (Z)-hexen-3-al and ethylene, a large amount of hexenal and hexen-3-ol as compared to sole (Z)-hexen-3-al exposure, which indicated that the release of wounding signals of P. simonii × P. pyramidalis ‘Opera 8277’ could be synergized by ethylene and (Z)-hexen-3-al. __________ Translated from Journal of Northwest Forestry University, 2008, 23(2): 143–146 [译自: 西北林学院学报]     

Effects of Cold Acclimation on Several Enzyme Activities in Euonymus radicans ‘Emorald & Gold’ and Its Relation to Semi-lethal Temperature

The changes in activities of superoxide dismutase (SOD), peroxidase (POD) and ATPase in the leaves of Euonymus radicans were studied when seedlings were cold-acclimated (at 4℃) for 1 week, 2 weeks, 3 weeks and then treated for 1d under low temperature stress (at-5℃).The semi-lethal temperatures of acclimated and unacclimated seedlings were also investigated.The results indicated that the activities of the three enzymes in the leaves of the seedlings treated at 4℃ for 1, 2 and 3 weeks were all higher than those of unacclimated seedings (treated at 22℃ as controls). The activities of SOD and POD increased continuously with the prolongation of the time of cold acclimation, but stepped up to summits then down to the levels of the controls. The activities of SOD culminated at the first week, and the activities of POD at the second week. When acclimated and unacclimated seedlings were both treated at -5℃ for 1d, the activities of the three enzymes in the leaves of acclimated seedlings were a little lower than those before stress, but higher than those of the controls. Moreover, the decrease rate of enzyme activities was greatly lower than that of the controls. The results showed that cold acclimation could enhance the stability of the three enzymes in the leaves of seedlings under low temperature stress; the semi-lethal temperature was -19.1℃ when the seedlings were treated at 4℃ for 3 weeks, but it was -5.4℃ when the seedlings were treated at 22℃. The decline of the semi-lethal temperature caused by the adaptive changes of enzyme activities was one of the foundations of enhancing the cold tolerance.     

A ‘mixed model’ for the formulation of a multipurpose mountain forest policy.: Theory vs. practice on the example of Kyrgyzstan

The formulation of policies, which can promote multiple use of forests in mountain regions, requires rigorous methods and approaches, based on established theories. A relevant conceptual framework is the ‘mixed model’, which is based on both rationalist and communicative action theories. With such a model, based on the policy cycle theory, the precision of multipurpose forestry objectives and means remains as the main task of the public authority (especially the forest service), but this can only result from discussions with various stakeholders in both public and private sectors, at central and local levels. The model works through a permanent confrontation between owners’ and users’ interests, expressed by representatives involved in policy formulation. Such a negotiation approach is used for analysing the present situation and issues (strong and weak points), for defining and structuring various objectives of the policy, as well as for defining different strategies and measures to be implemented to achieve those objectives. Further discussions of different positions among the participants finally lead to negotiated common solutions for future policy. Such a method is particularly adapted to public decision-making in mountain forests, where demands from various stakeholders are numerous and problems urgently need to be solved. The mixed model necessarily brings compromises between competitive or complementary social needs and interests, and automatically promotes multifunctional forestry management schemes and measures. However, that does not mean an easy implementation of such a conceptual frame.     

Effects of environmental factors on seedling growth and anthocyanin content in <Emphasis Type="Italic">Betula</Emphasis> ‘Royal Frost’ leaves

Determining the influences of environmental factors on seedling growth and leaf color may improve our understanding of the chromogenic mechanisms in leaves and the biosynthesis of anthocyanin. To determine the optimum conditions for Betula ‘Royal Frost’ seedling cultivation, we assessed seedling growth and anthocyanin content under natural conditions. The temperature had a significant influence on height but not on radial growth. Between June and September, the anthocyanin content was significantly positively correlated with light intensity and air moisture and significantly negatively correlated with temperature. In single-factor experiments to determine the variation in anthocyanin content in the greenhouse, anthocyanin content increased with increasing soil water content and at first increased, then decreased with increasing pH of the irrigation water and temperature, but decreased with increasing light intensity. K₂SO₄ can increase the anthocyanin content. So to maintain leaf color, seedlings should be cultivated with < 200 μmol m^?2 s^?1 light intensity at 20 °C and soil moisture content between 60 and 90%, and the irrigation water should be neutral or alkaline. Additionally, spraying with K₂SO₄ can be beneficial.