Browsing by Subject "Scots pine"

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  • Hu, Man; Lehtonen, Aleksi; Minunno, Francesco; Mäkelä, Annikki (2020)
    Tree structure equations derived from pipe model theory (PMT) are well-suited to estimate biomass allocation in Scots pine (Pinus sylvestrisL.) and Norway spruce (Picea abies[L.] Karst.). However, age dependence of parameters should be accounted for when applying the equations.
  • Calleja-Rodriguez, Ainhoa; Li, Zitong; Hallingbäck, Henrik R.; Sillanpää, Mikko J.; Wu, Harry X.; Abrahamsson, Sara; Garcia-Gil, Maria Rosario (2019)
    In forest tree breeding, family-based Quantitative Trait Loci (QTL) studies are valuable as methods to dissect the complexity of a trait and as a source of candidate genes. In the field of conifer research, our study contributes to the evaluation of phenotypic and predicted breeding values for the identification of QTL linked to complex traits in a three-generation pedigree population in Scots pine (Pinus sylvestris L.). A total of 11 470 open pollinated F-2-progeny trees established at three different locations, were measured for growth and adaptive traits. Breeding values were predicted for their 360 mothers, originating from a single cross of two grand-parents. A multilevel LASSO association analysis was conducted to detect QTL using genotypes of the mothers with the corresponding phenotypes and Estimated Breeding Values (EBV). Different levels of genotype-by-environment (G x E) effects among sites at different years, were detected for survival and height. Moderate-to-low narrow sense heritabilities and EBV accuracies were found for all traits and all sites. We identified 18 AFLPs and 12 SNPs to be associated with QTL for one or more traits. 62 QTL were significant with percentages of variance explained ranging from 1.7 to 18.9%. In those cases where the same marker was associated to a phenotypic or an ebvQTL, the ebvQTL always explained higher proportion of the variance, maybe due to the more accurate nature of Estimated Breeding Values (EBV). Two SNP-QTL showed pleiotropic effects for traits related with hardiness, seed, cone and flower production. Furthermore, we detected several QTL with significant effects across multiple ages, which could be considered as strong candidate loci for early selection. The lack of reproducibility of some QTL detected across sites may be due to environmental heterogeneity reflected by the genotype- and QTL-by-environment effects. (C) 2018 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license.
  • Pyorala, Jiri; Liang, Xinlian; Saarinen, Ninni; Kankare, Ville; Wang, Yunsheng; Holopainen, Markus; Hyyppa, Juha; Vastaranta, Mikko (2018)
    Terrestrial laser scanning (TLS) accompanied by quantitative tree-modeling algorithms can potentially acquire branching data non-destructively from a forest environment and aid the development and calibration of allometric crown biomass and wood quality equations for species and geographical regions with inadequate models. However, TLS's coverage in capturing individual branches still lacks evaluation. We acquired TLS data from 158 Scots pine (Pinus sylvestris L.) trees and investigated the performance of a quantitative branch detection and modeling approach for extracting key branching parameters, namely the number of branches, branch diameter (b(d)) and branch insertion angle (b) in various crown sections. We used manual point cloud measurements as references. The accuracy of quantitative branch detections decreased significantly above the live crown base height, principally due to the increasing scanner distance as opposed to occlusion effects caused by the foliage. b(d) was generally underestimated, when comparing to the manual reference, while b was estimated accurately: tree-specific biases were 0.89cm and 1.98 degrees, respectively. Our results indicate that full branching structure remains challenging to capture by TLS alone. Nevertheless, the retrievable branching parameters are potential inputs into allometric biomass and wood quality equations.
  • Nadal-Sala, Daniel; Grote, Ruediger; Birami, Benjamin; Lintunen, Anna; Mammarella, Ivan; Preisler, Yakir; Rotenberg, Eyal; Salmon, Yann; Tatarinov, Fedor; Yakir, Dan; Ruehr, Nadine K. (2021)
    Climate change will impact forest productivity worldwide. Forecasting the magnitude of such impact, with multiple environmental stressors changing simultaneously, is only possible with the help of process-based models. In order to assess their performance, such models require careful evaluation against measurements. However, direct comparison of model outputs against observational data is often not reliable, as models may provide the right answers due to the wrong reasons. This would severely hinder forecasting abilities under unprecedented climate conditions. Here, we present a methodology for model assessment, which supplements the traditional output-to-observation model validation. It evaluates model performance through its ability to reproduce observed seasonal changes of the most limiting environmental driver (MLED) for a given process, here daily gross primary productivity (GPP). We analyzed seasonal changes of the MLED for GPP in two contrasting pine forests, the Mediterranean Pinus halepensis Mill. Yatir (Israel) and the boreal Pinus sylvestris L. Hyytiala (Finland) from three years of eddy-covariance flux data. Then, we simulated the same period with a state-of-the-art process-based simulation model (LandscapeDNDC). Finally, we assessed if the model was able to reproduce both GPP observations and MLED seasonality. We found that the model reproduced the seasonality of GPP in both stands, but it was slightly overestimated without site-specific fine-tuning. Interestingly, although LandscapeDNDC properly captured the main MLED in Hyytiala (temperature) and in Yatir (soil water availability), it failed to reproduce high-temperature and high-vapor pressure limitations of GPP in Yatir during spring and summer. We deduced that the most likely reason for this divergence is an incomplete description of stomatal behavior. In summary, this study validates the MLED approach as a model evaluation tool, and opens up new possibilities for model improvement.
  • Metsämuuronen, Sari; Sirén, Heli (2019)
    Phenolics and extracted phenolic compounds of Scots pine (Pinus sylvestris) and Norway spruce (Picea abies) show antibacterial activity against several bacteria. The majority of phenolic compounds are stilbenes, flavonoids, proanthocyanidins, phenolic acids, and lignans that are biosynthesized in the wood through the phenylpropanoid pathway. In Scots pine (P. sylvestris), the most abundant phenolic and antibacterial compounds are pinosylvin-type stilbenes and flavonol- and dihydroflavonol-type flavonoids, such as kaempferol, quercetin, and taxifolin and their derivatives. In Norway spruce (P. abies) on the other hand, the main stilbene is resveratrol and the major flavonoids are quercetin and myricetin. In general, when the results from the literature regarding the activities of flavonoid glycosides and their aglycones against a total of twenty-one microorganisms are summarized, it was found that phenolic glycosides are less active than the corresponding aglycones, although a number of exceptions are also known. The aglycones in plants respond to various kinds of biotic stress. Synergistic effects between aglycones and their glycosides have been observed. Minimum inhibition concentrations of below 10 mg L−1 against bacteria have been reported for gallic acid, apigenin, and several methylated and acylated flavonols present in these industrially important trees. In general, the phenolic compounds are more active against Gram-positive bacteria, but apigenin is reported to exhibit strong activity against Gram-negative bacteria. The present review lists some of the biosynthesis pathways for the antibacterial phenolic metabolites found in Scots pine (P. sylvestris) and Norway spruce (P. abies). The antimicrobial activity of the compounds is collected and compared to gather information about the most effective secondary metabolites.
  • Lintunen, Anna; Lindfors, Lauri; Kolari, Pasi; Juurola, Eija; Nikinmaa, Eero; Hölttä, Tuomo (2014)
  • Andreou, Gregory Michael (Helsingin yliopisto, 2021)
    Understanding the biomes and niches within forest ecosystems is key to maintaining and predicting micro-organism led processes, such as, nutrient recycling and disease proliferation. Insect-vectored fungi occupy the tree bark biosphere as incidental associates. Also, more selective transmission of fungi is seen via the beetle’s specialised structure called the mycangium. Mites carried by these insects, have also been described to vector fungi. Within these fungi are mycoviruses that express cryptic, beneficial, or detrimental effects to the host. The positive and negative effects on fungal host phenotypes encourage investigations into unknown virospheres. A study into the distribution of mycoviruses within bark-beetle vectored fungi in Finnish forests has yet to be carried out. The master’s thesis work continued an evaluation of viromes from 52 forest, bark-beetle vectored, fungal isolates transformed into 4 RNA libraries via high throughput sequencing platforming, using Illumina chemistry. Scots pine, Pinus sylvestris, and Norway spruce, Picea abies, logs were sampled. A further 31 fungal isolates were screened, via RT-PCR, for 22 putative viral sequences recovered from the RNA libraries. Patterns in viral sequence host range, co-infectivity and similarities between viral sequences were investigated. The viral sequences described in this study were unique to the databases searched against and could be looked at when maintaining the Finnish forest ecosystem. It was shown that positive-sense ssRNA viruses could play a major role in the virome of bark-beetle vectored fungi as 77.3 % of viral sequences described were classified as so. Mitovirus infections were most frequent across the two forests and, the interspecies-infective Ophiostomatoid mitovirus 2 strain was seen to infect at least four species, across two fungal genera. The description of Kuraishia capsulata narna-like virus 1 showing RNA dependent RNA polymerases (RdRp) across 2 genomes segments, supports current growing evidence, which in turn could contribute to the new classification of viruses within the Narnaviridae family.
  • Rissanen, Kaisa; Hölttä, Teemu; Bäck, Jaana; Rigling, Andreas; Wermelinger, Beat; Gessler, Arthur (2021)
    Droughts and other rapid changes in abiotic environmental conditions can predispose trees to damage by pest insects and pathogens. For survival of coniferous trees, functional resin-based defences are essential, and it is important to know how they react to changes in environmental conditions at various time scales. We studied the effects of differing water availabilities on resin-based defences in mature Scots pine (Pinus sylvestris) trees in a naturally drought-prone forest within a long-term irrigation experiment. Our objectives were to understand the effects of long-term drought on carbon allocation to resin production and to analyse its influence on resin flow and pressure in comparison to the shorter-term effects of seasonal drought. We tracked carbon allocation to resin after C-13-pulse labelling experiment in late summer 2017 and compared the observed resin dynamics between drought-exposed control trees and irrigated trees from June to August during the dry hot summer of 2018. Dry control trees showed higher allocation of labelled carbon to resin than irrigated trees. Resin pressure was higher in dry control than in irrigated trees with similar water potentials, and resin flow in June was higher in dry control than in irrigated trees with similar crown transparency. Yet, resin pressures of dry control trees in particular decreased with decreasing water availability from June to August. Resin flow was little affected by short-term changes in water availability and mostly associated with crown transparency. We suggest that because of differing timescales of direct drought effects and changes in allocation patterns, dry conditions may support resin-based defences in the long term, but a drought period decreases resin pressure in the short term.
  • Virkkunen, Eero (Helsingin yliopisto, 2017)
    This study aimed at conducting a baseline for optimal harvesting schedules with economic criteria for Scots pine, Norway spruce and silver birch in Estonia. Additionally, this study aimed at providing comparison to previous findings about optimal schedules in boreal forests and recommendation for practitioners. Faustmann’s (1849) forest rotation theory provides the theoretical foundation for the thesis. The study was performed by including Estonian whole-stand forest growth models and local timber prices and forest regeneration costs in the optimization, which was based on the Hooke and Jeeves’ (1961) direct optimization method. Scots pine was found to be the optimal species in most site classes, silver birch being the optimum in the most fertile site. The schedules for silver birch were found to be less sensitive to changes in the rate of interest, site fertility and timber price than the conifers. The current legal restrictions lead to longer rotations, more thinnings and economic losses when compared to the unrestricted optimal scenarios. The optimal number of thinnings in most scenarios for all species turned out to be three, if the legal restrictions are followed. In general, the optimal rotation periods were found to be shorter and the timing of the first thinning earlier in many scenarios than in Finland. Also the optimal number of thinnings was found to be more stable in Estonia than in Finland. It was found that if the initial stand stocking for the main tree species falls below a certain threshold in mid-rotation mixed-species stands including less valuable broadleaves, it is optimal to clear fell the stand immediately and regenerate the stand according to the optimal stocking recommendations. From the practical point of view, given the current limitations regarding the timing of clear fell, forestry practitioners have the most value creation potential in improving the forest regeneration methods and thinning schedule. In comparison to Finnish studies, it was found that there exists many similarities regarding the schedules and the suitability of species for different forest sites between the findings of this study and previous Finnish studies and the Finnish silvicultural recommendations. Thus, the extensive Finnish recommendations and findings provide a good basis for practitioners also in Estonia. However, given also the found differences, harvesting schedules in Estonia should be developed in more detail for more sophisticated recommendations for local practices.
  • Parkatti, Vesa-Pekka (Helsingfors universitet, 2017)
    This study optimizes the management regime of boreal Norway spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestric L.) stands. The aim is to compare the economic profitability of continuous cover management and clearcut management and to study the hypothesis that continuous cover forestry is more favorable in the case of Norway spruce, compared to Scots pine. Additionally, the study analyses the outcomes of two different growth models for these tree species and compares the results with the requirements of the Finnish Forest Act of 2014. Earlier studies comparing the suitability of Norway spruce and Scots pine to continuous cover forestry have applied unclear model specifications and unnecessary limitations in the optimization methods. In this study, the optimization is carried out using a theoretically sound economic optimization model that determines the choice of the management regime as an outcome of the optimization. The model uses empirically estimated ecological growth models and includes both fixed and variable harvesting costs. Two different empirically estimated ecological growth models are used and compared. The optimization model is solved as a bi-level problem where harvest timing is the upper-level problem and harvesting intensity the lower-level problem. The optimization is solved using gradient-based methods for the lower-level problems and genetic and hill-climbing algorithms for the upper-level problems. This is the first study using this method to solve optimal continuous cover solutions for Scots pine. The results show that the main differences in optimal solutions between the two species are independent of the ecological two growth models used. According to both ecological models, continuous cover forestry is less favorable for Scots pine compared to Norway spruce, in both low and average fertility sites. However, the magnitude of this favorability and the characteristics of the optimal solutions strongly depend on the ecological model. Optimal continuous cover solutions for Scots pine are also found to have very low stand densities. Almost all economically optimal solutions are illegal because of their low number of trees or basal area per hectare.
  • Hänninen, Heikki; Pelkonen, Paavo (Suomen metsätieteellinen seura, 1988)
  • Latva-Käyrä, Petri (Helsingfors universitet, 2012)
    The intensity and frequency of insect outbreaks have increased in Finland in the last decades and they are expected to increase even further in the future due to global climate change. In 1998-2001 Finland suffered the most severe insect outbreak ever recorded, over 500,000 hectares. The outbreak was caused by the common pine sawfly (Diprion pini L.). The outbreak has continued in the study area, Palokangas, ever since. To find a good method to monitor this type of outbreaks, the purpose of this study was to examine the efficacy of multitemporal ERS-2 and ENVISAT SAR imagery for estimating Scots pine defoliation. The study area, Palokangas, is located in Ilomantsi district, Eastern-Finland and consists mainly even-aged Scots pine forests on relatively dry soils. Most of the forests in the area are young or middle-aged managed forests. The study material was comprised of multi-temporal ERS-2 and ENVISAT synthetic aperture radar (SAR) data. The images had been taken between the years 2001 and 2008. The field data consisted 16 sample plots which had been measured seven times between the years 2002 and 2009. In addition, eight sample plots were added afterwards to places which were known to have had cuttings during the study period. Three methods were tested to estimate Scots pine defoliation: unsupervised k-means clustering, supervised linear discriminant analysis (LDA) and logistic regression. In addition, it was assessed if harvested areas could be differentiated from the defoliated forest using the same methods. Two different speckle filters were used to determine the effect of filtering on the SAR imagery and subsequent results. The logistic regression performed best, producing a classification accuracy of 81.6% (kappa 0.62) with two classes (no defoliation, >20% defoliation). LDA accuracy was with two classes at best 77.7% (kappa 0.54) and k-means 72.8 (0.46). In general, the largest speckle filter, 5 x 5 image window, performed best. When additional classes were added the accuracy was usually degraded on a step-by-step basis. The results were good, but because of the restrictions in the study they should be confirmed with independent data, before full conclusions can be made that results are reliable. The restrictions include the small size field data and, thus, the problems with accuracy assessment (no separate testing data) as well as the lack of meteorological data from the imaging dates.
  • Mukrimin, Mukrimin; Kovalchuk, Andriy; Ghimire, Rajendra P.; Kivimaenpaa, Minna; Sun, Hui; Holopainen, Jarmo K.; Asiegbu, Fred O. (2019)
    Main conclusion Two terpene compounds and four genes were identified as potential biomarkers for further evaluation for Scots pine susceptibility or tolerance against Heterobasidion annosum. Scots pine (Pinus sylvestris) is one of the main sources of timber in the boreal zone of Eurasia. Commercial pine plantations are vulnerable to root and butt rot disease caused by the fungus Heterobasidion annosum. The pathogen affects host growth rate, causes higher mortality and decreases in timber quality, resulting in considerable economic losses to forest owners. Genetic and biochemical factors contributing to Scots pine tolerance against H. annosum infection are not well understood. We assessed the predictive values of a set of potential genetic and chemical markers in a field experiment. We determined the expression levels of 25 genes and the concentrations of 36 terpenoid compounds in needles of 16 Scots pine trees randomly selected from a natural population prior to artificial infection. Stems of the same trees were artificially inoculated with H. annosum, and the length of necrotic lesions was documented 5 months post inoculation. Higher expression level of four genes included in our analysis and encoding predicted alpha-pinene synthase (two genes), geranyl diphosphate synthase (GPPS), and metacaspase 5 (MC5), could be associated with trees exhibiting increased levels of necrotic lesion formation in response to fungal inoculation. In contrast, concentrations of two terpenoid compounds, beta-caryophyllene and alpha-humulene, showed significant negative correlations with the lesion size. Further studies with larger sample size will help to elucidate new biomarkers or clarify the potential of the evaluated markers for use in Scots pine disease resistance breeding programs.
  • Tienaho, Noora (Helsingin yliopisto, 2021)
    Structural complexity of trees is related to various ecological processes and ecosystem services. It can also improve the forests’ ability to adapt to environmental changes. In order to implement the management for complexity and to estimate its functionality, the level of structural complexity must be defined. The fractal-based box dimension (Db) provides an objective and holistic way to define the structural complexity for individual trees. The aim of this study was to compare structural complexity of Scots pine (Pinus sylvestris) trees measured by two remote sensing techniques, namely, terrestrial laser scanning (TLS) and aerial imagery acquired with unmanned aerial vehicle (UAV). Structural complexity for each Scots pine tree (n=2065) was defined by Db-values derived from the TLS and UAV measured point clouds. TLS produced the point clouds directly whereas UAV imagery was converted into point clouds with structure from motion (SfM) technology. The premise was that TLS provides the best available information on Db-values as the point density is higher in TLS than in UAV, and be-cause TLS is able to penetrate vegetation. TLS and UAV measured Db-values were found to significantly differ from each other and, thus, the techniques did not provide comparable information on structural complexity of individual Scots pine trees. On average, UAV measured Db-values were 5% bigger than TLS measured. The divergence between the TLS and UAV measured Db-values was found to be explained by the differences in the number and distribution of the points in the point clouds and by the differences in the estimated tree heights and number of boxes in the box dimension method. Forest structure (two thinning intensities, three thinning types and a control group) significantly affected the variation of both TLS and UAV measured Db-values. However, the divergence between TLS and UAV measured Db-values remained in all the treatments. In terms of the individual tree detection, the number of obtained points in the point cloud, and the distribution of these points, UAV measurements were better when the forest structure was sparser. In conclusion, while aerial imaging is a continuously developing study area and provides many advantageous attributes, at the moment, the TLS methods still dominate in accuracy when measuring the structural complexity at the tree-level. In the future, it should be studied whether TLS and UAV could be used as complementary techniques to provide more accurate and holistic view of the structural complexity in the perspective of both tree- and stand-level.
  • Päivänen, Juhani (Suomen metsätieteellinen seura, 1973)
  • Leikola, Matti (Suomen metsätieteellinen seura, 1967)
  • Mäki, Mari; Ryhti, Kira; Fer, Istem; Ťupek, Boris; Vestin, Patrik; Roland, Marilyn; Lehner, Irene; Köster, Egle; Lehtonen, Aleksi; Bäck, Jaana; Heinonsalo, Jussi; Pumpanen, Jukka; Kulmala, Liisa (2022)
    Northern forest soils are a major carbon (C) reservoir of global importance. To estimate how the C balance in these soils will change, the roles of tree roots and soil microbes in C balance should first be decoupled. This study determined how the activity of heterotrophs and tree roots together with root-associated microbes in the rhizosphere varies in coniferous forest soils in boreal, hemiboreal, and temperate climates along a latitudinal gradient using a trenching approach. We created experimental plots without living tree roots, measured soil respiration (CO2 efflux) from these and from unmanipulated plots using the chamber technique, and partitioned the efflux into root-rhizosphere (RR) and heterotrophic (RH) respiration. The share of RR in ecosystem gross primary production (GPP) decreased from north to south in the Scots pine (Pinus sylvestris L.) and the Norway spruce (Picea abies (L.) Karst.) forests, with the exception of a mixed site, where the share of RR in GPP varied strongly between the years. RR per ground area and per root biomass were mainly independent of climate within the gradient. RH per ground area increased from north to south with temperature, while RH per soil C did not change with temperature. Soil moisture did not significantly affect the respiration components in the northernmost site, whereas soil moisture was positively connected with RH and negatively with RR in other Scots pine sites and positively connected with RR in pure Norway spruce stands. The dynamic ecosystem model LPJ-GUESS was able to capture the seasonal dynamics of RH and RR at the sites, but overall accuracy varied markedly between the sites, as the model underestimated RH in the southern site and RR elsewhere. Our study provides knowledge about the nature of soil respiration components. The valuable insights can be used in more accurate land-ecosystem modelling of forest ecosystems.
  • Rajewicz, Paulina A.; Atherton, Jon; Alonso, Luis; Porcar-Castell, Albert (2019)
    Successful measurements of chlorophyll fluorescence (ChlF) spectral properties (typically in the wavelength range of 650-850 nm) across plant species, environmental conditions, and stress levels are a first step towards establishing a quantitative link between solar-induced chlorophyll fluorescence (SIF), which can only be measured at discrete ChlF spectral bands, and photosynthetic functionality. Despite its importance and significance, the various methodologies for the estimation of leaf-level ChlF spectral properties have not yet been compared, especially when applied to leaves with complex morphology, such as needles. Here we present, to the best of our knowledge, a first comparison of protocols for measuring leaf-level ChlF spectra: a custom-made system designed to measure ChlF spectra at ambient and 77 K temperatures (optical chamber, OC), the widely used FluoWat leaf clip (FW), and an integrating sphere setup (IS). We test the three methods under low-light conditions, across two broadleaf species and one needle-like species. For the conifer, we characterize the effect of needle arrangements: one needle, three needles, and needle mats with as little gap fraction as technically possible. We also introduce a simple baseline correction method to account for non-fluorescence-related contributions to spectral measurements. Baseline correction was found especially useful in recovering the spectra nearby the filter cut-off. Results show that the shape of the leaf-level ChlF spectra remained largely unaffected by the measurement methodology and geometry in OC and FW methods. Substantially smaller red/far-red ratios were observed in the IS method. The comparison of needle arrangements indicated that needle mats could be a practical solution to investigate temporal changes in ChlF spectra of needle-like leaves as they produced more reproducible results and higher signals.
  • Tarvainen, Lasse; Wallin, Goran; Linder, Sune; Nasholm, Torgny; Oren, Ram; Lofvenius, Mikaell Ottosson; Rantfors, Mats; Tor-Ngern, Pantana; Marshall, John D. (2021)
    Several studies have suggested that CO2 transport in the transpiration stream can considerably bias estimates of root and stem respiration in ring-porous and diffuse-porous tree species. Whether this also happens in species with tracheid xylem anatomy and lower sap flow rates, such as conifers, is currently unclear. We infused C-13-labelled solution into the xylem near the base of two 90-year-old Pinus sylvestris L. trees. A custom-built gas exchange system and an online isotopic analyser were used to sample the CO2 efflux and its isotopic composition continuously from four positions along the bole and one upper canopy shoot in each tree. Phloem and needle tissue C-13 enrichment was also evaluated at these positions. Most of the C-13 label was lost by diffusion within a few metres of the infusion point indicating rapid CO2 loss during vertical xylem transport. No C-13 enrichment was detected in the upper bole needle tissues. Furthermore, mass balance calculations showed that c. 97% of the locally respired CO2 diffused radially to the atmosphere. Our results support the notion that xylem CO2 transport is of limited magnitude in conifers. This implies that the concerns that stem transport of CO2 derived from root respiration biases chamber-based estimates of forest carbon cycling may be unwarranted for mature conifer stands.