Aleksi Lehtonen

Aleksi Lehtonen
Natural Resources Institute Finland (Luke) · Management and Production of Renewable Resources

Dr.

About

119
Publications
34,219
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
3,386
Citations
Citations since 2016
58 Research Items
2090 Citations
20162017201820192020202120220100200300400
20162017201820192020202120220100200300400
20162017201820192020202120220100200300400
20162017201820192020202120220100200300400
Additional affiliations
January 2015 - present
Natural Resources Institute Finland (Luke)
Position
  • Group Leader
May 2001 - January 2015
Finnish Forest Research Institute
Position
  • Senior Researcher

Publications

Publications (119)
Article
Full-text available
There is evidence that carbon fluxes and stocks decrease with increasing latitude in boreal forests, suggesting a reduction in carbon use efficiency. While vegetation and soil carbon dynamics have been widely studied, the empirical finding that ectomycorrhizal fungi (ECM) become more abundant towards the north has not been quantitatively linked to...
Preprint
Full-text available
Aim: Linking local population dynamics and species distributions is critical to predicting the impacts of climate change. While many studies focus on the mean fitness of populations, theory shows that species distributions can be shaped by demographic stochasticity or population resilience. Here we examine how mean fitness (measured by invasion rat...
Article
Full-text available
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 varie...
Preprint
Full-text available
Forest characteristics vary largely at the regional level and in smaller geographic areas in Finland. The amount of greenhouse gas emissions is related to changes in biomass and the soil type (e.g. upland soils vs. peatlands). Forest characteristics affect forest management practices and how vulnerable single stands are to disturbances. Spatially a...
Article
Aim The population processes that drive tree species distribution are still widely debated. We test the hypotheses that metapopulation processes of colonization and extinction are linked to predictions of species distribution models. Location Europe: Spain, France, Germany, Finland and Sweden. Taxon Angiosperms and Gymnosperms. Methods For 17 tr...
Article
Full-text available
Offsetting nation-wide CO2 emissions by carbon sinks from land use change (LUC), e.g. agricultural fields extensification and afforestation, is considered as a major climate change mitigation option. We evaluated the LUC potential for reducing emissions and creating annual soil and ecosystem carbon sinks in Finland. We used agricultural statistics,...
Article
Information on carbon stocks and the rate of carbon accumulation is needed to harness the climate change mitigation potential of boreal forests. While previous studies have revealed general patterns and mechanisms for age-dependence of stand biomass, simple stand-level models that address the age-biomass relationship on average in managed boreal fo...
Article
Full-text available
[This corrects the article DOI: 10.1371/journal.pone.0254876.].
Article
We used a simulation model to analyse the effect of continuous-cover forestry on the carbon dioxide (CO2) and methane (CH4) emissions from nutrient-rich drained peatland sites in southern Finland. The simulation scenarios were constructed by varying harvesting interval and post-harvest basal area in a typical mature Norway spruce (Picea abies (L.)...
Article
The changing forest disturbance regimes emphasize the need for improved damage risk information. Here, our aim was to (1) improve the current understanding of snow damage risks by assessing the importance of abiotic factors, particularly the modelled snow load on trees, versus forest properties in predicting the probability of snow damage, (2) prod...
Article
Full-text available
Root rot, caused by the decay fungus Heterobasidion annosum, damages both below- and above-ground parts of Scots pines (Pinus Sylvestris L.). The diseased pines are often first characterized by deteriorated crowns and they will eventually be killed by the infection, but the process is gradual and difficult to be observed before the symptoms are sev...
Article
Aim Tree mortality is increasing world‐wide, leading to changes in forest composition and altering global biodiversity. Nonetheless, owing to the multifaceted stochastic nature of tree mortality, large‐scale spatial patterns of mortality across species ranges and their underlying drivers remain difficult to understand. Our main goal was to describe...
Article
Full-text available
Background and Aims Branch biomass and other attributes are important for estimating the carbon budget of forest stands and characterizing crown structure. As destructive measuring is time-consuming and labour-intensive, terrestrial laser scanning (TLS) as a solution has been used to estimate branch biomass quickly and non-destructively. However, b...
Article
Full-text available
Forest biomass can be used in two different ways to limit the growth of the atmospheric greenhouse gas (GHG) concentrations: (1) to provide negative emissions through sequestration of carbon into forests and harvested wood products or (2) to avoid GHG emissions through substitution of non-renewable raw materials with wood. We study the trade-offs a...
Preprint
Full-text available
The changing forest disturbance regimes emphasize the need for improved damage risk information. In this study, our aim was to improve the current understanding of snow damage risks by assessing the importance of abiotic factors, particularly the modelled snow load on tree crowns, versus forest properties in predicting the probability of snow damag...
Preprint
Full-text available
Aim Tree mortality is increasing worldwide, leading to changes in forest composition and altering global biodiversity. Yet, due to the multi-faceted stochastic nature of tree mortality, large-scale spatial patterns of mortality across species ranges and their underlying drivers remain difficult to understand. Our main goal is to describe the geogra...
Article
Full-text available
1. Species range limits are thought to result from a decline in demographic performance at range edges. However, recent studies reporting contradictory patterns in species demographic performance at their edges cast doubt on our ability to predict climate change demographic impacts. To understand these inconsistent demographic responses, we need to...
Article
Full-text available
Key message Tree structure equations derived from pipe model theory (PMT) are well-suited to estimate biomass allocation in Scots pine ( Pinus sylvestris L.) and Norway spruce ( Picea abies [L.] Karst.). However, age dependence of parameters should be accounted for when applying the equations. Context Pipe model theory-based (PMT-based) structure...
Article
Full-text available
Contributions from all land‐uses are needed when Ethiopia fulfils its Paris Agreement targets. The magnitude of soil carbon stock and the role of Ethiopian forest soils in climate change mitigation has not yet been clarified. In this study, soil carbon inventory in forests was carried out as a part of the Ethiopia REDD+ program. The performance of...
Article
Full-text available
Climate change is expected to cause major changes in forest ecosystems during the 21 st century and beyond. To assess forest impacts from climate change, the existing empirical information must be structured, harmonised and assimilated into a form suitable to develop and test state-of-the-art forest and ecosystem models. The combination of empirica...
Article
Full-text available
Carbon allocation plays a key role in ecosystem dynamics and plant adaptation to changing environmental conditions. Hence, proper description of this process in vegetation models is crucial for the simulations of the impact of climate change on carbon cycling in forests. Here we review how carbon allocation modelling is currently implemented in 31...
Chapter
Full-text available
Methods to estimate greenhouse gas emissions and removals in the Agriculture, Forestry and Other Land Use (AFOLU) Sector can be divided into two broad categories: 1) methods that can be applied in a similar way for any of the types of land use (i.e., generic methods for Forest Land, Cropland, Grassland, Wetlands, Settlements and Other Land); and 2)...
Chapter
Full-text available
As countries advance in greenhouse gas accounting for climate change mitigation, consistent estimates of aboveground net biomass change are needed. Countries with limited forest monitoring capabilities in the tropics and sub‐ tropics rely on IPCC 2006 default rates, which are values per ecological zone, per continent. Similarly, research into fores...
Article
Full-text available
Drained organic forest soils in boreal and temperate climate zones are believed to be significant sources of the greenhouse gases (GHGs) carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O), but the annual fluxes are still highly uncertain. Drained organic soils exemplify systems where many studies are still carried out with relatively small...
Article
Windstorms cause major disturbances in European forests. Forest management can play a key role in making forests more persistent to disturbances. However, better information is needed to support decision making that effectively accounts for wind disturbances. Here we show how empirical probability models of wind damage, combined with existing spati...
Article
The pipe model approach was compared with foliage biomass models by using the cross-sectional area at the tree crown base for predicting foliage biomass of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.). We evaluated the impacts of site type, fertilization, and climate on the relationship between foliage biomass and cr...
Preprint
Full-text available
Species range limits are thought to result from a decline in demographic performance at range edges. However, recent studies reporting contradictory patterns in species demographic performance at their edges cast doubt on our ability to predict climate change demographic impacts. To understand these inconsistent demographic responses at the edges,...
Article
Full-text available
For decades, ecologists have investigated the effects of tree species diversity on tree productivity at different scales and with different approaches ranging from observational to experimental study designs. Using data from five European national forest inventories (16,773 plots), six tree species diversity experiments (584 plots), and six network...
Preprint
Full-text available
Aim Processes driving current tree species distribution are still largely debated. Attempts to relate species distribution and population demography metrics have shown mixed results. In this context, we would like to test the hypotheses that the metapopulation processes of colonization and extinction are linked to species distribution models. Loca...
Article
Full-text available
Drained organic forest soils in boreal and temperate climate zones are believed to be significant sources of the greenhouse gases (GHG) carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O), but the annual fluxes are still highly uncertain. Drained organic soils exemplify systems where many studies are still carried out with relatively small...
Preprint
Full-text available
Windstorms cause major disturbances in European forests and forest management can play a key role in making forests more persistent to disturbances. However, better information is needed to support decision making that effectively accounts for wind disturbances. Here we show how empirical probability models of wind damage, combined with existing sp...
Article
We can curb climate change by improved management decisions for the most important terrestrial carbon pool, soil organic carbon stock (SOC). However, we need to be confident we can obtain the correct representation of the simultanous effect of the input of plant litter, soil temperature and water (that could be altered by climate or management) on...
Preprint
Full-text available
Aim: Background tree mortality is a complex demographic process that affects forest structure and long-term dynamics. We aimed to test how drought intensity interacts with interspecific and intraspecific competition (or facilitation) in shaping individual mortality patterns across tree species ranges. Location: European latitudinal gradient (Spain...
Article
1.Forest ecosystem functioning generally benefits from higher tree species richness, but variation within richness levels is typically large. This is mostly due to the contrasting performances of communities with different compositions. Evidence‐based understanding of composition effects on forest productivity, as well as on multiple other function...
Conference Paper
Full-text available
Wind damage in Northern European forests is increasing with the changing climate. As the period of winter soil frost shortens, trees are left exposed to strong winds without the anchorage provided by frozen soils. Changes in wind climate are also expected. Forest wind damage causes substantial economic losses and affects the ecosystem services prov...
Article
The Arctic tundra plays an important role in the carbon cycle as it stores 50% of global soil organic carbon reservoirs. The processes (fluxes) regulating these stocks are predicted to change due to direct and indirect effects of climate change. Understanding the current and future carbon balance calls for a summary of the level of knowledge regard...
Article
Full-text available
Accurate carbon-balance accounting in forest soils is necessary for the development of climate change policy. However, changes in soil organic carbon (SOC) occur slowly and these changes may not be captured through repeated soil inventories. Simulation models may be used as alternatives to SOC measurement. The Yasso07 model presents a suitable alte...
Article
Full-text available
Humans require multiple services from ecosystems, but it is largely unknown whether trade-offs between ecosystem functions prevent the realisation of high ecosystem multifunctionality across spatial scales. Here, we combined a comprehensive dataset (28 ecosystem functions measured on 209 forest plots) with a forest inventory dataset (105,316 plots)...
Article
Full-text available
Models attempting to predict treeline shifts in changing climates must include the relevant ecological processes in sufcient detail. A previous correlative model study has pointed to nutrients, competition, and temperature as the most important factors shaping the treelines of Pinus sylvestris L., Picea abies (L.) H. Karst. and Betula pubescens Ehr...
Article
Intense droughts combined with increased temperatures are one of the major threats to forest persistence in the 21(st) century. Despite the direct impact of climate change on forest growth and shifts in species abundance, the effect of altered demography on changes in the composition of functional traits is not well known. We sought to: (1) quantif...
Article
Full-text available
Future climate change will dramatically change the carbon balance in the soil, and this change will affect the terrestrial carbon stock and the climate itself. Earth system models (ESMs) are used to understand the current climate and to project future climate conditions, but the soil organic carbon (SOC) stock simulated by ESMs and those of observa...
Conference Paper
Full-text available
Allocation of carbon to plant organs is considered as one of the most important plant adaptation mechanisms to environmental changes. Several empirical studies presented that carbon partitioning between individual plant organs depends on environmental conditions and stand structure. From the modelling perspective, carbon allocation is one of the cr...
Article
Full-text available
Dynamic soil models are needed for estimating impact of weather and climate change on soil carbon stocks and fluxes. Here, we evaluate performance of Yasso07 and ROMULv models against forest soil carbon stock measurements. More specifically, we ask if litter quantity, litter quality and weather data are sufficient drivers for soil carbon stock esti...
Article
Biodiversity loss and climate-driven ecosystem modification are leading to substantial changes in forest structure and function. However, the effects of diversity on demographic responses to the environment are poorly understood. We tested the diversity hypothesis (measured through functional diversity) and the mass ratio hypothesis (measured throu...
Article
Full-text available
Neglecting tree size and stand structure dynamics might bias the interpretation of the diversity-productivity relationship in forests. Here we show evidence that complementarity is contingent on tree size across large-scale climatic gradients in Europe. We compiled growth data of the 14 most dominant tree species in 32,628 permanent plots covering...
Article
Full-text available
Inaccurate estimate of the largest terrestrial carbon pool, soil organic carbon (SOC) stock, is the major source of uncertainty in simulating feedback of climate warming on ecosystem–atmosphere carbon dioxide exchange by process-based ecosystem and soil carbon models. Although the models need to simplify complex environmental processes of soil carb...
Article
Full-text available
We test whether litter quality, litter quantity and weather data are enough to estimate soil carbon stocks by models. We also test whether inclusion of soil water holding capacity improves soil carbon stock model estimates. Litter input was estimated from stem volume maps provided by the National Forest Inventory, while understorey vegetation was e...
Article
The carbon (C) cycle of forests produces ecosystem services (ES) such as climate regulation and timber production. Mapping these ES using simple land cover -based proxies might add remarkable inaccuracy to the estimates. A framework to map the current status of the C budget of boreal forested landscapes was developed. The C stocks of biomass and so...
Article
Full-text available
Soil carbon dynamics are a key process in the terrestrial carbon cycle. Future climate change will dramatically change the carbon balance in soil, and this change will affect the terrestrial carbon stock and the climate itself. Earth system models (ESMs) are used to understand the current climate and to produce future climate projections, but the s...
Article
The compilation of GHG inventories has become a common practice to support environmental decision- and policy-making, for example in the context of the UNFCCC. To estimate GHG emissions, simulation models present viable alternatives to measured data. In order to make an informed decision on model selection, clear information on the purpose and appl...
Article
The relative contribution of community functional diversity and composition to ecosystem functioning is a critical question in ecology in order to enable better predictions of how ecosystems may respond to a changing climate. However, there is little consensus about which modes of functional biodiversity are most important for tree growth at large...
Article
Full-text available
Boreal forests contain 30% of the global forest carbon with the majority residing in soils. While challenging to quantify, soil carbon changes comprise a significant, and potentially increasing, part of the terrestrial carbon cycle. Thus, their estimation is important when designing forest-based climate change mitigation strategies and soil carbon...