How remedial silviculture can improve poorly performing pole-stage broadleaves

The last 20 years has seen the planting of 30,000 hectares of broadleaf trees in Ireland. Action must be taken to achieve the best return on this investment, writes Dr. Ian Short and Jerry Campion, Teagasc Forestry Development Department.CoFoR

A review of stumping back and case study of its use in the rehabilitation of poorly performing pole-stage sycamore

peer-reviewedProject funded by CoFoRD, Dept. of Agriculture, Food and the Marine.First rotation broadleaf plantations present a range of inherent challenges to the achievement of good form and vigour. Where biotic and/or abiotic factors compromise early growth and stem quality, appropriate management interventions to improve these are required. An historical review of “stumping back” literature is presented together with a case-study. The B-SilvRD broadleaf silviculture research project includes a “rehabilitation” strand, whereby innovative measures to improve poorly performing stands of commercial broadleaves are being trialled. One such pilot trial involves a 17year-old sycamore (Acer pseudoplatanus L.) plantation, which had not performed well and required significant intervention to improve its silvicultural and economic viability. This paper reviews the literature on stumping back and presents a case-study with results of three different line thinning/stumping back treatments, including analysis of different light regimes and the impact of light levels on coppice regrowth.Project funded by CoFoRD, Dept. of Agriculture, Food and the Marine

Eucalyptus Foliage Production

End of Project ReportThe main objective of this project was to determine, for the main species of Eucalyptus grown in the south west of Ireland (Kerry), the best means of pruning to optimise marketable juvenile foliage production and quality over the crops life cycle. The majority of the trials were carried out in Co. Kerry where a higher concentration of production is located. The favourable climate and light acid soils in this region promote satisfactory growth and enables harvesting to take place from autumn to March which is the premium period. Results of extensive trials over a four year trial period showed that new plantations should not be pruned until the end of the second growing season to allow the trees to become well established and help build up photosynthetic food reserves and prevent tree losses. However in some situations where very vigorous growth was achieved during the first growing season a very light pruning at 1.3 m high helped stabilise trees. After the second year's growth, pruning back to a height of 1.2 m consistently produced the highest marketable production of quality juvenile foliage of Eucalyptus species pulverulenta, perriniana, parvifolia, and 'Glaucescens' over the trial period. Pruning back to this level helped develop a single or multiple main stem framework (2-3 stems) for future production purposes, providing a nice manageable tree facilitating not only harvesting but other technical operations such as pruning and spraying. It was found that more severe pruning, especially back to 15-25 cm from the ground, reduced output and in some cases quality but was responsible for significant tree losses varying from 8-12% in the second growing year to over 30% losses with four year plantations, with further losses of 5-10% expected as well because of very weak plants. The main recommendations of this study are that no pruning be carried out for the first two growing seasons and thereafter a relatively light pruning of all main framework leaders back to 1.2 m high after the winter period. As the plantations grew older, stronger side branches could be shortened and later still could be removed to facilitate management of the crop. The light pruning treatments to 1.2 m high in contrast to the most severe pruning regimes produced no significant tree losses in the main production areas in Co. Kerry and would appear to be the most sustainable system of pruning management over the crops life cycle

Optimising Nutrition Of Containerised Nursery Stock

End of Project ReportIrish peat, used as a growing medium in horticulture, tends to have a higher state of decomposition and a higher potential buffering capacity than some of the younger peats from Scandinavian or Baltic countries. Particularly where hard water, with high bicarbonate content, is used for irrigation this could be an important property in giving the peat greater stability with respect to pH levels throughout the cropping period. It may also influence the optimum rate of lime to be applied to adjust the pH prior to cropping. The effect of peat type on the performance of nursery stock plants, Azalea and Hebe in 2-litre containers, was studied when irrigated with both soft and hard water and with different rates of lime in the peat growing medium. When irrigated with hard water, the rate of pH increase was less with relatively decomposed Irish peat than with younger Baltic peats. Using Irish peat, a rate of dolomitic lime addition to the peat of 4 kg/m3 was best for Hebe when irrigated with soft water. Irrigating with hard water the lime rate could vary between 2 and 4 kg/m3 without affecting plant performance. With the Baltic peats, increasing the rate of lime addition above 2 kg/m3 tended to reduce growth of Hebe. Azalea gave better results when irrigated with soft water. In hard water areas therefore it is advisable, if possible, to collect rain water from a greenhouse roof for irrigation purposes. A zero rate of lime gave inferior results with Azalea. With hard water a rate of 1 kg/m3 was optimum. With soft water this could be increased to 2 kg/m3 without damage. New formulations of the controlled release fertiliser (CRF) have been introduced recently. An experiment was carried out to evaluate the CRFs available in Ireland for the production of containerised nursery stock over a 12 month period. The effect of rate of CRF was also studied. Experiments were also located in the Colleges of Horticulture in Warrenstown and Kildalton. All the CRFs in these experiments produced acceptable results in terms of plant performance. There were differences between the CRFs but these were not consistent between the experiments. The vigorous species Lonicera pileata and Escallonia macrantha responed positively to rates of CRF up to 8 kg/m3. The conifer, Thuja plicata gave no response to rates above 6 kg/m3. In an experiment over two seasons using 20 nursery stock species, a liquid feeding system resulted in heavier plants of most species than did one based on a controlled release fertiliser.European Union Structural Funds (EAGGF

The use of tensiometers to control the irrigation of nursery stock in containers.

End of Project ReportThe use of digital tensiometers to control the irrigation of nursery stock in containers was studied over a three year period. Over this time the tensiometers performed satisfactorily and successfully automated the irrigation of the plants. The results indicate the feasibility of using them to control nursery stock irrigation under Irish conditions. An irrigation tension of 50 hPa to trigger an irrigation period resulted in larger plants than those grown under drier regimes with irrigation tensions of 100 and 200 hPa. Measurements of stomatal resistance indicated that the plants in the drier regimes were growing under greater moisture stress. The drier regimes reduced the number of irrigations and also the overall usage of water. They reduced plant size but did not impair plant appearance. It may be possible to use this approach in the future to control plant growth. There was no difference in performance between plants gown with ebb and flood irrigation and those irrigated via overhead spraylines. The ebb and flood system gave a considerable reduction in water use.European Union Structural Funds (EAGGF

Comparison of photosynthetic performance of Fagus sylvatica seedlings under natural and artificial shading

peer-reviewedCommitment to sustainable forest management (alternatives to clearfelling) has led to a renewed interest in continuous cover forestry systems, which promote the control of light to produce stand benefits. Physiological performance of shade-tolerant European beech (Fagus sylvatica L.) in response to light availability was investigated in natural regeneration below the canopy in contrast to planted seedlings under artificial-shade conditions. Although beech seedlings had higher photosynthetic capacity with increasing light availability, they were able to maintain positive CO2 assimilation rates under low light levels in both field and controlled conditions. Leaves of seedlings under low light had the ability to use light more efficiently (higher PSII efficiency) than those in high light, which offer some physiological explanation for the ability of beech seedlings to grow under very low light conditions. Whilst caution is advised to interpret results from controlled to field studies, the overall general correspondence in the trend of the physiological response to light levels within beech grown below the canopy and under artificial-shade conditions suggests that it might be possible to extrapolate results from studies performed under artificial shade (nets) to field conditions. Hence, the use of nets may be an alternative way of assessing the potential physiological responses of seedlings to light availability.This research was funded by the COFORD Forest Research Programme under the 2007–2013 National Development Plan, administered by the Irish Department of Agriculture, Food and the Marine (DAFM). Ignacio Sevillano was supported by a Walsh Fellowship from Teagasc (Ireland)

Exploring Parents' Everyday Experiences With Digital Media: Barriers and Opportunities for Digital Inclusion

This article presents qualitative research findings on parents' digital media practices. Through 32 in-depth interviews with parents of 0-6-year-olds in French-speaking Belgium, the study addresses digital inclusion by exploring the diverse ways parents experience and benefit (or not) from digital media. Our research uncovers the dual nature of digital media use in parenting, presenting both advantageous and problematic outcomes across four dialectical dimensions. Our work sheds light on how digital media can (a) offer informational support or constitute an informational challenge, (b) provide emotional assistance or cause emotional struggles, (c) grant access to social support or contribute to social pressures, and (d) serve as a tool for the daily organisation or complicate daily life. Our article also investigates the factors associated with either positive or negative outcomes. We show the role of personal, situational, social, and normative factors. To conclude, we identify strategies for childcare and parenting support professionals to promote digital inclusion among parents by addressing barriers to positive experiences and outcomes related to the use of digital media. By integrating the outcomes of parents' experiences with digital media into discussions of digital inclusion, this article contributes to a comprehensive approach to promoting digital equity beyond questions of access and skills. It calls for user-centric strategies that consider the diverse experiences and concrete outcomes associated with digital media use and emphasises the importance of supporting parents and families regarding these tools

Edmonds et al. Reply

This article is a response to an article by M. Adell et al. [Phy. Rev. Lett. 94, 139701 (2005)] about semiconductor-based spintronics research