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Articles containing the keyword 'uneven-aged'

Category : Article

article id 5341, category Article

Hannu Hökkä, Jukka Laine. (1988). Suopuustojen rakenteen kehitys ojituksen jälkeen. Silva Fennica vol. 22 no. 1 article id 5341. https://doi.org/10.14214/sf.a15498

English title: Post-drainage development of structural characteristics in peatland forest stands.

Original keywords: metsikön rakenne; turvemaat; ojitetut suot; eri-ikäisrakenne; runkoluku; läpimittajakauma

English keywords: stand structure; drained peatlands; diameter distribution; forest drainage; uneven-aged structure

Abstract | View details | Full text in PDF | Author Info

The effect of drainage on structure of tree stands is analysed by comparing the average structural characteristics (e.g. diameter distribution) of stands in the data for different drainage age classes and selected site types. The material consists of ca. 4,400 relascope sample plots, which are part of a large drainage area inventory project. The uneven-aged structure of the virgin peatland forest is preserved for several decades after drainage. This is enhanced by the post-drainage increase of small-diameter trees, especially birch. The number of trees per hectare increased during a period of ca. 30 years and levelled off thereafter. The increase in the number of saw log stems is clearly related to the fertility of the site and its geographical location.

The PDF includes a summary in English.

Hökkä, E-mail: hh@mm.unknown
Laine, E-mail: jl@mm.unknown

article id 5220, category Article

Peitsa Mikola. (1984). Harsintametsätalous. Silva Fennica vol. 18 no. 3 article id 5220. https://doi.org/10.14214/sf.a15399

English title: Selection system in timber harvesting in Finland.

Original keywords: kuusi; metsänhoito; harsinta; eri-ikäiskasvatus; eri-ikäisrakenteinen metsä; tasaikäiskasvatus; tasa-ikäinen metsä

English keywords: forest management; Norway spruce; Picea abies; yield; Finland; selection system; even-aged stands; selection cuttings; uneven-aged stands

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This article reviews experiments and practical experience of forest management by the selection system in Finland. In an experiment of 25-year duration the annual growth of uneven-aged Norway spruce (Picea abies (L.) H. Karst.) stands was only about 50% of the average annual yield of even-aged stands in normal rotation on the same site.

In Finland the selection system is applicable under exceptional conditions only, viz. In intensively managed park stands and, on the other hand, on very marginal sites, e.g. on peat bogs and mountains near the tree-line. Even normal silviculture, however, may include cuttings which somewhat resemble selection system, e.g. removal of standards or restoration of mismanaged forests.

The PDF includes a summary in English.

Mikola, E-mail: pm@mm.unknown

Category : Research article

article id 1741, category Research article

Seppo Nevalainen. (2017). Comparison of damage risks in even- and uneven-aged forestry in Finland. Silva Fennica vol. 51 no. 3 article id 1741. https://doi.org/10.14214/sf.1741

Keywords: forest damage; uneven-aged forestry; even-aged forestry

Highlights: Damage risks in two forest management regimes were estimated by means of a literature review and a questionnaire to Finnish forestry experts; Damage risks were usually estimated to be higher in even-aged than in uneven-aged management regimes; In some cases, however, damage risks may be higher in uneven-aged stands (root-rot infected Norway spruce stands and mechanical damage due to repeated thinnings).

Abstract | Full text in HTML | Full text in PDF | Author Info

The literature on the most prominent forest damage related to even-aged and uneven-aged forest management regimes was reviewed. A questionnaire to expert researchers was conducted to estimate risks in even-aged and uneven-aged forest management chains in Finland. There are only a few empirical comparisons of damage risks in even- and uneven-aged stands in the literature. The results from the expert survey showed that the damage risks were higher in even-aged management in Norway spruce and Scots pine. However, the variation in the risks between individual chains and between individual causes was high. The highest risks in Scots pine were caused by moose (in even-aged chains) and harvesting damage (in uneven-aged chains). In Norway spruce, root rot caused the highest risks in both even-aged and uneven-aged chains. The higher risks in even-aged forestry are largely due to the many associated practices which favour various types of damage. However, there are some important exceptions: the damage risks may be higher in some uneven-aged stands, especially in Norway spruce stands infected with root rot where the utilization of undergrowth or natural regeneration can be risky. Moreover, the repeated thinnings in uneven-aged stands may lead to increased mechanical damage.

Nevalainen, Natural Resources Institute Finland (Luke), Natural Resources and Bioproduction, Yliopistokatu 6, FI-80100 Joensuu, Finland E-mail: seppo.nevalainen@luke.fi

article id 1046, category Research article

Eva-Maria Nordström, Hampus Holmström, Karin Öhman. (2013). Evaluating continuous cover forestry based on the forest owner’s objectives by combining scenario analysis and multiple criteria decision analysis. Silva Fennica vol. 47 no. 4 article id 1046. https://doi.org/10.14214/sf.1046

Keywords: forest planning; decision making; sustainable forest management; uneven-aged forestry

Highlights: Scenario analysis and multiple criteria decision analysis were combined to evaluate alternative forest management strategies for Linköping municipality, Sweden; Continuous cover forestry (CCF) promoted ecological and social objectives better than even-aged forestry but was worse for economic objectives; Ecological and social objectives were important to the municipality and thus, in summary, CCF seemed to be a suitable strategy.

Abstract | Full text in HTML | Full text in PDF | Author Info

Forests are increasingly managed both to provide a sustainable yield of timber and for supplying a range of ecosystem services in line with the concept of sustainable forest management. Several incommensurable interests must then be considered, and it is necessary to strike a balance between different objectives. In evaluation of trade-offs to be made, both objective factors and subjective values need to be taken into account. In recent years, continuous cover forestry (CCF) has been put forward as an alternative to even-aged forestry. The aim of this study was to use scenario analysis in combination with multi criteria decision analysis (MCDA) to evaluate whether CCF is a suitable strategy based on the decision makers’ objectives and preferences for sustainable forest management in a specific landscape. This approach was applied to a planning case on the forest estate of the Linköping municipality in southwestern Sweden. The scenario analyses provided insights into relevant quantitative factors, while the MCDA evaluation helped in clarifying the objectives of the forest management and in assessing the relative importance of various objectives. The scenario analyses showed that in this case CCF is a good management strategy in ecological and social terms but yields worse economic outcomes than conventional even-aged forestry. In the Linköping case, there was a relatively strong emphasis on ecological and social aspects and thus, in summary, CCF seemed to be the most suitable option.

Nordström, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden E-mail: eva-maria.nordstrom@slu.se
Holmström, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden E-mail: hampus.holmstrom@slu.se
Öhman, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden E-mail: karin.ohman@slu.se

article id 409, category Research article

Hubert Sterba. (2004). Equilibrium curves and growth models to deal with forests in transition to uneven-aged structure – application in two sample stands. Silva Fennica vol. 38 no. 4 article id 409. https://doi.org/10.14214/sf.409

Keywords: uneven-aged forests; growth models; stem number distribution; transformation

Abstract | View details | Full text in PDF | Author Info

Stem number distributions in uneven-aged forests are assumed to be stable, if they follow special functions, e.g. de Liocourt’s reverse J-shaped breast height diameter distribution. These distributions therefore are frequently regarded as a target in all-aged forests. Intending to convert an even-aged forest or any other forest, not yet exhibiting this sort of equilibrium, towards a steady state forest, the question rises, how to choose an appropriate equilibrium curve and how to achieve this stem number distribution by an appropriate thinning and harvesting schedule. Two stands are investigated: One dominated by Norway spruce (Picea abies), having developed from a 120 year old even-aged stand 25 years ago, after several “target diameter thinnings”. The other one is a mixed species stand of Norway spruce, white fir (Abies alba), larch (Larix europea), common beech (Fagus silvatica), and Scots pine (Pinus sylvestris), having lost its typical uneven-aged structure 20 years ago. These stands were used, together with the distance independent individual tree growth model PrognAus, to reveal that 1) there are more than only one equilibrium curve per stand, 2) not every hypothesised equilibrium can be reached with any stand, 3) an equilibrium in stem number does not necessarily mean a stable species distribution, and 4) growth models provide an excellent help to decide between several equilibrium curves and harvesting schedules to reach them.

Sterba, BOKU – University of Natural Resources an Applied Life Sciences, Vienna, Peter Jordanstrasse 82, A-1190 Vienna, Austria E-mail: hubert.sterba@boku.ac.at

article id 405, category Research article

Timo Saksa. (2004). Regeneration process from seed crop to saplings – a case study in uneven-aged Norway spruce-dominated stands in southern Finland. Silva Fennica vol. 38 no. 4 article id 405. https://doi.org/10.14214/sf.405

Keywords: boreal forest; Picea abies; regeneration; uneven-aged

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The dynamics of spruce regeneration, from seed crop to saplings, was studied based on five permanent plots in uneven-aged, spruce-dominated, boreal forest stands, cut with single-tree selection in the beginning of the 1990’s. The annual fluctuation of the spruce seed crop was very similar in uneven-aged and even-aged stands. The correlation between seed crop and number of germinants was significant; but stem number, basal area or volume of the stand did not influence on seedling emergence. The effects of good seed crops were seen as peaks or an increase in the number of germinants and smallest seedlings. The mean number of ‘stabilised’ spruce seedlings (height 11 cm to 130 cm) varied from 6000 ha^–1 to over 25 000 spruce seedlings ha^–1 from one monitoring plot to another. On a monitoring plot the number of ‘stabilised’ spruce seedlings was stable over time. Neither stand basal area nor stand volume influenced the number of ‘stabilised’ spruce seedlings, but the height of these seedlings was higher on subplots with lower stand volume and smaller basal area. In this study the monitoring period, 5–10 years, was too short to obtain reliable figures for ingrowth, i.e. the transition of seedlings to the sapling stage (h > 130 cm). The adjusted mean ingrowth was 26 stems ha^–1 year^–1.

Saksa, Finnish Forest Research Institute, Suonenjoki Research Station, FI-77600 Suonenjoki, Finland E-mail: timo.saksa@metla.fi

article id 435, category Research article

Rebecca Ralston, Joseph Buongiorno, Jeremy S. Fried. (2004). Potential yield, return, and tree diversity of managed, uneven-aged Douglas-fir stands. Silva Fennica vol. 38 no. 1 article id 435. https://doi.org/10.14214/sf.435

Keywords: diversity; simulation; uneven-aged management; Douglas-fir; WestPro; economics

Abstract | View details | Full text in PDF | Author Info

The effects of different management regimes on uneven-aged Douglas-fir stands in the Pacific Northwest of the United States were predicted with a simulation model. Management alternatives were defined by residual stand structure and cutting cycle. The residual stand structure was set by basal area–diameter-q-ratio (BDq) distributions, diameter-limit cuts (assuming concurrent stand improvement), or the current diameter distribution. Cutting cycles of 10 or 20 years were applied for 200 years. The current diameter distribution was defined as the average of the uneven-aged Douglas-fir stands sampled in the most recent Forest Inventory and Analysis conducted in Oregon and Washington. Simulation results were compared in terms of financial returns, timber productivity, species group diversity (hardwoods vs softwoods), size class diversity, and stand structure. Other things being equal, there was little difference between 10- and 20-year cutting cycles. The highest financial returns were obtained with either a 58.4 cm diameter-limit cut, or a BDq distribution with 8.4 m2 of residual basal area, a 71.1 cm maximum diameter, and a q-ratio of 1.2. Using the current stand state as the residual distribution was the best way to obtain high tree size diversity, and high species group diversity. Several uneven-aged regimes gave net present values comparable to that obtained by converting the initial, uneven-aged stand to an even-aged, commercially thinned, plantation.

Ralston, Dept of Forest Ecology and Management, University of Wisconsin, Madison, WI 53706, USA E-mail: rr@nn.us
Buongiorno, Dept of Forest Ecology and Management, University of Wisconsin, Madison, WI 53706, USA E-mail: jbuongio@facstaff.wisc.edu
Fried, USDA Forest Service, Pacific Northwest Forest Experiment Station, Forest Inventory and Analysis Program, P.O. Box 3890, Portland, OR 97208, USA E-mail: jsf@nn.us

article id 627, category Research article

Joseph Buongiorno, Audra Kolbe, Mike Vasievich. (2000). Economic and ecological effects of diameter-limit and BDq management regimes: simulation results for northern hardwoods. Silva Fennica vol. 34 no. 3 article id 627. https://doi.org/10.14214/sf.627

Keywords: diversity; hardwoods; simulation; uneven-aged management; economics; mixed-species stands

Abstract | View details | Full text in PDF | Author Info

The long-term financial and ecological effects of diameter-limit regimes and basal-area-diameter-q-ratio (BDq) regimes were compared by simulation in the case of northern hardwood forests. Varying the cutting cycle between 10 and 20 years had little effect on returns or stand structure. A 28-cm diameter-limit cut gave the highest production and financial returns, and the highest species diversity, but considerably lower size diversity. A 38-cm diameter-limit cut and a heavy BDq selection harvest gave high returns, while maintaining high levels of diversity. On lands of equal site quality, Michigan’s stands were more productive than Wisconsin’s. The results suggest that it is possible to manage northern hardwood stands sustainably with diameter-limit cuts, combined with removal of poorly performing understory trees. Adjusting the diameter limit gave rise to stands similar in productivity and structure to those obtained by BDq cutting regimes. Given their simplicity of implementation and monitoring, more attention should be given to diameter-limit cutting regimes, with attendant stand improvement measures, as a practical means for uneven-aged management of northern hardwoods.

Buongiorno, Department of Forest Ecology and Management, University of Wisconsin-Madison, 1630 Linden Drive, Madison, WI 53705, USA E-mail: Jbuongio@facstaff.wisc.edu
Kolbe, Department of Forest Ecology and Management, University of Wisconsin-Madison, 1630 Linden Drive, Madison, WI 53705, USA E-mail: ak@nn.us
Vasievich, USDA Forest Service, North Central Forest Experiment Station, 1407 S. Harrison Road, Suite 220, East Lansing, MI 48823, USA E-mail: mv@nn.us

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