Efficiency of growth biostimulators in production of planting material of northern white cedar

An assessment of the efficacy of preparations (Kornevin, SP; Albit, TPS; Epin-extra) in the production of planting material of Northern white cedar by vegetative propagation with wood cuttings under the conditions of the Central Black Earth Region of the Russian Federation is given on the example of the Orel region. All the studied preparations had a significant effect on the rooting process of cuttings. The obtained and analyzed data of phenological observations showed that the greatest effect on the acceleration of the onset of the of root formation phase had preparation “Albit, TPS”, 3-4 weeks earlier than the control. The number of formed cuttings and their length were also mainly influenced by “Albit, TPS”, which increased the average number of roots by 3 pcs., and their average length by 44 mm, in comparison with the control. The effect of the use of the biostimulator “Albit, TPS” had a significant influence on the number of established cuttings, providing 20 rooted cuttings or 28% more than in the control.

The Northern White-Cedar Recruitment Bottleneck: Understanding the Effects of Substrate, Competition, and Deer Browsing

Research Highlights: Regenerating northern white-cedar (Thuja occidentalis L.) is challenging throughout much of its range. This study attempts to relate differences in natural regeneration to stand- and seedbed-level factors. Background and Objectives: Lack of regeneration of northern white-cedar is often attributed to overbrowsing by white-tailed deer (Odocoileus virginianus Zimmerman) because white-cedar is a preferred winter browse species. However, there are many other factors that may contribute to regeneration failure for white-cedar including its specific seedbed requirements and competition from other, often faster-growing trees and shrubs. Materials and Methods: We surveyed five mature white-cedar stands in Wisconsin, USA that have had little to no management in the past 50+ years to find stem densities of natural white-cedar regeneration in three height classes. We also collected data at each stand on potential predictor variables including overstory attributes, competitive environment, seedbed, and browsing by deer. We used model selection to create separate models to predict stem density of each white-cedar regeneration height class. Results: None of the measures of deer browsing used in this study were found to be associated with white-cedar regeneration. Soil pH, competition from other seedlings and saplings, and stem density of white-cedar in the overstory were found to be potentially associated with white-cedar regeneration. Conclusions: While browsing by deer is likely a factor affecting white-cedar regeneration in many areas, this study highlights the challenge of quantifying deer browse effects, as well as showing that other factors likely contribute to the difficulty of regenerating white-cedar.

Small Roadside Sacral Structures in the Borzechów Commune (Lublin Region) and Their Dendroflora

Trees and shrubs significantly increase the visual value of roadside crosses and shrines. The paper presents results of the inventory of small roadside sacral structures in Borzechów Commune (Central-Eastern Poland). The species composition and the age status of dendroflora surrounding small roadside sacral structures were examined. We have inventoried 94 small roadside sacral structures in Borzechów Commune. Only 68 of them were surrounded by trees and shrubs that represent 39 species. The most common deciduous species are small leaved lime (Tilia cordata Mill.) and common lilac (Syringa vulgaris L.), but the most common coniferous species is northern white-cedar (Thuja occidentalis L.). In the research area the most common small roadside sacral structures are crosses. Shrines and statues of saints are very rare.

Variations in northern white-cedar (Thuja occidentalis) regeneration following operational selection cutting in mixedwood stands of western Quebec

Poorly adapted silvicultural practices and increases in white-tailed deer (Odocoileus virginianus (Zimmerman, 1780)) populations have most likely contributed to the decline of northern white-cedar (Thuja occidentalis L.) in many regions of eastern North America. Selection cutting has been suggested to regenerate northern white-cedar in mixedwood stands, but the approach has not yet been validated in an operational framework. The objective of this study was to determine how local variations in stand condition and treatment application influence northern white-cedar regeneration at an operational scale in mixedwood stands. Seventy treated and control permanent plots, having at least 10% of basal area in cedar, were selected in an operational harvesting site. A regeneration survey was conducted in 2014, 15 to 20 years after harvesting, and data on harvested trees and tree cover, as well as regeneration state and abundance, were collected. Results indicate that selection cutting allows for the establishment of northern white-cedar when deer densities are low, which was the case in the study sites. However, abundance of seed trees nearby, harvesting intensity, competition, and availability of establishment microsites influenced abundance, growth, and recruitment of northern white-cedar seedlings and saplings in the residual stand. Deer browsing had no effect on regeneration.