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

Forests ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 501 ◽  
Author(s):  
Laura F. Reuling ◽  
Christel C. Kern ◽  
Laura S. Kenefic ◽  
Dustin R. Bronson

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.

2019 ◽  
Vol 22 (1) ◽  
pp. 23-28
Author(s):  
Magdalena Lubiarz ◽  
Piotr Kulesza ◽  
Małgorzata Żak-Kulesza

Abstract 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.


1996 ◽  
Vol 26 (3) ◽  
pp. 389-393 ◽  
Author(s):  
Rodney A. Chimner ◽  
James B. Hart

Many harvested northern white-cedar (Thujaoccidentalis L.) sites have not regenerated to cedar but have become dominated by other species such as balsam fir (Abiesbalsamea (L.) Mill.) and tag alder (Alnusrugosa (Du Roi) Spreng.) A regenerating cedar fen near Escanaba, Mich., was used to study factors related to regeneration success and failure. Twelve plots (6.1 × 6.1 m) were established on the site to collect data on hydrology, microtopography, stand composition, and stem density. Abundance of cedar regeneration was positively correlated with percentage of hummocks. There were more cedar on microsites with drier conditions (numerous hummocks) while more shrubs and hardwoods were found on the wetter areas (fewer hummocks) of the fen. The shallow depth to groundwater and unsaturated soil thickness early in the growing season are suggested to be factors.


Forests ◽  
2014 ◽  
Vol 5 (6) ◽  
pp. 1194-1211 ◽  
Author(s):  
Jean-Claude Ruel ◽  
Jean-Martin Lussier ◽  
Sabrina Morissette ◽  
Nicolas Ricodeau

Forests ◽  
2017 ◽  
Vol 8 (9) ◽  
pp. 326 ◽  
Author(s):  
Olivier Villemaire-Côté ◽  
Jean-Claude Ruel ◽  
Luc Sirois

2011 ◽  
Vol 41 (3) ◽  
pp. 568-582 ◽  
Author(s):  
Catherine Larouche ◽  
Jean-Claude Ruel ◽  
Jean-Martin Lussier

Regeneration of northern white-cedar ( Thuja occidentalis L.) is often deficient after harvesting in mixedwood stands growing on mesic sites even where browsing pressure is low. We compared the effectiveness of silviculture treatments on early regeneration of white-cedar after single-tree selection cutting (25% of basal area removed), shelterwood seed cut (50% of basal area removed), and group selection cutting (gaps of 625 m2) in three yellow birch ( Betula alleghaniensis Britt.) – softwood uneven-aged stands in Quebec, Canada. Three years after harvesting, the combination of factors that maximized abundance of white-cedar seedlings was single-tree selection cutting with artificial seeding on exposed mineral seedbeds (68.8% of plots with the presence of white-cedar). Early growth of planted white-cedar seedlings (40 cm tall) and biomass production were proportional to light availability, i.e., best under group selection cutting (mean height increment = 14.8 cm/year, mean root collar diameter increment = 3.0 mm/year). Browsing pressure has regional impacts depending on herbivore occupancy of the area. Our study was conducted near the northern limit of white-tailed deer ( Odocoileus virginianus (Zimmerman, 1780)), and deer were locally absent, while snowshoe hare ( Lepus americanus Erxleben, 1777) did not have a consistent effect on seedling abundance and early survival, limiting height growth only during the first year following planting.


2018 ◽  
Vol 48 (11) ◽  
pp. 1311-1319 ◽  
Author(s):  
Laurence Saucier ◽  
Jean-Claude Ruel ◽  
Catherine Larouche

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.


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