Search

The demand for wood in Europe is expected to increase in the coming decades. However, any theoretical maximum supply will be affected by sustainability constraints, the motivations of forest owners and regional factors, such as incentives, species and assortments. However, the influence of these factors on supply is changeable. In this study, we quantify what might be realistically available as additional wood supply from currently existing European forests, based on a combination of results of the forest resource model EFISCEN-Space and a literature review of national supply projections. Wood mobilization scenarios for 10 representative Model Regions in Europe that assume forest owners and managers in the simulated regions will adapt their behaviour to alternative behaviour as recorded from other regions were projected with the EFISCEN-Space model. The realistic additional potential based on the literature review is 90 million m3 yr−1. This potential should be attainable within 10–20 years. However, the simulations in the Model Regions found potentials to be lower in 7 out of 10 cases as compared with the country they are located in. On average, the model regions reached less than half of the potential as compared with the literature review. This suggests that the realistic additional potential at the European scale may well be lower if all mobilization barriers are taken into account in more detail, but also highlights the uncertainty surrounding these estimates. We conclude from the analyses that although there are large differences in potential between regions and the analysis method employed, there are no ‘hotspots’ where a large pool of accessible wood can be quickly mobilized using existing infrastructure for nearby industries. An increase in harvest would therefore only be possible with a large effort that spans the whole chain, from forest owners’ behaviour to capacity building, financial incentives and matching resources to harvesting capacity. The additionally available wood can most likely only be mobilized against higher marginal costs and will thus only become available in times of higher stumpage prices. The largest potential lies in privately owned forests which often have a fragmented ownership but will most likely be able to supply more wood, though mostly from deciduous species. In the long term (more than 20 years), additional wood, compared with the amounts we found for short term, can only be made available through investments in afforestation, forest restoration, improved forest management and more efficient use of raw material and recycled material.

Sustainable forest management is driving the development of forest decision support systems (DSSs) to include models and methods concerned with climate change, biodiversity and various ecosystem services (ESs). The future development of forest landscapes is very much dependent on how forest owners act and what goes on in the wider world; thus, models are needed that incorporate these aspects. The objective of this study is to assess how nine European state-of-the-art forest DSSs cope with these issues. The assessment focuses on the ability of these DSSs to generate landscape-level scenarios to explore the output of current and alternative forest management models (FMMs) in terms of a range of ESs and the robustness of these FMMs in the face of increased risks and uncertainty. Results show that all DSSs assessed in this study can be used to quantify the impacts of both stand- and landscape-level FMMs on the provision of a range of ESs over a typical planning horizon. DSSs can be used to assess how timber price trends may impact that provision over time. The inclusion of forest owner behavior as reflected by the adoption of specific FMMs seems to be also in the reach of all DSSs. Nevertheless, some DSSs need more data and development of models to estimate the impacts of climate change on biomass production and other ESs. Spatial analysis functionality needs to be further developed for a more accurate assessment of the landscape-level output of ESs from both current and alternative FMMs. European Commission Horizon 2020 Portuguese Science Foundation

Losses of carbon (C) and nitrogen (N) from the decomposition of woody debris in harvested forest ecosystems is of interest in national C accounting, regional water quality assessment as well as for managing long-term localised forest fertility. The main commercial forest type in Ireland is Sitka spruce dominated plantations and the woody debris from harvesting is routinely gathered into windrows in reforested stands. This study examined woody decomposition losses via two pathways namely respiration to the atmosphere and rainwater leaching to soil water. A chronosequence of forest stands was sampled, ranging in age (of the harvest debris) from three to fifteen years. Respiratory C loss from windrows was found to be 11.5 t C ha−1 year−1 three years after reforestation. This rate had dropped by 29% to 8.1 t C ha−1 yr−1 twelve years later. There was a strong seasonal trend in this efflux and the main driver of this variation was soil temperature, however moisture content and drying/rewetting cycles also played a role. Leached losses of C followed a similar trend to respired losses, but their rate was consistently less than 1% of respiration. Total dissolved N fluxes in woody debris leachate followed a different pattern, where more was retained by the system than lost. Thus, windrowed woody debris acted as a nutrient reservoir for N but as a steady source of C.

Meeting the reporting requirements of the Kyoto Protocol has focused attention on the potential of forests in sustainably sequestering carbon (C) to mitigate the effects of rising levels of atmospheric CO2. Much uncertainty remains concerning the ultimate effect of management on such sequestration effects. The management of woody debris (WD) and other deadwood stocks is an example of a management intervention with the scope of affecting the source-sink dynamics of forest C. Windrowing is the most commonly employed approach to the management of post-harvest WD. This study investigated the quantities of windrowed deadwood C across a chronosequence of reforested commercial Sitka spruce stands in Ireland and how its decomposition rate affected its contribution to forest C sequestration. The C stocks in windrowed WD ranged from 25 to 8 t C ha−1 at the 4- and 16-year-old stands, respectively. Losses due to the decomposition of these stocks ranged from 5.15 t C ha−1 yr−1 at the youngest site (4 years old) to 0.68 t C ha−1 yr−1 at the oldest site (16 years old). Using a visual decay-class categorization of WD components and an assessment of wood density, decay rate constants were estimated for logs, branches, and stumps (the main WD constituents of windrows) as 0.037, 0.038, and 0.044, respectively. These results, derived from stand stock evaluations, were placed into context with data previously published from the same chronosequence that characterized the day-to-day fluxes to or from this pool. This comparison indicated that though only a very small quantity of C was lost in dissolved leachate form, the most significant pathway for loss was respiratory and ranged from 16 to 8 t C ha−1 yr−1 at the 9- and 16-year-old sites. These estimates were many times greater in extent than estimates made using a density-loss approach, the difference indicating that fragmentation and weathering play a large role in woody decomposition in intensively managed forests.

Research into deer population dynamics has mostly focused on community or landscape scales in the Republic of Ireland. However, in order to propose national deer management strategies to confront t...

Forest management in Ireland has traditionally focused on timber production and policies have been implemented with this in mind. Since the mid-1990s, the focus is transitioning from timber production to a more multifunctional forest management approach following the principles of sustainable forest management. A method known as &ldquo, backcasting&rdquo, has the potential to include local stakeholders into land-use and policy planning. Two case study areas were chosen to investigate the potential of backcasting for integrated forest landscape planning in Ireland: Western Peatlands and Newmarket. Potential beneficial policies produced by local stakeholders in participatory workshops were assessed for robustness using a goal programming model and the resulting changes in forest management and ecosystem service provisions were analysed. While each evaluated backcasting policy increased the provision of that policy&rsquo, s targeted ecosystem service(s), it was at a cost to some others. The widening of buffer zones did reduce the landscape level risk to water sedimentation and the policy to enhance each landscape&rsquo, s recreation potential did the intended. However, both policies reduced the amount of timber produced for most potential futures. The option of using genetically improved tree species showed potential to mitigate the effect of these policies on timber production. We present this study as a useful reference point toward evaluating the efficacy of a range of potentially implementable scenarios in Ireland. We believe the backcasting approach has promise for future use in other landscapes, given the success of this approach in our study. Given that much of the information required to model the ecosystem services was extracted from scientific research and datasets from outside of Ireland, the approach may well be useful for others seeking to do similar outside of Ireland.

Two models, Carbware (CW) and Growfor (GF), of different resolution and based on different frameworks were evaluated in relation to stand-level forecasts of volume and basal area using Ireland’s National Forest Inventory (NFI) data. CW is a distance-independent single-tree model that is based on diameter increment. GF is a stand-level dynamic empirical model that uses the von Bertalanffy–Richards growth equation in a state-space framework. NFI data were used as input to the models, and each model’s projections were compared to NFI data at the next measurement cycle. The NFI is a permanent sampling system with the objective to assess the composition and extent of the forest estate. A subset of the NFI was used in the study, single-species even-aged plots comprising Sitka spruce and lodgepole pine. The accuracy and performance of the CW and GF models were analysed using residual analysis and standard statistical techniques. Results show that both models require improvement, though the study has raised concerns regarding the suitability of the NFI data for this type of investigation.

Farm-level tree planting has been suggested to have potential to decrease pressures on natural forests and, consequently, contribute towards reducing deforestation and forest degradation. However, the scientific evidence for such a link is limited. We examined farmers’ beliefs, attitudes and behaviours in relation to tree planting on farms and cutting down trees from the forest, as one way of establishing this link. A household survey was administered to 200 farmers in two rural districts in Malawi, which included an attitude scale based on the theory of planned behaviour. The results showed that farmers in Malawi recognise the benefits of planting trees, feel encouraged by fellow farmers, and feel capable of planting trees on their land. In addition, they believe cutting down trees from the forest will result in mainly negative outcomes, and feel discouraged by others and hindered by control factors to cut down trees from the forest. In total, 76 % of respondents planted trees in the past 5 years, 50 % collected firewood from the forest and 21 % collected poles. There was no evidence for a direct relationship between attitudes towards planting trees and cutting down trees, nor were the behaviours in relation to tree planting and cutting down trees from the forest significantly associated. However, there was evidence for an indirect relationship between tree planting behaviour and cutting down trees from the forest, as respondents who had planted trees had more negative attitudes towards cutting down trees from the forest. Future research should further explore the direct relationship between agroforestry and deforestation to establish if and under what conditions such a relationship might exist.

Information on stem quality of standing (broadleaf) timber is of great importance to the forestry sector to help optimise harvesting and marketing strategies. Manual assessment of such quality parameters in standing trees is extremely difficult, time consuming and costly. The objectives of this study were therefore to assess stem quality parameters such as taper, lean and sweep in ash (Fraxinus excelsior L.) stands, during leaves-on and leaves-off conditions, using terrestrial laser scanning technology, and to compare the estimated parameters with manually measured values in a mature and young stand. Diameter estimation was more accurate during the leaves-off condition in both stands, resulting in taper estimates that were closer to the manually obtained values as well. However, in general, the taper values did not match those obtained manually very closely. Given that the sample trees were chosen deliberately to include noticeable defects such as non-circularity, bending, swellings, knots resulting from ...

LiDAR data (low-density data, 0.5 pulses m −2 ) represent an excellent management resource as they can be used to estimate forest stand characteristics in short-rotation willow coppice (SRWC) with reasonable accuracy. The technology is also a useful, practical tool for carrying out inventories in these types of stands. This study evaluated the use of very low-density airborne LiDAR (light detection and ranging) data (0.5 pulses m−2), which can be accessed free of charge, in an SRWC established in degraded mining land. This work aimed to determine the utility of low-density LiDAR data for estimating main forest structural attributes and biomass productivity and for comparing the estimates with field measurements carried out in an SRWC planted in marginal land. The SRWC was established following a randomized complete block design with three clones, planted at two densities and with three fertilization levels. Use of parametric (multiple regression) and non-parametric (classification and regression trees, CART) fitting techniques yielded models with good predictive power and reliability. Both fitting methods were used for comprehensive analysis of the data and provide complementary information. The results of multiple regression analysis indicated close relationships (Rfit 2 = 0.63–0.97) between LiDAR-derived metrics and the field measured data for the variables studied (H, D20, D130, FW, and DW). High R 2 values were obtained for models fitted using the CART technique (R 2 = 0.73–0.94). Low-density LiDAR data can be used to model structural attributes and biomass yield in SRWC with reasonable accuracy. The models developed can be used to improve and optimize follow-up decisions about the management of these crops.

The application of terrestrial laser scanning (TLS) in capturing forest inventory parameters such as diameter at breast height, height and diameters along stem profiles, and in monitoring forest growth, was investigated and validated by comparison with conventionally measured individual tree parameters and plot-level forest growth in a stand of Sitka spruce (Picea sitchensis (Bong.) Carr.) in Ireland. The data acquisition for all the plots with different tree sizes and different slopes was carried out using a terrestrial laser scanner (FARO LS 800 HE80) in November 2007 and November 2009, using the same plot centres and measurement procedures. The point cloud data were processed with Autostem™ software. The results showed that TLS enables the acquisition of forest stand parameters with an acceptable accuracy. Pruning of the lower branches did not improve tree recognition and the number of (partly) occluded trees stayed the same. Over the 2-year period, the average difference between the volume increment of the trees visible to the scanner derived using the conventional method and Autostem™ was 4.77 m3 ha−1 and resulted in scanner-derived estimates that were lower than the estimates obtained by conventional method by 6.1 %. Using a simple correction factor to account for occlusion in the laser scanner data, the difference between these estimates for all trees in the stand became an over-estimation by 6.96 m3 ha−1 (8.1 %). At heights up along the stems >15 m, the errors in stem diameter estimates started to escalate.

Research Highlights: Predicting impacts on forest management of Climate Change (CC) and dynamic timber prices by incorporating these external factors in a Forest Management Decision Support System (FMDSS). Background and Objectives: Forest managers must comply with Sustainable Forest Management (SFM) practices, including considering the long-term impacts that CC and the bioeconomy may have on their forests and their management. The aims of this study are: (1) incorporate the effects of CC and Dynamic Prices (DP) in a FMDSS that was developed for Ireland’s peatland forests, (2) analyse the impact of global climate and market scenarios on forest management and forest composition at the landscape level. Materials and Methods: Remsoft Woodstock is a strategic planning decision support system that is widely used for forest management around the world. A linear programming model was developed for Ireland’s Western Peatland forests while using Woodstock. Data from Climadapt, which is an expert-based decision support system that was developed in Ireland, were used to include CC effects on forest productivity and species suitability. Dynamic market prices were also included to reflect the changing demands for wood fibre as part of the European Union (EU) and global effort to mitigate CC. Results: DP will likely have more impact on harvest patterns, volumes, and net present value than CC. Higher assortment prices, especially for pulpwood, stimulate the harvesting of forests on marginal sites and off-set some of the negative CC growth impacts on forest profitability. Conclusions: Incorporating CC and bioeconomy prices in a forest decision support system is feasible and recommendable. Foresters should incorporate the expected global changes in their long-term management planning to mitigate the negative effects that un-informed management decisions can have on the sustainability of their forests.

The decomposition of harvest residues (brash) in managed forests has an important influence on the carbon (C) and nitrogen (N) stocks of these ecosystems. The brash input from thinning events in a 25-year-old Sitka spruce plantation was determined. A litter-bag method was used to determine the mass loss and decomposition rate of brash left on the forest floor. The changes in C and N concentrations and the C:N ratio of the needles and branches were also monitored as decomposition progressed for 2.5 years. Using the decomposition rate (k b) and estimated brash inputs, we then determined the total cumulative stock of C that the brash could supply to the deadwood pool over a 41-year rotation period. The three thinning events resulted in the addition of 37.99 t C ha−1 and 0.61 t N ha−1 to the forest floor. A significant mass loss of 44 % was recorded from brash decomposition bags after 2.5 years, with a rapid loss of 35 % in the first year, after which the rate of decomposition slowed. The k b-value and residence time (95 % decomposition) were 0.311 year−1 and 9.6 years, respectively. There was a 69 % increase in the N concentration of needles after 1.5 years, while an increase of 185 % in the N concentration of branches was recorded after 2.5 years. The C concentration (48.55 ± 0.20 %) did not differ significantly between the needles and branches over time. The accumulated C stock from decomposing brash at clearfell was estimated at 18.51 t C ha−1.

In order to share information on the development and use of forest management decision support systems (FMDSS), a European-initiated network has established a wiki website as part of its activities. Case studies and associated lessons learned were solicited from the network using semantic structures built on the wiki. A total of 31 cases from 10 different countries and 80 associated lessons were entered into the wiki. The resulting lessons were categorized (non-exclusively) using four major themes: (1) decision support system architecture and design (40 lessons), (2) methods and models (26), (3) knowledge management processes (34) and (4) participatory processes (32). The semantic wiki proved useful for gathering case information and relating it to other information objects, such as FMDSS software descriptions; however, it was not as well suited to the task of analysis and synthesis as commercial qualitative analysis software packages. Future development possibilities for the semantic structures are suggested, and more cases are solicited from the FMDSS community.

This study develops some components to complete a management-oriented dynamic model system for simulating current and future volume and biomass of even-aged stands of managed downy birch (Betula pubescens Ehrh.) in Galicia (NW Spain). The specific components developed are a mortality equation, a basal area growth equation, a diameter distribution prediction system and equations for total and component biomass prediction. Functions to predict decreases in numberof trees per hectare and basal area growth were simultaneously fitted using Nonlinear Seemingly Unrelated Regression (NSUR) and a base-age invariant dummy variable method; critical errors of 19 and 16 per cent were obtained, respectively, when projections were made. The Weibull function modelled successfully all but four of the 198 diameter distributions examined, using the parameter recovery method through moments. To predict components and total aboveground biomass, a system of additive equations was simultaneously fitted using the generalized method of moments (GMM), which takes into account heteroscedasticity and inherent correlations among the biomass components. A two-step fitting procedure was used because of the different number of observations for the components considered. The biomass equations explained more than 85 per cent of the observed variability. The Galician birch stands which were surveyed were found to have grown by 3–10 m ha year in volume and by 2–8 Mg ha year in aboveground total biomass, with rotations between 30 and 60 years. The model system now forms an accessible decision support system for forest management and land development in the region.

a b s t r a c t Commercial forest plantations need to be actively managed, through tree removal, in order to improve wood quality, maintain productivity and provide an economic return, although this could compromise an important role for forests in carbon sequestration and greenhouse gas mitigation. The impact of for- est thinning on net primary productivity (NPP) and net ecosystem exchange (NEE) was assessed using a combination of biometric and eddy covariance (EC) techniques. Two thinning operations were per- formed in close succession, which reduced the basal area of the stand by 17% and 11% and removed a timber volume of 48 m3 ha−1 and 50 m3 ha−1, respectively. Annual rates of NPP ranged from 13.24 (±3.96) to 18.94 (±4.88) t C ha −1 and 13.22 (±3.72) to 17.77 (±5.30) t C ha −1 for the pre- and post-thinning peri- ods, respectively. Estimates of NEE varied between 8.44 (±1.34) to 8.87 (±1.48) t C ha −1 and 6.75 (±1.19) to 10.33 (±1.41) t C ha−1 in the pre- and post-thinning periods. Forest thinning did not have a significant impact on carbon stocks or fluxes when pre-thinning (2002-2006) and post-thinning (2007-2009) esti- mates of NPP and NEE were compared, however the range of inter-annual variability in NEE increased after thinning. The partitioning of annual NEE carbon budgets into gross primary productivity (GPP) and ecosystem respiration (Reco) together with an analysis of key physiological parameters suggested that the impacts of forest thinning are largely dependent on temperature. An expected decrease in GPP after the initial thinning in 2007 was not observed due, in part, to the higher mean annual air temperatures and incident photosynthetic active radiation (PAR) and a compensatory increase in photosynthesis by the remaining trees. A continual decline in Reco, was observed in the years subsequent to the first thinning and was attributed to both biomass removal and climatic factors. Inter-annual variations in climate had a significant impact on NEE, GPP and Reco. Annual mean air temperature, total precipitation and total incident PAR were all shown to influence the processes driving CO2 exchange. Overall, these results suggest that the impacts of the thinning practices, as implemented in this study, are dependent on climate and under similar conditions are unlikely, in the short-term, to compromise a role for forest ecosystems in carbon sequestration and greenhouse gas mitigation.

Forest thinning influences soil processes by altering key microclimatic conditions, root density, microbial communities, organic matter turnover and nutrient budgets. It introduces a large pulse of harvest residues (brash) to the soil surface and can alter the balance between autotrophic and heterotrophic respiration. This study determined the influence of thinning, microclimatic factors and plant productivity on carbon (C) losses through the emission of carbon dioxide (CO 2 ) respired from thinning lines (brash lanes or BL) and the forest floor (FF: without brash) in a first rotation Sitka spruce ( Picea sitchensis (Bong.) Carr.) forest in Ireland. Weekly measurements of CO 2 efflux were carried out using an Infra-Red Gas Analyser connected to static chambers; while soil moisture content and soil surface temperature were measured, using theta probes and data loggers, respectively. The soil respiration measurements were also correlated with the gross primary productivity (GPP) determined by eddy covariance techniques.The highest CO 2 efflux were observed at the peak of summer in July/2010 (FF = 699.20 mg CO 2 m −2 h −1 and BL = 374.22 mg CO 2 m −2 h −1 ) and were associated with maximum soil surface temperatures and higher rates of GPP. Soil temperature had a strong positive influence on the variation of CO 2 from the forest (FF = 75% and BL = 59%), and the temperature sensitivity ( Q 10 ) of soil respiration from the FF (5.47) was higher than from the BL (2.72). Soil moisture was inversely correlated with soil respiration from both FF ( R = −0.73, p R = −0.53, p = 0.003). The combined effect of temperature and moisture gave a better description of the variability in CO 2 respired from both the FF ( R 2 = 0.85, p R 2 = 0.67, p R 2 = 0.73, p R 2 = 0.45, p −2 year −1 ) was significantly higher than BL (351.77 g C m −2 year −1 ). The annual soil respiratory C loss was 435.32 g C m −2 year −1 (calculated based on the contribution of the BL (14%) and FF (86%) to the total forest area).

We examined the relationships between Sitka spruce ( Picea sitchensis (Bong.) Carr.) site index, windspeed, former land use, soil moisture and soil nutrients with a view to identifying factors limiting the growth potential of the species in three climate regions in Ireland. We selected plantations covering three climate regions (delineated on the basis of ‘growing season’ balance of precipitation and potential evapotranspiration; representing dry, moist and wet climate regions) located on sites representing the range of soil moisture regimes (SMR), soil nutrient regimes (SNR), and land use types found throughout Ireland. Site index of Sitka spruce varied among climate region, with significantly lower site index associated with the wet climate region mainly due to the deterioration in edaphic conditions and adverse climatic conditions. The effect of edaphic variables (SMR, SNR) on site index was consistent across climate regions, site index increasing with increasing SNR, and decreasing with excess moisture or moisture deficit. Site index reached a maximum on fresh/very rich sites in the dry and moist climate regions and on moist/rich sites in the wet climate region. In the dry climate region, water supply (SMR) was the most important variable regulating growth, in wetter windier climates nutrient supply (SNR) was the most important factor, accounting for 69% of the variation in site index. The study has allowed region-specific recommendations to be made for successful plantation establishment in Ireland and for countries with similar climatic regions.

Coarse woody debris (CWD) has become recognised as an important component of the carbon (C) pool in forest ecosystems. In Ireland, managed Sitka spruce (Picea sitchensis (Bong) Carr.) forests account for 52.3% of the total forest estate. To determine the stock and decay dynamics of above and belowground CWD, field surveys using fixed area sample plots, were conducted in six even-aged Sitka spruce stands, representing the young, intermediate and mature stages of a typical commercial rotation. The volume, mass, density loss and C:N ratio of all CWD types (logs, stumps, and coarse roots) were determined using a five-decay class (DC) system. The decay rates and half life of CWD was also determined. To estimate CWD coarse root mass; roots associated with stumps classified in different decay classes were excavated. The coarse roots were categorised into small (2–10 mm), medium (10–50 mm) and large (>50 mm) diameter classes. CWD C-mass ranged from 6.98 to 18.62 Mg ha−1 and was highest in an intermediate forest (D35), while the aboveground volume varied from 6.31 to 42.27 m3 ha−1. Coarse roots accounted for 21% to 85% of the total CWD C-pool in the surveyed stands. The total CWD C-mass was poorly correlated with the number of thinning events (R2 = 0.29), when data from D35 was excluded. The density loss was significant in logs (45%), stumps (58%), and small- (38%), medium- (50%) and large roots (38%) as decay progress from DC 0 to 4. There was a 46%, 41%, 51%, 72% and 57% decline in C:N ratio of logs, stumps, small-, medium- and large roots, respectively, as decay progressed from DC 0 to 4. The density decay rates were 0.059, 0.048 and 0.036 kg m−3 year−1 for logs, stumps and coarse roots, respectively. The size classification of roots did not significantly affect their decay rate. The half life (50% decomposition) of CWD was estimated has 12-, 14- and 19 years for logs, stumps and roots of Sitka spruce. Regression curves showed a strong correlation between the density and C:N ratio (R2 = 0.69, 0.74 and 0.93 for logs, stumps and coarse roots, respectively). The long term storage of C and its slow rate of decomposition make CWD a vital structural and functional component of the CWD C-pool and a major controller of forest ecosystem C-retention.

To examine the relationships between Sitka spruce (Picea sitchensis (Bong.) Carr.) site index and site quality variables, we sampled 201 Sitka spruce stands covering the entire range of sites supporting the growth of the species in Ireland. Site index varied significantly with climate and climate surrogate variables, some site quality variables, soil physical and chemical properties, edatopes (combinations of soil nutrient and moisture regimes), rotation types, provenance, and fertilizer regimes. We developed a series of models to predict site index using climate, site, soil physical and chemical properties, edaphic variables, and management factors as predictor variables. Soil nutrient regime (SNR) exhibited the strongest relationship of all variables examined in the study, explaining 51% of the variation in site index, with site index increasing with increasing SNR. We found that edaphic variables of soil moisture regime and SNR produced the best prediction of site index. The species showed the best development on fresh to very moist sites, with rich to very rich soil nutrient regimes. We also developed a composite model explaining 62% of the variation in site index and an elevation zone model (>300 m) explaining 74% of the variation in site index.

In this paper, a literature overview is presented on the use of laser rangefinder techniques for the retrieval of forest inventory parameters and structural characteristics. The existing techniques are ordered with respect to their scale of application (i.e. spaceborne, airborne, and terrestrial laser scanning) and a discussion is provided on the efficiency, precision, and accuracy with which the retrieval of structural parameters at the respective scales has been attained. The paper further elaborates on the potential of LiDAR (Light Detection and Ranging) data to be fused with other types of remote sensing data and it concludes with recommendations for future research and potential gains in the application of LiDAR for the characterization of forests.

The most common form of forest stand parameter estimation is undertaken based on field-based forest inventory data. Parameter estimations are implemented at a range of scales depending on the user needs and requirements. Due to time and cost constraints, these approaches are sample based, with measurements collected using sampling frames, which tend to be sparsely distributed when inventories are carried out across a country (e.g. national forest inventories) or region (Matthews and Mackie, 2006). Commonly, forest managers require detailed information on individual stands in order to plan silvicultural management strategies. Such information is typically derived from a stand-based inventory, where detailed measurements from several plots are collected within each stand, providing more precise forest parameter estimates. In recent decades, forest practitioners have increasingly integrated remote sensing data as a means of assisting and complementing forest inventories. Aerial photography has been used extensively to estimate forest attributes, which include species identification, tree height, crown diameter and the delineation of forest boundaries (Tuominen and Pekkarinen, 2005). Top height is an important forest parameter that is used in the UK and Ireland to estimate Yield Class (annual production potential) and as an indicator of standing biomass. Using remote sensing, tree height can be measured using high-resolution stereoscopic aerial photos, with photogrammetric techniques to measure the lengths of shadows projected onto level open ground (Kovats, 1997). However, these techniques are dependent on a number of factors that include level open ground and the need to determine the sun elevation and latitude, which consequently limits the operational use of these techniques. However, a more effective approach to determine tree heights in forests is by using parallax measurements from stereoscopic photographs (Schut and Van Wijk, 1965). More recently, research has been conducted that combines space-borne satellite imagery with forest inventory Forest canopy height retrieval using LiDAR data, medium-resolution satellite imagery and kNN estimation in Aberfoyle, Scotland

We assessed age-related alterations in carbon (C) stocks and sequestration rates of first rotation Sitka spruce (Picea sitchensis (Bong.) Carr) plantations on predominantly surface-water gley soils. Sites were selected to represent a typical Sitka spruce chronosequence following land use transition from grasslands dominated by surface-water gley soils. Based on inventory, eddy covariance, physiological and modelling assessments of net ecosystem productivity (NEP), we show that afforested stands are a C sink at 10 years, and possibly earlier, followed by an increase to a maximum of 9 t C ha−1 year−1 before the first thinning cycle. NEP subsequently declined from 9 t C ha−1 year−1, at closed canopy, to 2 t C ha−1 year−1 in older and thinned stands. Reductions in the C sequestration rate of older stands were coupled with a decrease in gross primary productivity, increases in maintenance/growth respiration and decomposition losses following harvest. We suggest that the high sequestration potential of these forests may be associated with the high net primary productivity of these plantations in Ireland, a high allocation of assimilates and litter into the belowground C pool and accumulation of C in mineral gley soils following afforestation.

Summary The requirement for reporting of changes in forest carbon (C) stocks under the United Nations Framework Convention on Climate Change and to the Kyoto Protocol has underlined a need for information on the deadwood pool. As the coarse woody debris (CWD) component of the deadwood pool falls outside the remit of most C-stock change models used in reporting processes, this study set out to develop a methodology to evaluate the C-content of CWD stocks in the main Irish forest type (Sitka spruce plantations). In order to calculate CWD stocks without information on thinning/harvesting dates, the development of a system of classifying CWD into fi ve decay classes (DCs) is presented. DCs were based mainly on visual characteristics linked to the degree of decomposition. Samples were taken from thinned fi rst rotation plantations to establish the basic density loss associated with each DC. Stocks, including logs, stumps and roots, ranged from 5.1 to 13.1 t C ha − 1 in forests aged 30 and 33 years, respectively. Decay rates for both stump and log material were 0.0592 and 0.0466 g cm − 3 a − 1 , respectively.

The assessment of a forest resource in national inventories provides a firm basis for the calculation of biomass and carbon (C) stocks of forests. Biomass expansion factors (BEFs) and conversion factors provide a robust and simple method of converting from forest tree stem volume to total forest biomass. These factors should be constructed on the basis of nationally specific data in order to take account of regional differences in growth rates, management practices, etc. The objective of this study is to improve the accuracy of biomass estimation by calculating a range of age-dependant BEFs from representative data that more accurately describe the allometry of present forests. The results from this study show that the allocation of biomass to compartments in forest stands and throughout a rotation varies considerably, and that the use of BEFs for the calculation of C stocks in forests of sub-timber dimensions is highly impractical.

A comparison was made of annual net ecosystem productivity (NEP) of a closed canopy Sitka spruce forest over 2 years, using either eddy covariance or inventory techniques. Estimates for annual net uptake of carbon (C) by the forest varied between 7.30 and 11.44 t C ha−1 year−1 using ecological inventory (NEPeco) measures and 7.69–9.44 t C ha−1 year−1 using eddy covariance-based NEP (-NEE) assessments. These differences were not significant due to uncertainties and errors associated with estimates of biomass increment (15–21%) and heterotrophic respiration (12–19%). Carbon-stock change inventory (NEPΔC) values were significantly higher (27–32%), when compared to both NEPeco- and -NEE-based estimates. Additional analyses of the data obtained from this study, together with published data, suggest that there was a systematic overestimation of NEPΔC-based assessments due to unaccounted decomposition processes and uncertainties in the estimation of soil-C stock changes. In contrast, there was no systematic difference between NEPeco and eddy covariance assessments across a wide range of forest types and geographical locations.

While sustainable forestry in Europe is characterized by the provision of a multitude of forest ecosystem services, there exists no comprehensive study that scrutinizes their sensitivity to forest management on a pan-European scale, so far. We compile scenario runs from regionally tailored forest growth models and Decision Support Systems (DSS) from 20 case studies throughout Europe and analyze whether the ecosystem service provision depends on management intensity and other co-variables, comprising regional affiliation, social environment, and tree species composition. The simulation runs provide information about the case-specifically most important ecosystem services in terms of appropriate indicators. We found a strong positive correlation between management intensity and wood production, but only weak correlation with protective and socioeconomic forest functions. Interestingly, depending on the forest region, we found that biodiversity can react in both ways, positively and negatively, to increased management intensity. Thus, it may be in tradeoff or in synergy with wood production and forest resource maintenance. The covariables species composition and social environment are of punctual interest only, while the affiliation to a certain region often makes an important difference in terms of an ecosystem service’s treatment sensitivity info:eu-repo/semantics/publishedVersion

Summary The relationship between leaf area and diameter at breast height (d.b.h.) or sapwood area (AS) has been used to estimate stand leaf area or biomass of forest canopies. It has been suggested that intra-specifi c variations in the relationship between stand leaf area and d.b.h. or AS can introduce a systematic error in these estimates for younger and older stands unless additional parameters relating to canopy structure are included in allometric functions. We collected data from a Sitka spruce chronosequence to parametrize and test different algorithms for the estimation of foliar biomass (FB) and litter inputs over a range of forest ages. FB estimates were signifi cantly improved when additional biometric information relating to crown structure (canopy openness and height of live crown) was included in the models. Although the use of the relationship between leaf area and AS for the estimation of leaf area is justifi ed by theoretical considerations (pipe model theory), we show that d.b.h. and other canopy parameters provided the most robust estimation of leaf area across different-aged stands. Our results also suggest that the accuracy of litter input estimates depends on needle retention time and annual turnover rate, particularly immediately before and after canopy closure.

World-wide, forest managers have long recognised the benefits of using optimisation-based modelling techniques to improve decision-making. With no such systems in operation in Irish forestry, optimisation-based economic models were developed for harvest scheduling on a forest level within the context of a hierarchical approach. These new techniques were compared to those currently employed by Coillte Teoranta (the Irish Forestry Board). The development of the optimisation models involved the evaluation of: different management options strategies, optimisation techniques, model types and constraint strategies. Evaluation of the models was carried out in Clonbrock forest (294.8 ha), a typical Irish plantation forest, owned and managed by Coillte. The application of the selected model resulted in an increase in net present value (NPV) over the 5-year planning period of 14.2% compared to the NPV produced by Coillte's current process.

Summary The research reported in this article, carried out in the period 1995‐1997, was part of a large-scale project investigating the impact of soil cultivation/drainage practices upon water-table depth, rooting depth, root architecture and biomass production of young Sitka spruce (Picea sitchensis (Bong.) Carr.) trees on surface water gley soils. On two sites in the mid-west of Ireland, a total of 207 trees, 5 and 7 years old, were excavated over a 2-year period, during which water-table depths were monitored. Results showed that neither mound drains nor mole drains had as great an effect on tree rooting depth as the presence of a planting mound. In the cultivation treatments that included planting on mounds, tree roots were mainly confined within the mounds, with the exception of the tree root systems in the mole-and-mound treatment on one of the sites, where the mean root depth of both the 5-year-old and 7-year-old trees reached almost 20 cm below the original soil level. Continued evaluation of these experiments is required to assess the long-term effectiveness of the different drainage and cultivation methods in increasing rooting depth and improving tree stability.

Recent labour shortages and rapid increases in labour costs in Irish forestry have directed attention to mechanised, containerised tree planting systems as an alternative to the traditional manual planting of bare-rooted stock. The objective of this study was to compare mechanised planting with manual operations, on both reforestation and afforestation sites, using Sitka spruce ( Picea sitchensis (Bong.) Carr.) plants in three container types (i.e. hard container, root trainer, fen container). The Bracke tree planting machine was selected for the study, as it is capable of handling a wide range of site conditions and a variety of plant types and sizes. A qualitative analysis of the collected data showed that, in general, manual planting scored significantly higher than mechanised planting for plant position and planting quality. However, the quality of planting resulting from mechanised operations was well within acceptable operational requirements. On the reforestation site, plant growth after one growing season was investigated. No overall significant differences in height growth and root collar diameter increment were found in the first growing season between mechanised and manual planting operations. Plants grown in `fen containers' had the highest relative increase in height growth and root collar diameter, irrespective of planting method. The results showed that the Bracke planting machine was capable of planting a range of containerised plants to an acceptable standard on both reforestation and afforestation sites. Further research to optimise the combination of machine, plant size and container type should result in improvements in both the quality and productivity of the planting operations.

Summary This article reports on a study initiated to assess in detail the volume and value recovery losses associated with damage resulting from a 1998 catastrophic storm in Ireland. The results are based on a 0.39 ha representative site in Swanlinbar forest, County Cavan. Detailed analysis showed that the loss in recovery in the broken stems amounted to a volume loss of 27 per cent with an associated value loss of 29 per cent. On a stand basis this corresponded to 13.4 per cent of stems broken, resulting in a 2.6 per cent volume loss. The value loss of IR£0.87 per cubic metre recovered amounted to IR£310.94/ha or 2.8 per cent of the potential revenue. During the milling of the blown timber, no additional loss was incurred as a result of log defects resulting from storm damage. A significant relationship between diameter at breast height (d.b.h.) and the occurrence of breakage was established, with the smaller diameter trees more likely to snap than those with larger d.b.h. measurements. No significant relationship between the location of the breakage along the stem and the d.b.h. of the trees was found.

Birch in Ireland has long been regarded a timber species of minor importance, and it is noted more often for its invasiveness in young coniferous forests and clearfelled areas than for its potential as a commercial forestry species. While research on other native hardwood species such as oak or ash has been ongoing for a number of years, very little is known about the Irish birch resource. The lack of quantitative data relating to height growth, diameter growth and volume increment of birch in this country is of particular concern. The objective of this study was to examine the growth potential of birch in Ireland. Following a field survey, eight well-stocked, unthinned birch stands were selected for inclusion in the study. All of the selected stands were determined to be downy birch. Following analysis of sample tree disc sections, two stands were excluded (because of indistinct annual rings) and the study was restricted to the six remaining stands. A total of 100 sample trees were felled at the six sites. Tree ring data were collected from a total of 1333 sample tree disc sections. Using these ring data, the historic patterns of radial growth at breast height, height growth and volume growth of the six stands were reconstructed, examined and analysed in detail. The results showed that for well-stocked, unthinned, even-aged stands the period of maximum radial growth, and therefore diameter growth, occurred between the ages of 5 and 20 years. The fastest growing tree achieved a diameter of 25 cm in 32 years. It is suggested that for the stands included in this study, the lack of management, in particular the lack of adequate thinning, will have resulted in excessive crown competition and consequently reduced diameter growth. Maximum height increment occurred before the age of 20 years and fast growing trees achieved a height growth of >1 m per year during this period. The results showed that a well-stocked, unthinned downy birch stand can achieve a standing volume (under-bark) of 200 m 3 ha - 1 in 42 years. While some of the stands included in the study had not reached the age of maximum mean annual increment, comparison with the Forestry Commission yield models showed that stands of downy birch in Ireland can achieve a yield class of 8 and, given the correct thinning regime, total recovered volume production could possibly be raised to that equivalent with yield class 10.

Significant expansion has occurred in Ireland's forest estate since the 1950s. However, the design of the monocultural plantations established in the 1950s and 60s is now considered insensitive to local landscapes and re-design intervention and transformation is needed to improve integration into the environment. This case study was carried out in Laracus forest, Co. Donegal. The rotation of all stands in this 581-ha property has reached the final production phase, with coupes scheduled for clearfelling from 2003 to 2015. The implications of forest re-design for both the volume production in the current rotation and the financial return of the current and subsequent rotations were examined. Results indicated a volume loss due to design planning for the current rotation of 5.6% compared to the volume produced under the standard regime. In financial terms, this represents a loss of 4.6%. For the subsequent rotation, a significant financial gain of 22% in net present value was achieved as a result of redesigning the plantation. The overall financial out-turn for the property, when both the current and subsequent rotations were considered, was a 3.4% lower net present value for the design plan than for the standard regime. This result represents a lower impact of design planning in Laracus than most other forest restructuring studies have reported.

The climate in Ireland is oceanic and windy. An occasional feature of this climate is the occurrence of storms, which cause damage to forests on a catastrophic scale. Such storms can cause substantial economic losses. On 24 December l997 a major storm caused extensive damage to forests in the south of Ireland. Maximum gusts of 101 m.p.h. were recorded in Valentia, 92 m.p.h. at Cork Airport and 94 m.p.h. at Rosslare. The exceptional feature of the storm was the high mean wind speeds recorded. Average wind speeds over 10-min periods of 69, 64 and 54 m.p.h. were recorded for Valentia, Cork Airport and Rosslare, respectively. The damage was almost exclusively concentrated in Counties Cork, Kerry and Waterford, with minor wind blows occurring in Counties Limerick and Wicklow (Anon., l998). Survey results suggested that trees with a combined Financial impact evaluation of catastrophic storm damage in Irish forestry: a case study. I. Stumpage losses

SYNOPSIS Eucalyptus nitens (Deane & Maiden) Maiden is an economically important Eucalyptus species with a broad natural range in Australia and has been identified as a priority fuelwood plantation species in Lesotho. Unlike most eucalypts, E. nitens is a shy seed bearer. This study was aimed at propagating Eucalyptus nitens using stem cuttings. These were taken seasonally from an 11-year-old E. nitens stand and three-year-old stock plants. Cuttings were prepared in a factorial combination of four types of media (viz. peat, sand, vermiculite and a 1:1:1 mixture of the three) and two hormone dipping treatments (viz. no dipping and dipping in Seradix No. 3 rooting powder containing 0,8% IBA). In the last experiment, 0,2% IBA was used. Rooting performance was evaluated under glasshouse conditions using a warm bench propagation unit. Adventitious root formation on cuttings of E. nitens was not effectively influenced by the application of IBA. Rooting of cuttings obtained from 11-year-old E. nitens decreased fr...

This article describes the development and validation of a decision-support system for sawmill wood procurement, dealing specifically with the integration of the pre-harvest inventory procedures, site-specific dbh/height models and a generic taper equation, with a crosscutting simulator. The crosscutting simulation program faithfully mimics the process of cut-to-length harvesting and provides detailed information on the potential volume, logs count and diameter distributions for different log assortment specifications. Four data sets, consisting of a total of 4153 diameter and height measurements, were used in the validation process. The sites included two Sitka spruce clearfells, a Sitka spruce thinning and a Norway spruce clearfell. The evaluation process has shown that the developed decision-support system produced accurate results for a wide range of stand types, as long as sufficient large data sets were used, and that it provides the wood procurement manager of a sawmill with an efficient means of gaining a comprehensive insight into the yield potential of standing timber lots and, as such, represents a valuable aid to timber procurement and production planning.