Effect of thinning on the ring characteristics of Japanese cedar plantation trees

The purpose of this study was to explore the ring characteristics of Japanese cedar (Cryptomeria japonica) tree growth with thinning and unthinning regimes. The trees grown with thinning regimes increased in average ring width (RW), earlywood width, latewood width, ring density (RD), earlywood density, latewood density, maximum ring density, and latewood percentage (LWP) for the entire period of 16 years after thinning, as compared to those grown with unthinning regimes. The RW and RD components showed different reactions lasting several years after thinning. Overall, thinning caused immediate production (first year) of higher RD, lasting for several years; however, wider RW was delayed up to several years after treatment. There was a weak relationship between RW (growth rate) and wood density; and there were significant positive relationships between the RD and LWP. The results suggest that the compression wood produced after thinning.     

Effect of thinning on the development of compression wood in stems of Corsican pine

This study considered the effects of thinning on the development of compression wood in stems of 35-year-old stand of Corsican pine (Pinus nigra L.). Part of the stand had been thinned at 5-yearly intervals and part left unthinned. Twenty trees each from the thinned and unthinned stands were randomly selected and felled. Measurements were made on tree height, stem diameter, stem slenderness and canopy depth. Wood samples were removed from the central part of the main log and cross-sectional measurements made on ring width, basic density and compression wood content. Cross-sectional area of compression wood was found to be three time higher in stems from the unthinned trees in comparison with those from the thinned trees. No significant differences in mean radial ring width or basic density were found between treatments. Correlations indicated that, with increasing in stem diameter, compression wood content increased in the unthinned trees, while a decline in compression was observed in the thinned trees. Tree height was also positively correlated with compression wood content in unthinned trees, while no equivalent relationship was observed in thinned trees. Observations from this study, while not conclusive, suggest that phototropic stimulus may be producing stem inclinations in the unthinned stand as trees compete for space in the canopy, whereas crown competition has been largely eliminated in the thinned stand; and that this is responsible for compression wood levels recorded in this study.     

The effects of thinning treatments on density, MOE, MOR and maximum crushing strength of Pinus brutia Ten. wood

The purpose of this study was to determine the effects of plantation thinning on various wood properties of Pinus brutia Ten. Tree samples were obtained from heavily and moderately thinned and unthinned 33–35 year-old plantations. Wood properties were examined in various wood zones including 16 annual rings after the first treatment. The results of this study showed that there was a significant relationship between thinning intensity and radial increment (1.30 m) for an individual tree. Thinning treatments increased annual ring width especially a few years after thinning. Heavy thinning treatments were especially effective in impacting mean ring width values at breast height. However, the percentage of late wood did not differ much between the samples. Based on the results of correlation analysis between ring width and late wood percentage there was no significant correlation identified. Mean wood density was not affected by the treatments. Also, no significant correlation was found between thinning and examined strength properties (MOR, MOE and compression strength parallel to grain). However, a relationship was found between wood density and all strength properties except for MOE. The current results suggest that thinning can produce improvements in ring width without any negative impacts on investigated wood properties. It is recommended that subsequent studies should be designed to understand genetic effects and maximize treatment effects.     

抚育间伐对杉木人工林生长及出材量的影响

间伐对人工林生长及木材质量具有重要影响。在浙江开化开展了间伐强度（强度、中度和对照）和间伐方式（间伐1次,间伐2次）对杉木人工林生长及出材量等的影响研究,第1试验区大径材培育林分在第7年和第14年进行了2次间伐,第2试验区中径材培育林分仅在第12年时进行1次间伐。结果表明：22年生大径材培育林分和19年生中径材培育林分不同间伐处理之间树高、总断面积的差异均不显著。间伐显著增加了林木胸径的生长,大径材培育林分强度和中度间伐处理的平均胸径分别比对照增加13.78%和9.69%,中径材培育林分强度和中度间伐处理的平均胸径分别比对照增加12.28%和7.02%。间伐显著促进了林木单株材积的增加,2组试验林分活立木材积随着间伐强度的增加而降低,第1试验区22年生林分不同间伐强度之间活立木材积的差异不显著（P>0.05）,第2试验区强度间伐活立木材积显著低于对照（P<0.05）,中度间伐林分活立木材积与对照和强度间伐之间的差异不显著（P>0.05）。2组试验林分总蓄积和出材量也随着间伐强度的增加而降低,二者在3种间伐处理之间均没有显著差异（P>0.05）。间伐强度不能有效增加林分活立木材积和林分出材量,间伐次数对林分出材量及出材规格有重要影响。试验区杉木大径材培育以2次间伐,总间伐强度50%左右较为适宜,而中径材培育则以1次中度间伐（约25%）为宜。     

To thin or not to thin: bio-economic analysis of two alternative practices to increase amount of coarse woody debris in managed forests

Maintenance of biodiversity in commercial forests has become a main goal in forestry, and several new management principles to reach that goal have been introduced lately. For example, in even-aged forestry, tree retention (leaving a proportion of trees standing in clear-cut sites) is widely used to increase the structural diversity and the amount of dead wood in forests. However, the cost-efficiency of the new management principles is poorly studied. To increase the amount of dead wood, an alternative way could be a change in the thinning regime, so that the self-thinning builds up of woody debris of a growing stand. We used long-term (200?years) simulations to compare ecological and economical effects of the two alternative management practices to increase the amount of dead wood in forest stands: (1) green tree retention and (2) growing stands unthinned. We simulated stand growth and management of 12 pine and 12 spruce stands that represented sites in different parts of Finland. We found that growing stands unthinned produced about 5–6?times more dead wood than retention with 20 trees left per hectare. In terms of economical loss, leaving stands unthinned reduced the net present value of harvest revenues less than 20%. Consequently, leaving stands unthinned offers a cost-effective option to increase the amount of dead wood in commercial forests. The effects of unthinned management were, however, dependent on thermal sum and initial stand density, indicating that biodiversity-oriented management practices should be designed for local conditions.     

杉木林分密度效应研究

该项试验共分2个部分.(1)造林密度试验,小区面积为600 m2,5个处理,即1 667株.hm-2(A)、3 333株.hm-2(B)、4～983株.hm-2(C)、6 633株.hm-2(D)、9967株.hm-2(E);(2)造林密度调控试验,造林设计方法与造林密度试验相同,但在林分生长过程中,按密度管理图的密管线0.5为标准进行间伐,间伐后保留密度要与临近的下一个初植密度较稀植的林分密度基本相同,两者进行比较.试验结果(1)造林密度试验,优势高、平均高、平均胸径均随年龄的增加而递增,随密度的增加而递减,优势高9a、平均高6 a、平均胸径5 a,密度间差异已达显著性水平;林分蓄积量则随年龄增加而递增,5～7 a,密度间差异显著,8～18a,只有A密度与E、D密度差异显著;枝下高随密度、年龄的增加而递增,12～a后,C、D、E密度间的差异很小;冠幅随密度的增加而递减,随年龄的增加而递增,9～10a后,各密度则随年龄增加而缓慢递减.(2)造林密度调控试验,同一指数级,间伐后的林分与其密度基本相同未间伐的林分比较,其优势高、平均高差异不明显;立木蓄积前者小于后者;总蓄积(立木蓄积+间伐蓄积)前者大于后者;同一指数级,初植密度不同的林分,间伐后与密度基本相同未间伐林分的蓄积百分比,初植密度大的大于初植密度小的;指数级不同,而初植密度相同的林分,间伐后与密度基本相同未间伐的林分总蓄积百分比,高指数级的比值大于低指数级的比值.     

Crown radius of pedunculate oak (Quercus robur L.) depending on stem size,stand density and site productivity

Crown size is a good indicator of the growth potential of trees and is often used in forest management for outlining thinning guidelines or constructing forest growth models. The aim of this study was to analyse mean crown radius as a function of stem size, stand density and site productivity in even-aged stands of pedunculate oak (Quercus robur L.). Data included measurements of 620 trees from 53 plots in nine thinning experiments and one operational stand in Sweden, Denmark and Great Britain, representing a wide spectrum of thinning practices ranging from the strictly unthinned control to extremely heavy thinning with essentially solitary trees. Three sets of models were constructed based on different predictor variables, including indicators of individual stem size (diameter at breast height, DBH), stand density/thinning grade (quadratic mean diameter and stand basal area) and site productivity (stand top height). Preliminary results indicated a significant effect of DBH and (nominal) thinning grade on crown radius. The response pattern of the final models indicated an increasing crown radius with increasing DBH, with increasing thinning grade (decreasing stand density) and with decreasing site productivity. The models are valid for predicting the crown radius of pedunculate oak in even-aged forest stands.     

Line thinning promotes stand growth and understory diversity in Japanese cedar (<Emphasis Type="Italic">Cryptomeria japonica</Emphasis> D. Don) plantations

We studied the effects of line thinning on stand structure, microclimate and understory species diversity of two Cryptomeria japonica D. Don plantations in south-central Japan. In each of two study sites we compared stand structure between the thinned stand and an adjacent unthinned stand and found that line thinning increased the growth rate of residual trees such that stand basal area may recover within 10 years after thinning. In the thinned stand, more open canopy conditions resulted in higher maximum temperatures on the forest floor during the early growing season than in the unthinned stand. The thinned stand had greater understory plant species richness and biomass than the unthinned stand. This study suggested that line thinning could potentially enhance biodiversity while simultaneously increasing tree-growth rates in overstocked Cryptomeria japonica plantations.     

Effects of thinning level and site productivity on age-related changes in stand volume growth can be explained by a single rescaled growth curve

In this study, I developed a nonlinear mixed-effects model based on the Richards curve that describes the effects of thinning and site productivity on stand volume growth. I fitted the model to data from 29 long-term experimental monitoring plots in Japanese cedar (Cryptomeria japonica D. Don) plantations in northeastern Japan. Simulations using the model on high-productivity sites and at moderate thinning intensities indicated that net yields after ca. 80 years were lower in unthinned stands than in thinned stands; in other cases, such as at younger ages and at sites with low and average productivities, net yields were similar for each thinning intensity (including no thinning). These results could be attributed to the fact that the net current annual increment in stand volume (CAI_net) in the thinned stands exceeded that of the unthinned stands after a certain age (the “inversion” age) and to the negative correlation between site productivity and the inversion age. In addition, I found that a single rescaled growth curve was capable of describing the growth in stand volume at sites with different thinning histories and site productivities. This rescaled curve simply and clearly explained the effects of thinning and site productivity on stand volume growth. The existence of a single curve suggests that the positive effect of thinning on stand volume growth does not depend on site productivity, but it will require patient measurements over longer periods to reveal a positive effect at sites with low productivity.     

Do thinnings influence biomass and soil carbon stocks in Mediterranean maritime pinewoods?

The effects of silvicultural treatments on carbon sequestration are poorly understood, particularly in areas like the Mediterranean where soil fertility is low and climatic conditions can be harsh. In order to improve our understanding of these effects, a long-term thinning experiment in a stand of Mediterranean maritime pine (Pinus pinaster Ait.) was studied to identify the effects of thinning on soil carbon (forest floor and mineral soil), above and belowground biomass and fine and coarse woody debris. The study site was a 59-year-old pinewood, where three thinnings of differing intensities were applied: unthinned (control), moderate thinning and heavy thinning. The three thinning interventions (for the managed plots) involved whole-tree harvesting. The results revealed no differences between the different thinning treatments as regards the total soil carbon pool (forest floor + mineral soil). However, differences were detected in the case of living aboveground biomass and total dead wood debris between unthinned and thinned plots; the former containing larger amounts of carbon. The total carbon present in the unthinned plots was 317 Mg ha^?1; in the moderately thinned plots, it was 256 Mg ha^?1 and in the case of heavily thinned plots, 234 Mg ha^?1. Quantification of these carbon compartments can be used as an indicator of total carbon stocks under different forest management regimes and thus identify the most appropriate to mitigate the effects of global change. Our results indicated that thinning do not alter the total soil carbon content at medium term, suggesting the sustainability of these silvicultural treatments.     

近自然化改造对杉木人工林物种多样性的影响

在广西凭祥市热林中心青山实验场设置杉木人工林近自然化改造样地,进行3种间伐强度处理(75%、55%、35%),均匀套种4种阔叶树。改造5年后,研究不同间伐强度近自然经营对群落组成、物种多样性和林分生长状况的影响。结果表明:近自然化改造5年后,乔、灌、草3层的物种数明显增加,灌草层的优势种有所变化,但各间伐处理的优势物种大致相同;各间伐处理的灌木层物种多样性指数无显著差异;改造后各处理草本层物种多样性指数均高于未改造的纯林,各处理草本层的Simpon指数和均匀度指数均显著高于改造前的纯林。杉木胸径随间伐强度的增大而增加且差异显著,但各处理间树高无显著差异;套种的4种阔叶树的胸径、树高随间伐强度的增大而增加,大叶栎、红椎的胸径、树高生长量在不同间伐处理林分中有显著差异;高间伐强度改造的杉木人工林适合套种阳性树种大叶栎、米老排和中性树种红椎,中等间伐强度改造的杉木人工林适合套种耐阴性树种润楠。     

Effects of thinning on plant species diversity and composition of understory herbs in a larch plantation

The effects of thinning on plant species diversity and composition of understory herbs in a larch plantation were investigated. The relationships between plant species diversity and composition of understory herbs and light conditions were established. Twenty-five 1 m × 1 m plots and fifteen 13 m × 1 m transects were set up in unthinned and thinned stands, respectively. All the transects in the thinned stands were set across the thinned rows and unthinned rows, and each of them was divided into nine 1 m × 1 m sub-plots. The herb diversity and light conditions were observed in each plot and sub-plot. The results show that there was a significant difference in herb diversity between the thinned and unthinned stands. All biodiversity indices except for evenness index in the thinned stand were higher than those of the unthinned stand, i.e., the herb diversity increased after thinning. According to the changes in herb densities and whether one species could be found in a stand or not before and after thinning, all herb species were classed into three types: positive, neutral and negative species, which referred to a species newly appeared and having an obviously increased density after thinning, with no obvious changes in its appearance and density after thinning, and disappeared and having an obviously decreased density after thinning, respectively. Many new species were found in the thinned stand like Corydalis pallida, Prenanthes tatarinowii, Vicia unijuga and Sonchus brachyotus etc. However, most species found in both the thinned and unthinned stands were negative species. In all nine subplots, only 11 and 10 species were found in spring and in autumn respectively, accounting for 17.74% and 15.15% of all the species in the thinned stand, respectively. All biodiversity indices were the highest in the center sub-plots and most of them tended to reduce from middle to side sub-plots. There was a close correlation between most of the three types of species and light conditions which was similar to each other in the thinned and unthinned stands. __________ Translated from Chinese Journal of Ecology, 2006, 25(10): 1201–1207 [译自: 生态学杂志]     

Commercial thinning that maintained species diversity of a mixed black spruce–jack pine stand enhanced productivity

Commercial thinning enables forest managers to meet timber production objectives. Thinning reduces tree density to alleviate competition for resources and favour growth of selected tree species. However, in doing so, thinning can homogenize the composition of mixed-species forests and raise biodiversity issues. There is increasing evidence that species richness can lead to higher productivity through a complementarity effect. Hence, thinning that would maintain species diversity of mixed-species forests could enhance stand productivity and help forest managers to reconcile timber production objectives and biodiversity issues. The objective of this study was to compare post-thinning stand production, experimentally over 10 years, in mixed and monospecific stands of black spruce (Picea mariana [Mill.] B.S.P.) and jack pine (Pinus banksiana Lamb.). The post-thinning stand production curve of the mixed stand converged toward that of the unthinned mixed stand while the production curves of the thinned and unthinned monospecific stands remained parallel. The convergent productivity of the mixed stand could be explained by a positive interaction between effects of thinning and niche complementarity. We propose that thinning that maintains species diversity of mixed stands could help forest managers who are implementing ecosystem management to reconcile timber production objectives with biodiversity issues.     

Effect of half-systematic and systematic thinning on the increment of Scots pine and Norway spruce in Finland

Diameter, height and volume increment of Scots pine (Pinus sylvestrisL.) and Norway spruce (Picea abies (L.) Karst.) stands wereinvestigated in long-term thinning experiments in southern Finland.The measurement period was on average 19 years, and thinningsconsisted of five different treatments: (1) unthinned; (2) selectivethinning from below where thinning intensity was determinedaccording to the number of stems; (3) selective thinning frombelow where thinning intensity was determined according to standbasal area; (4) systematic thinning where corridors were openedat regular intervals in the stand; and (5) half-systematic thinningwhere corridors were opened at regular intervals and the remainingstrips thinned from below, i.e. a combination of selective andsystematic thinning. The selective (basal area) thinning ofScots pine resulted in a volume growth reduction of about 12per cent, but in Norway spruce it resulted in no marked reductioncompared with the unthinned plots. In both tree species, volumeincrement in the half-systematic and selective (basal area)thinning differed only slightly from each other. The systematicthinning resulted in the lowest volume increment. In the systematicthinning, the total yield (m³ ha^–1) somewhat decreasedwith increasing corridor width. In half-systematic thinning,on the other hand, the total yield was not clearly related tocorridor width. A corridor accelerated the diameter incrementof the edge trees. The edge effect progressively diminishedwhen moving deeper into the strip and ended at a distance ofabout 3–4 m from the corridor edge. After the thinning,the height increment first decreased, but later on it recovered.The unthinned plots had more dead trees than the other treatments,but there were no significant differences between the othertreatments. It can be concluded that the prevailing thinningmethod in the Nordic countries, i.e. half-systematic thinning,most probably results in no significant growth and yield losses.     

Influence of Shelterwood Density on Survival and Height Increment of Picea abies Advance Growth

Abstract

The increases in the arithmetic mean diameter at breast height (dbh) of the 100, 200, 300 and 400 largest stems ha^?1 by dbh associated with six different thinning regimens for periods up to 35 years were compared, by analyses of variance, to the corresponding stem fractions in unthinned stands using permanent sample plot data. In addition, the expected mean dbh of these stand fractions at future points in time was modelled, based on site and stand data obtained at the time of the first thinning. Thirty-five years after the first thinning, the thinning from below regimens resulted in actual increases (a measure affected by both the thinning intensity and the thinning method), compared with the unthinned stands, in the mean dbh for the 100, 200, 300 and 400 largest stems ha^?1 of 2.6–9.0 cm. The corresponding genuine increases (a measure principally affected solely by the thinning intensity) were 4–11 cm. The functions predicting the future dbh of these stand fractions yielded good fits.     

Effects of pruning and stand density on the productionof new epicormic shoots in young stands of pedunculate oak (Quercus robur L.)

Context

Avoidance or control of epicormic shoots is among the major silvicultural challenges for the production of high-quality oak timber. In northern Europe, contemporary oak silviculture aims to produce valuable timber on a relatively short rotation, applying early, heavy thinning combined with artificial pruning.

Aims

The aim of this study was to analyse the effects of pruning and stand density on the production of new epicormic shoots on young trees of pedunculate oak (Quercus robur L.).

Methods

The study was based on two field experiments in even-aged stands of pedunculate oak subjected to different thinning practices and early selection of potential future crop trees. From ages 13 to 15 years, stem density was reduced to 300 trees ha^?1, 1,000 ha^?1 or stands remained unthinned. Pruning was conducted on selected trees at ages 22–24 years. At that age, the stem density in unthinned control plots ranged from 2,500 to 3,100 ha^?1. All treatments were replicated twice within each experiment.

Results

Pruning led to an overall increase in the total production of new epicormic shoots. More epicormic shoots were produced in the lower part of the stem (0–3 m in height) than in the upper part (3–6 m). The number of new epicormic shoots increased with increasing stand density.

Conclusion

Early, heavy thinning combined with high pruning at regular intervals may help shorten the rotation length for pedunculate oak without further reduction in wood quality than that which is caused by wider annual growth rings.     

林分断面积生长模型研究评述

林分断面积生长模型是林分生长和收获预估模型的体系的主要组成部分。在对常用的新面积生长模型Ｒｉｃｈａｒｄｓ型和Ｓｃｈｕｍａｃｈｅｒ型分析的基础上，总结出断面积生长模型研究中应注意的４个问题；（１）选择的自变量应为３个，即立地质量指标、年龄和林分密度指标；（２）间伐林分模型应与未间伐林分模型同时考虑，进而详细介绍了用于间伐林分断面积预估的被压指数法；（３）间伐指标的构造需要伐前和后伐后的林分因子；（４     

Yield—Density diagram for natural deciduous broadleaved forest stands

A yield—density diagram for natural deciduous broad-leaved forests in Hokkaido was devised. It consists of Y—N curves, equivalent diameter curves, equivalent mean diameter curves, a B-point curve and a full density curve. The Y—N curve is derived from the relation between cumulative summation (Y) of individual tree volume from the maximum sized tree to one of a certain given volume, and number (N) of these trees, and is expressed by the reciprocal equation of two parameters, A and B. The equivalent diameter curve expresses the number of trees whose diameters are larger than a certain size. The equivalent mean diameter curves express the number and volume of trees of selected mean diameters. The B-point curve is a hypothetical trajectory of the B-point of the C—D curved ruler (C—D rule) which is fitted to each Y—N relation, throughout the course of stand development. The full density curve indicates the upper limit of the number and volume of the standing trees. Utilizing this diagram, we can comprehend numbers, volumes and tree diameters in a stand and among stands.A method is devised of predicting the number and volume of each diameter class of a stand several years after thinning. Thinned trees are assumed to be selected equally from each diameter class so that the Y—N curves are fitted equally to the Y and N data before and after thinning. Volume growth of individual trees is assumed to be proportional to their volumes after thinning. The current volume growth of the stand after crown closure is assumed to be constant irrespective of the stand age. Tree mortality after thinning is assumed to be negligible. With these assumptions, a trajectory of the Y—N curve through thinning is determined, and a yield after n years from thinning is predicted. Comparing the Y—N curve of a thinned stand with that of an unthinned stand after n years from thinning, we can comprehend the thinning effect.     

Genetic variation of wood tracheid traits and their relationships with growth and wood density in clones of <Emphasis Type="Italic">Pinus tabuliformis</Emphasis>

To improve wood quality for pulpwood industries, it is important to examine not only wood density but also its components, especially tracheid characteristics. We studied genetic variations in the following tracheid traits by earlywood (EW) and latewood (LW): tracheid length (TL), double wall thickness (WT), radial lumen diameter (R_D1), tangential lumen diameter (T_D1), radial central diameter (R_D2), and tangential central diameter (T_D2). We also studied the relationship with the following growth traits: diameter at breast height (DBH), height (H), crown breadth south-north axis (NSC), crown breadth east–west axis (EWC), ring width (RW), latewood percentage (LWP), and wood density (WD). All sample materials were collected from a 33-year old clonal seed orchard of Pinus tabuliformis Carr. Genetic variation among clones was moderate for all tracheid traits, 9.49–26.03%. Clones significantly affected WT, R_D1, R_D2, T_D1, T_D2, and the two ratios WT/R_D1 and TL/T_D2 in EW but had no effects in LW. Clones significantly affected TL in LW but had no effects in EW. \( H\frac{2}{C} \) was higher in LW (0.50) than in EW (0.20) for TL, while \( H\frac{2}{C} \) was higher in EW (0.27–0.46) for other tracheid traits and the two ratios (TL/T_D2 and WT/R_D1) than in EW (0.06–0.22). WD and TL were significantly positively correlated, but WT and TL were negatively correlated both at individual and clone levels; all tracheid diameters and the four ratio values (EW_WT/R_D1, LW_WT/R_D1, EW_TL/T_D2 and LW_TL/T_D2), were strongly positively correlated with DBH, H, NSC, WEC and RW, and strongly negatively correlated with WD both at individual and clone levels. The most important variables for predicting WD were LW_TL, EW_WT and R_D1 in both EW and LW (r² = 0.22). Selecting the top 10% of the clones by DBH would improve DBH growth by 12.19% (wood density was reduced by 0.14%) and produced similar responses between EW and LW for all tracheid traits: a reduction of 0.94 and 3.69% in tracheid length and increases in tracheid diameters (from 0.36 to 5.24%) and double wall thickness (0.07 and 0.87%). The two ratios WT/R_D1 and TL/T_D2 across tissues (EW and LW) declined 0.59 and 4.56%, respectively. The decreased tracheid length and the ratio between tracheid length and diameter is disadvantageous for pulp production. The unfavorable relationship of tracheid traits with wood density indicate that multiple trait selection using optimal economic weights and optimal breeding strategies are recommended for the current long-term breeding program for P. tabuliformis.     

Impacts of initial stand density and thinning regimes on energy wood production and management-related CO<Subscript>2</Subscript> emissions in boreal ecosystems

An ecosystem model (Sima) was utilised to investigate the impact of forest management (by changing both the initial stand density and basal area thinning thresholds from current recommendations) on energy wood production (at energy wood thinning and final felling) and management-related carbon dioxide (CO₂) emissions for the energy wood production in Finnish boreal conditions (62°39′ N, 29°37′ E). The simultaneous effects of energy wood, timber and C stocks in the forest ecosystem (live and dead biomass) were also assessed. The analyses were carried out at stand level during a rotation period of 80 years for Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies L. Karst.) growing in different fertility sites. Generally, the results showed that decreased basal area thinning thresholds, compared with current thinning, reduced energy wood (logging residues) and timber production, as well as carbon stocks in the forest ecosystem. Conversely, increased thinning thresholds increased energy wood production (ca. 1–27%) at both energy wood thinning and final felling and reduced CO₂ emissions (ca. 2–6%) related to the production chain (e.g. management operations), depending on the thinning threshold levels, initial stand density, species and site. Increased thinning thresholds also enhanced timber production and carbon stocks in the forest ecosystem. Additionally, increased initial stand density enhanced energy wood production for energy wood thinning for both species, but this reduced energy wood production at final felling for Scots pine and Norway spruce. This study concluded that increases in both initial stand density and thinning thresholds, compared with the current level, could be useful in energy wood, timber and carbon stocks enhancement, as well as reducing management-related CO₂ emissions for energy wood production. Only 2.4–3.3% of input of the produced energy (energy wood) was required during the whole production chain, depending on the management regime, species and sites. However, a comprehensive substitution analysis of wood-based energy, in respect to environmental benefits, would also require the inclusion of CO₂ emissions related to ecosystem processes (e.g. decomposition).