The Influence of Desiccation, Rough Handling and Cold Storage on the Quality and Establishment of Sitka Spruce Planting Stock

In January 3-year-old Sitka spruce were lifted and treated eithercarefully or roughly. Plants in each treatment were either transferredto the laboratory for testing, or transferred to cold storageat –1°C. In the laboratory, half of the plants ineach treatment were desiccated to shoot water potentials ofless than –2.0 MPa. Plants were then tested for root growthpotential (RGP), bud dormancy, frost hardiness and carbohydratecontent before transplanting at a field site, Additional plantswere removed from the nursery and cold store at approximatelymonthly intervals until late April, and then treated as above.In April, plants in each treatment were transferred to on-sitefield storage (sheughs), for 2 or 4 weeks prior to testing asabove. Carefully handled plants maintained large RGP which was positivelycorrelated with plant water potential, root water content, shootrelative growth rate and field survival. Overall RGP was reduced: 59 per cent by desiccation; 85 percent by rough handling; and 98 per cent by desiccation and roughhandling in combination. On site storage for 4 weeks in April/May reduced RGP. Whereplants produced more than 30 new roots > 1 cm long in RGPtests, field survival exceeded 90 per cent. Cold storage at–1°C maintained RGP, (of carefully handled plants),bud dormancy and shoot frost hardiness at approximately pre-storagevalues. In contrast, total nonstructural carbohydrate contentdeclined in cold store but increased in March/April for plantsin the nursery.     

Shading Reduces both Visible and Invisible Frost Damage to Norway Spruce Seedlings in the Field

Two-year-old cuttings of Norway spruce were subjected to nightfrosts in spring on an exposed site in southern Sweden. Shadingwas used to assess the influence of sunlight on the extent ofdamage resulting from night frost. Chlorophyll fluorescencewas measured in needles in flushing shoots, and in shoots atthe stage of bud burst. The F_v:F_m ratio was significantly lowerfor plants exposed to light, compared with shaded plants onthe days following the night frost (minimum temperature –6°C).The effect was similar both in 1-year-old and current year needles.The low F_v:F_m ratios indicate damage to photosystem H, causedby an interaction between sub freezing temperatures and highlight intensity. Shading also increased the survival of flushingshoots. It is suggested that regeneration of Norway spruce onsites exposed to frost should be carried out in partial shade,for example under a shelterwood.     

The Effects of Nitrogen Fertiliser at Different Rates and Times of Application on the Growth of Sitka Spruce in Upland Britain

At seven experiment sites in Scotland and northern England theeffects of different rates (0 to 150 kg N ha^–1) and seasonof nitrogen (N) fertiliser application on the height growthof Sitka spruce were examined. A comparison of urea and ammoniumnitrate was included to determine the most effective sourceof N. At each site, height and foliar nutrient concentrationswere measured. The sites chosen displayed different degrees of N-deficiencywhich was reflected in foliar N levels and height growth responses.The largest responses to application of N occurred at the mostdeficient sites and foliar N concentration of the untreatedcrop could be used to predict the likely magnitude of response.However, neither the season of application nor the differentfertilisers used had any effect on height growth.     

Root growth in Sitka spruce and Douglas-fir transplants: dependence on the shoot and stored carbohydrates

When dormant Sitka spruce (Picea sitchensis (Bong.) Carr.) transplants were lifted from the nursery in March and transferred to favorable growing conditions in a controlled environment chamber, new roots emerged and elongated even when the plants were bark-ringed so that the roots could not receive metabolites from the shoot by phloem translocation. Carbohydrate analysis showed that starch reserves in the roots of the bark-ringed plants were depleted, indicating that these reserves provided the energy source for new root growth. The shoot also had a role in new root growth as excised root systems showed greatly reduced root growth. This response is compared to that of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) in which bark-ringing prevented root growth indicating that current photosynthate is needed for new root growth. The findings are discussed in relation to the problems of establishing these species in forest plantations.     

不同氮、磷、钾量对金叶榆容器苗生长效果的比较

采用正交试验设计,研究了N、p、K施肥处理对容器培育金叶榆苗高和地径的影响.结果表明:各施肥处理间苗高差异不显著(p>0.05),而地径差异显著(p<0.05),其中P肥的影响最大,其次为N肥和K肥;地上部分的高生长与根系00.05).而地径的生长与根系0相似文献   

Root diseases in bareroot and container nurseries of the Pacific Northwest: epidemiology, management, and effects on outplanting performance

In forest and conservation nurseries in the Pacific Northwest USA, seedling production can be limited by root diseases caused by fungi in the genera Fusarium Link:Fr., Cylindrocarpon Wollenw., Phytophthora de Barry, and Pythium Pringsh. Fusarium, Cylindrocarpon, and Pythium are the most ubiquitous, whereas incidence of Phytophthora is mostly associated with coastal bareroot nurseries. All of these root pathogens are encouraged by water saturated soils or media. Seedlings infected with Fusarium, Phytophthora, or Pythium often appear chlorotic or necrotic with extensive root decay. Cylindrocarpon often causes serious root decay without shoot symptoms. The best approach to mitigate losses from these diseases is to use a holistic integrated pest management program. This program should combine chemical controls with cultural practices, particularly those that increase soil permeability and drainage and reduce potential sources of inoculum, especially by disinfesting seeds and containers reused for crops. In general, we found that seedlings meeting nursery specifications for outplanting on forest soil (proper height, root collar diameter, healthy shoot color, lack of disease symptoms) but having these disease organisms on their root systems perform as well as non-infected seedlings.     

Enhancing Tree Seedling Supply to Smallholders in Leyte Province, Philippines: An Evaluation of the Production System of Government Nursery Sector and Support to Smallholder Tree Farmers

A decentralized seedling production is regarded as the most effective means of providing smallholders with planting materials. However, the sustainability of smallholder nursery operation is constrained by several factors, including the limited availability of germplasm, lack of technical skills and low seedling demand low viability of seedling market. The government nursery sector could complement the weaknesses of the smallholder nursery group but government nurseries are not operating effectively to enhance the availability of high quality seedlings of a wide species base for smallholder forestry. Seedling production in government nurseries is quantity-orientated with low emphasis on the production of high quality planting materials. Germplasm used in seedling production is mostly collected from unselected sources and seedlings produced are mostly of low physical quality. The species selection in government nurseries is heavily based on the availability of germplasm which resulted in the production of a few species which are commonly raised on private nurseries. The duplication of species of most seedlings raised in government nurseries with those produced in private nurseries and the far distance of government nurseries from the villages has resulted in low uptake of seedlings by smallholder tree farmers. For the government nursery sector to become more effective in providing support in the present paradigm of decentralized seeding production, a change from its production system and a broadening of the role it plays is needed. The social mobilization on seedling production as a scheme of implementing the Green Philippines Program has led the Department of Environment and Natural Resources to acknowledge the seedling production activity of private individual and communal nursery groups. This can be an opportunity for organizing the private and government nursery sectors to promote the operational effectiveness of the overall forest nursery industry.     

Potential fecundity of the bamboo gall maker,Aiolomorphus rhopaloides (Hymenoptera: Eurytomidae), and its inquiline,Diomorus aiolomorphi (Hymenoptera: Torymidae), in relation to gall size and body size

I examined the adult potential fecundity of the bamboo gall maker,Aiolomorphus rhopaloides Walker (Hymenoptera: Eurytomidae), and its inquiline,Diomorus aiolomorphi Kamijo (Hymenoptera: Torymidae) by dissection just after emergence, and at death after rearing. Emerging females ofA. rhopaloides hadca. 80 mature eggs in their ovaries. The number of eggs at emergence and after death at rearing was not significantly different. However, emerging females ofD. aiolomorphi had no eggs in their ovaries but hadca 20 eggs at death after rearing. These results suggest thatA. rhopaloides is pro-ovigenic andD. aiolomorphi is synovigenic. Female body sizes of both species were positively correlated with the size of galls from which each emerged. Number of eggs in each species was also correlated with female body size, suggesting that gall size might be a good predictor of potential fecundity. This study was supported in part by a Grant-in-Aid for scientific Research (No. 11460068) from the Ministry of Education, Science, Sports, and Culture, Japan.     

Growth and survival of the Mayan palm <Emphasis Type="Italic">Chamaedorea hooperiana</Emphasis> in two villages of Los Tuxtlas Biosphere Reserve,Veracruz, Mexico: a comparison between primary and secondary forests

In the Los Tuxtlas Biosphere Reserve, Veracruz, México, managers and farmers of two communities have promoted the cultivation of Chamaedorea hooperiana amid primary forest (P_F) on the assumption that this would provide viable economic income while contributing to forest sustainability. The aim of this study was to test whether or not C. hooperiana is able to grow in P_F without canopy management, and to compare its growth pattern to the one observed in secondary forest (S_F) (acahual) managed by farmers. The performance of C. hooperiana was evaluated for nearly a thousand days in patches of forest from two communal lands dedicated to palm extraction. The results indicate that the palms grew four to five times faster in the S_F than in the P_F, although the number of leaves was only about one-and-a-half times greater. Also, a different growth pattern was detected at each site in terms of plant height and length of leaves, i.e., allometric growth was negative in the P_F (the length of leaves increased more slowly than the height of the palms) and positive in the S_F (length of leaves increased faster than the height of the palms). It was concluded that although C. hooperiana may be defined as a shade-tolerant plant species growing best under intermediate light, seedlings will not grow under a closed canopy of P_F, except at those gaps with enough light. Growing the Mayan palm under S_F opens up the possibility of rehabilitating deforested areas.