Allelopathy: A Potential Cause of Forest Regeneration Failure

Author(s):  
Richard F. Fisher
2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Kevin J. Barrett ◽  
Oswald J. Schmitz

Elevated deer densities have led to reports of forest regeneration failure and ecological damage. However, there is growing evidence that the biophysical conditions of a forest that make it attractive to deer may be a contributing factor in determining browsing levels. Thus, an understanding of settling stimulus—how attractive an area is to deer in terms of food-independent habitat requirements—is potentially important to manage deer browsing impacts. We tested the settling stimulus hypothesis by evaluating the degree to which thermal settling stimulus and deer density are related to spatial variation in browsing intensity across different forest harvesting strategies over the course of a year. We determined if deer were impacting plant communities and if they resulted in changes in plant cover. We quantified the thermal environment around each harvest and tested to see if it influenced deer density and browsing impact. We found that deer had an impact on the landscape but did not alter plant cover or diminish forest regeneration capacity. Deer density and browse impact had a relationship with thermal settling stimulus for summer and fall months, and deer density had a relationship with browse impact in the winter on woody plants. We conclude that thermal settling stimulus is an important predictor for deer density and browsing impact.


2018 ◽  
Vol 48 (1) ◽  
pp. 58-67 ◽  
Author(s):  
Jeffrey S. Ward ◽  
Scott C. Williams ◽  
Megan A. Linske

While both chronic white-tailed deer (Odocoileus virginianus Zimmermann) overbrowsing and invasive shrubs have been linked to native regeneration failure in temperate hardwood forests, little is known of their relative importance and possible synergistic effects. Therefore, we established three study areas in Connecticut to examine the interaction of three levels of invasive shrub control and absence or presence of deer herbivory on forest regeneration over 9 years. Five observations suggest that obtaining forest regeneration requires a comprehensive management strategy. First, competitive interference by invasive shrubs in intact thickets continued to impede forest regeneration, especially taller seedlings, after deer were excluded. Second, density of small seedlings increased following removal of the competitive interference by invasive shrubs. Third, deer browsing depressed growth of small seedlings into taller height classes. Fourth, preferential browsing reduced species richness, especially in taller seedling classes, by favoring growth of low palatability species such as beech. Lastly, if a disturbance (e.g., cutting) does not kill the root system of the invasive shrubs, the window of forest regeneration recruitment may be narrow because invasive shrubs can quickly recover. In stands with both established shrub thickets and high deer densities, invasive shrub control and multiyear reduction of deer densities are both recommended to obtain adequate forest regeneration.


Author(s):  
Nick A. Povak ◽  
Derek J. Churchill ◽  
C. Alina Cansler ◽  
Paul F. Hessburg ◽  
Van R. Kane ◽  
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2009 ◽  
Vol 160 (8) ◽  
pp. 232-234
Author(s):  
Patrik Fouvy

The history of the forests in canton Geneva, having led to these being disconnected from productive functions, provides a symptomatic demonstration that the services provided by the forest eco-system are common goods. Having no hope of financial returns in the near future and faced with increasing social demands, the state has invested in the purchase of forest land, financed projects for forest regeneration and improvement of biological diversity and developed infrastructures for visitors. In doing this the state as a public body takes on the provision of services in the public interest. But the further funding for this and for expenses for the private forests, which must be taken into account, are not secured for the future.


1999 ◽  
Vol 150 (7) ◽  
pp. 249-251
Author(s):  
Heinz Kuhn

As in many parts of the Swiss Central Plateau, vast coppices with standards have grown in the region of Diessenhofen for centuries. While in other parts of the first decades of the 20th century the forests were converted to areas of forest regeneration species, the foresters of the Diessenhofen region altered numerous pillaged coppices with standards to a stratified continuous forest. The advantages of this form of management such as species and structure diversity and lower costs in comparison with the forest stratified by age are being presented. Each of the four foresters in the region has formed different stand images through his personal intervention intensity. There are different ways possible for achieving a continuous forest, in order to prove this, differences of managing a selection forest system are carried out by the four regional foresters. After decades of experience in tending stands established out of former coppices with standards, the approach of converting plenter forests from existing forests stratified by age to stratified continuous forests is experienced. The successes also encouraged the foresters of the neighbouring district Steckborn to do the same. This creative task is being accompanied scientifically by the WSL (Federal Institute of Forest, Snow and Landscape Research, Birmensdorf, Switzerland), which has established permanent observation areas. The steps in the previously intuitive procedure can, therefore, now be traced.


1983 ◽  
Vol 49 ◽  
Author(s):  
M. Van Miegroet

Spontaneous  natural regeneration under variable conditions on sandy soils and continental  sand dunes were analysed in 5 locations in N.E. Belgium.     The number of seedlings varies between 14.000 and 522.000/ha. The most  prominent invading species are red oak, pedunculate oak and Scots pine.    Two principal types of regeneration are recognized : homogeneous groups of  oak or pine and mixtures, predominantly composed by the same species.  Pioneers such as birch, willow, white poplar and wild black cherry do not  play an important role.    Social differentiation sets in quite early and is mainly provoked by age  differences. Therefore early silvicultural intervention is advisable. The  growth relationships between the species indicate that Scots pine is not in  danger of spontaneous elemination by other species. Because of the density  and variability of spontaneous forest regeneration, the conversion of pure  pine stands into mixed forest, using group regeneration to this end, poses no  real technical problems.


Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 593
Author(s):  
Janet E. Nichol ◽  
Sawaid Abbas

Global trends predict a continuous increase in the proportion of forest occupied by plantations up to the end of the 21st century, while a dramatic loss of biodiversity is foreseen as a result of anthropogenic exploitation and climate change. This study compares the role and performance of plantation policies in Hong Kong, with natural regeneration of secondary forest, using detailed spatio-temporal data extracted from a previous study. The study extends over a 70-year period from 1945 to 2014 using aerial photographs and satellite images of five time periods to document spatio-temporal trends in plantation forestry and natural forest succession. Field data on species richness and woody biomass at different stages of forest succession are compared with available data from plantations in the same study area. Results indicate that plantation forests support relatively few native species in the understory, with much lower species richness than naturally regenerated forest, even after 6 to 7 decades. Time-sequential maps of habitat change show that natural forest succession from barren grassy hillsides, progressed at an annual rate of 7.8%, from only 0.2% of the landscape post WWII, to over 37% today. Plantation forestry on the other hand has been less successful, and has even acted as a barrier to natural forest regeneration, as mono-cultural plantations from the late 1960s to 1980s are still plantations today, whereas other similar areas have succeeded naturally to forest. The theory of plantations acting as a nurse crop for a woody native understory is not supported, as Pinus massoniana plantations, destroyed by two deadly nematodes during the 1970s, apparently had no woody understory, as they were seen to have reverted to grassland in 1989 and are still mainly grassland today.


Human Ecology ◽  
2021 ◽  
Author(s):  
Adam Pain ◽  
Kristina Marquardt ◽  
Dil Khatri

AbstractWe provide an analytical contrast of the dynamics of secondary forest regeneration in Nepal and Peru framed by a set of common themes: land access, boundaries, territories, and rights, seemingly more secure in Nepal than Peru; processes of agrarian change and their consequences for forest-agriculture interactions and the role of secondary forest in the landscape, more marked in Peru, where San Martín is experiencing apparent agricultural intensification, than in Nepal; and finally processes of social differentiation that have consequences for different social groups, livelihood construction and their engagement with trees, common to both countries. These themes address the broader issue of the necessary conditions for secondary forest regeneration and the extent to which the rights and livelihood benefits of those actively managing it are secured.


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