Tracer gas studies and oxygen uptake measurements have shown that pressurized gas transport improves oxygen supply to roots in the wetland tree species Taxodium distichum L. Rich. (Taxodiaceae), Betula pubescens J.F. Ehrh. (Betulaceae), and Populus tremula L. (Salicaceae), but not in Acer pseudoplatanus L. and Ilex aquifolium L., which are found in drier habitats. In the deciduous tree species ...

The aim of the study was to create and evaluate models for predicting high levels of daily pollen concentration of Corylus, Alnus, and Betula using a spatiotemporal correlation of pollen count. For each taxon, a high pollen count level was established according to the first allergy symptoms during exposure. The dataset was divided into a training set and a test set, using a stratified random sp...

The aim of the study was to determine the characteristics of temporal and space-time autocorrelation of pollen counts of Alnus, Betula, and Corylus in the air of eight cities in Poland. Daily average pollen concentrations were monitored over 8 years (2001-2005 and 2009-2011) using Hirst-designed volumetric spore traps. The spatial and temporal coherence of data was investigated using the autoco...

In rapidly changing environments species conservation can be hindered by uncertainties in distinguishing closely related species. Cryptic ongoing hybridization add further uncertainty and could beneficial or destructive. Here, we show that a declining birch tree is hybridizing with more widespread relative the Junggar basin, NW China, their hybrids have been previously named as rare sub-species...

Tree roots of northern hardwoods are shallow rooted, winter active, and minimally frost hardened; dieback is a winter freezing injury to roots incited by frost penetration in the absence of adequate snow cover and exacerbated by drought in summer. High soil water content greatly increases conductivity of frost. We develop a model based on the sum of z-scores of soil frost (December–February) an...

Klebs (12) reported in 1914 that the growth of beach, oak, ash, and hornbeam could be maintained even in winter if they were placed under continuous electric light. Since Klebs' report on the effect of day length on the growth of woody plants, there have been many studies pertaining to photoperiodism and dormancy in woody plants. They were amply reviewed by Samish (21), Wareing (24,26), and Nit...

A detailed, well-dated record of pollen and sedimentary ancient DNA (sedaDNA) for the period 15 000–9500 cal a bp describes changes at Lake Bolshoye Shchuchye in Polar Ural Mountains, located far east classical Lateglacial sites western Europe. Arctic tundra rapidly changed to lusher vegetation, possibly including both dwarf (Betula nana) tree birch (B. pubescens), dated our take place 14 565 b...