Search results for "Plane"

Nonlinear effects of climate on boreal rodent dynamics: mild winters do not negate high-amplitude cycles

2013

Small rodents are key species in many ecosystems. In boreal and subarctic environments, their importance is heightened by pronounced multiannual population cycles. Alarmingly, the previously regular rodent cycles appear to be collapsing simultaneously in many areas. Climate change, particularly decreasing snow quality or quantity in winter, is hypothesized as a causal factor, but the evidence is contradictory. Reliable analysis of population dynamics and the influence of climate thereon necessitate spatially and temporally extensive data. We combined data on vole abundances and climate, collected at 33 locations throughout Finland from 1970 to 2011, to test the hypothesis that warming winte…

Leaf-Level Spectral Fluorescence Measurements : Comparing Methodologies for Broadleaves and Needles

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 …

Spatio‐temporal patterns of tree growth as related to carbon isotope fractionation in European forests under changing climate

2019

Aim The aim was to decipher Europe‐wide spatio‐temporal patterns of forest growth dynamics and their associations with carbon isotope fractionation processes inferred from tree rings as modulated by climate warming. Location Europe and North Africa (30‒70° N, 10° W‒35° E). Time period 1901‒2003. Major taxa studied Temperate and Euro‐Siberian trees. Methods We characterize changes in the relationship between tree growth and carbon isotope fractionation over the 20th century using a European network consisting of 20 site chronologies. Using indexed tree‐ring widths (TRWi), we assess shifts in the temporal coherence of radial growth across sites (synchrony) for five forest ecosystems (Atlantic…

On the tolerance of charophytes to high-nitrate concentrations

2017

Currently a debate exists about whether the reduced growth of macrophytes with increased nitrogen loading in shallow ecosystems is determined by ecological or physiological factors. To discover whe...

Guidelines for risk management in forest planning – what is risk and when is risk management useful?

2018

Managing forest resources occurs under various sources of uncertainty. Depending on the management problem, this uncertainty may have a substantial impact on the quality of the solution. As our knowledge on the sources and magnitude of uncertainty improves, integrating this knowledge into the development of management plans becomes increasingly useful, as additional information can improve the decision-making process. This adjustment requires a fundamental shift in how planning problems are viewed: instead of interpreting risk management as a technique needed only for addressing problems with natural hazards, risk management should be an integral part of most planning problems. Managing ri…

Potential of using data assimilation to support forest planning

2017

Uncertainty in forest information typically results in economic and ecological losses as a consequence of suboptimal management decisions. Several techniques have been proposed to handle such uncertainties. However, these techniques are often complex and costly. Data assimilation (DA) has recently been advocated as a tool that may reduce the uncertainty, thereby improving the quality of forest planning results. It offers an opportunity to make use of all new sources of information in a systematic way and thus provides more accurate and up-to-date information to forest planning. In this study, we refer to literature on handling uncertainties in forest planning, as well as related literature…

2021

A millennium-long perspective on high-elevation pine recruitment in the Spanish central Pyrenees

2018

Long-term fluctuations in forest recruitment, at time scales well beyond the life-span of individual trees, can be related to climate changes. The underlying climatic drivers are, however, often understudied. Here, we present the recruitment history of a high-elevation mountain pine (Pinus uncinata Ram.) forest in the Spanish central Pyrenees throughout the last millennium. A total of 1108 ring-width series translated into a continuous chronology from 924 to 2014 CE, which allowed estimated germination dates of 470 trees to be compared against decadal-scale temperature variability. High recruitment intensity mainly coincided with relatively warm periods in the early 14th, 15th, 19th, and 2…

Economics of mixed-species forestry with ecosystem services

2019

The Faustmann–Hartman setup is widely established for specifying the economics of forest values besides timber, but it is criticized as restrictive for capturing diversity values. We show that extending the model to cover diversity attributes, i.e., mixed species and internal heterogeneity within species, is not enough to overcome these restrictions. Additionally, it is necessary to extend forest harvesting regimes to cover thinning, continuous cover forestry, and the management of commercially useless trees. Restrictions in the Faustmann–Hartman setup are first shown analytically with optimized thinning but without tree size structures. The empirical significance of these findings is show…

Linking species interactions with phylogenetic and functional distance in European bird assemblages at broad spatial scales

2017

Aim Understanding the relative contribution of different species interactions in shaping community assembly has been a pivotal aim in community ecology. Biotic interactions are acknowledged to be important at local scales, although their signal is assumed to weaken over longer distances. We examine the relationship between positive, neutral and negative pairwise bird abundance distributions and the phylogenetic and functional distance between these pairs after first controlling for habitat associations. Location France and Finland. Time period 1984 to 2011 (Finland), 2001 to 2012 (France). Major Taxa studied Birds. Methods We used results from French and Finnish land bird monitoring program…