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Optimizing Early Successional Habitat to Support
Biodiversity in the Acadian Forest Region
by
Michael Speelman
A thesis submitted in conformity with the requirements for the degree of Master of Forest Conservation
Faculty of Forestry University of Toronto
© Copyright by Michael Speelman, 2018
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Optimizing early successional habitat to support biodiversity in the
Acadian forest region
Michael Speelman
Master of Forest Conservation
Faculty of Forestry University of Toronto
2018
Abstract
Early successional forest area a critical habitat for many forest species. They are a
natural part of forest ecosystems resulting from disturbances like wind storms and fires.
Unique early successional forest features like dense, low vegetation and high fruit
production attract a variety of generalist and early successional specialist species.
Particularly, many bird species nest and feed in these habitat types. Early successional
forest habitats are slowly declining throughout the province of Prince Edward Island
largely due to the reforestation of agricultural lands. Due to this decline in available
habitat, some species dependant on early successional forest are now of concern. To
address this problem, a review of literature was conducted to inform management
recommendations on how to best create and maintain early successional habitat to
support the wildlife that relies on it for the Macphail Woods Ecological Forestry Project,
which manages 2000 acres of public land.
ii
Acknowledgements
I would like to thank my academic supervisor, Dr. John Caspersen, for his guidance and
help throughout my capstone. I would also like to thank my external examiner, Gary
Schneider, for helping me to develop a capstone topic stemming from my internship, for
mentoring me during my time at Macphail Woods and this project, and for introducing
me to the field of forestry in the first place. Finally, I would like to thank my fiancée,
Cadence, for supporting me through each step of this process.
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Table of Contents
Page Number Introduction……………………………………………… 1-5 Methods…………………………………………………. 5 Results…………………………………………………… 5-12 Recommendations……………………………………… 12 Bibliography……………………………………………… 13-16
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1. Introduction
1.1 Historical forest of Prince Edward Island
Prince Edward Island, the smallest province in Canada (5660 km2), is located in the Gulf of St.
Lawrence and its native forests are often referred to as the Acadian forest type (Weighs, 1995;
Catling et al, 1985; McAskill, 1987). The Acadian forest originally found in the province was
primarily composed of sugar maple (Acer saccharum), American beech (Fagus grandifolia), red
spruce (Pincea rubens), white pine (Pinus strobus), yellow birch (Betula alleghaniensis), and
eastern hemlock (Tsuga canadensis), along with balsam fir (Abies balsamea) and a variety of
other species in lower densities (Catling et al, 1985; McAskill, 1987). After centuries of
European settlement in the province, over 70% of the Acadian forest had been harvested and
much of it repurposed for agricultural land (PEI Department of Agriculture and Forestry, 1997).
The 30% that had remained was largely degraded and fragmented by road networks, agricultural
land, and logging (Sobey and Glen, 1999; Sobey, 2002; McAskill, 1987). Over time, largely due
to the abandonment of farmland and efforts of the provincial government, the forest cover of the
province increased to 50%, but less than half of that forest cover is considered to representative
of the natural Acadian forest type and much of that is degraded to varying degrees (PEI
Department of Agriculture and Forestry, 1997; Sobey and Glen, 1999; Sobey, 2002).
In December of 2005, the Department of Environment, Energy, and Forestry turned over
management of 2000 acres of public forest land to the Macphail Woods Ecological Forestry
Project to restore the native Acadian forest and to demonstrate sustainable forest management
(Macphail Woods Ecological Forestry Project, 2017). The Macphail Woods Ecological Forestry
Project is an environmental non-profit that aims to combine protection of natural areas with
environmental education, watershed protection, wildlife enhancement, forest stewardship, and
ecological research (Macphail Woods Ecological Forestry Project, 2017). Throughout these
managed forests almost all of the stands, whether old growth forest, reforested agricultural land,
second-growth forest, or softwood plantation, are in the age range of 20-100 years (Macphail
Woods Ecological Forestry Project, 2017). Typically, about 15 years after a disturbance (clearcut,
fire, etc) a forest canopy establishes, beginning the elimination of the characteristics of early
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successional forest and the habitat that early successional species rely on (Aber, 1979; Latham,
2003; Schlossberg and King, 2009). Less than three percent of the managed forest stands have
been clearcut in the past 15 years and there has been essentially no forests clearcut in the last ten
years due to the management practices of Macphail Woods, which generally only harvests timber
through single-tree selection or very small patch cuts (<30 m diameter) and there have been no
stands consumed by fire along with little wind throw disturbance (Macphail Woods Ecological
Forestry Project, 2017). A similar trend can be seen across the province, as early successional
habitats are slowly becoming less common, primarily due to the reforestation of agricultural land
and old, abandoned fields returning to forests (Environment Canada, 2013).
1.2 Early successional/shrub dominated forest types
An early successional forest type is a site where the dominating vegetative species are
herbaceous, shrubs, and/or trees in the seedling/sapling stage, starting after a disturbance and
continuing until canopy closure, typically about 15 years later (Litvaitis, 2003; Lormier and
White, 2003; Aber, 1979). An alternative, more common term used to describe this forest type is
a ‘thicket’ (Litvaitis, 2003). Early successional forest occurs throughout forest landscapes
because of natural disturbances such as fire, windthrow, and insect outbreaks (Lormier and
White, 2003). While it is difficult to establish a baseline of the amount of natural early
successional forest that should be present on a landscape due to several historical factors, such as
First Nations land management practices and European agricultural land usage, it is estimated
that between 2.4% and 7.1% of forest land would typically have been disturbed within the last 15
years, ‘restarting’ the successional process (Lormier and White, 2003). The largest historical
driver of forest disturbances was windthrow, with disturbances ranging from <1 to 700 hectares
in size, but less windthrow disturbance than the historical average is experienced in the modern
forest (Lormier and White, 2003). This is principally because windthrow disturbance is less
common in younger stands and the age of stands in Macphail Woods and Prince Edward Island
are relatively young due to historical management practices (Lormier and White, 2003; Macphail
Woods, 2017; Rich et al, 2007; Department of Agriculture and Forestry, 2010). While the
percentage of early successional forest in Macphail Woods managed forests still falls within this
range (2.8%), this number will likely fall below the 2.4% threshold, as the managed forests have
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almost no large disturbances within the last decade (Macphail Woods Ecological Forestry
Project, 2017).
Shrub dominated areas can sometimes persist for long periods of time in a single location instead
of following the typical successional stages of the surrounding forest (Latham, 2003). This can
often be attributed to environmental factors that favor the shrubby plants rather than mature
forest trees, such as the presence of a ‘frost pocket’, poor soils, or regularly occurring fires
(Latham, 2003). More recently, researchers have also begun to suspect some persistent dominant
shrub species of creating positive feedback loops that favors shrubland, such as shrubs that
acidify soil over time and are also tolerant of acidified soil (Latham, 2003).
The early successional and/or shrub dominated forest type plays an important role in forest
ecosystems, providing conditions that support a variety of both floral and faunal species (Howard
and Lee, 2003; King et al., 2001; Litvaitis, 2001; Schlossberg and King, 2009). While often
species associated with early successional habitats were thought of as generalist species, research
has begun to show that the converse is more accurate: most of the early successional species are
specialists in their requirements for the specific habitat type and focus has been turning to many
of these species as concern grows with the loss early successional habitat throughout much of
north-eastern North America (De Graaf and Yamasaki, 2003). Many bird species are only found
in early successional habitats due to needs for nesting or feeding. Trends in populations show
significant changes shortly after disturbances, with many species of bird completely disappearing
from an area less than 20 years following a disturbance, some beginning to decline as soon as
three years post-disturbance (Schlossberg and King, 2009).
Many plant species occur in early successional habitat that aren’t found in later successional
stages of forest. Species richness of tree, shrubs, and herbaceous vegetation is highest in sites
less than fifteen years after a disturbance, with a large part of these species tending to propagate
using animal-dispersed fleshy fruits (Howard and Lee, 2003). This vegetative species richness in
early successional forests is related to the amount of sunlight available near the ground, which
tends to decrease with time as forest canopies shade out the ground below and correlates with the
reduction in species richness (Howard and Lee, 2003).
Many faunal species also rely on early successional and/or shrub dominated forest land. Avian
species richness peaks approximately ten years after a disturbance and decreases over time as
4
succession towards a closed canopy forest continues (Schlossberg and King, 2009). A significant
factor in the decrease of avian species richness with the progression of succession is that many of
these species tend to build their nests on or near the ground and many often rely on the shrub
layer to forage for insects (Schlossberg and King, 2009). There are eleven bird species that rely
on shrublands that are listed as priority species in Environment Canada’s Bird Conservation
Strategy: American redstart, American woodcock, black-billed cuckoo, brown-headed cowbird,
eastern kingbird, mourning warbler, rose-breasted grosbeak, veery, white-throated sparrow,
common nighthawk, and short-eared owl, with the latter two species being considered species at
risk (Environment Canada, 2013). The primary threat to these species is listed as loss of habitat,
largely due to forest succession without adequate amounts of forest disturbance to replace the
lost habitat (Environment Canada, 2013).
While mammals do not tend to rely as heavily on early successional habitats as avian species,
several small mammal species use these habitats seasonally, if not daily, often to capitalize on
food availability (Litvaitis, 2001). A prime example of this is Myotis lucifugus (little brown bat),
a native of the Acadian forest, which does not roost in early successional habitats, but often visits
these sites daily for feeding purposes (Litvaitis, 2001). Many amphibious, reptilian, and insect
species also rely on early successional/shrub dominated forest types to various extents (Litvaitis,
2003).
Due to the low levels of early successional/shrub dominated forest in the public forests managed
by the Macphail Woods Ecological Forestry Project and the decreasing amount of this habitat
type throughout the province of Prince Edward Island, it is valuable to create and maintain early
successional habitats to support the species that depend upon or are supported by them. This
makes it important to understand how to optimize early successional/shrub dominated habitat to
support wildlife in the Acadian forest region.
This paper is a best practices manual for creating and managing early successional habitat in the
forests managed by the Macphail Woods Ecological Forestry Project. The recommendations of
this manual primarily focus on providing habitat that supports early successional faunal species.
Other considerations include the cost-efficiency of management plans, as well as providing area
where Macphail Woods can plant and maintain rare, uncommon, and high fruit producing plants
and shrubs.
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2 Methods
The project was a review of pertinent literature, which was then synthesized into a best
practices manual for use by the Macphail Woods Ecological Forestry Project. The review of
literature consisted chiefly of a search of peer-reviewed journals using a variety of online
databases, such as Web of Science and Google Scholar. The reference section of articles found
were also searched to locate additional pertinent research. When the review of peer-reviewed
literature did not contain information needed, the grey literature was consulted. The results of
this review were then compiled into a comprehensive document that establishes the best
practices for optimizing early successional habitat for wildlife.
3 Results
3.1 Establishment of early successional habitat
It is becoming increasingly common for forest managers to consider emulating natural
disturbance regimes in the forest landscape (Long, 2008). The driving principal behind emulating
natural disturbance regimes is that traditional timber harvesting approaches (clearcuts, etc.) may
not resemble the disturbances that typically shape the forest, and as a result may not be suitable
for all the organisms that have adapted to the natural disturbance regime (Long, 2008). For
example, while both a clearcut and windthrow result in early successional forest, the disturbed
areas have many key differences. First, while a clearcut harvests the bulk of the stems in a stand
for timber or other uses, forest disturbed by wind often leaves many standing structures and the
trees felled by the wind remain on the ground to decompose over time (Lormier and White,
2003; Long, 2008). Another key difference between the two is the creation of pit and mound
topography resulting from windthrow, which covers as much as 50% of the forest floor in north
eastern North America and is not created from clearcut or other timber harvesting activities
(Schaetzl et al., 1989). In both these cases there are several legacies from windthrow (number of
standing trees, large amounts of large woody debris, and creation of pit and mound topography)
that are not present in the typical clearcut. However, there are several concerns surrounding
natural disturbance emulation, such as the extent to which attempts to emulate the disturbances
are representative of the natural disturbance and the difficulty of understanding the complex
6
relationships in natural disturbances and of mimicking these complex relationships (Long, 2008;
Lormier and White, 2003; Schaetzl et al, 1989). As a result of these concerns, the present project
has a heavier focus on creation of conditions that support early successional species rather
focussing on accurately mimicking a natural disturbance.
Partial retention harvests have been investigated and implemented to harvest timber while
leaving standing structures as an attempt to more closely mimic natural disturbances. Partial
retention harvests support higher richness and abundance of species than clear cuts and more
early successional species than un-harvested forests, and thus are worth investigating as an
option (Fedrowitz, 2014; Vanderwel et al., 2007). However, early successional species
(mammals, birds, plants, etc.), when examined as a group, show a trend toward increased
abundance and diversity with the intensity of harvest, reaching peak abundances with clearcuts
(Fedrowitz, 2014). The same trend holds true when focussing on examining the abundance of
early successional bird species (Baker and Lacki, 1997, Vanderwel et al., 2007). This suggests
that clearcuts (or a least large patch cuts) should be used rather than partial retention harvesting
and similar silvicultural systems to meet the objective of best supporting early successional
species. However, the Macphail Woods properties as a whole are managed for many ecological
values, not just supporting early successional species, and the gains of retaining small amounts of
standing live trees and snags for forest organisms in general outweighs the possible small
difference in efficacy as early successional habitat (Swanson, 2011; Macphail Woods Ecological
Forestry Project, 2017). Best estimates of a minimum retention of standing trees and snags is 5%
to 10% to achieve a positive ecological response (Gustafsson et al, 2012). Additionally, there are
many positive ecological effects from retaining of large woody debris (which also more closely
resembles a natural disturbance from wind) suggesting that whatever felled trees not needed for
harvest should be left on site (Schaetzl et al., 1989; Swanson et al., 2011)
3.2 Methods for maintaining levels of early successional habitat
The primary method for maintaining man-made early successional habitat is practicing even-
aged silviculture throughout a landscape. The silvicultural method is the most commonly used
and preferred by forest managers, as it uses constant timber harvests to create a shifting mosaic
of early successional habitat throughout the managed landscape (De Graaf and Yamasaki, 2003).
The benefits here are two-fold: money can be made from the harvest of timber and habitat is
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provided for early successional species (De Graaf and Yamasaki, 2003; Smetzer et al., 2014).
Through this type of management ‘new’ early successional habitat is constantly being created to
replace that lost as other stands age. Often, industrial forest managers use herbicides to supress
competition for regenerating hardwoods as part of their silvicultural operations, but hardwoods
can show a resistance to the herbicides and help to provide early successional habitat (De Graaf
and Yamasaki, 2003). Also, untreated ‘skip’ areas, where herbicides are not applied following
clear cuts, tend to result in dense shrub patches that persist for several years (De Graaf and
Yamasaki, 2003). Ideally, the use of precommercial thinnings would extend this stage (De Graaf
and Yamasaki, 2003). In many cases throughout New England, where even-aged silvicultural
practices area not acceptable to the general public, group cuts have also been used to maintain
both a steady supply of timber and a steady level of early successional habitat, though the
effectiveness of that habitat for many species is dependent on the size of the cuts (King et al.,
2001).
While maintaining a shifting mosaic of early successional habitat through silvicultural practices
is perhaps the most cost-effective method of maintaining this type of habitat in the long term, due
to the management objectives in the properties managed by Macphail Woods this will not be a
viable option. Most of the stands managed by Macphail Woods are plantations, reforested
farmland, or second growth and the species composition and age typically does not reflect that of
an old-growth Acadian forest (Macphail Woods, 2017). Macphail Woods has therefore decided
that continually shifting the remaining degraded forests on their managed properties towards an
old-growth Acadian forest takes precedence over the ‘shifting mosaic’ approach for maintaining
early successional habitat (Macphail Woods, 2017). Instead, Macphail Woods wishes to maintain
early successional habitat in set areas indefinitely (Macphail Woods, 2017). The decision to
avoid maintaining early successional forest through silvicultural means will also likely have a
positive effect on the abundance of avian species present, as in order to maintain the same
abundance of birds in a silviculturally managed early successional forest as an indefinitely
maintained early successional forest, the area openings would have to be increased 50-300%, and
thus would need to take up a significantly larger portion of the landscape to achieve the same
results (Smetzer et al., 2014; King et al., 2009). The silviculturally managed openings were also
found to have fewer forbs and graminoids (Smetzer et al., 2014). As a result, this approach will
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not be considered further and the focus will turn to managing an area indefinitely as early
successional forest.
Powerline corridors provide an example of managing early successional habitat in an area
indefinitely. Typically managed with mechanical methods, the use of herbicidal sprays that
hinder growth of broadleaf vegetation, or both, the general idea of managing vegetation in
powerline corridors is to keep the trees and shrubs relatively low so as not to interfere with the
powerlines (Luken et al., 1991). Though not primarily created or managed to be early
successional habitat, powerline corridors tend to provide suitable conditions for many early
successional plant and wildlife species (Peterson, 2015; King and Beyers, 2017). However, there
are many differences in goals, values, and restraints between power line management and
Macphail Woods. Largely, for powerline management the creation of early successional habitat is
essentially a side effect, as opposed to the main objective of the area (Luken et al., 1991).
Furthermore, powerline corridor maintenance often involves the use of herbicides, which do not
fit with the management objectives of Macphail Woods as the use of herbicides raises several
environmental concerns (Macphail Woods Ecological Forestry Project, 2017).
Prescribed burns and mechanical methods are often used to maintain early successional habitats
indefinitely (Chandler et al., 2009). Both methods have a relatively similar effect on avian
richness and abundance (Chandler et al., 2009; Smetzer et al., 2014). Maintenance by prescribed
burning involves using fire to ‘reset’ the successional progression of an area (Chandler et al.,
2009). Fires would have to be used at regular intervals to keep the area in an early successional
state. One downside to the use of prescribed burns is that a certain amount of area needs to be
dedicated as a firebreak, which ideally should be three times wider than the expected height of
the flames (Department of Natural Resources, 2017). Another drawback to using this method is
that it will make it difficult for the early successional space to meet one of Macphail Woods other
goals for the area: providing habitat for rare, uncommon, and high fruit producing plant and
shrub species, as species that do not regenerate well after a fire disturbance will likely not fare
well in this type of management regime.
Mechanical methods typically involve the use of mechanical mowing or manual cutting of
woody growth (Luken et al, 1991). Mechanical methods are often used to manage powerline
corridors (which need to maintain low vegetation as not to interfere with the infrastructure) to
9
varying success (Luken et al., 1991). The primary difficulty in using this method is that many
hardwood species tend to simply resprout when cut, often resulting in increased stem densities
that make can make site access difficult (Luken et al, 1991). This method, over multiple cutting
rotations, tends to favor stump or root sprouting species and shifts the species composition in the
area (Luken et al, 1991). This may be viewed as a positive in the case however, as increasing
hardwood stem density is positively related with bird density (Labbe, 2011). One strength this
method has over the prescribed burn method is that rare plants and shrubs can be cut around
relatively easily and be left where they are. Overall, this method seems to balance the objectives
of Macphail Woods better than the previous two methods, and therefore is the recommended
method of site maintenance.
3.3 Frequency of artificial disturbance
To maintain the chosen site(s) in an early successional state in perpetuity, disturbances will need
to happen in such a manner that they continually provide for the species that rely on them. On a
typical forest site, disturbances should occur approximately every 14 years to maintain suitable
habitat for early successional species (Schlossberg and King, 2009). After this point, the canopy
tends to become concentrated several meters above the ground and moves upwards, shading out
the foliage below that make up the habitat the early successional species depend on and
decreasing plant diversity (Aber, 1979; Howard and Lee, 2003). In areas where succession is
slowed disturbances may be required much less often to maintain early successional habitat
(Latham, 2003). In these cases, disturbances will only need to take place when a dense canopy
begins to form, which may not occur until some trees have reached 10 m in height (Swanson et
al., 2011; Aber, 1979).
An added layer of complexity is that early successional bird species tend to fall in to one of two
categories: ‘decreasers’, species that peak in density in the first years following disturbance, with
woody vegetation generally below two meters, and sharply decrease in abundance in the
following years; and ‘modal species’, which peak in density approximately 10 years after
disturbance, with woody vegetation typically between two and five meters, and disappear
completely from the site within 20 years of the disturbance as the overstory canopy develops
(Labbe, 2011; Schlossberg and King, 2009; Chandler, 2009; Aber, 1979). Due to these trends, it
is important to maintain levels of ‘young’ and ‘old’ early successional habitat within a landscape
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to provide habitat for as many early successional species as possible, which a manager could
accomplish by disturbing the early successional site(s) approximately every seven years, but only
disturbing half of the total early successional habitat each disturbance cycle. For example, if the
forest manager has two early successional sites then site ‘1’ should be disturbed in 2018, 2032,
and 2046 and site ‘2’ should be disturbed in 2025, 2039, and 2053.
3.4 Site location
There are many factors to consider when selecting a site for the creation of an early successional
ecosystem. To reduce costs of maintaining the site over a long period of time, priority sites
should be those that are poorly stocked, as this likely reflects an environment in which tree
species do not grow as easily, and thus will presumably need less maintenance over time and
reduce costs (Latham, 2003; De Graaf and Yamasaki, 2003). Under the right conditions, early-
successional/shrub-dominated habitat can persist for hundreds of years as opposed to less than
twenty in normal conditions (Latham, 2003; Aber, 1979). Several environmental factors, such as
the presence of a frost pocket, poor soil conditions, and high winds can result in poorly stocked
stands that many shrubs and plants can survive in (Latham, 2003). These long-lasting early
successional sites also tend to produce more fruit than a ‘normal’ early successional site
(Swanson, 2011). However, it is important to consider that plant species diversity is often
relatively low in these sites and may run counter to the objective of supporting rare or
uncommon plants (Latham, 2003).
A site with poor soil conditions that may be an ideal choice for establishing an early successional
habitat on is a forested site on abandoned farmland, which is present throughout many of
Macphail Woods’ managed forests (Macphail Woods, 2017). Many forest species struggle to
establish on former agricultural land, which may provide a competitive edge to shrub species and
decrease the costs of site maintenance (Cavallin and Vasseur, 2008; Latham, 2003; De Graaf and
Yamasaki, 2003).
Areas where sheep-laurel (K. angustifolia) is present may also provide an opportunity for a long-
lasting early successional/shrub land habitat. Sheep-laurel is suspected of creating its own
positive feedback loop that can slow succession for decades. Sheep-laurel, along with other
members of the Ericaceae family, has a strong acidifying effect on the soil while at the same time
11
being highly tolerant of soil acidity (Read 1984; Griffiths et al., 1992; Marschner, 1992). This
feedback loop continues to acidify the soil over time, favoring sheep-laurel over tree species less
tolerant of soil acidity, increasing the dominance of the sheep-laurel, which continues in turn to
increase soil acidity (Read 1984; Griffiths et al., 1992; Marschner, 1992). One downside of this
approach is that it may eliminate the possibility of keeping populations of rare or uncommon
plants in the area, as they may not be tolerant of high soil acidity. Therefore, choosing to use this
method may rely on whether or not its cost-efficiency is more valuable to the forest manager
than providing habitat for priority plant species.
3.5 Site Size
An important consideration when creating an early successional habitat is what size the site
should be. Economically speaking, the less area dedicated to these long term early successional
habitats there is, the less money it will cost. While bird nesting success is not impacted by the
size of the site, avian and mammal species diversity and abundance is (King et al., 2001;
Chandler, 2009; Roberts and King, 2017; Litvaitis, 2003). Both species diversity and abundance
have a positive relationship with increasing disturbance size, with the relationship starting to
level off shortly after 1 ha in size (Roberts and King, 2017; Chandler, 2009; King and De Graaf,
2004). Many shrubland birds are completely absent from openings less than 1 ha in size, possibly
due to vegetation composition and structure or necessary territory sizes for species (Rodewald
and Smith, 1998; Costello et al., 2000; Roberts and King, 2017). The minimum recommended
size for early successional habitat sites in Macphail Woods’ properties is therefore 1 ha, as
suggested by other management documents (Roberts and King, 2017; Chandler 2009; De Graaf
and Yamasaki, 2003). While benefits do not increase as drastically with size after the first
hectare, larger sites continue to provide increasing benefits for both small mammal and bird
species diversity, suggesting that early successional habitat sites should be as large as costs and
other forest property constraints allow (De Graaf and Yamasaki, 2003). However, due to the
degraded nature of the forests on the properties and the forest restoration goals of Macphail
Woods, large clearcuts are not recommended regardless of impacts on early successional species
(Macphail Woods, 2017). By making 1 ha patch cuts, sites will balance the desire to support
early successional species, while at the same time remain relatively small, reduce costs, and
disrupt less of the forested land.
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3.6 Landscape considerations
It’s also important to consider the landscape context and the spatial distribution of early
successional site(s). The proximity of shrubland patches to other large shrubland sites and
landscapes that have higher proportions of early successional sites in general tend to allow the
site to support higher avian species abundance per hectare (Roberts and King, 2017). For forest
management purposes, this suggests that it could be beneficial to a) concentrate early
successional sites on one or a few properties rather than trying to spread the sites out throughout
the managed properties; and b) to establish the early successional sites in areas where the
landscape contains higher proportions of early successional habitat, such as near power line right
of ways, blueberry fields, or recently abandoned agricultural land.
4 Recommendations
As a result of the review of the literature, the following recommendations have been
made:
Select poorly stocked stands to increase the length of the early
successional period and to reduce maintenance costs;
Creates sites using approximately 1 ha patch cuts;
Locate sites near other early successional habitats, especially those larger
than 5 ha;
If creating multiple sites, congregate them in one area as opposed to
spreading them out across properties;
Leave 5%-10% of trees standing minimum, including snags;
Leave as much large woody debris (felled stems) as possible;
Maintain site using mechanical methods;
Offset disturbance schedule, with half of the total area being disturbed
every seven years.
13
Bibliography
Aber, J. D. (1979). Foliage-height profiles and succession in northern hardwood forests. Ecology, 60(1), 18-23. doi:10.2307/1936462
Baker, M. D., & Lacki, M. J. (1997). Short-term changes in bird communities in response to silvicultural prescriptions. Forest Ecology and Management, 96(1-2), 27-36. doi:10.1016/s0378-1127(97)00052-2
Catling, P, Erskine, D., & MacLaren, R. (1985). The plants of Prince Edward Island with new records, nomenclatural changes and corrections and deletions. Agric. Can. Res. Branch Rep.
Cavallin, N., & Vasseur, L. (2009). Red spruce forest regeneration dynamics across a gradient from Acadian forest to old field in Greenwich, Prince Edward Island National Park, Canada. Plant Ecology, 201(1), 169-180. doi:10.1007/s11258-008-9497-8
Chandler, R. B., King, D. I., & Chandler, C. C. (2009). Effects of management regime on the abundance and nest survival of shrubland birds in wildlife openings in northern New England, USA. Forest Ecology and Management, 258(7), 1669-1676. doi:10.1016/j.foreco.2009.07.025
Costello, C., Yamasaki, M., Jenkins, P., Leak, W., & Neefus, C. (2000) Songbird response to group selection harvests in clearcuts in a New Hampshire northern hardwood forest. Forest Ecology and Management, 127(1-3), 41-54
DeGraaf, R. M., & Yamasaki, M. (2003). Options for managing early-successional forest and shrubland bird habitats in the northeastern United States. Forest Ecology and Management, 185(1-2), 179-191. doi:10.1016/s0378-1127(03)00254-8
Environment Canada. (2013) Bird conservation strategy for bird conservation region 14 in Prince Edward Island and marine biogeographic unit 12: Atlantic Northern Forest and Gulf of St. Lawrence. Retrieved from https://www.ec.gc.ca/mbc-com/default.asp?lang=En&n=F3CB3594-1
Fedrowitz, K., Koricheva, J., Baker, S. C., Lindenmayer, D. B., Palik, B., Rosenvald, R., … Gustafsson, L. (2014), REVIEW: Can retention forestry help conserve biodiversity? A meta-analysis. Journal of Applied Ecology, 51, 1669–1679. doi:10.1111/1365-2664.12289
Griffiths, R.P., Caldwell, B.A., & Baham, J.E., (1992) Soil solution chemistry of ectomycorrhizal mat soils. In: Mycorrhizas in Ecosystems. CAB International, Wallingford, UK, 380–381
14
Gustafsson, L., Baker, S., Bauhus, J., Beese, W., Brodie, A., Kouki, J., … Franklin, J. (2012) Retention forestry to maintain multifunctional forests: A world perspective. Bioscience, 62(7), 633-645
Howard, L. F., & Lee, T. D. (2003). Temporal patterns of vascular plant diversity in southeastern New Hampshire forests. Forest Ecology and Management, 185(1-2), 5-20. doi:10.1016/s0378-1127(03)00243-3
Illinois Department of Natural Resources (2017) Early Successional Habitat Management. Retrieved from https://www.dnr.illinois.gov/conservation/CSP/Documents/ EarlySuccessionalHabitat.pdf
King, D. I, & Byers, B. (2002) An evaluation of powerline rights-of-way as habitat for earlv-successional shrubland birds. Wildlife Society Bulletin. 30
King, D. I., Chandler, R. B., Schlossberg, S., & Chandler, C. C. (2009). Habitat use and nest success of scrub-shrub birds in wildlife and silvicultural openings in western Massachusetts, USA. Forest Ecology and Management, 257(2), 421-426. doi:10.1016/j.foreco.2008.09.014
King, D. I., Degraaf, R. M., & Griffin, C. R. (2001). Productivity of early successional shrubland birds in clearcuts and groupcuts in an eastern deciduous forest. Journal of Wildlife Management, 65(2), 345-350. doi:10.2307/3802914
Labbe, M. (2011) Habitat use, productivity, and fruit selection of birds in early successional habitats in Western Massachusetts. Department of Environmental Conservation.
Latham, R. E. (2003). Shrubland longevity and rare plant species in the northeastern United States. Forest Ecology and Management, 185(1-2), 21-39. doi:10.1016/s0378-1127(03)00244-5
Litvaitis, J. A. (2001). Importance of early successional habitats to mammals in eastern forests. Wildlife Society Bulletin, 29(2), 466-473.
Litvaitis, J. A. (2003). Preface - Shrublands and early-successional forests: critical habitats dependent on disturbance in the northeastern United States. Forest Ecology and Management, 185(1-2), 1-4. doi:10.1016/s0378-1127(03)00242-1
Long, J. N. (2009a). Emulating natural disturbance regimes as a basis for forest management: A North American view. Forest Ecology and Management, 257(9), 1868-1873. doi:10.1016/j.foreco.2008.12.019
Lorimer, C. G., & White, A. S. (2003). Scale and frequency of natural disturbances in the northeastern US: implications for early successional forest habitats and
15
regional age distributions. Forest Ecology and Management, 185(1-2), 41-64. doi:10.1016/s0378-1127(03)00245-7
Luken, J. O., Hinton, A. C., & Baker, D. G. (1991). Assessment of frequent cutting as a plant-community management technique in power-line corridors. Environmental Management, 15(3), 381-388. doi:10.1007/bf02393884
Macphail Woods Ecological Forestry Project. (2017) 2000 Acres. Retrieved from http://macphailwoods.org/forestry/public-land-management/2000-acres/
Marschner, H., 1992. Nutrient dynamics of the soil–root interface (rhizosphere). In: Read, D.J., Lewis, D.H., Fitter, A.H.,
McAskill, J.D. (1987) The people’s forest. Island Mag. 22, 20–28.
P.E.I. Department of Agriculture and Forestry. (1997). Map of Prince Edward Island forest area circa 1900. Department of Agriculture and Forestry, Charlottetown, P.E.I.
Peterson, C. (2015) Habitat use by early successional bird species along powerline rights of way: making connections across private lands. Graduate college dissertations and theses
Read, D.J., 1984. Interactions between ericaceous plants and their competitors with special reference to soil toxicity. Aspects of Applied Biology, 5, 195–209
Roberts, H. P., & King, D. I. (2017). Area requirements and landscape-level factors influencing shrubland birds. Journal of Wildlife Management, 81(7), 1298-1307. doi:10.1002/jwmg.21286
Rodewald, P., & Smith, K. (1998). Short-Term Effects of Understory and Overstory Management on Breeding Birds in Arkansas Oak-Hickory Forests. The Journal of Wildlife Management, 62(4), 1411-1417. doi:10.2307/3802007
Schaetzl, R.J., Burns, S.F., Johnson, D.L., & Small, T.W. (1989) Tree uprooting: review of impact on forest ecology. Vegetation, 79, 1165–1176.
Schlossberg, S., & King, D. I. (2009). Postlogging Succession and Habitat Usage of Shrubland Birds. Journal of Wildlife Management, 73(2), 226-231. doi:10.2193/2007-518
Smetzer, J., King, I., & Schlossberg, S. (2014). Management Regime Influences Shrubland Birds and Habitat Conditions in the Northern Appalachians, USA. The Journal of Wildlife Management 78(2), 314-324
Sobey, D. (2002). Early descriptions of the forests of Prince Edward Island: A source-book. I. The French period (1534–1758). Prince Edward Island Department of Agriculture and Forestry, Charlottetown, P.E.I
16
Sobey, D., & Glen, W. (1999). Analysis of the ground flora and other data collected during the 1990– 92 Prince Edward Island forest biomass inventory. IV — The distribution of forest types. P.E.I. Department of Agriculture and Forestry, Forestry Division, Charlottetown, P.E.I.
Department of Agriculture and Forestry (2010) State of the Forest Report 2010. Retrieved from https://www.princeedwardisland.ca/sites/default/files/publications/2010_state_of_the_forest_report.pdf
Swanson, M. E., Franklin, J. F., Beschta, R. L., Crisafulli, C. M., DellaSala, D. A., Hutto, R. L., . . . Swanson, F. J. (2011). The forgotten stage of forest succession: early-successional ecosystems on forest sites. Frontiers in Ecology and the Environment, 9(2), 117-125. doi:10.1890/090157
Weighs, J., (1995). Facts About Canada, Its Provinces, and Territories. H.W. Wilson, New York.
Vanderwel, M. C., Maicolm, J. R., & Mills, S. C. (2007). A meta-analysis of bird responses to uniform partial harvesting across North America. Conservation Biology, 21(5), 1230-1240. doi:10.1111/j.1523-1739.2007.00756.x