Mean Tree Volume Research Articles

Growth and yield patterns of black locust (Robinia pseudoacacia L.) sample trees affected by site conditions: case studies

The trees removed from the long-term experiment plots are available for the measurements as lying trees. Through the determination of the volume in sections along the stem, the stem form, the stem volume and other factors can be specified. The comparison of the stems of individual trees of first and third yield classes of black locust (Robinia pseudoacacia L.) stands shows that site conditions have a main effect on the yield (mean tree volume). The difference can be as high as 53% at the age of 30 depending on the sites. To determine the growth patterns based on tree volume is rather a new approach in the light of the relevant literature. The obtained results also highlight the importance of choosing the appropriate tree species for a given site.

Effects of thinning on growth performance of teak (Tectona grandis) plantations in Tain II Forest Reserve, Ghana

Although recent interest in commercial teak plantation establishment has soared, knowledge of intensive silvicultural management of residual stands is limited in most parts of West Africa. This study evaluated the effects of thinning regimes on the growth responses and pruning requirements of teak plantations, two years after thinning, in the transition zone of Ghana. The thinning trial was conducted on a 4-year-old stand with initial stocking of 1 111 trees ha−1 in the Tain II Forest Reserve, Ghana. The treatments were four thinning regimes: 50%, 30%, 0% thinning intensities and 50% decrowning, arranged in a completely randomised design with four replicates. Two years after thinning, the treatments were significantly different in diameter at breast height (DBH) (p < 0.00029), total height (p = 0.017) and stem density (p < 0.0002). The 50% thinning intensity had the highest mean tree DBH, volume, height and basal area of 15.57 cm, 0.13 m3, 11.94 m and 0.02 m2 respectively. The lowest was found in the control (no thinning) except height which was least in decrowned plots. Maximum mean annual increment of DBH, total height and volume were respectively 2.00 cm, 1.34 m and 9.9 m3 ha−1 for the heavily thinned stand. The number of epicormic shoots per tree increased with the thinning intensity/regime, hence increasing the pruning requirement. It is concluded that 50% thinning intensity promotes positive growth of residual stand but increases the pruning requirements and possibly the pruning costs. Long-term evaluation of this trial is essential to validate the recommendations from this study.

Stand growth modeling system for planted teak (Tectona grandis L.f.) in tropical highlands

We developed a system for modeling the growth and yield of planted teak (Tectona grandis L.f.) for small diameter products under varying management regimes in the tropical Central Highlands of Viet Nam. We compared an independent and simultaneous system of models to predict dominant height (Ho), quadratic mean diameter (Dg), averaged tree height (Hg) with Dg, and mean tree volume (V) versus stand age (A). In addition, the model system performance with and without site index (SI) and stand density (N) as covariates were compared using K-fold cross-validation. The best modeling system was obtained with the simultaneously fit models that included SI and N and were in the form of: Dg=Dm/(1 + a × exp(-b × A)) × exp[e1 × (SI– 15) + e2/1000 × (N – 722)]; Hg=Hm × exp(-a × exp(-b × A)) × exp[e1 × (SI– 15) + e2/1000 × (N – 722)]; and V=π4×104Dg2×Hg×0.45; where Dm, Hm, a, b, e1and e2 were the parameters to be estimated. These models will help predict the growth and yield of teak planted for different planting schemes, includings monoculture, agroforestry, and forest enrichment planting in this region.

Analyses of periodic annual increment by diameter and volume in differently aged black locust (Robinia pseudoacacia L.) stands: Case study

Black locust is one of the most commonly planted exotic tree species in the world. It has a crucial role in mitigating the negative effects of climate change. Its increment analyses have a key role in forest planning. Increment is added to the wood stock of the forest over and over again, and only this continuous replenishment makes the sustainable forest management possible. This study presents the results of the analysis of periodic annual increment (PAI) by diameter (dbh) and volume (v) of two differently aged black locust (Robinia pseudoacacia L.) stands, growing under similar ecological conditions. The main correlations are as follows: PAI&lt;sub&gt;dbh&lt;/sub&gt; and diameter at breast height: r = 0.601 and 0.704 (P = 0.01); PAI&lt;sub&gt;v&lt;/sub&gt; and mean tree volume (v): r = 0.721 and 0.849 (P = 0.01). The presented correlations clearly demonstrate the importance of individual differentiation within a stand.

A species- and site-specific stand density index based on growth and mortality

A stand density index (SDI) was derived from three hypotheses, of which two concern mortality and growth up to the age at which there is an inflection point in growth, and the third relates mean tree volume and dbh (quadratic mean diameter at breast height) up to that age. The equations are [Formula: see text] or [Formula: see text], reference dbh = 25.4 cm or 10 inches. The parameters λ and β relate mean tree volume to dbh and stand volume to number of trees. Either equation provides a simple alternative to determining the self-thinning line and finding its slope, and also provides a direct comparison to the Reineke equation. Comparison of SDI values and exponents from the above equations to others’ results indicates the equations tend to produce smaller exponents, and larger SDI values, for dbh less than 25.4 cm. Values of [Formula: see text] varied with species and site quality, generally with smaller values than 1.605 for conifers, and larger values for angiosperms, when these were determined from yield tables, while values from experimental plots were always smaller than those from yield tables. Parameters must be estimated from data that are not significantly beyond the inflection age, and β and the ratio of growth to mortality parameters must be comparable.

Stand structure and growth of Robinia pseudoacacia 'Jászkiséri' - 'Jászkiséri' black locust

Black locust (Robinia pseudoacacia L.) is one of the most widespread tree species introduced into Europe and also into Hungary. It covers 24% of the total Hungarian forest area, providing 25% of the annual timber output of the country. Due to the demands of consumers, new cultivars are to be produced by means of improvement techniques and are to be introduced into the practical forestry use. Mono- and multiclonal cultivars were developed, then variety comparison trials and cultivation tests were established. Based on preliminary yield tests the locust cultivar ‘Jászkiséri’ (Robinia pseudoacacia ‘Jászkiséri’) proved to be one of the best black locust cultivars. Consequently, a more precise investigation of the stand structure of this cultivar may also make a significant contribution to the improvement of the relevant cultivation technology. In this study, based on full inventories of 13 stands in 7 subcompartments, age of 5 to 35 years, relationships of mean tree volume to diameter (R&lt;sup&gt;2&lt;/sup&gt; = 0.9797) and basal area (R&lt;sup&gt;2&lt;/sup&gt; = 0.9781), furthermore the relationship between mean tree volume and diameter of the stands (R&lt;sup&gt;2&lt;/sup&gt; = 0.9993) were examined. Besides that, the comparison of 15-year-old ‘Jászkiséri’ and common black locust (a case study) were presented in this paper, where ‘Jászkiséri’ proved to be better: significant differences (P &amp;lt; 0.05) were found in diameter, mean tree volume and stem form.

Fertilization modifies forest stand growth but not stand density: consequences for modelling stand dynamics in a changing climate

Abstract Knowledge of the maximum forest stand density and the self-thinning process is important for understanding, modelling and scheduling thinnings in silviculture. The upper trajectories of stem number, N, vs mean diameter, dq or mean tree volume vs stem number are often used for quantifying maximum stand density. The long debate about how site conditions modify these relationships is presently revived due to global change. A crucial question is whether environmental conditions alter the trajectories themselves or just the velocity at which stands move along them. Our contribution is based on fully stocked plots from long-term Scots pine (Pinus sylvestris L.) fertilization experiments along an ecological gradient in South Germany. This allows us to compare the self-thinning trajectories of fertilized and unfertilized plots under different environmental conditions. We can show that repeated fertilization with nitrogen did not change the N ~ dq trajectories. Assuming that fertilization affects forests in a similar way as an ongoing atmospheric N-deposition, this means that presently growth, mortality, and volume accumulation in forest stands proceed faster in time but still follow the same N ~ dq allometric trajectories. Furthermore, we found that the level of the self-thinning line generally increases with the annual precipitation. The allometric self-thinning exponent, however, did not respond to environmental conditions. Finally, we quantitatively demonstrate and discuss the implications and consequences of the results regarding understanding and modelling forest stand dynamics, carbon sequestration and the development and adaptation of silvicultural guidelines in view of climate change.

Tree growth as affected by stem and crown structure

Key messagePrediction of tree growth based on size or mass as proposed by the Metabolic Scaling Theory is an over-simplification and can be significantly improved by consideration of stem and crown morphology.Tree growth and metabolic scaling theory, as well as corresponding growth equations, use tree volume or mass as predictors for growth. However, this may be an over-simplification, as the future growth of a tree may, in addition to volume or mass, also depend on its past development and aspects of the current inner structure and outer morphology. The objective of this evaluation was to analyse the effect of selected structural and morphological tree characteristics on the growth of common tree species in Europe. Here, we used eight long-term experiments with a total of 24 plots and extensive individual measurements of 1596 trees in monospecific stands of European beech (Fagus sylvatica L.), Norway spruce (Picea abies (L.) Karst.), Scots pine (Pinus sylvestris L.) and sessile oak (Quercus petraea (Matt.) Liebl.). Some of the experiments have been systematically surveyed since 1870. The selected plots represent a broad range of stand density, from fully to thinly stocked stands. We applied linear mixed models with random effects for analysing and modelling how tree growth and productivity are affected by stem and crown structure. We used the species-overarching relationship mathrm{iv}={{a}_{0}times v} between stem volume growth, mathrm{iv}and stem volume, v, as the baseline model. In this model {a}_{0} represents the allometric factor and α the allometric exponent. Then we included tree age, mean stem volume of the stand and structural and morphological tree variables in the model. This significantly reduced the AIC; RMSE was reduced by up to 43%. Interestingly, the full model estimating mathrm{iv} as a function of v and mean tree volume, crown projection area, crown ratio and mean tree ring width, revealed a alpha cong 3/4 scaling for the relationship between mathrm{iv}propto {v}^{alpha }. This scaling corresponded with Kleiber’s rule and the West-Brown-Enquist model of the metabolic scaling theory. Simplified approaches based on stem diameter or tree mass as predictors may be useful for a rough estimation of stem growth in uniform stands and in cases where more detailed predictors are not available. However, they neglect other stem and crown characteristics that can have a strong additional effect on the growth behaviour. This becomes of considerable importance in the heterogeneous mixed-species stands that in many countries of the world are designed for forest restoration. Heterogeneous stand structures increase the structural variability of the individual trees and thereby cause a stronger variation of growth compared with monocultures. Stem and crown characteristics, which may improve the analysis and projection of tree and stand dynamics in the future forest, are becoming more easily accessible by Terrestrial laser scanning.

Growing of Black Locust (Robinia pseudoacacia L.) Candidate Cultivars on Arid Sandy Site

In the late 1990s, Hungarian Forest Research Institute researchers produced 15 micropropogated black locust (Robinia pseudoacacia L.) clones as part of a program to select clones that could be successfully grown on arid sites. Five of these clones (R.p. ‘Vacsi’, R.p. ‘Szálas’, R.p. ‘Oszlopos’, R.p. ‘Homoki’ and R.p. ‘Bácska’) have been categorized as cultivar candidates. The current study presents information concerning the ‘Bácska’, ‘Vacsi’ and ‘Homoki’ candidate cultivars. Based on research results obtained thus far, the three aforementioned candidate cultivars seem the most promising. The cultivars, aged 6-15 years, were tested in a variety comparison trial under arid, sandy soil conditions in the Danube–Tisza Interfluve near the town of Helvécia. Significant differences (p&lt;0.05) were observed during results evaluation of full inventories and during the comparison of candidate cultivars partly with common black locust and partly with ‘Jászkiséri’ cultivars. The 15-yearold ‘Homoki’ outperformed common black locust in diameter and mean tree volume; ‘Vacsi’ outperformed in stem quality. The 14-year-old ‘Bácska’ candidate cultivar was compared with the ‘Jászkiséri’ cultivar and the ‘Oszlopos’ cultivar candidate. ‘Bácska’ proved to be significantly better in diameter and mean tree volume than Jászkiséri’, but weaker in trunk quality. The South Korean National Institute of Forest Science has supported this research for several years. The growing technology of the mentioned candidate cultivars are also examined in Korea, taking local ecological conditions into account.

Diversity and Volume Assessment of Tree Species in the Tropical Forest at Obanla, Akure, Nigeria

This study focused on the assessment of tree species diversity and abundance at The Federal University of Technology, Akure Tropical Forest Obanla. The research was carried out from May, 2019 to September, 2019. Complete enumeration sampling was adopted for the data collection and all trees with diameter at breast height (Dbh) above 0.1 m were identified and measured. Other tree growth variables, such as diameter at the base (db), diameter at the middle (dm), diameter at the top (dt) and the total height were all measured for volume estimation. Ricinodendron heudelotii Hd the highest number of stems (13), so it was the dominant tree species.The result shows that mean tree volume ranges from a minimum of 0.26 m3 for Olalaceae family, to a maximum of 77.70 m3 for Euphorbiaceae family. Ceiba pentandra of Malvaceae family had the highest mean volume (14.62 m2) while the lowest was recorded for both Khaya senegalensis and Newbouldia laevis with a volume of 0.13 m2. The family of Euphorbiaceae was regarded as the dominant family in the natural forest with 26 tree species which is the highest in this study and with the highest volume (77.70 m2). Shannon Wiener diversity index and species equitability index according to Pielou’s of 3.24 and 0.92 were respectively obtained for the study area. This study revealed the efficacy of an undisturbed natural forest in in situ conservation. Active regeneration can be carried out for proper stocking of the forest so has to make it a potential biodiversity hotspot.

Forest Variable Estimations Using TanDEM-X Data in Hyrcanian Forests

The objective of this study was to estimate forest variables using TanDEM-X interferometric synthetic aperture radar (InSAR) data acquired over the Shastkalate forest of Gorgan in northern Iran. Inventory variables, including diameter at breast height, tree height (Lorey’s mean tree height), basal area and volume, were collected from 112 circular sample plots with a size of 0.1 ha. Interferometric phase height and coherence were computed from TanDEM-X data. Stepwise multiple linear regression was used to develop models describing the relationship between field-derived forest variables and the InSAR based statistical metrics. The validation was carried out using the leave-one-out cross-validation method. The estimation accuracy results in terms of relative RMSE for Lorey’s mean tree height, basal area and volume were 11.0, 34.1, and 37.8%, respectively, whereas the corresponding figures for R2adj were 32.0, 10.0, and 16.0%, respectively. The results were good enough for estimating forest variables and it was concluded that TanDEM-X could be used in Hyrcanian hardwood forests.

Estimating Tree Volume Distributions in Subtropical Forests Using Airborne LiDAR Data

Accurate and reliable information on tree volume distributions, which describe tree frequencies in volume classes, plays a key role in guiding timber harvest, managing carbon budgets, and supplying ecosystem services. Airborne Light Detection and Ranging (LiDAR) has the capability of offering reliable estimates of the distributions of structure attributes in forests. In this study, we predicted individual tree volume distributions over a subtropical forest of southeast China using airborne LiDAR data and field measurements. We first estimated the plot-level total volume by LiDAR-derived standard and canopy metrics. Then the performances of three Weibull parameter prediction methods, i.e., parameter prediction method (PPM), percentile-based parameter recover method (PPRM), and moment-based parameter recover method (MPRM) were assessed to estimate the Weibull scale and shape parameters. Stem density for each plot was calculated by dividing the estimated plot total volume using mean tree volume (i.e., mean value of distributions) derived from the LiDAR-estimated Weibull parameters. Finally, the individual tree volume distributions were generated by the predicted scale and shape parameters, and then scaled by the predicted stem density. The results demonstrated that, compared with the general models, the forest type-specific (i.e., coniferous forests, broadleaved forests, and mixed forests) models had relatively higher accuracies for estimating total volume and stem density, as well as predicting Weibull parameters, percentiles, and raw moments. The relationship between the predicted and reference volume distributions showed a relatively high agreement when the predicted frequencies were scaled to the LiDAR-predicted stem density (mean Reynolds error index eR = 31.47–54.07, mean Packalén error index eP = 0.14–0.21). In addition, the predicted individual tree volume distributions predicted by PPRM of (average mean eR = 37.75) performed the best, followed by MPRM (average mean eR = 40.43) and PPM (average mean eR = 41.22). This study demonstrated that the LiDAR can potentially offer improved estimates of the distributions of tree volume in subtropical forests.

Promising black locust (Robinia pseudoacacia L.) cultivars in Hungary

In Hungary, black locust (Robinia pseudoacacia L.) is one of the most important exotic stand-forming tree species, growing mostly under unfavourable ecological conditions. Considering the climate change effects its importance is increasing in many other countries. As a result of a selection programme, several black locust cultivars have been improved for setting up cultivar trials. In the paper four black locust cultivars were evaluated in Central Hungary under arid hydrological and brown forest soil conditions. Significant differences (P&lt;5%) were found in height, DBH, mean tree volume and average stem form value (SFV). At the age of 35 the cultivar ‘R.p. Jászkiséri’ appeared to be the most promising one for yield production and ‘R.p. Zalai’ for SFV.

Growth characteristics of natural and planted Dahurian larch in northeast China

Abstract. Dahurian larch (Larix gmelinii Rupr.) is the dominant species in both natural and planted forests in northeast China, which is situated in the southernmost part of the global boreal forest biome and is undergoing great climatically induced changes. Published studies (1965–2015) on tree above-ground growth of Dahurian larch forests in northeast China were collected in this study and critically reviewed, and a comprehensive growth data set was developed from 122 sites, which are distributed between 40.85 and 53.47∘ N in latitude, between 118.20 and 133.70∘ E in longitude and between 130 and 1260 m in altitude. The data set is composed of 743 entries and includes growth data (mean tree height, mean diameter at breast height (DBH), mean tree volume and/or stand volume) and associated information, i.e., geographical location (latitude, longitude, altitude, aspect and slope), climate (mean annual temperature (MAT) and mean annual precipitation (MAP)), stand description (origin, stand age, stand density and canopy density) and sample regime (observation year, plot area and plot number). It provides a quantitative reference for plantation management practices and boreal forest growth prediction under future climate change. The data set is freely available for noncommercial scientific applications, and the DOI for the data is https://doi.org/10.1594/PANGAEA.880984.

Selection of promising black locust (Robinia pseudoacacia L.) cultivars in Hungary

In Hungary the black locust (Robinia pseudoacacia Linnaeus) is one of the most important exotic stand-forming tree species growing mostly under unfavourable ecological conditions. Considering the climate change effects its importance is increasing also in many other countries. As a result of a selection programme several black locust cultivars have been improved for setting up cultivar trials. In the paper four black locust cultivars were evaluated in Central Hungary under arid hydrological and brown forest soil conditions. Significant differences (P &amp;lt; 5%) were found in height, DBH, mean tree volume and average stem form value (SFV). At the age of 35 years the cultivar “R.p. Jászkiséri” appeared to be the most promising one for yield production and “R.p. Zalai” and “R.p. Nyírségi” for SFV.

Impact of operational factors on fossil energy inputs in motor-manual tree felling and processing: results of two case studies

In many cases tree felling and processing operations are carried out motor-manually and knowledge about fossil fuel consumption and direct energy inputs when using such equipment is required for different purposes starting with operational costing and ending with environmental assessment of forest operations. In this study, fuel mixture, chain oil and direct fossil energy inputs were evaluated for two chainsaws which were used to fell and process trees in two silvicultural systems. The results of this study suggest that there is a strong dependence relation between selected tree size variables such as the diameter at breast height and tree volume on one hand and the fuel mixture, chain oil and direct fossil energy inputs when felling and processing broadleaved hardwood and resinous softwood trees on the other hand. For the broadleaved trees (mean tree volume of 1.50 m3 × tree-1, DBH of 45.5 cm and tree height of 21.84 m) the mean direct fossil energy input was of 3.86 MJ m-3 while for resinous trees (mean tree volume of 1.77 m3 tree-1, DBH of 39.28 cm and tree height of 32.49 m) it was of 3.93 MJ m-3. Other variables, including but not limited to the technology used, work experience and procedural pattern, may influence the mentioned figures and extensive studies are required to clarify their effects.

Development of forest-yield maps generated from Global Navigation Satellite System (GNSS)-enabled harvester StanForD files: preliminary concepts

The productivity of fast-growing forest plantation stands varies across short distances depending on site and forest characteristics. This indicates that forest managers would benefit from a site-specific approach to forest management. One tool used to characterise such productivity variations is a yield map, and a cost-effective source of data for these maps is automatically collected by harvesters. In order to generate such maps, it is necessary to understand the effect of geospatial accuracy of tree location recorded by the harvester. This study investigated data sets from four stands, and very accurate tree location was available for two of these. The tree-location data for the remaining two sites were collected by a harvester and contained some inaccuracies associated with Global Navigation Satellite System (GNSS) recording under forest canopy and the physical dislocation of the GNSS. The GNSS unit is on the cabin of the machine, but the tree is felled using a boom and could be up to 12 m from the cabin. A suitable spatial resolution for studying variations in stand productivity, mean tree volume, and stocking rate across stands were established that enabled useful forest-yield maps from harvester data to be developed. By assessing variability in volume per hectare, stocking rate, and mean tree volume across a range of cell sizes from 10 × 10 to 100 × 100 m, we conclude that a cell length between 30 and 40 m is suitable for use as a reference when calculating volume per hectare and mean stem volume, while a 60-m-long cell is more suitable for evaluating stocking density. The variability pattern is consistent for the various accuracy levels. When the known positions of trees are relatively inaccurate, using mean tree volume and stocking rate per cell might be a method for mapping productivity from harvester data.

General productivity model for single grip harvesters in Australian eucalypt plantations

ABSTRACTAustralia’s eucalypt plantation estate (>900 000 ha) has largely been established since 1995. The main species is Eucalyptus globulus producing wood chips for export on a short rotation (~10 years). Two main harvesting methods are used: cut-to-length (CTL) at the stump and infield chipping (IFC). CTL harvesting is typically carried out with single-grip harvesters and forwarders. The study objective was to develop a general productivity model for medium-sized single-grip harvesters performing CTL harvesting at the stump in short-rotation E. globulus plantations under typical Australian operating conditions, as few harvester productivity models have been developed for these plantations. The model was developed from 47 harvester productivity studies carried out in Australian E. globulus plantations. Studies were predominantly short-term counts of the trees cut over at least an hour multiplied by an estimate of mean merchantable tree volume derived from inventory plots measured where the harvester was about to work or an adjacent area. The model developed explained 80% of the variability in harvester productivity (79% was explained by mean tree volume and 1% by harvester engine power). Results from comparable published CTL eucalypt studies generally supported the model. The strength of the relationship suggests the model could be used to estimate harvester productivity for similar site conditions and harvester/harvester head combinations (which represent most Australian E. globulus plantations) where mean merchantable tree volume and harvester engine power were known or estimated.

Enriching ALS-Derived Area-Based Estimates of Volume through Tree-Level Downscaling

Information on individual tree attributes is important for sustainable management of forest stands. Airborne Laser Scanning (ALS) point clouds are an excellent source of information for predicting a range of forest stand attributes, with plot and single tree volume being among the most important. Two approaches exist for estimating volume: area-based approach (ABA) and individual tree detection (ITD). The ABA is now routinely applied in operational forestry applications, and results in generalized plot- or stand-level attribute predictions. Alternatively, ITD-based estimates provide detailed information for individual trees, but are typically biased due to challenges associated with individual tree detection. In this study, we applied an ABA to estimate tree counts and individual tree volumes by downscaling plot-level predictions of total volume derived using ALS data in a highly productive and complex coastal temperate forest environment in British Columbia, Canada, characterized by large volumes and multi-species and multi-age stand structures. To do so, a two-parameter Weibull probability density function (PDF) was used to describe the within-plot tree volume distribution. The ABA approach was then used to model the total plot volume and the two Weibull PDF parameters. Next, the parameters were used to calculate mean tree volume and derive the number of trees and the individual tree volume distribution. Tree count estimates were minimally biased with RMSE of 149 trees·ha−1 or 24.4%. The volume distributions showed good agreement with reference data (mean Reynold’s error index = 71.7). We conclude that the approach was suitable for enriching ABA-derived forest stand attributes in the majority of the studied forest stands; however the accuracy was lower in multi-layered stands that had a multimodal individual tree volume distribution.

Machine function integration and its effect on the performance of a timber yarding and processing operation

An assessment of the benefits of a fully integrated yarder-processor was made against the alternative of splitting the yarding and processing functions onto two base machines. The effect of productivity rates, specific costs, and crew sizes on the relative performance of each working configuration was investigated. The systems analysis showed that for the integrated yarder machine, a two-man crew was considerably cheaper than a three-man crew at all yarding distances, although the difference became less pronounced with increasing mean tree volumes. The single integrated machine with a 2-man crew was cheaper than the modelled 2-machine system at medium and longer extraction distances, as the processor base machine in the 2-machine systems incurred a considerable cost penalty in waiting idly for the yarder. At shorter distances (75 m) the 2-machine system was cheapest, but became less competitive with increasing mean tree volume. For mid-sized trees (0.38 m3) on a medium corridor length of 150 m, overall system productivity rates ranged from 5.2 m3 per productive system hour (PSH) for the single machine system to 9.4 PSH−1 for the 2-machine system, although the specific net costs were almost identical at 31.5 € m−3. A sensitivity analysis showed that reduced labour costs would promote use of the 2-machine system, suggesting that the optimum system configuration would be country specific. Despite being marginally more costly in small trees at short corridor lengths (75 m), the single fully-integrated machine was considered the working configuration of choice under Norwegian conditions.