Search

Sustainable forestry requires efficient regeneration methods to ensure that new forests are established quickly. In Sweden, 99% of the planting is manual, but finding labor for this arduous work is difficult. An autonomous scarifying and planting machine with high precision, low environmental impact, and a good work environment would meet the needs of the forest industry. For two years, a collaborative group of researchers, manufacturers, and users (forest companies) has worked together on developing and testing a new concept for autonomous forest regeneration (Autoplant). The concept comprises several subsystems, i.e., regeneration and route planning, autonomous driving (path planning), new technology for forest regeneration with minimal environmental impact, automatic plant management, crane motion planning, detection of planting spots, and follow-up. The subsystems were tested separately and integrated together during a field test at a clearcut. The concept shows great potential, especially from an environmental perspective, with significantly reduced soil disturbances, from approximately 50% (the area proportion of the area disturbed by disc trenching) to less than 3%. The Autoplant project highlights the challenges and opportunities related to future development, e.g., the relation between machine cost and operating speed, sensor robustness in response to vibrations and weather, and precision in detecting the size and type of obstacles during autonomous driving and planting. [ABSTRACT FROM AUTHOR]

This study quantified the effects of different establishment practices on survival, dieback and early growth of Juglans × intermedia NG23 and NG38 planted in a statistically designed field experiment on glacial till in southern Sweden. Establishment practices included the use or absence of nurse trees (Populus maximowiczii × trichocarpa var. OP42 planted one year before J. × intermedia), weed control (2 m2·tree−1) and fertilization (+25 g N·tree−1·year−1). NG23 transplants were smaller than NG38 at the time of planting. The overall survival rate was 97%. NG23 suffered marginally more mortality than NG38. Leader shoot dieback occurred in all treatment combinations but was most severe in the presence of nurse trees. NG23 suffered less dieback than NG38. Annual height growth of trees unaffected by dieback increased with increasing levels of precipitation during the growing season (194–407 mm) and with increasing soil quality in terms of nitrogen (94·10−3–607·10−3 g·g−1), base saturation (14–99%) or available soil water capacity (8.6–30.6 l·m−3). It was negatively influenced by poplar nurse trees and positively by fertilization. Weed control had no impact on height growth, possibly due to inefficient implementation. With nurse trees, NG23 had stronger growth than NG38. The opposite was true without nurse trees. It was hypothesized that less growth and more dieback resulted from competition for water. [ABSTRACT FROM AUTHOR]

Private forest owners' management decisions significantly impact the development of forest values in Sweden. This study explored the potential to develop environmental values on privately owned land in southern Sweden. Data were collected through interviews with 23 forest owners and analyzed with semantic content analysis. The interviewees owned estates of productive, predominantly coniferous forest ranging in size from 10–825 ha. They were aged 36–84, and 26% were female. Results showed that there is considerable potential to develop environmental values on private land since 1) Forest owners demonstrated multi-functional views of primarily social and emotional dimensions surrounding forest ownership, and the mindset of combining goals enables many different values to be developed, 2) Desired management showed numerous ideas that could bring a diversity of benefits, and 3) Practical management included various production-favoring measures, but even more for environmental, social, cultural, and emotional purposes that, largely unnoted, bring environmental conservation benefits. All forest owners perceived barriers to management and ownership, categorized primarily to structural or surrounding society factors. Financial incentives, policies encouraging forest owners' initiatives, an adequate supply of resources and sound management advice are suggested measures to reduce barriers and facilitate the development of environmental values. [ABSTRACT FROM AUTHOR]

Reforestation is performed after the final felling as an important and often law-mandated step to ensure that wood production is sustainable. In Sweden alone, over 400 millions seedlings are planted annually. This work is physically demanding and the quality is uneven. Therefore, automatic production systems are under research and development. A necessary effort in this endeavor is presented in this paper: the development and evaluation of a mission supervisor utilized to control the mission and behavior of a full-scale autonomous forest regeneration machine tested in realistic environments. The mission supervisor is implemented in the Robot Operating System framework using a finite state machine package called SMACH. A terrain machine built as a research platform with an added full-scale forwarder crane is used as a base machine. First, we describe the scenario in which planting is conducted, whereupon we develop the composite tasks required as states. A simplified simulator then enables an intermediate step before field experiments. The system is implemented and operated in real time on a full-scale machine. Results show that the developed SMACH mission supervisor can be used as a sound basis for an autonomous forest regeneration machine and the chosen communication solution between different systems works well. The simulations show good agreement with the experiments. The results also show that crane movements take 70% of the machine time, emphasizing the importance of limiting crane movement, improving the actuator movement speed and integrating the composite solutions. Further development with a holistic approach is required before the concept can reach the prototype level. [ABSTRACT FROM AUTHOR]

In temperate Europe, oak-dominated forests are widespread, supporting high biodiversity and providing important ecosystem services. Insufficient natural regeneration has, however, been a concern for over a century. The objective of this study was to gain insights into differences in regeneration success using artificial and natural regeneration techniques for reforestation of oak (Quercus robur L.) stands. We monitored seedlings following planting, direct seeding and natural regeneration over five years in a randomized block experiment in southern Sweden with fenced and non-fenced plots. Fencing had a strong positive effect on height growth, especially for planted seedlings that were taller than the other seedlings and more frequently browsed in non-fenced plots. In contrast, there was little effect of fencing on survival, establishment rate and recruitment rate of seedlings. Due to aboveground damage on seedlings from voles, protection of acorns did not improve establishment rate following direct seeding. Under current circumstances at the site with a sparse shelterwood of old oaks, we conclude that natural regeneration was the most cost-efficient regeneration method. It resulted in the most seedlings at the lowest cost. However, regeneration success was heavily influenced by interference from herbaceous vegetation. With a small additional investment in vegetation control, the results might have been improved for planting and direct seeding. [ABSTRACT FROM AUTHOR]

Forestry contractors have doubled their share of work in Swedish forests since the 1990s and have thus become important actors in the industry's supply chain. Yet, their profitability has often been low. It is essential for a firm's success to have a well-functioning business model. Therefore, the aim of this study was to characterize business models currently used by forestry contractors and identify differences in the contractors' financial performance in relation to a chosen business model. A survey was sent to all limited liability companies in northern Sweden that were registered to carry out logging or silviculture. One hundred and ninety-eight contractors responded, and their financial performance was analysed based on information in financial statements. The study highlights that there are clear differences both within and between contractor categories in relation to several business model components, as well as their financial performance. Logging contractors had the lowest profitability, measured as return on assets, and also a lower solidity and liquidity compared to silvicultural and mixed service contractors. The largest logging contractors tended to have a better and more stable profitability than small ones, although the differences were small and varied between years. However, a negative trend in profitability was identified for all contractor groups. [ABSTRACT FROM AUTHOR]

Soil scarification is widely used in boreal forestry to promote the growth and survival of seedlings. The aim of the study was to describe and analyze the impact of disc trenching on soil temperature and water content dynamics during the first six growing seasons after clearcutting. The site is a sub-xeric, coarse textured, coniferous field experiment, near Hagfors, central Sweden. Soil temperature and water content were measured hourly both 20 and 45 cm below the original surface of the mineral soil in three types of microsites created by disc trenching (furrows, ridges, and between-furrow areas) and an undisturbed control microsite outside the disc-trenched area. Pinus sylvestris L. seedlings were planted in the furrows and the control area before the measurements. The soil temperature and water content data were analyzed using linear mixed-effect models. Numbers of days exceeding critical thresholds of soil temperature and water content for seedling growth at each microsite were also calculated. Disc trenching increased soil temperature in the topsoil (<20 cm) of the furrows throughout the study period, but the effect declined over time. Similar, but weaker, effects were detected in ridges and between-furrows areas. Likewise, the largest daily and seasonal temperature amplitudes at 20 cm depth were recorded beneath the furrows, and the soil temperature sums (baseline 5 °C) over the whole study period were 20% higher in these microsites than in the control area. Soil temperatures never exceeded values considered optimal for root growth at any of the microsites. The soil water content in the furrows and control area only significantly differed during the last three years, when it was somewhat higher beneath the furrows. During the study period, the total number of days with potential water stress for the planted seedlings (volumetric soil water content <0.09 m 3 /m 3 ) was 423 in the furrows compared to 554 in the control area. None of the microsites was wet enough to hamper aeration of roots in the topsoil. In conclusion, soil temperature and water regimes were more favorable for the seedlings in the furrows than in the control area for at least six growing seasons. We recommend planting soon after disc trenching to maximize benefits from the improved soil temperature conditions in the furrows. [ABSTRACT FROM AUTHOR]

• Young forests may return to carbon sinks already eight years after reforestation. • Increased forest productivity shortens the time needed to return to carbon sink. • Harvest of logging residues/stumps for bioenergy may improve the carbon balance. We analyzed ecosystem carbon fluxes from eddy-covariance measurements in five young forests in southern Sweden where the previous stand had been harvested by clear-cutting or wind-felled: three stands with Norway spruce (Picea abies (L.) Karst.), one with Scots pine (Pinus sylvestris) and one with Larch (Larix x eurolepis A. Henry). One of the spruce stands had the stumps harvested, one was fertilized and one without any special treatments. These stands returned from positive (sources) to negative (sinks) annual carbon fluxes 8–13 years after disturbance, depending on site productivity and management. This corresponds to approximately 15% of the rotation periods at these sites. Extrapolation in combination with chronosequence data suggests that conventionally regenerated stands reach a neutral carbon balance after approximately 30% of the rotation period. The lowest carbon emissions and shortest recovery time was observed in a stand where the stumps of the trees, in addition to the stems and logging residues, were removed after harvest. This stand not only returned to a carbon sink within this time period but the total carbon gains since disturbance also equaled the total losses after only 11 years. These results stress that production stands in southern Sweden are carbon sources during a relatively small part of the rotation period, and that this part can be considerably shortened by measures that increase productivity or reduce the amount of woody debris left after disturbance. [ABSTRACT FROM AUTHOR]

Identification of the ecosystem services provided by oak-dominated forests in southern Sweden is a prerequisite for ensuring their conservation and sustainable management. These forests seem well-suited for multiple-use forestry, but knowledge is limited regarding how to manage them for multiple uses. Management for the production of high-value timber species like oaks and management to conserve biodiversity, or for cultural services can be in conflict with each other. This study evaluates the capacity of three contrasting management regimes to provide societies with economic revenue from timber production, habitats for biodiversity and cultural services, and the study analyses associated trade-offs and synergies. The three regimes were: intensive oak timber production (A), combined management for both timber production and biodiversity (B) and biodiversity conservation without management intervention (C). We synthesized relevant scientific literature, governmental statistics and grey literature. Our assessments identified that Regime A provided the highest levels of economic returns and the lowest level of biodiversity. Regime C provided higher levels of habitat provision but at expense of wood production and cultural services. In contrast, Regime B provided a balanced delivery of timber production, biodiversity conservation and cultural services. We identified several stand-management options which provide comparatively synergistic outcomes in ecosystem services delivery. The use of these management options in combination with more traditional stand-management approaches may be a more effective means of achieving sustainable forest goods and services. EDITED BY Nicholas Brokaw [ABSTRACT FROM PUBLISHER]

There is a growing demand for alternatives to Sweden's current dominant silvicultural system, driven by a desire to raise biomass production, meet environmental goals and mitigate climate change. However, moving towards diversified forest management that deviates from well established silvicultural practices carries many uncertainties and risks. Adaptive management is often suggested as an effective means of managing in the context of such complexities. Yet there has been scepticism over its appropriateness in cases characterised by large spatial extents, extended temporal scales and complex land ownership-characteristics typical of Swedish forestry. Drawing on published research, including a new paradigm for adaptive management, we indicate how common pitfalls can be avoided during implementation. We indicate the investment, infrastructure, and considerations necessary to benefit from adaptive management. In doing so, we show how this approach could offer a pragmatic operational model for managing the uncertainties, risks and obstacles associated with new silvicultural systems and the challenges facing Swedish forestry. [ABSTRACT FROM AUTHOR]

About three times the annual cut in southern Sweden (Götaland) was damaged by the storm Gudrun in January 2005, i.e. almost as much as the normal annual cut for all of Sweden. To establish any differences in forest management and state before and after the storm, measures such as growing stock volume, age-class distribution, and species composition were analyzed within the damaged area. As a reference the situation before and after the storm within the area in Götaland not damaged by the storm was also analyzed. For all analyses, sample plots from the Swedish National Forest Inventory were used. Results based on mean values for the years 2000–2004/2005–2009 showed that the total growing stock for the damaged area decreased by approximately 30 million m3after the storm. This was mainly caused by a decrease in Norway spruce (Picea abies(L.) H. Karst). Annual growth for pine, spruce, and deciduous trees decreased by 1.8 million m3in the damaged area. This mainly included stands already thinned and not, as expected, in the stands ready for final felling. Also, the proportional area within each of the age classes 21–40, 41–60, and 61–80 years decreased. The storm led to an increased area in immediate need of precommercial thinning. No changes in choice of species when regenerating could be observed. Furthermore, only marginal adaptation by forest owners to future risk of wind throw could be detected. [ABSTRACT FROM AUTHOR]

Contractors perform the majority of forestry activities in Sweden, yet little is known about the development of their company structures and strategies. By analyzing data from the Swedish Forest Agency's yearly survey to forestry contractors for 2006–2009 and comparing the results with previous data for 1993–1998, we examined the current profiles of Swedish forestry contractors and their recent development. For 2006–2009, responses were received from 700 to 770 forestry contractors, corresponding to ca. 20% of the estimated total number of Swedish forestry contractors. In 2009, 60% of contractors were mainly performing logging activities, whereas 30% were mainly performing silvicultural activities. Between 1993 and 2009, the number of contractors increased by ca. 80%, while the number of forestry working contractors and their employees increased by 157%. These increases were mainly due to increased silvicultural activities. Although one-person enterprises still dominate among Swedish forestry contractors, most logging work is performed by small-sized enterprises, whereas most silviculture work is performed by large-sized enterprises. Our study suggests that there is an increased dependency upon contractors and forestry contractors have become more diversified, but still specialized, in the type of work they perform. [ABSTRACT FROM AUTHOR]

This paper analyzes how sustained yield (SY) forestry is defined and implemented in Sweden and Russia, two countries with different forest-industrial regimes. We first compare definitions of SY forestry in national legislation and policies. Then we study forest management planning in two large forest management units with respect to: delivered forest products and values, how the harvest level of timber is defined, where the harvest takes place, and what treatments are used to sustain desired forest products and values. In Sweden SY forestry is maximum yield based on high-input forest management, and in Russia it is forestry based on natural regeneration with minimum investments in silviculture. We conclude that how SY forestry contributes to SFM depends on the context. Finally, we discuss the consequences of SY forestry as performed in Sweden and Russia related to its ability to support diverse forest functions, as envisioned in sustainable forest management policy. [ABSTRACT FROM AUTHOR]

A model including site-specific microclimate-affecting properties of a forest regeneration area together with seedling characteristics was used to evaluate the accumulated risk of frost damage to Norway spruce (Picea abies (L.) Karst.) seedlings. Climate change in Sweden was simulated on the basis of the regional climate model RCA3. The daily average temperature, the driving factor for bud burst in the model, was adjusted using the difference between the mean of the climate model data for the years 1961-1990 and 2036-2065. The model was run for a highly frost prone, clear-cut site in which bare-rooted Norway spruce seedlings of mid-Swedish provenance were planted. Alternate runs were conducted with data for containerized seedlings and seedlings of Belarusian origin. The study showed that bud burst will occur at earlier dates throughout Sweden in the period 2036-2065 if the climate changes according to either of the climate scenarios examined, compared to the reference period 1961-1990. Furthermore, the risk of damage to Norway spruce seedlings as a result of frost events during summer will increase in southern Sweden and be unaffected or decrease in northern Sweden. The risk of frost damage was exacerbated in containerized seedlings, while the risk was lower for the seedlings of Belarusian provenance when compared with bare-rooted seedlings or seedlings of mid-Swedish origin. [ABSTRACT FROM AUTHOR]

Abstract: We reviewed 53 studies of forest landscape preferences carried out as quantitative surveys in Finland, Sweden and Norway and published between 1972 and 2006. Most of these were related to boreal coniferous forests in which even-aged forestry had been the rule. There was a great diversity in survey designs, ranging from nation-wide or regional surveys where target populations and sampling frames were clearly defined, to studies where neither a target population nor a sampling frame could be identified. The latter type of surveys, however, often had a high validity, with measurements made either in the forest or indoors by use of colour slides or advanced digital imaging. A common feature was that people''s preferences for a forest stand increased with increasing tree size and advancing stage of stand development. Some surveys indicated that the public tended to give high scores to irregular stands with a mixture of trees of different sizes, but on the other hand, a feeling of accessibility and provision of a view was also very important. Large clear-cuts and obvious traces from forest operations were little appreciated. Trained foresters were more positive to clear-cuts than the general population. Few studies included virgin stands, and those that did mostly found low scores for unmanaged forests. Preferences appeared to be fairly stable over time. Elderly or handicapped people, and children and young adolescents, were strongly under-represented in the surveys. [Copyright &y& Elsevier]

Browsing by large herbivores can cause serious costs in forest production. The most important costs related to browsing damage are insufficient stand regeneration, volume losses and timber quality impairment. In Sweden, moose (Alces alces) and roe deer (Capreolus capreolus) are the most abundant deer species and therefore cause the majority of browsing damage. Balancing costs and benefits related to deer density is difficult since few data about the final losses in timber volume or quality impairment is available. Simulations of browsing and the impact on stand growth suggest that a minor or moderate browsing intensity has little effect on final harvest volume. The reason is that trees seem to recover some of the lost growth as they grow out of reach of the animals. Balancing between different uses of the forestry resource is complicated by our limited capability to predict the impact of different management regimes. [ABSTRACT FROM AUTHOR]