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Articles by Jānis Liepiņš

Category : Research article

article id 23040, category Research article
Jānis Liepiņš, Ieva Jaunslaviete, Kaspars Liepiņš, Līga Jansone, Roberts Matisons, Andis Lazdiņš, Āris Jansons. (2023). Effect of stem rot on wood basic density, carbon, and nitrogen content of living deciduous trees in hemiboreal forests. Silva Fennica vol. 57 no. 3 article id 23040. https://doi.org/10.14214/sf.23040
Keywords: wood specific gravity; birch; climate change mitigation; biomass estimation; alder; aspen; wood decay
Highlights: Stem rot significantly reduces the basic density of wood and increases its nitrogen content in living deciduous trees, while the carbon content appears irresponsive; The effect of the distance from the pith on the basic density and nitrogen content of wood varies, depending on presence of discoloration or decomposition in the wood.
Abstract | Full text in HTML | Full text in PDF | Author Info
While numerous studies have focused on analyzing various aspects of the carbon (C) budget in forests, there appears to be a lack of comprehensive assessments specifically addressing the impact of stem rot on the C budget of broadleaf tree species, especially in old-growth forests where stem rot is prevalent. One of the main challenges in accurately quantifying C losses caused by stem rot is the lack of precise data on the basic density and C content of decayed wood, which are crucial for converting decayed wood volume into biomass and C stocks. Using linear mixed-effects models, we examine the variability of wood basic density, C content, and nitrogen (N) content. Discolored and decomposed wood was collected from the stems of 136 living deciduous trees common in hemiboreal forests in Latvia. Our research indicates a noticeable reduction in the wood basic density, coupled with an increase in the N content within the stem wood throughout the decomposition process in birch (Betula spp.), European aspen (Populus tremula L.), grey alder (Alnus incana (L.) Moench), and common alder (Alnus glutinosa (L.) Gaertn.). While aspen wood showed a decreasing trend in C content as decay progressed, a pairwise comparison test revealed no significant differences in C content between discolored and decomposed wood for the studied species, unlike the findings for basic density and N content. This study emphasizes the need to account for stem rot in old-growth forest carbon budgets, especially in broadleaf species, and calls for more research on stem rot-induced carbon losses.
  • Liepiņš, Latvian State Forest Research Institute “Silava,” Rigas Street 111, LV-2169 Salaspils, Latvia ORCID https://orcid.org/0000-0003-3030-1122 E-mail: janis.liepins@silava.lv (email)
  • Jaunslaviete, Latvian State Forest Research Institute “Silava,” Rigas Street 111, LV-2169 Salaspils, Latvia ORCID https://orcid.org/0009-0000-7322-2729 E-mail: ieva.jaunslaviete@silava.lv
  • Liepiņš, Latvian State Forest Research Institute “Silava,” Rigas Street 111, LV-2169 Salaspils, Latvia ORCID https://orcid.org/0000-0002-1179-8586 E-mail: kaspars.liepins@silava.lv
  • Jansone, Latvian State Forest Research Institute “Silava,” Rigas Street 111, LV-2169 Salaspils, Latvia ORCID https://orcid.org/0000-0003-2748-3797 E-mail: liga.jansone@silava.lv
  • Matisons, Latvian State Forest Research Institute “Silava,” Rigas Street 111, LV-2169 Salaspils, Latvia E-mail: roberts.matisons@silava.lv
  • Lazdiņš, Latvian State Forest Research Institute “Silava,” Rigas Street 111, LV-2169 Salaspils, Latvia ORCID https://orcid.org/0000-0002-7169-2011 E-mail: andis.lazdins@silava.lv
  • Jansons, Latvian State Forest Research Institute “Silava,” Rigas Street 111, LV-2169 Salaspils, Latvia ORCID https://orcid.org/0000-0001-7981-4346 E-mail: aris.jansons@silava.lv

Category : Research note

article id 7798, category Research note
Jānis Liepiņš, Jānis Ivanovs, Andis Lazdiņš, Jurģis Jansons, Kaspars Liepiņš. (2017). Mapping of basic density within European aspen stems in Latvia. Silva Fennica vol. 51 no. 5 article id 7798. https://doi.org/10.14214/sf.7798
Keywords: Populus tremula; wood quality; wood density; bark density; density variations
Highlights: Stem bark is significantly denser than wood and does not follow the same variation patterns along the stem; The main trend in radial variation of wood density was the increase from pith to bark; There is a weak relationship between mean basic density and commonly measured stand and tree parameters.
Abstract | Full text in HTML | Full text in PDF | Author Info

The objective of this study was to investigate basic density and its within-stem variation by studying 84 European aspen stems from 28 forest stands in Latvia. The studied forest stands covered all age classes from young stands to matured forests in representative growth conditions of European aspen. The densities of 2722 wood and 1022 bark specimens were measured from the sampled trees. Only the knot-free wood specimens without obvious wood defects were chosen for analyses. A map of basic density summarizing its radial and axial variations was constructed to show species-specific, within-stem variability and the relationships between density and tree and stand variables were examined. Stem wood and bark of the European aspen show different patterns of basic density variation along the tree stem. Wood density increases from pith to bark up to certain dimensions and shows a slight decrease afterwards. The weighted basic density of bark (446 ± 39.6 kg m–3) was higher than stem wood density (393 ± 30.4 kg m–3). Our results suggest that wood and bark density measurements obtained at breast height can be used for reliable estimation of the densities of whole-tree stem components, while tree parameters such as diameter at breast height (DBH), tree height and social status or stand parameters, including number of trees, basal area and age, are weak predictors in this context.

  • Liepiņš, Latvian State Forest Research Institute “Silava”, 111 Rigas Str., LV 2169, Salaspils, Latvia E-mail: janis.liepins@silava.lv (email)
  • Ivanovs, Latvian State Forest Research Institute “Silava”, 111 Rigas Str., LV 2169, Salaspils, Latvia E-mail: janis.ivanovs@silava.lv
  • Lazdiņš, Latvian State Forest Research Institute “Silava”, 111 Rigas Str., LV 2169, Salaspils, Latvia E-mail: andis.lazdins@silava.lv
  • Jansons, Latvian State Forest Research Institute “Silava”, 111 Rigas Str., LV 2169, Salaspils, Latvia E-mail: jurgis.jansons@silava.lv
  • Liepiņš, Latvian State Forest Research Institute “Silava”, 111 Rigas Str., LV 2169, Salaspils, Latvia E-mail: kaspars.liepins@silava.lv

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