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Silva Fennica vol. 48 no. 2 | 2014

Category : Research article

article id 1072, category Research article

Polina Volkova, Alexey Shipunov, Polina Borisova, Reed Moseng, Ranelle Ivens. (2014). In search of hybridity: the case of Karelian spruces. Silva Fennica vol. 48 no. 2 article id 1072. https://doi.org/10.14214/sf.1072

Keywords: cpDNA; Picea; plant mtDNA; introgression; northern taiga

Highlights: Karelian spruces have morphology that is typical for P. obovata and characterized with genetic variation, described previously for P. abies; Karelian spruces evolved due to introgression between P. abies and P. obovata. However, it is unclear whether Karelian spruces could be treated as P. fennica, because unequivocal morphological and genetic characters of the latter are still absent.

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

Distribution ranges of spruces, European Picea abies and Siberian P. obovata intersect in the Eastern Europe and Urals, forming wide zone of introgressive hybridization where species discrimination is difficult. We applied both molecular (mtDNA and cpDNA sequences) and morphological approaches with goals of elucidating the origin of spruces in undisturbed forests of Russian Karelia (considered as part of the abovementioned introgression zone). Karelian spruces have morphology that is typical for P. obovata and characterized with genetic variation, described previously for P. abies. This contradiction between morphology and organellar DNA could be itself an evidence of hybrid origin because morphological data should have a genetic basis. If the genes responsible for the observed morphological differences are nuclear, that explains why we did not see any deviation of Karelian spruces towards P. obovata in organellar markers. In this situation nuclear gene flow from P. obovata should be performed via pollen. Thus, we should expect Karelian spruces to have cpDNA haplotypes (inherited paternally in conifers) typical for P. obovata. However, it is not the case for the majority of plants sampled and requires additional explanation like chloroplast capture in the introgresson zone. In all, we think that Karelian spruces evolved due to introgression between P. abies and P. obovata. However, it is unclear whether Karelian spruces could be treated as P. fennica, because unequivocal morphological and genetic characters of this hybridogenous species are still absent.

Volkova, Moscow South-West High School (No. 1543), 26 Bakinskikh komissarov str. 3–5, RU-119571 Moscow, Russia E-mail: avolkov@orc.ru
Shipunov, Department of Biology, Minot State University, Minot, North Dakota, USA 58707 E-mail: dactylorhiza@gmail.com
Borisova, Biological Department, Moscow State University, Vorobjevy Gory, RU-119899, Moscow, Russia E-mail: salixhastata@ya.ru
Moseng, Minot High School, Minot, North Dakota, USA 58701 E-mail: dactylorhiza@gmail.com
Ivens, Department of Biology, Minot State University, Minot, North Dakota, USA 58707 E-mail: dactylorhiza@gmail.com

article id 1064, category Research article

Back Tomas Ersson, Urban Bergsten, Ola Lindroos. (2014). Reloading mechanized tree planting devices faster using a seedling tray carousel. Silva Fennica vol. 48 no. 2 article id 1064. https://doi.org/10.14214/sf.1064

Keywords: productivity; cost analysis; seedling feed; silviculture; time study; tree planting machine; containerized seedling

Highlights: Seedling reloading onto the Bracke Planter crane-mounted planting device was twice as fast with the MagMat tray-wise-loaded carousel as today’s seedling-wise-loaded carousel; Tray-wise reloading combined with deplugging seedlings from suitable cultivation trays has the potential to be an efficient and robust way to feed seedlings on any type of tree planting machine.

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

On Nordic clearcuts, today’s tree planting machines produce high-quality but costly regenerations. Much of this high cost is attributable to the planting machines’ low productivity. One promising way of raising productivity is to lessen the time spent manually reloading seedlings onto the carousels of crane-mounted planting devices. Using MagMat, a carousel test-rig designed by engineering students, we studied how much faster tray-wise seedling reloading is on the Bracke Planter compared to reloading with today’s seedling-wise-loaded carousel. The MagMat test-rig held eight Hiko cultivation trays from which seedlings were deplugged individually and dropped into the planting tube. The time study confirmed that seedling reloading was on average twice as fast with MagMat compared to today’s seedling carousel, thereby increasing assumed planting machine productivity by 8–9% depending on the planting device used. MagMat’s cost-efficiency was analysed to be particularly reliant on its added investment cost, mechanical availability and how quickly trays can be switched automatically. Nevertheless, MagMat’s field performance illustrated the overall potential of tray-wise loading compared to piecewise seedling loading for increasing the productivity of crane-mounted planting devices. Also, deplugging proved to be a reliable method of extracting seedlings from the rigid, copper-painted Hiko cultivation trays even when performed at the excavator’s boom-tip during mounding work. We conclude that, rather than piecewise seedling loading, tray-wise loading combined with deplugging seedlings from suitable cultivation trays is a reliable and much more time-efficient method to feed seedlings on probably any type of tree planting machine.

Ersson, Department of Forest Biomaterials and Technology, SLU, SE-90183 Umeå, Sweden E-mail: back.tomas.ersson@slu.se
Bergsten, Department of Forest Biomaterials and Technology, SLU, SE-90183 Umeå, Sweden E-mail: urban.bergsten@slu.se
Lindroos, Department of Forest Biomaterials and Technology, SLU, SE-90183 Umeå, Sweden E-mail: ola.lindroos@slu.se

article id 1019, category Research article

Michael Henke, Stephan Huckemann, Winfried Kurth, Branislav Sloboda. (2014). Reconstructing leaf growth based on non-destructive digitizing and low-parametric shape evolution for plant modelling over a growth cycle. Silva Fennica vol. 48 no. 2 article id 1019. https://doi.org/10.14214/sf.1019

Keywords: growth modelling; non-destructive data acquisition; automated data extraction; image processing tool; leaf shape modelling; reusable modules; Populus x canadensis

Highlights: A complete pipeline for plant organ modelling (at the example of poplar leaves) is presented, from non-destructive data acquisition, over automated data extraction, to growth and shape modelling; Leaf contour models are compared; Resulting “organ” modules are ready for use in FSPMs.

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A simple and efficient photometric methodology is presented, covering all steps from field data acquisition to binarization and allowing for leaf contour modelling. This method comprises the modelling of area and size (correlated and modelled with a Chapman-Richards growth function, using final length as one parameter), and four shape descriptors, from which the entire contour can be reconstructed rather well using a specific spline methodology. As an improvement of this contour modelling method, a set of parameterized polynomials was used. To model the temporal kinetics of the shape, geodesics in shape spaces were employed. Finally it is shown how this methodology is integrated into the 3D modelling platform GroIMP.

Henke, Department Ecoinformatics, Biometrics & Forest Growth, University of Göttingen, 37077 Göttingen, Germany E-mail: mhenke@uni-goettingen.de
Huckemann, Institute of Mathematical Stochastics, University of Göttingen, 37077 Göttingen, Germany E-mail: huckeman@math.uni-goettingen.de
Kurth, Department Ecoinformatics, Biometrics & Forest Growth, University of Göttingen, 37077 Göttingen, Germany E-mail: wk@informatik.uni-goettingen.de
Sloboda, Department Ecoinformatics, Biometrics & Forest Growth, University of Göttingen, 37077 Göttingen, Germany E-mail: bslobod@web.de

article id 1013, category Research article

Nils Fahlvik, Björn Elfving, Peder Wikström. (2014). Evaluation of growth functions used in the Swedish Forest Planning System Heureka. Silva Fennica vol. 48 no. 2 article id 1013. https://doi.org/10.14214/sf.1013

Keywords: basal area; simulation; validation; volume; empirical

Highlights: Growth models based on historical growth data gave reliable growth predictions up to the century shift; Detailed single tree growth models had lower precision for estimation of total growth than one single stand-based model; The prediction error was in average about 15% and did not increase with extended prediction period.

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

The performance of growth models implemented in the Swedish Forest Planning System Heureka was evaluated. Four basal area growth models were evaluated by comparing their predictions to data from five-year growth records for 1711 permanent sample plots of the National Forest Inventory (NFI-data). Also, two alternative implementations of Heureka, including a combined stand- and tree-level basal area growth model and a single tree-level model, respectively, were evaluated using data from 57 blocks in a thinning experiment (GG-data) involving Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst) in which the trees were monitored for 30 years after the first thinning. The predicted volume growth was also compared to observed values. Growth models based on data from 1970’s and 1980’s overestimated growth in the NFI test plots from the early 2000’s by about 3%. Stand-level models had larger precision than tree-level models. Basal area growth was underestimated in dense NFI-plots and overestimated in non-thinned GG-plots, illustrating an un-solved modelling problem. Basal area growth was overestimated by 2–5% also in the GG-plots over the whole observation period. Volume growth was however accurately predicted for pine and underestimated by 2% for spruce. The relative prediction error did not increase with increasing length of prediction period. Thinning response models calibrated with GG-data worked well in the total application and produced growth levels for different thinning alternatives in line with observations.

Fahlvik, Department of Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, P.O. Box 49, SE-230 53 Alnarp, Sweden E-mail: nils.fahlvik@slu.se
Elfving, Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden E-mail: bjorn.elfving@slu.se
Wikström, Peder Wikström Skogsanalys AB, c/o Peder Wikström, Huldrans väg 1, SE-907 52 Umeå, Sweden E-mail: peder.wikstrom@slu.se

article id 983, category Research article

Sakari Tuominen, Juho Pitkänen, Andras Balazs, Kari T. Korhonen, Pekka Hyvönen, Eero Muinonen. (2014). NFI plots as complementary reference data in forest inventory based on airborne laser scanning and aerial photography in Finland. Silva Fennica vol. 48 no. 2 article id 983. https://doi.org/10.14214/sf.983

Keywords: airborne laser scanning; National Forest Inventory; aerial imagery; plot sampling

Highlights: Using NFI plots in forest management inventories could provide a way for rationalising forest inventory data acquisition; NFI plots were used as additional reference data in laser scanning and aerial image based forest inventory; NFI plots improved the estimates of some forest variables; There are differences between the two inventory types that cause difficulties in combining the data.

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

In Finland, there are currently two, parallel sample-plot-based forest inventory systems, which differ in their methodologies, sampling designs, and objectives. One is the National Forest Inventory (NFI), aimed at unbiased inventory results at national and regional level. The other is the Forest Centre’s management-oriented forest inventory based on interpretation of airborne laser scanning and aerial images, with the aim of locally accurate stand-level forest estimates. The National Forest Inventory utilises relascope sample plots with systematic cluster sampling. This inventory method is optimised for accuracy of regional volume estimates. In contrast, the management-oriented forest inventory utilises circular sample plots with an allocation system covering certain pre-defined forest classes in the inventory area. This method is optimised to produce reference data for interpretation of the remote-sensing materials in use. In this study, we tested the feasibility of the National Forest Inventory sample plots in provision of additional reference data for the management-oriented inventory. Various combinations of NFI plots and management inventory plots were tested in the interpretation of the laser and aerial-image data. Adding NFI plots in the reference data generally improved the accuracy of the volume estimates by tree species but not the estimates of total volume or stand mean height and diameter. The difference between the plot types in the NFI and management inventories causes difficulties in combination of the two datasets.

Tuominen, Finnish Forest Research Institute, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: sakari.tuominen@metla.fi
Pitkänen, Finnish Forest Research Institute, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: juho.pitkanen@metla.fi
Balazs, Finnish Forest Research Institute, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: andras.balazs@metla.fi
Korhonen, Finnish Forest Research Institute, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: kari.t.korhonen@metla.fi
Hyvönen, Finnish Forest Research Institute, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: pekka.hyvonen@metla.fi
Muinonen, Finnish Forest Research Institute, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: eero.muinonen@metla.fi

article id 982, category Research article

Karri Uotila, Timo Saksa, Juho Rantala, Nuutti Kiljunen. (2014). Labour consumption models applied to motor-manual pre-commercial thinning in Finland. Silva Fennica vol. 48 no. 2 article id 982. https://doi.org/10.14214/sf.982

Keywords: productivity; pre-commercial thinning; forest vegetation management; early cleaning; release treatment; mixed linear regression

Highlights: When a young stand grows and gets older, the work time needed to make pre-commercial thinning increases. The stands of Norway spruce (Picea abies (L.) Karst.), Scots pine (Pinus sylvestris L.) and hardwoods (Betula spp.) required an additional 8.2%, 5.2%, and 3.3% work-time per year, respectively.

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

Labour models were developed to estimate the time required to Pre-Commercially Thin (PCT) with a clearing saw 4- to 20-year-old stands of the main commercial tree species in Finland. Labour (i.e., work-time consumption) was estimated from the density and stem diameter of the removal of 448 stands via an existing work productivity function. The removal based estimator attained was used as the basis for a priori mixed linear regression models. The main finding was that when a young stand grows and gets older, the work time needed to make a PCT increases. The stands of Norway spruce (Picea abies (L.) Karst.), Scots pine (Pinus sylvestris L.) and hardwoods (Betula spp.) required an additional 8.2%, 5.2%, and 3.3% work-time per year, respectively. Site fertility also played a role in that the most fertile site (mesic OMT) had an estimated labour requirement 114% higher than that for dryish VT. We also note that, per unit area, small stands require less labour than large ones and soil preparation method had a minor effect on the labour estimate. The stands which had previously gone through PCT were separately analysed. In those stands, the only significant variable concerning the labour estimate was age. The a priori models described here can help foresters to develop economic management programmes and issue quotes for forestry services.

Uotila, Finnish Forest Research Institute, Juntintie 154, FI-77600 Suonenjoki, Finland E-mail: karri.uotila@metla.fi
Saksa, Finnish Forest Research Institute, Juntintie 154, FI-77600 Suonenjoki, Finland E-mail: timo.saksa@metla.fi
Rantala, Metsä Group, Lielahdenkatu 10, FI-33400 Tampere, Finland E-mail: juho.rantala@metsagroup.com
Kiljunen, Metsähallitus, Asemakatu 7, FI-70107 Kuopio, Finland E-mail: nuutti.kiljunen@metsa.fi

article id 975, category Research article

Renats Trubins, Ola Sallnäs. (2014). Categorical mapping from estimates of continuous forest attributes – classification and accuracy. Silva Fennica vol. 48 no. 2 article id 975. https://doi.org/10.14214/sf.975

Keywords: Sweden; land cover maps; forest type maps; map accuracy assessment; class membership probability; Bayesian network; k-NN estimates

Highlights: The paper presents an approach to classification and accuracy assessment of ad-hoc categorical maps based on existing spatial datasets with estimates of continuous forest variables; Pixel level class membership probabilities are estimated using a Bayesian network model.

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

Spatially explicit data on forest attributes is demanded for various research with landscape perspective. Existing datasets with estimates of continuous forest variables are often used as the basis for producing categorical forest type maps. Normally, this type of maps are used without knowing their accuracy. This paper presents a Bayesian network model for estimating pixel level class membership probabilities of thus derived categorical maps. Class membership probabilities can be used as a post-classification measure of map accuracy and in the process of map classification affecting the assignments of class labels. The method is applied in mapping deciduous dominated forests on the basis of the k-NN Sweden 2005 dataset in a study area in southern Sweden. The results indicate rather low accuracy for deciduous class regardless of the map classification method: 0.48 versus 0.50 in the maps classified without and with the use of the class membership probabilities given equal deciduous area. When probability-based classification is applied, the level of accuracy varies with the assumed map class proportions. Thus, when deciduous class area corresponding to the National Forest Inventory estimate was used, the accuracy of only 0.35 was obtained for the deciduous map class.

Trubins, Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, Box 49, 230 53 Alnarp, Sweden E-mail: renats.trubins@slu.se
Sallnäs, Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, Box 49, 230 53 Alnarp, Sweden E-mail: ola.sallnas@slu.se

Category : Research note

article id 1125, category Research note

Anssi Krooks, Sanna Kaasalainen, Ville Kankare, Marianna Joensuu, Pasi Raumonen, Mikko Kaasalainen. (2014). Predicting tree structure from tree height using terrestrial laser scanning and quantitative structure models. Silva Fennica vol. 48 no. 2 article id 1125. https://doi.org/10.14214/sf.1125

Keywords: remote sensing; terrestrial lidar; tree modelling; branch size distribution

Highlights: The analysis of tree structure suggests that trees of different height growing in similar conditions have similar branch size distributions; There is potential for using the tree height information in large-scale estimations of forest canopy structure.

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

We apply quantitative structure modelling to produce detailed information on branch-level metrics in trees. Particularly we are interested in the branch size distribution, by which we mean the total volume of branch parts distributed over the diameter classes of the parts. We investigate the possibility of predicting tree branch size distributions for trees in similar growing conditions. The quantitative structure model enables for the first time the comparisons of structure between a large number of trees. We found that the branch size distribution is similar for trees of different height in similar growing conditions. The results suggest that tree height could be used to estimate branch size distribution in areas with similar growing conditions and topography.

Krooks, Finnish Geodetic Institute, Geodeetinrinne 2, FI–02431 Masala, Finland E-mail: Anssi.Krooks@fgi.fi
Kaasalainen, Finnish Geodetic Institute, Geodeetinrinne 2, FI–02431 Masala, Finland E-mail: Sanna.Kaasalainen@fgi.fi
Kankare, Department of Forest Sciences, University of Helsinki, P.O. Box 27, FI-00014 Helsinki, Finland E-mail: ville.kankare@helsinki.fi
Joensuu, Department of Forest Sciences, University of Helsinki, P.O. Box 27, FI-00014 Helsinki, Finland E-mail: marianna.joensuu@alumni.helsinki.fi
Raumonen, Tampere University of Technology, Department of Mathematics, P.O. Box 553, Tampere, FI-33101, Finland E-mail: Pasi.Raumonen@tut.fi
Kaasalainen, Tampere University of Technology, Department of Mathematics, P.O. Box 553, Tampere, FI-33101, Finland E-mail: Mikko.Kaasalainen@tut.fi

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