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Silva Fennica vol. 56 no. 4 | 2022

Category: Editorial

article id 23005, category Editorial
Matti Maltamo. (2023). What does it actually mean to measure a sample plot in forest? Silva Fennica vol. 56 no. 4 article id 23005. https://doi.org/10.14214/sf.23005
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  • Maltamo, University of Eastern Finland, Faculty of Science, Forestry and Technology, Joensuu ORCID 0000-0002-9904-3371 E-mail: matti.maltamo@uef.fi

Category: Research article

article id 22007, category Research article
Ilkka Korpela, Antti Polvivaara, Saija Papunen, Laura Jaakkola, Noora Tienaho, Johannes Uotila, Tuomas Puputti, Aleksi Flyktman. (2023). Airborne dual-wavelength waveform LiDAR improves species classification accuracy of boreal broadleaved and coniferous trees. Silva Fennica vol. 56 no. 4 article id 22007. https://doi.org/10.14214/sf.22007
Keywords: crown modeling; laser scanning; photogrammetry; individual tree detection; Scandinavia
Highlights: First study to assess dual-wavelength waveform data in tree species identification; New findings regarding waveform features of previously unstudied species; Waveform features correlated with tree size displaying wavelength- and species-specific differences linked to bark reflectance, height growth rate and foliage density; Effects by pulse length and beam divergence are highlighted.
Abstract | Full text in HTML | Full text in PDF | Author Info
Tree species identification constitutes a bottleneck in remote sensing applications. Waveform LiDAR has been shown to offer potential over discrete-return observations, and we assessed if the combination of two-wavelength waveform data can lead to further improvements. A total of 2532 trees representing seven living and dead conifer and deciduous species classes found in Hyytiälä forests in southern Finland were included in the experiments. LiDAR data was acquired by two single-wavelength sensors. The 1064-nm and 1550-nm data were radiometrically corrected to enable range-normalization using the radar equation. Pulses were traced through the canopy, and by applying 3D crown models, the return waveforms were assigned to individual trees. Crown models and a terrain model enabled a further split of the waveforms to strata representing the crown, understory and ground segments. Different geometric and radiometric waveform attributes were extracted per return pulse and aggregated to tree-level mean and standard deviation features. We analyzed the effect of tree size on the features, the correlation between features and the between-species differences of the waveform features. Feature importance for species classification was derived using F-test and the Random Forest algorithm. Classification tests showed significant improvement in overall accuracy (74→83% with 7 classes, 88→91% with 4 classes) when the 1064-nm and 1550-nm features were merged. Most features were not invariant to tree size, and the dependencies differed between species and LiDAR wavelength. The differences were likely driven by factors such as bark reflectance, height growth induced structural changes near the treetop as well as foliage density in old trees.
  • Korpela, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID 0000-0002-1665-3984 E-mail: ilkka.korpela@helsinki.fi
  • Polvivaara, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail:
  • Papunen, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID 0000-0001-5383-4314 E-mail: saija.papunen@outlook.com
  • Jaakkola, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: laura.jaakkola@helsinki.fi
  • Tienaho, University of Eastern Finland, Faculty of Science and Forestry, P.O. Box 111, FI-80101 Joensuu, Finland ORCID 0000-0002-6574-5797 E-mail: noora.tienaho@uef.fi
  • Uotila, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: johannes.uotila@helsinki.fi
  • Puputti, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID 0000-0003-1972-1636 E-mail: tuomas.puputti@helsinki.fi
  • Flyktman, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID 0000-0002-5235-317X E-mail: aleksi.flyktman@helsinki.fi
article id 10798, category Research article
Perttu Anttila, Johannes Ojala, Teijo Palander, Kari Väätäinen. (2023). The effect of road characteristics on timber truck driving speed and fuel consumption based on visual interpretation of road database and data from fleet management system. Silva Fennica vol. 56 no. 4 article id 10798. https://doi.org/10.14214/sf.10798
Keywords: fuel consumption; forest roads; CAN bus; forest logistics; greenhouse gas emissions; log truck; road classes
Highlights: Finnish road and pavement classes explain driving speed and fuel consumption of a timber truck; Other significant explanatory variables include the number of road crossings, season, proportion of distance travelled with a loader, and total laden mass of a truck; In the future, higher-resolution tracking data is needed to construct generalisable models for 76-tonne vehicles.
Abstract | Full text in HTML | Full text in PDF | Author Info

Road transport produces 90% of greenhouse gas emissions in timber transport in Finland. It is therefore necessary to understand the factors that affect driving speed, fuel consumption, and ultimately, emissions. The objective of this study was to assess the effect of road characteristics on timber truck driving speed and fuel consumption. Data from the fleet management and transport management systems of two timber trucks were collected over a year. A sample of 104 trips was drawn, and the tracking points were overlaid on the road data in a geographical information system. Thereafter, work phases were determined for the points, and they were visually classified into road and pavement classes. Subsequently, the data of 80 trips were utilised in regression analysis to further study the effects of the visually interpreted variables on driving speed and fuel consumption. Fuel consumption was explained by the proportion of forest roads and distance travelled with a loader, and the number of crossings and season when driving without a load. When driving with a load, both asphalt and gravel pavements decreased consumption, in contrast to an unpaved road. Crossings increased fuel consumption, as did the winter and spring months, and the total laden mass of the truck. In conclusion, the study showed that the functional Finnish road and pavement classes can be used to predict driving speed and fuel consumption.

  • Anttila, Natural Resources Institute Finland (Luke), Latokartanonkaari 9, FI-00790 Helsinki, Finland ORCID https://orcid.org/0000-0002-6131-392X E-mail: perttu.anttila@luke.fi (email)
  • Ojala, UPM Metsä, Sirkkalantie 13 b, FI-80100 Joensuu, Finland E-mail: johannes.ojala@upm.com
  • Palander, School of Forest Sciences, University of Eastern Finland (UEF), Yliopistokatu 7, FI-80100 Joensuu, Finland ORCID https://orcid.org/0000-0002-9284-5443 E-mail: teijo.s.palander@uef.fi
  • Väätäinen, Natural Resources Institute Finland (Luke), Yliopistokatu 6, FI-80100 Joensuu, Finland ORCID https://orcid.org/0000-0002-6886-0432 E-mail: kari.vaatainen@luke.fi
article id 10769, category Research article
Harri Mäkinen, Pekka Nöjd, Samuli Helama. (2022). Recent unexpected decline of forest growth in North Finland: examining tree-ring, climatic and reproduction data. Silva Fennica vol. 56 no. 4 article id 10769. https://doi.org/10.14214/sf.10769
Keywords: Pinus sylvestris; Picea abies; precipitation; temperature; seed production; tree-ring width; growth variation
Highlights: Tree-ring indices of Scots pine showed decadal variations and a prolonged reduction both on mineral soil sites and peatlands after the mid 2000s; The indices of Norway spruce had less pronounced decadal variations and no trend-like reduction over the last 15 years; Temperature and drought explain some part of the observed growth variability.
Abstract | Full text in HTML | Full text in PDF | Author Info

After a decades-long increasing trend, the recent results of the National Forest Inventory (NFI) reported a decline of forest growth in North Finland. The aim of this study was to assess climatic and reproduction influences behind the growth decline. We used tree-ring data that had been collected by NFI using systematic sampling. The tree-ring width series were detrended using the regional curve standardisation (RCS) removing age-related trends. The resulting tree-ring indices of Scots pine (Pinus sylvestris L.) showed decadal variations with low increment in the 1990s, and high increment in the 1980s and the early years of the current century. Thereafter, a prolonged growth reduction for pine started both on the mineral soil sites and peatlands. The tree-ring indices of Norway spruce (Picea abies (L.) Karst.) had less pronounced decadal variations and no trend-like reduction over the last 15 years. High spring and summer temperatures were found to enhance radial growth, but high winter temperatures were related to low growth for pine and spruce in the following summer. Temperature variation, accompanied by variables indicating years of drought and intensive flowering, accounted for 34% annual growth variance of pine and 21–44% for spruce. Thus, the results imply that climatic factors may have to some extent contributed to the recent growth reduction of pine. Due to its ecological and economic consequences growth decline needs to be further monitored and investigated. Moreover, analyses of stand and age structure, potentially affecting the growth decline, were beyond the scope of this paper, but also warrant further investigation.

  • Mäkinen, Natural Resources Institute Finland (Luke), Latokartanonkaari 9, 00790 Helsinki ORCID https://orcid.org/0000-0002-1820-6264 E-mail: harri.makinen@luke.fi (email)
  • Nöjd, Natural Resources Institute Finland (Luke), Latokartanonkaari 9, 00790 Helsinki E-mail: pekka.nojd@luke.fi
  • Helama, Natural Resources Institute Finland (Luke), Ounasjoentie 6, 96200 Rovaniemi, Finland ORCID https://orcid.org/0000-0002-9777-3354 E-mail: samuli.helama@luke.fi
article id 10762, category Research article
Karri Uotila, Jaana Luoranen, Timo Saksa, Tiina Laine, Juha Heiskanen. (2022). Long-term growth response of Norway spruce in different mounding and vegetation control treatments on fine-textured soils. Silva Fennica vol. 56 no. 4 article id 10762. https://doi.org/10.14214/sf.10762
Keywords: boreal forest; establishment; regeneration; site preparation; plantation; tree growth; scarification; fine-textured soils; mechanical vegetation control
Highlights: Spot and ditch mounding methods favoured spruce sapling development on fine-textured soils; Inverted and unprepared plots showed the weakest growth; Vegetation control suppressed the growth differences between site preparation methods; Vegetation control reduced the density of resprouts after early cleaning.
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Mechanical site preparation (MSP) is a common practice that precedes the planting of Norway spruce (Picea abies (L.) H. Karst.) in Nordic forests. Mounding has become the most used method in spruce planting in recent years. This study examined the effects of different mounding treatments (spot and ditch mounding, inversion, unprepared control with or without herbicide application) and a mechanical vegetation control (MVC) treatment done 3–4 years after planting on the post-planting growth of spruce container seedlings and their development to saplings during the first 11–13 years on two forest till soils in central Finland, one on flat terrain and other on a southwest slope. On these fine-textured soils the spot and ditch mounding methods favoured spruce saplings development. Inversion and unprepared plots showed weakest growth. On the site with flat terrain, 11 years post planting, spruce saplings were 78–144 cm (38–80%) taller and their breast height diameters were 11–13 mm (60–74%) thicker for ditch or spot mounding than for inversion or herbicide treatment. On the site with sloped terrain the differences were minor between the MSP treatments. MVC improved spruce height growth on sites which did not have intensive MSP, especially on control saplings planted on unprepared soil in herbicide and inversion treatments. On the flat terrain, MVC reduced the density of resprouts to be removed later in pre-commercial thinning. As a conclusion, spot or ditch mounding favoured the growth of spruce over inversion especially on flat terrain with fine-textured soil.

  • Uotila, Natural Resources Institute Finland (Luke), Natural resources, Juntintie 154, FI-77600 Suonenjoki, Finland E-mail: karri.uotila@luke.fi (email)
  • Luoranen, Natural Resources Institute Finland (Luke), Natural resources, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID https://orcid.org/0000-0002-6970-2030 E-mail: jaana.luoranen@luke.fi
  • Saksa, Natural Resources Institute Finland (Luke), Natural resources, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID https://orcid.org/0000-0002-1776-2357 E-mail: timo.saksa@luke.fi
  • Laine, Metsä Forest, Revontulenpuisto 2, FI-02100 Espoo, Finland ORCID https://orcid.org/0000-0002-6448-8274 E-mail: tiina.laine@metsagroup.com
  • Heiskanen, Natural Resources Institute Finland (Luke), Natural resources, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID https://orcid.org/0000-0002-0549-835X E-mail: juha.heiskanen@luke.fi
article id 10757, category Research article
Silvana M.J. Sione, Silvia G. Ledesma, Pablo G. Aceñolaza, Marcelo G. Wilson. (2022). Biomass Carbon and Nitrogen allocation in different tree species: do tree compartments and size affect C:N relationship? Silva Fennica vol. 56 no. 4 article id 10757. https://doi.org/10.14214/sf.10757
Keywords: Neltuma nigra; Neltuma affinis; Vachellia caven; biomass compartments; C:N ratio; native forests
Highlights: C:N relationship variations in biomass compartments were positively correlated with N concentration and did not exhibit significant association with C; C:N ratios differed significantly among species and compartments; Only in Neltuma affinis and Vachellia caven stems C:N relationship differed among tree size.
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Tree carbon (C) and nitrogen (N) concentrations and C:N ratio are critical for understanding the elemental compositions of forests, N use efficiency, productivity and the biogeochemical cycles. We evaluate differences in C and N allocation among biomass compartments of three N‑fixing tree species of Espinal Argentine eco-region; the scaling relationship between C and N and the C:N ratio variation among compartments and tree size. Neltuma affinis (Spreng.) C.E. Hughes & G.P. Lewis, Neltuma nigra (Griseb.) C.E. Hughes & G.P. Lewis and Vachellia caven (Molina) Seigler & Ebinger plants (n = 30 for each species) were felled, grouped by stem basal diameter-based size classes and partitioned into 3 biomass compartments: stem (st), large branches (lb) and small branches + leaves, flowers and fruits (sbl). C and N concentrations were markedly influenced by species and biomass compartments. In general, sbl compartment presented more N than the st and lb, while C concentrations in Neltuma stems were the highest. Overall, no isometric C–N scaling relationships were found in different compartments. C:N variations in compartments were positively correlated with N concentrations but did not exhibit any significant association with C concentrations. C:N ratios differed significantly among species and biomass compartments. The C:N ratio for compartments ranked in an order of st > lb > sbl. C:N ratio variability in sbl was the least. Only in N. affinis and V. caven stems C:N relationship differed among tree size. Our results provide evidence of the importance of using in situ C and N concentration per main tree species and biomass compartments, to more accurate estimates of C and N stocks.

  • Sione, National University of Entre Ríos, Faculty of Agricultural Sciences, Ruta 11 Km 10,5 (3101) Oro Verde, Entre Ríos, Argentina; CICyTTP-CONICET (National Research and Technological Investigation Council), Materi y España (3105) Diamante, Entre Ríos, Argentina ORCID https://orcid.org/0000-0002-2119-0363 E-mail: silvana.sione@fca.uner.edu.ar (email)
  • Ledesma, National University of Entre Ríos, Faculty of Agricultural Sciences, Ruta 11 Km 10,5 (3101) Oro Verde, Entre Ríos, Argentina ORCID https://orcid.org/0000-0002-9264-1766 E-mail: silvia.ledesma@fca.uner.edu.ar
  • Aceñolaza, National University of Entre Ríos, Faculty of Agricultural Sciences, Ruta 11 Km 10,5 (3101) Oro Verde, Entre Ríos, Argentina; CICyTTP-CONICET (National Research and Technological Investigation Council), Materi y España (3105) Diamante, Entre Ríos, Argentina ORCID https://orcid.org/0000-0002-5033-3466 E-mail: pablo.acenolaza@fca.uner.edu.ar
  • Wilson, National University of Entre Ríos, Faculty of Agricultural Sciences, Ruta 11 Km 10,5 (3101) Oro Verde, Entre Ríos, Argentina ORCID https://orcid.org/0000-0002-1214-1041 E-mail: wilson.marcelo@inta.gob.ar
article id 10676, category Research article
Eva Ring, Fredrik Johansson, Claudia von Brömssen, Isabelle Bergkvist. (2022). A snapshot of forest buffers near streams, ditches, and lakes on forest land in Sweden – lessons learned. Silva Fennica vol. 56 no. 4 article id 10676. https://doi.org/10.14214/sf.10676
Keywords: forestry; conifer; harvest; lake; riparian; stream; watercourse
Highlights: Forest buffers were inventoried on 174 harvested and site-prepared compartments bordering surface water in Sweden; Buffers with 100% shoreline coverage were present beside all 16 lakes and 55% of the natural or modified stream reaches; Judging streams´ character from field inspection of individual reaches alone proved difficult on forest land affected by historic drainage activities.
Abstract | Full text in HTML | Full text in PDF | Author Info

Forest buffers beside surface water can mitigate negative effects of logging. To gain more information on buffer implementation in operational forestry, forest buffers were inventoried during 2018 on 174 harvested and site-prepared compartments traversed by or bordering streams, ditches and lakes in three regions across Sweden 2–4 years after clearcutting. Most of the inventoried stream and ditch reaches were ≤5 m wide. The water reaches were categorized as lakes (n = 16), natural streams (n = 50), modified streams (n = 21) or ditches (n = 87). Forest buffers with 100% shoreline coverage were present along all lake reaches and 55% and 10% of the natural or modified stream and ditch reaches, respectively. Buffers were absent beside 14% of the natural or modified stream reaches and 61% of the ditch reaches. Lake reaches had significantly wider buffers on average than ditch reaches and natural or modified stream reaches. The mean (SE) buffer widths beside lakes, natural or modified stream reaches and ditch reaches across all three regions and shoreline coverage classes were 12 (1.1), 6.6 (0.6) and 1.5 (0.5) m, respectively. The character of the local stream networks (natural or modified streams or ditches) containing each inventoried reach, were assessed using map information and the reaches´ field classifications. This illustrated the difficulty of judging a streams´ character based solely on field inspections of individual reaches on forest land where historic drainage activities have been performed. We recommend that also upstream and downstream conditions should be considered when planning environmental measures to protect surface water bodies.

  • Ring, Skogforsk (The Forestry Research Institute of Sweden), Uppsala Science Park, 751 83 Uppsala, Sweden ORCID https://orcid.org/0000-0002-8962-9811 E-mail: eva.ring@skogforsk.se (email)
  • Johansson, Skogforsk (The Forestry Research Institute of Sweden), Uppsala Science Park, 751 83 Uppsala, Sweden E-mail: fredrik.johansson@skogforsk.se
  • von Brömssen, Department of energy and technology, Division of applied statistics and mathematics, Swedish University of Agricultural Sciences, 750 07 Uppsala, Sweden ORCID https://orcid.org/0000-0002-1452-8696 E-mail: Claudia.von.Bromssen@slu.se
  • Bergkvist, Mellanskog, Uppsala Science Park, Box 127, 751 04 Uppsala, Sweden E-mail: isabelle.bergkvist@mellanskog.se

Category: Research note

article id 22008, category Research note
Eeva Terhonen. (2023). First report of Diplodia tip blight on Scots pine in Finland. Silva Fennica vol. 56 no. 4 article id 22008. https://doi.org/10.14214/sf.22008
Keywords: Pinus sylvestris; drought; Diplodia sapinea; Sphaeropsis sapinea; emerging fungal disease
Highlights: Diplodia tip blight is a new disease on Scots pine in Finland; Diplodia sapinea can be identified reliably with the presented pipeline.
Abstract | Full text in HTML | Full text in PDF | Author Info
Diplodia sapinea (Fr.) Fuckel causes shoot blight on Scots pine (Pinus sylvestris L.). This fungus has been discovered in Finland as a saprophyte in 2015 on Scots pine cones. The endophytic mode of this fungus was later discovered in healthy Scots pine twigs. In 2021 the disease, Diplodia tip blight was observed on Scots pine in Finland. Currently, the disease symptoms are poorly identified so the role of D. sapinea in disease outbreaks in Finland are easily overlooked. The identification of the fungi is challenging in field conditions and requires targeted identification in laboratory. In this research note I report the first Diplodia tip blight outbreaks observed in Finland, the typical disease symptoms, and methodology for the species identification. Samples were collected from symptomatic trees based on observations made by the citizens. Diplodia sapinea was isolated from defoliated and surface sterilized twigs. The species identification by morphological characters was further confirmed with sequencing of ITS region of rDNA and with species-specific primers. A pathogenicity test confirmed that D. sapinea was the disease agent causing shoot blight. This is the first report of Diplodia tip blight on Scots pine in Finland.
  • Terhonen, Natural Resources Institute Finland (Luke), Forest health and biodiversity, Latokartanonkaari 9, FI‐00790 Helsinki, Finland ORCID 0000-0002-9288-440X E-mail: eeva.terhonen@luke.fi

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