• Acoustic measurement differences on trees and logs from hardwoods in wet and dry condition

      Llana, Daniel F.; Short, Ian; Harte, A. M.; Department of Agriculture, Food and Marine; 15-C-666 (U. S. Department of Agriculture, 2019-09)
      Acoustic velocities measured on standing trees using time-of-flight (TOF) devices have been found to be between 7% and 36% higher for softwoods than those in logs using resonance techniques based on longitudinal frequencies. This effect was explained in three different ways: (1) TOF devices on standing trees measure outerwood containing more mature wood while resonance methods assess the whole crosssection, (2) the variation in the velocity is due to loading conditions in standing trees, while logs are free of loads and (3) the acoustic waves are dilatational waves in the case of TOF measurements on standing trees and one-dimensional longitudinal waves in the case of resonance on logs. This is an important topic considering the fact that resonance methods are considered more accurate for predicting mechanical properties and it has been proposed that correction factors should be applied on TOF measurements. In the present work, four hardwoods from Irish forests were studied and, on average, TOF velocities measured in the forest above fibre saturation point (FSP) were 19.8% higher than those from resonance measurements taken on logs immediately after felling. However, this difference reduced to 5.4% when the measurements were repeated at a moisture content (MC) of about 18% in the laboratory. Therefore, there is a MC effect on the velocity differences. Furthermore, higher differences were systematically found in older specimens in wet condition. However, this age effect was small in most cases.
    • Alley coppice—a new system with ancient roots

      Morhart, Christopher D.; Douglas, Gerry C.; Dupraz, Christian; Graves, Anil R.; Nahm, Michael; Paris, Perluigi; Sauter, Udo H.; Sheppard, Jonathan; Spiecker, Heinrich; European Commission (Springer, 2014-05)
      Context: Current production from natural forests will not satisfy future world demand for timber and fuel wood, and new land management options are required. Aims: We explore an innovative production system that combines the production of short rotation coppice in wide alleys with the production of high-value trees on narrow strips of land; it is an alternative form of alley cropping which we propose to call ‘alley coppice’. The aim is to describe this alley coppice system and to illustrate its potential for producing two diverse products, namely high-value timber and energy wood on the same land unit. Methods: Based on a comprehensive literature review, we compare the advantages and disadvantages of the alley coppice system and contrast the features with well-known existing or past systems of biomass and wood production. Results: We describe and discuss the basic aspects of alley coppice, its design and dynamics, the processes of competition and facilitation, issues of ecology, and areas that are open for future research. Conclusion: Based on existing knowledge, a solid foundation for the implementation of alley coppice on suitable land is presented, and the high potential of this system could be shown.
    • Ash dieback in Ireland – A review of European management options and case studies in remedial silviculture

      Short, Ian; Hawe, Jerry; Woodland Trust NI; COFORD; Teagasc (Society of Irish Foresters, 2018)
      Ash dieback, caused by Hymenoscyphus fraxineus, is developing rapidly across the island of Ireland. Ireland’s ash (Fraxinus excelsior L.) woodlands, particularly first rotation plantations, are quite unique and are at particular risk of very rapid decline. Urgent action is required in order to minimise the economic, ecological and social impact of the disease. However, for this to happen forest owners require guidance regarding potential positive management interventions. This article outlines the wider, mainly European, experience of remedial silviculture. It presents three case studies on existing remedial silviculture trials in Ireland. In the absence of silvicultural research data specific to the evolving situation with ash dieback, this article explores the potential benefits of positive practical actions which may minimise the impact of the disease. Despite the seriousness of the situation, such silvicultural activity may even result in a positive economic outcome. It is hoped that by beginning to document potential mitigatory management options, this paper may bring some reassurance to owners and managers of ashdominated woodlands.
    • Ash dieback on the island of Ireland

      McCracken, A.R.; Douglas, Gerry C.; Ryan, C.; Destefanis, M.; Cooke, L.R.; European Co-Operation in Science and Technology (Swedish University of Agricultural Sciences, 2017)
      On the island of Ireland it is estimated that there are over half a million kilometres of hedgerows (400,000+ km in the Republic of Ireland (Rep. Ireland) and 113,000+ in Northern Ireland (Northern Ireland). Ash (Fraxinus excelsior) is the second most important component, after hawthorn (Crataegus monogyna), in large proportions of this hedgerow network. In the Rep. Ireland over 20,000 ha of ash have been planted since 1990, primarily for sawlogs and to provide material for the manufacture of hurleys, which are used in an important national sport called hurling, and for camogie sticks used to play camogie. Ash dieback, caused by Hymenoscyphus fraxineus, was first identified on the island in October 2012 and since then has been detected at 306 sites (195 in Rep. Ireland and 111 in Northern Ireland). In the vast majority of cases the outbreaks have been on young, imported trees planted within the previous 5 – 6 years and it was evident that the pathogen had been introduced on trees for planting. On a small number of occasions there was evidence of the pathogen cycling within a plantation or moving from the plantation to infect neighbouring hedgerow trees. One possible mechanism by which the pathogen can build up sufficient inoculum is by the formation of apothecia on infected woody tissue high up on the plants. Rep. Ireland and Northern Ireland have strict policies of eradication and containment, as set out in the All-Ireland Chalara Control Strategy. To date over 2.1 million trees have been destroyed as part of an eradication strategy. It is considered that this prompt and far-reaching action has had a significant impact, significantly mitigating and preventing the rapid establishment of the pathogen and limiting its spread. The interventions since the disease was first confirmed have helped to protect the considerable investment in ash plantations of the last 20 years. The pathogen has not, however, been eradicated from the island of Ireland and it remains to be seen how widespread, and how quickly ash dieback will become established on the island of Ireland. The latest figures from the Republic of Ireland are that 733 hectares of ash plantation has been reconstituted with another species as a result of Chalara and this has cost our state €2.6 million so far; in addition, Chalara has been found and confirmed in all 26 counties of the Republic of Ireland to a greater or lesser extent. As a result the current policies and procedures regarding Chalara are under review.
    • Broadleaf thinning in Ireland - a review of European silvicultural best practice

      Hawe, Jerry; Short, Ian; Department of Agriculture, Food and the Marine, Ireland (Society of Irish Foresters, 2016)
      A substantial first-rotation broadleaf plantation resource in Ireland is progressively entering a thinning phase. Silvicultural best practice in support of such a management intervention needs to be developed for this new woodland resource to achieve its maximum commercial potential. National research trials are key to the provision of information for the development of best practice. Determining the current state-of-the-art is a prerequisite to the design and implementation of appropriate research trials. This study reviews the literature concerning the fundamental principles of broadleaf thinning with particular regard to timing, intensity and impacts on crop tree growth response, focussing on a range of commonly planted broadleaf species in Ireland. The overall aim of this review is to gain a fuller understanding of the most effective thinning methodology to be employed to maximise the production of high quality hardwood timber. In doing so it is intended that the information presented may support ongoing and future research trials with regard to potential silvicultural treatments to apply, data types and analysis and the likely results of practical application to commercial forestry.
    • Combining transcriptomics and genetic linkage based information to identify candidate genes associated with Heterobasidion-resistance in Norway spruce

      Chaudhary, Rajiv; Lundén, Karl; Dalman, Kerstin; Dubey, Mukesh; Nemesio Gorriz, Miguel; Karlsson, Bo; Stenlid, Jan; Elfstrand, Malin; Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning; 2012-1276; et al. (Springer Science and Business Media LLC, 2020-07-29)
      The Heterobasidion annosum s.l species complex comprises the most damaging forest pathogens to Norway spruce. We revisited previously identified Quantitative Trait Loci (QTLs) related to Heterobasidion-resistance in Norway spruce to identify candidate genes associated with these QTLs. We identified 329 candidate genes associated with the resistance QTLs using a gene-based composite map for Pinaceae. To evaluate the transcriptional responses of these candidate genes to H. parviporum, we inoculated Norway spruce plants and sequenced the transcriptome of the interaction at 3 and 7 days post inoculation. Out of 298 expressed candidate genes 124 were differentially expressed between inoculation and wounding control treatment. Interestingly, PaNAC04 and two of its paralogs in the subgroup III-3 of the NAC family transcription factors were found to be associated with one of the QTLs and was also highly induced in response to H. parviporum. These genes are possibly involved in the regulation of biosynthesis of flavonoid compounds. Furthermore, several of the differentially expressed candidate genes were associated with the phenylpropanoid pathway including a phenylalanine ammonia-lyase, a cinnamoyl-CoA reductase, a caffeoyl-CoA O-methyltransferase and a PgMYB11-like transcription factor gene. Combining transcriptome and genetic linkage analyses can help identifying candidate genes for functional studies and molecular breeding in non-model species.
    • Comparison of photosynthetic performance of Fagus sylvatica seedlings under natural and artificial shading

      Sevillano, Ignacio; Short, Ian; Campion, Jerry; Grant, Olga M.; Grant, Jim; O’Reilly, Conor; Department of Agriculture, Food and the Marine; Teagasc Walsh Fellowship Programme (Elsevier, 2018-03-14)
      Commitment 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.
    • Comparison of three inventory protocols for use in privately-owned plantations under transformation to Continuous Cover Forestry

      Spazzi, Jonathan; O Tuama, Padraig; Wilson, Edward R.; Short, Ian (Society of Irish Foresters, 2019)
      Interest is growing in Continuous Cover Forestry (CCF) as a management approach among private forest owners in Ireland. Developments in forest policy are directed at promoting CCF as a means of enhancing forest resilience, sustaining forest production and delivering diverse ecosystem services. In 2019 the Department of Agriculture, Food and the Marine (DAFM) introduced a new pilot funding measure to support the adoption of CCF management in suitable private forests. Currently the area of forest under CCF management is relatively small (estimated at around 1% of the total forest area) and several barriers to wider adoption have been identified. These include the lack of a simple template for the transformation of planted forests to CCF and a monitoring protocol with known inventory costs and outputs. In this study three inventory protocols were compared in terms of their ease of use, the types of data outputs and cost effectiveness in a forest stand at an early stage of transformation to CCF. These protocols were compared to a complete enumeration approach. The inventory protocols being tested were developed by the UK Forestry Commission (FCIN45), a group of French and Belgian researchers (VISUAL) and the Irregular Silviculture Network (ISN). Results indicate that by using modern technology and careful design, a cost-effective inventory protocol can be implemented to collect information of sufficient accuracy to inform management decisions. Advantages and limitations of each protocol are discussed. The ultimate outcome would be the development and adoption of a common inventory and monitoring approach to enable private owners to critically compare stand management and performance. This is essential to support and guide forest managers and forest owners during the transformation process.
    • Continuous Cover Forestry: The rise of transformational silviculture

      Wilson, Edward; Short, Ian; Ni Dhubhain, Aine; Purser (2018)
      CCF has been a popular discussion topic in forestry circles for some time. Now a body of research and an increasing number of working examples are demonstrating the true potential of this flexible and resilient silvicultural approach. Here, Edward Wilson, Ian Short, Áine Ní Dhubháin and Paddy Purser comment on current developments
    • Coppice-with-standards: An old silvicultural system with new potential?

      Short, Ian; Campion, Jerry; COFORD (Select Media Ltd, 01/03/2014)
      The last two decades have seen a dramatic increase in the area of broadleaf afforestation in Ireland.Some of these plantations are not performing as well as was expected when planted. This article describes the coppice-with-standards silvicultural system. With the increased demand for fuelwood and greater broadleaf plantation area, some of which may require alternative silvicultural management to the conventional due to poor performance, the coppice–with–standards system has the potential to fulfil many objectives.
    • COST E42 Growing Valuable Broadleaves Silviculture Matrix: An Irish example

      Short, Ian; Bulfin, Michael; Radford, Toddy; European Co-Operation in Science and Technology; COFORD (Teagasc, Oak Park, Carlow, Ireland & Coford, Ireland, 2008)
      The purpose of developing the silvicultural matrix in COST E 42 was to provide a vehicle whereby information on silviculture of valuable broadleaved species could be gathered from as many participating countries as possible. The aim of this matrix is to determine what are considered the optimum silvicultural treatments for each of our target species in countries across Europe. In many cases only one or two countries will have experience of a particular species. Also it must be realised that, for many of the larger countries in Europe, there are different climatic regimes and no single matrix can encapsulate the recommendations for that country. In this case a number of climatic regional matrices would be preferable. For this reason, not all countries felt in a position to contribute a matrix and preferred to provide a narrative discussion on various species. As an illustration of how the matrix can provide a guideline for farmers wishing to plant, the example of ash (Fraxinus excelsior L.) in Ireland is taken. Based on the research we carried out, we developed a set of guidelines to assist farmers in making critical decisions. These guidelines now form the basis for government support to farmers.
    • Developing new hardwood markets for Irish timber – the Hardwood Focus group’s study tour to Wales

      Spazzi, Jonathan; Garvey, Seán; Short, Ian; Department of Agriculture, Food and the Marine (Society of Irish Foresters, 2019-12-30)
      A discussion-group called Hardwood Focus (HF) was formed in Limerick in 2018 among broadleaf-forest owners in the region. This initiative is part of the Limerick Tipperary Woodland Owners (LTWO) Group and is facilitated by Jonathan Spazzi, the local Teagasc Forestry Development Officer. The group travelled to Wales between 30th September and 4th October 2019. This article discusses the outcomes.
    • Establishment of a bovine/Quercus silvopastoral experiment in lowland Ireland.

      Short, Ian; McAdam, J.; Culleton, Noel; Douglas, Gerry C. (CAB International, 2005)
      A silvopastoral experiment was established at Teagasc in County Wexford, Ireland, in 2002 with oak (Quercus robur L.) in an alley design and bovines. The experiment includes some treatments with trees produced with an enhanced root system (RPM). The treatments are: (1) control pasture plots; (2) RPM agroforestry (400 stems/ha); (3) conventional agroforestry (400 stems/ha); (4) RPM forestry (6600stems/ha; and (5) conventional forestry (6600 stems/ha). The trees were successfully established and cattle were successfully managed in combination with the trees. In the first year, height growth of bare-root oaks was significantly greater in the forestry treatment compared to the agroforestry treatment and, overall, RPM oaks were taller than bare-root plants. Among the RPM trees, the agroforestry system resulted in a greater stem diameter than those in the forestry plots. Height increment was greater for RPM trees than for bare-root trees.
    • European Mixed Forests: definition and research perspectives

      Bravo-Oviedo, Andres; Pretzsch, Hans; Ammer, Christian; Andenmatten, Ernesto; Barbati, Anna; Barreiro, Susana; Brang, Peter; Bravo, Felipe; Coll, Lluis; Corona, Piermaria; et al. (Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 2014-11)
      Aim of study: We aim at (i) developing a reference definition of mixed forests in order to harmonize comparative research in mixed forests and (ii) briefly review the research perspectives in mixed forests. Area of study: The definition is developed in Europe but can be tested worldwide. Material and methods: Review of existent definitions of mixed forests based and literature review encompassing dynamics, management and economic valuation of mixed forests. Main results: A mixed forest is defined as a forest unit, excluding linear formations, where at least two tree species coexist at any developmental stage, sharing common resources (light, water, and/or soil nutrients). The presence of each of the component species is normally quantified as a proportion of the number of stems or of basal area, although volume, biomass or canopy cover as well as proportions by occupied stand area may be used for specific objectives. A variety of structures and patterns of mixtures can occur, and the interactions between the component species and their relative proportions may change over time. The research perspectives identified are (i) species interactions and responses to hazards, (ii) the concept of maximum density in mixed forests, (iii) conversion of monocultures to mixed-species forest and (iv) economic valuation of ecosystem services provided by mixed forests. Research highlights: The definition is considered a high-level one which encompasses previous attempts to define mixed forests. Current fields of research indicate that gradient studies, experimental design approaches, and model simulations are key topics providing new research opportunities.
    • The Hardwood Focus Group: Exploring utilisation potential of Irish broadleaf forests

      Spazzi, Jonathan; O'Connell, John; Sykes, Jonathan; Short, Ian; Garvey, Seán; Department of Agriculture, Food and the Marine (Dawn Media Ltd,, 2020)
      Jonathan Spazzi of Teagasc Forestry outlines the work of the Hardwood Focus Group and lessons learned from a recent exploratory trip to counterparts in Wales.
    • High levels of variation in Salix lignocellulose genes revealed using poplar genomic resources

      Perdereau, Aude C; Douglas, Gerry C.; Hodkinson, Trevor R; Kelleher, Colin T; Teagasc Walsh Fellowship Programme (Biomed Central, 07/08/2013)
      Background: Little is known about the levels of variation in lignin or other wood related genes in Salix, a genus that is being increasingly used for biomass and biofuel production. The lignin biosynthesis pathway is well characterized in a number of species, including the model tree Populus. We aimed to transfer the genomic resources already available in Populus to its sister genus Salix to assess levels of variation within genes involved in wood formation. Results: Amplification trials for 27 gene regions were undertaken in 40 Salix taxa. Twelve of these regions were sequenced. Alignment searches of the resulting sequences against reference databases, combined with phylogenetic analyses, showed the close similarity of these Salix sequences to Populus, confirming homology of the primer regions and indicating a high level of conservation within the wood formation genes. However, all sequences were found to vary considerably among Salix species, mainly as SNPs with a smaller number of insertions-deletions. Between 25 and 176 SNPs per kbp per gene region (in predicted exons) were discovered within Salix. Conclusions: The variation found is sizeable but not unexpected as it is based on interspecific and not intraspecific comparison; it is comparable to interspecific variation in Populus. The characterisation of genetic variation is a key process in pre-breeding and for the conservation and exploitation of genetic resources in Salix. This study characterises the variation in several lignocellulose gene markers for such purposes.
    • How remedial silviculture can improve poorly performing pole-stage broadleaves

      Short, Ian; Campion, Jerry (Select Media Ltd., 2015-08)
      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.
    • Impact of competition on the early growth and physiological responses of potential short-rotation forestry species in Ireland

      Foreman, Susie; Department of Agriculture, Food and the Marine; 13/C/498 (2019-07)
      The impact of planting density on the growth and physiological response of three potential short rotation forestry species, shining gum (Eucalyptus nitens (Deane & Maiden) Maiden), Italian alder (Alnus cordata (Loisel.) Duby) and Sitka spruce (Picea sitchensis (Bong.) Carrière) were investigated in this study over a four-year period. The three species were planted in a field trial in Co. Wexford. The trial was laid down as a randomised block design containing four planting densities (1,333 – 40,000 stems ha-1) per species. Height, stem diameter, branch length, diameter and quantity, crown height, along with shade leaf only determinations of leaf area and leaf dry weight, chlorophyll concentration (Chleaf) and photosynthesis rates (PN) were measured periodically over the 4-year period. E. nitens trees produced the shallowest live crown of the three species, which decreased as planting density increased. Chleaf declined as planting density increased, but PN remained the same. E. nitens produced the greatest volume and biomass per ha-1 of the three species at the end of four years growth. Height increased and stem diameter decreased as planting density increased in A. cordata, although stem volume remained about the same. However, planting density did not affect crown volume or Chleaf in A. cordata, but PN declined as density increased. Trees of P. sitchensis grew more slowly than those of the other species during the four-year period, but it produced the densest crown at all planting densities. Competition effects were apparent at leaf level in P. sitchensis. Planting density did not affect the above-ground biomass in A. cordata or P. sitchensis, which was similar for the two species and was lower than that recorded for E. nitens. Of the three species examined, E. nitens was the most productive at all planting densities.
    • The impact of shade on photosynthetic characteristics in Fagus sylvatica and Quercus robur seedlings

      Sevillano, Ignacio; Short, Ian; O'Reilly, Conor (Teagasc, 10/03/2014)
    • Investigating the impact of varying levels of inventory data detail on private sector harvest forecasting

      Farrelly, Niall; O'Connor, Cian; Nieuwenhuis, Maarten; Phillips, Henry; Department of Agriculture, Food and the Marine; 14/C/824 (The Society of Irish Foresters, 2019-02-01)
      A comparison was made between four methods of generating roundwood production forecasts for private sector forests in Ireland which used varying levels of inventory data as inputs into the production Model. Two methods were based on stand variables: the Irish Dynamic Yield Model (IDYM) method and the General Yield Class (GYC) method. The other two methods were based on site variables used to derive predictions of productivity from climate and map-based data and include a local prediction (LPYC) and a national prediction of yield class (NPYC), the latter the same as that used in the All Ireland Roundwood Production Forecast 2016-2035 (Phillips et al. 2016). To determine the reliability of predictions for an individual stand, field measurements of yield class (GYC) were compared with the predictions of yield class derived using the NPYC and LPYC methods for 52 privately-owned stands of Sitka spruce in the north-west of Ireland. The prediction of yield class using the NPYC method had a low probability of agreement with GYC, with a large bias to under-predict yield class. The LPYC method had a higher probability of agreement and lower bias indicating a better assessment of local productivity. To assess the impact of the various productivity estimates on roundwood production forecasts, separate roundwood forecasts for the period 2016- 2035 were generated. The forecast produced using the NPYC method was used as a baseline for comparison purposes. As expected, the under-prediction of yield class using the NPYC method produced the lowest volume production estimate (318,454 m3) for the forecast period. Both the GYC and LPYC methods resulted in a significant increase in estimated volume production of between 25% and 29% over the baseline. The IDYM method provided the highest estimate of volume production (432,000 m3) for the forecast period, an increase of 35% over the baseline. The increased output predicted using the IDYM method is explained by the inclusion of stocking and basal area data, which more accurately reflected the increased growing stock of private forests than yield data derived using Forestry Commission yield models based on prescribed management. The increases in productivity associated with the use of LPYC, GYC and IDYM methods had the effect of producing shorter rotations and resulted in an increase in the area clearfelled and associated volume production. Perhaps more importantly, the timing of volume production was affected by using more accurate methods to assess productivity (i.e. LPYC, GYC, IDYM), owing to a higher yield-age profile of stands compared to those assessed using the NPYC predictions. The findings point to a possible under-estimation of the productivity for private stands in the All Ireland Roundwood Production Forecast and have implications for the timing of the forecasted volume which could be brought forward by 5 to 6 years. In the absence of field or aerial laser measurement of height and age, the use of the LPYC method is recommended for future private sector roundwood producion forecasts.