Browsing by Subject "STEMS"

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  • Tanhuanpää, Topi; Kankare, Ville; Setälä, Heikki; Yli-Pelkonen, Vesa; Vastaranta, Mikko; Niemi, Mikko T.; Raisio, Juha; Holopainen, Markus (2017)
    Assessment of the amount of carbon sequestered and the value of ecosystem services provided by urban trees requires reliable data. Predicting the proportions and allometric relationships of individual urban trees with models developed for trees in rural forests may result in significant errors in biomass calculations. To better understand the differences in biomass accumulation and allocation between urban and rural trees, two existing biomass models for silver birch (Betula pendula Roth) were tested for their performance in assessing the above-ground biomass (AGB) of 12 urban trees. In addition, the performance of a volume-based method utilizing accurate terrestrial laser scanning (TLS) data and stem density was evaluated in assessing urban tree AGB. Both tested models underestimated the total AGB of single trees, which was mainly due to a substantial underestimation of branch biomass. The volume-based method produced the most accurate estimates of stem biomass. The results suggest that biomass models originally based on sample trees from rural forests should not be used for urban, open-grown trees, and that volume-based methods utilizing TLS data are a promising alternative for non-destructive assessment of urban tree AGB. (C) 2017 Elsevier GmbH. All rights reserved.
  • Raatevaara, Antti; Korpunen, Heikki; Tiitta, Markku; Tomppo, Laura; Kulju, Sampo; Antikainen, Jukka; Uusitalo, Jori (2020)
    Scots pine (Pinus sylvestris L.) heartwood is naturally durable wood material which has not been fully utilized in the wood industry. Currently, there are no practical measurement methods for detecting and measuring heartwood in a tree harvesting. The objective of this study was to evaluate the applicability of an electrical impedance spectroscopy and an image analysis of a log end face for pine heartwood measurements from the harvesting perspective. Both methods were tested with a fresh wood material which was collected during the harvesting operations. The results indicate that both methods have potential to measure the heartwood from processed stems with an average heartwood diameter error being less than two centimeters for each method. However, the image analysis of the log end face is only appropriate when visible contrast between the heartwood and a sapwood exists. Our findings indicate that the studied heartwood detection methods show great potential in measuring the heartwood of the stem in the harvesting phase which would ideally benefit later links in wood value chains.
  • Epie, Kenedy E.; Santanen, Arja; Makela, Pirjo S. A.; Stoddard, Frederick L. (2018)
    Jerusalem artichoke (Helianthus tuberosus L.) produces substantial shoots not used as food. To test its potential as a sustainable bioenergy crop, we studied the effects of synthetic fertilizer and intercropped legumes as nitrogen (N) sources on the growth, aboveground biomass dry matter yield and energy qualities of this crop. Plant height, leaf area index (LAI), SPAD-value, biomass yield, ash content and mineral element composition were determined. Mean aboveground biomass yields were not significantly affected by N source (legume intercrops and synthetic fertilizer) and ranged from 13 to 17 t ha(-1). Remarkably, plants given no fertilizer yielded equally to plants given 90 N kg ha(-1). These results confirm that Jerusalem artichoke, compared to other energy crops, have less need for N and can potentially be sustained by N fixing legumes in an intercropped system. This could reduce or eliminate production and environmental cost in cultivation of biomass feedstock for energy use.
  • Uimari, Anne; Heliövaara, Kari; Tuba, Katalin; Poteri, Marja; Vuorinen, Martti (2018)
    Several young damaged Norway spruce stands in eastern and central Finland were observed from 2013 to 2016. The damage included trees with heavy resin flow, necrotic foliage, stem and branch cankers and dead trees. Pest identification resulted in the tortricid moth Cydia pactolana whose occurrence was always associated with the presence of the ascomycete pathogen Neonectria fuckeliana. Both the insect and the disease contributed to the extent of the damage, but it is not possible to say in which order they had attacked the trees. Apparently, changed climate has affected the increased occurrence of both the fungus and the moth. However, the characteristics of the insect-fungus interaction and the factors contributing to the coincidences are unknown. Emerging coexistence or potential symbiosis of the two damaging agents is a serious threat for Norway spruce cultivation. Understanding the biology of this fungus-insect interaction is important for controlling them.