Daniels Faculty of Architecture, Landscape, and Design

Permanent URI for this communityhttps://hdl.handle.net/1807/71883

The Daniels Faculty of Architecture, Landscape, and Design at the University of Toronto offers graduate programs in architecture, landscape architecture, urban design, forestry, and visual studies.

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25-year natural regeneration responses to varying levels of retention harvesting in a dry cool Montane forest of interior British Columbia
(2021-01-15) Jennings, Leanne; Caspersen, John
This study was conducted to investigate the effects that different levels of overstory retention have on the density and species composition of natural regeneration in Douglas-fir forests, 25-years post harvesting, and whether retention silviculture systems could help enhance the establishment of shade-tolerant, late successional tree species. This was assessed by analyzing natural regeneration data that was collected in the fall of 2019 at the Mount 7 research trial near Golden, BC in the dry cool Montane Spruce (MSdk) biogeoclimatic zone. The Mount 7 research trial was harvested in 1996 with four treatments: (1) a clearcut treatment, (2) a light retention treatment (where ~25% of the overstory basal area was retained), (3) a heavy retention treatment (where ~50% of the overstory basal area was retained), and (4) a control site. The results followed the same trends found by Newsome et al (2010), who analyzed the natural regeneration effects 10-years post harvesting. The heavy retention treatment units had the highest density of natural regeneration, followed by the light retention sites, with only small amounts of natural regeneration found at the uncut control and clearcut sites. This was also the case for conifer and shade-tolerant species, but broadleaf and shade-intolerant species had their density peak at the light retention sites, followed by the heavy retention sites. The species composition and richness was also found to be affected by the level of retention; there was a more diverse mixture of species when overstory trees were retained, unless 100 percent of the overstory was retained. These results reveal that by retaining overstory trees, thus increasing the seed supply, the density of natural regeneration will increase, but harvesting, which increases the light availability, is also essential for the establishment of natural regeneration.
A Review of Silvicultural Practices in Ontario Likely to Meet International Conservation Standards by Emulating Natural Disturbance
(2025) Osman, Halima; Caspersen, John
Canada has committed to the Kunming-Montreal Biodiversity Framework thereby agreeing to protect and conserve 30% of its land and oceans by 2030 (Government of Canada, 2022a; Government of Canada, 2023). To meet the objectives Canada must look towards innovative conservation strategies, such as Other Effective Area-Based Conservation Measures (OECMs). The goal of this study is to examine the potential for forests managed under Ontario’s sustainability standards, which include adaptive management practices that attempt to both conserving biodiversity and ensuring sustainable harvest levels to qualify as OECMs. This study compares these management guides with recent literature on ecological forestry and natural disturbance emulation to assess how well these practices conserve biodiversity long-term and to recommend modifications for enhancing their effectiveness. The results show that Ontario silviculture guides attempt to manage for biodiversity but often fall short of the standards associated with OECMs. However, current practices can be adjusted to better mimic disturbances and in turn enhance forest complexity and biodiversity, within managed forests. This study represents a first step toward identifying forestry practices that support in-situ conservation of biodiversity by mimicking natural disturbances, laying the foundation for future screening of these forests as potential OECMs.
Advancing Corporate Stewardship on Ravine Land: A Case Study of Sanofi Pasteur in Toronto
(2023-01) Biru, Tibebe; Smith, Sandy
With the rapid increase in climate change, urbanization, expansion of invasive species, excessive foot traffic, and litter we have continued to see the health of our ravines decline significantly. In order to address this concern within Toronto, several strategies and programs have been established to support biodiversity through the enhancement, protection, and restoration of flora and fauna. Having engagement from the community in stewarding public natural areas has allowed individuals to get involved in managing their local natural spaces. Community groups and individuals are not the only ones jumping at the opportunity to ensure they’re doing their part in protecting, restoring, and enhancing the environment. Corporations often want to be seen as good public citizens, so stewardship is often the route they take, but most of the frameworks and guidelines for corporations for stewardship are centered around private land stewardship. This is the problem that Sanofi Pasteur Canada has faced, over the last 3 years in stewarding G. Ross Lord Park as part of the Sanofi Pasteur Ravine Stewardship Initiative. Fostering collaboration and partnership between Sanofi Pasteur and Toronto Nature Stewards is recommended to address the problem. Toronto Nature Stewards work to educate and promote stewardship in Toronto in order to improve the overall quality of natural areas. In order to track Sanofi Pasteur’s internal efforts for ravine stewardship, Brown’s typology and McKinsey & Company’s analytical tool was used as a baseline to measure where Sanofi Pasteur is within the organizational development phase and what kind of internal steps need to be taken in order to build its organizational capacity. By using the elements from the Toronto Nature Stewards Program and Brown’s typology and McKinsey & Company’s framework, Sanofi Pasteur can move towards the next stage in the organizational development phase. In order to accomplish this the following there needs to be proper outreach, to employees and local community groups. Followed by five stewardship activities which are (1) Invasive Species Removal, (2) Litter Removal, (3) Trail Maintenance, (4) Tree Care, and (5) Lunch and Learn Sessions.
Alternatives to Chemical Herbicides: Responding to Social Pressures in the Boreal Mixedwood Forest of Alberta
(2020) London, Victoria; John, Caspersen
Forest Vegetation Management (FVM) can be defined as activities aimed at reducing vegetative competition with crop species. In Canada this is achieved mainly by using chemical herbicides, which kill or prevent the growth of the competing vegetation. Social opposition to herbicides has led to declines in herbicide spraying in some provinces. Alberta’s herbicide use has increased, while Quebec is managing without chemical herbicides entirely. The spikes in herbicide spraying in the province of Alberta have sparked concern over the necessity of herbicide use and concerns over the effects of its use. The need for vegetation control also calls into question the viability of regeneration standards in Alberta, and whether it is necessary to change the landscape to such an extent. My capstone will discuss the implementation of different vegetation management alternatives, and their transferability from Quebec to Alberta. With the research presented in this paper, I aim to provide a comprehensive review of herbicide use in the mixedwood forests of Alberta and Quebec and an overview of some vegetation management alternatives that could be employed in the west. In doing this, I will answer several questions: How viable are regeneration standards and are they contributing to the need for chemical herbicides? How could mixedwoods be better managed in order to reduce the need for chemical herbicides? How transferable are the methods used in Quebec to a more western setting? Ultimately, I find that many methods in Quebec are transferable in contexts where the same ecological mechanisms exist in both places.
An Analysis of Ontario Forest Governance Systems and their Ability to Effectively Include Indigenous People
(2018-01-25) Robinson, Stephanie Anne; Smith, C. Tattersall
In the past few decades, sustainability has taken the forefront in discussions in Canada broadly, and specifically in the Canadian forest industry. There has been much focus on economic and environmental sustainability, but social sustainability in forest management has alluded much attention. This paper focuses on social sustainability in terms of social justice and reconciliation with Indigenous people in Ontario. This paper analyses and assesses Ontario forest governance systems and their ability to effectively include Indigenous people. The analysis uses the concepts from Sustainable Development, sustainable forest management, and United Nations Declaration on the Rights of Indigenous Peoples as a lens to assess Ontario forest governance.
Analysis of Staff Retention and Recruitment in Ontario’s Wildland Fire Management System: Current Trends and Implications for the Future
(2021-01-30) Rosen, Dean; Martell, David
In 2015, the Aviation, Forest Fire and Emergency Services (AFFES) Branch of the Ontario Ministry of Natural Resources and Forestry (OMNRF) began to address an observed attrition of FireRangers’ collective expertise throughout Ontario that has continued to persist. Using aggregate data from the AFFES, the purpose of this project is to analyze this problem and to develop a prototype Microsoft Excel model that can be used to inform better strategies to recruit and retain more experienced FireRangers. The general hypothesis is that the continual loss of collective expertise of FireRanger staff over the last decade will create problematic ‘pinch points’ when Ontario’s demand for professionals who possess the ability to make complex decisions in the face of increasing wildfire risk will outweigh community needs. The practical value of this analysis and model is threefold: (1) to assess the magnitude of the current retention and recruitment problems faced by the AFFES; (2) to project the efficacy of proposed recommendations and policy changes that may be effective in mitigating the attrition of collective experience levels in the AFFES; (3) to serve as a stepping-stone in providing ongoing and improved predictive modeling to ensure that the human capacity in the AFFES is consistently available to address the evolving wildfire management needs of Ontario. Three recommendations based on the results of this analysis and the model are to (1) simultaneously address retention of Fire Crew Leaders and their feeder groups (e.g., Crew Bosses and Crew Members), (2) enact meaningful changes aimed at all FireRangers, regardless of their positions, and (3) improve intra-provincial data sharing and accessibility in order to enhance the scope of this model to demonstrate the importance of recruiting and retaining a diverse workforce. Ultimately, this model is a tool that could continuously be improved to emphasize the need for quickly and decisively implementing strategies to slow the attrition of expertise. Doing so will enable the AFFES to consistently respond to wildfire in accordance with the values and goals outlined in Ontario’s Wildland Fire Management Strategy into the future.
An Analysis of Toronto’s Urban Ravine Policies and the Achievement of Ecological Integrity
(2018-01) Richard, John (Jack); Smith, Sandy
In order to protect ravines and native species, the City of Toronto requires strong, meaningful policies that will direct the ecological management of this ecosystem. Ecological integrity represents a sound principle for ecological management within urban forest areas, such as Toronto’s ravines. This project reviewed the critical policies of the current policy framework that guides the management of Toronto’s ravines to evaluate how well compositional, structural, and functional measures of ecological integrity were protected within this framework. These policies included the City of Toronto Official Plan, the Ravine and Natural Feature Protection By-law of the Municipal Code, and the Conservation Authorities Act. These policies were found to contain provisions which promoted the achievement of certain components of ecological integrity but were inhibited by the scope of their policy framework, lacking clear guidelines, and specific management restrictions. Further, it was found that the body of policy governing Toronto’s ravines contained no outright restriction on the planting of invasive species, directly compromising the compositional integrity of the ecosystem. To increase the degree to which Toronto’s policy framework protects for components of ecological integrity within the ravines, both short and long-term policy recommendation were made.
Applying the 3-PG Model to Assess Carbon Sequestration and its Economic Impacts in Simcoe County Forest
(2025-01-07) Sun, Fanxuan; Yousefpour, Rasoul; Davis, Graeme
Are eastern grey squirrels a big problem for bigleaf maple?
(2022-01) Bokor, Adrienn; Thomas, Sean
Bigleaf maple (Acer macrophyllum Pursh) is an important tree species on the Pacific coast of North America. It is one of the few hardwoods in the Pacific Northwest and provides several ecological, economic, and social benefits. It supports a large variety of species, is used to make numerous items, and is culturally important to First Nations. However, for about the last ten years, bigleaf maple has been showing signs and symptoms of decline with an unknown cause in the Washington, Oregon, and California range of the species (Betzen, 2018; Christiansen, 2019). Given the important role bigleaf maple plays, its decline could have large-scale impacts. Root disease was suspected by forest professionals in Washington based on symptoms such as partial to entire crown dieback, reduced leaf size, and yellow flagging and dieback of entire branches. Forest professionals tested for and ruled out several potential biotic agents such as Verticillium albo-atrum, Verticillium dahlia, Armillaria, Ganoderma, and Xylella fastidiosa (Omdal & Ramsey-Kroll, 2012; Betzen, 2018). A newly published study in western Washington indicated that the cause of this decline is most likely linked to abiotic agents such as road proximity, increased land development, and escalating summer temperatures (Betzen et. al, 2021). Metro Vancouver Regional District in British Columbia, Canada, had a forest health report completed that identified bigleaf maple flagging in some parks. With little research regarding bigleaf maple decline and few reports on bigleaf maple in general in the British Columbia context, this present study investigates if there is a decline syndrome in Metro Vancouver Regional Parks and what the cause may be. Data were collected for GPS location, Dbh, and several crown health metrics such as dieback percent, canopy openness percent and chlorosis percent. Information was also gathered for the presence or absence of foliar diseases, fruiting bodies, damage, flagging and leaf tip dieback. General linear model regression (Morin et al, 2012) and direct ordination using correspondence analysis was performed using R to determine statistical significance of the data. This study found strong associations to bark-stripping indicating diminishing tree health. With eastern grey squirrels being an introduced species to the area, their known association to bark-stripping hardwoods, including maples (among other species), and their well-documented invasive behaviour of tree destruction in the United Kingdom, makes them the most likely culprit. Kretzschmaria deusta was also found to have strong associations to deteriorating tree health and with larger diameter trees. With strong associations of bark-stripping and Kretzschmaria deusta to declining tree health, this is a management concern for Metro Vancouver Regional District that needs to be addressed to prevent potentially large-scale impacts in the future. Recommendations include initiating management programs for eastern grey squirrels in highly effected parks such as Campbell Valley Regional Park and active monitoring for Kretzschmaria deusta along heavily used trails. It is also recommended to monitor for sooty bark disease (Cryptostroma corticale). Collaboration with the British Columbia Society for the Prevention of Cruelty to Animals (BC SPCA), invasives species councils, the regions’ municipalities and the province to create a unified and effective approach to eastern grey squirrel management in the Metro Vancouver Regional District and the rest of British Columbia is also suggested.
Are Urban Fruit Trees Healthy? Examining Health Indicators in Toronto’s Urban Orchard
(2022-12-16) Kitz, Friederike; Smith, Sandy
While urban fruit trees can provide food security and community, they are an understudied part of urban forestry. Using a Neighbourwoods© inventory (Kenney and Puric-Mladenovic, 1995), the purpose of this report was to examine how health varied across species, size classes, and neighbourhoods. Homeowners were requested to register their trees in the survey and 162 fruit trees were sampled in total. Each sample involved a Neighbourwoods© health assessment and a short interview with the owner where they were asked about the tree’s health and history. There was no significant difference in health rating between species, though apricots were the most likely to be extremely unhealthy. However, there was a significant difference in defoliation levels between species, with apricots being the most heavily defoliated. Additional findings from interviews suggest that homeowners are reluctant to care for their fruit trees due to a lack of knowledge, a perceived lack of time or energy, or the desire to remove them at some point. The most common reasons for removal were the mess of falling fruit or a new owner moving in after the tree was planted. Variance in health is important to examine in urban fruit trees to better understand which tree species might be the least healthy, the least productive, and the most likely to be replaced or removed soon. Interviewing homeowners is important to better understand where their frustrations and knowledge gaps lie, so urban forestry organizations and municipalities can tailor their services and educational programs.
Ash Tree Regeneration & Decline in Lake Simcoe Watershed
(2024-01-12) Newell, Jack; Puric-Mladenovic, Danijela
The invasive emerald ash borer (Agrilus planipennis) is currently a major threat to ash trees throughout southern Ontario. We examined 20 plots in the Lake Simcoe Watershed in the years 2017 and 2023 to determine the effect that EAB had on the regeneration of the three major ash species in the region: white (Fraxinus americana), black (Fraxinus nigra), and red ash (Fraxinus pennsylvanica). Analysis was conducted to determine if there were declines in any of the canopy, sub-canopy, shrub layer, ground layer, and basal area of ash trees over the period of six years. Significant decreases were found in both the canopy and basal area but not in the sub-canopy, shrub layer, or ground layer. EAB was found to be having a significant negative effect on only the most mature trees. However, the lower levels were found to have remained the same, indicating that seed production from the top layer has not been significantly hindered by EAB infestation.
Assessing Adopter Experience and Tree Health for Local Enhancement & Appreciation of Forest (LEAF)'s Adopt-A-Street-Tree Program in the City of Toronto
(2017) Dowell, Kimberly; Smith, Sandy
Assessing Coarse Woody Debris Nutrient Dynamics in Managed Northern Hardwood Forests Using a Matrix Transition Model
(Springer, 2020-04) Gorgolewski, Adam; Rudz, Philip; Jones, Trevor; Basiliko, Nathan; Caspersen, John
Coarse woody debris (CWD) is a dynamic source of nutrients in managed forests of eastern North America. The temporal patterns of nutrient export from CWD are challenging to study, and efficient methods are lacking. We made empirical measurements of CWD density, volume, and nutrient concentrations in 5 stages of decay, and paired them with a decay class transition model to project the long-term nutrient dynamics of CWD in a managed northern hardwood forest. The model was used to describe stand-level changes in CWD nutrient pools over 40 years following a selection harvest, and to compare CWD nutrient pools in managed and unmanaged stands. The C content of CWD decreased throughout decay, and mirrored density losses. N, P, and Ca content increased throughout decay, Mg content remained relatively constant, and K was rapidly lost. At the stand level, despite a rapid loss of mass and density, the model projected an initial gain in total N, P and Ca stored in CWD during the first 4–8 years after harvest, whereas net C, Mg, and K began to decrease immediately. The average volume, mass, C and K stocks of CWD in managed stands were approximately 10% lower than unmanaged stands, and N, P, Ca, and Mg were up to 16% lower. This is the first study to use a decay class transition model to study the dynamics of nutrients other than C, and the model serves as a template upon which other models of CWD decay can be built.
Assessing harvesting impacts on marten habitat at the scale of Indigenous traplines – a study in support of future Indigenous consultation
(2022-01) Chanda, Aditi; Malcolm, Jay; Kuttner, Ben
Clear-cut logging in boreal Ontario has long been investigated for its wildlife habitat impacts, however the effects of harvesting on populations of furbearers at the scale of traplines brings to the forefront issues not just of population survival but of cultural and economic impacts, particularly for First Nations trappers. This study was developed to model the change in habitat suitability for American marten due to planned future harvest for an Indigenous trapline in northeastern Ontario to infer the impacts on marten populations at this scale and situate the results in the context of current policy for marten management. Using R programming software, habitat suitability was modelled non-spatially and spatially. All modelling indicated that planned future harvesting over the ten-year horizon will cause a decrease in habitat suitability for marten in the study region, as well as impact the ability of the study region to act as an area with a source population of marten (due to decreasing home range and core areas). In a province where legislation for marten no longer mandates protection of core areas and does not address marten under fine filter management, the effects of silviculture on marten populations could be dire at the scale of traplines, and this study affirms the need for customized and considerate forest management approaches for Indigenous communities.
Assessing Maple Species in The Annex Neighbourhood from 2011 to 2022
(2023) Zihang, Wang; Puric-Mladenovic, Danijela
The Annex neighbourhood is an old neighbourhood located in downtown Toronto, Ontario. Due to its early history in land development, it started with tree planting back in the 1900s. The first tree inventory for the Annex was done from 2011 to 2014. The inventory project was conducted by volunteers and students from the University of Toronto with support from the Neighbourwoods© program. In 2022, the community started reassessing trees sampled in 2011. The objectives of this study were to understand the performance of the three most abundant maple species, Manitoba maple (Acer negundo), Norway maple (Acer platanoides), and silver maple (Acer saccharinum), in the Annex by analyzing the changes in their growth from 2011 to 2022. The other objective was to assess their health condition by analyzing three health indicators, rot/cavity on the trunk, crown defoliation, and branch poor attachment. The results show that Manitoba and silver maples have significantly faster growth rates than Norway maple in the Annex. Norway maple demonstrates a comparatively inferior performance when compared to Manitoba and silver maples. Notably, Norway maple exhibits a significantly slower diameter at breast height (DBH) growth rate than silver maple. While the defect of rot/cavity has a lesser impact on Norway maple compared to Manitoba and silver maples, crown defoliation and poor branch attachment emerge as the two pressing tree health issues that require attention. In 2022, there is an increase in the number of Norway maple trees exhibiting higher severity levels of these defects compared to the data collected in 2011, emphasizing the need for prompt resolution.
Assessing the connectivity of natural systems in the Golden Horseshoe: an application of the effective mesh size
(2021-02-08) Siddiqui, Amal; Puric-Mladenovic, Danijela
The Golden Horseshoe (GH) is a densely populated and rapidly developing region located in southern Ontario. It houses valuable agricultural lands and sensitive ecological features, including the Niagara Escarpment, Oak Ridges Moraine, and Ontario's Greenbelt, a permanently protected band of nearly 2 million acres. Urban development in the GH has accelerated fragmentation of natural cover and degraded its connectivity and quality. As urbanisation continues to pressure natural systems, it is critical to understand impacts on natural cover by monitoring and detecting changes over time. To assess changes in natural cover fragmentation and connectivity, the effective mesh size (meff) methodology was applied standard land cover data (SOLRIS) for the GH. We analysed meff across political and ecological boundaries and tested the metric at various spatial scales. The effective mesh size declined across the study area, indicating a general loss of connectivity throughout the GH despite protective policies, notably in the Oak Ridges Moraine, which declined from 3.15 to 1.68 km2. Our findings suggest that meff has the potential to be used as an indicator, as it provides a quantitative measure of a baseline condition upon which it is possible to monitor changes and establish management and policy targets. However, to implement the effective mesh size as an environmental indicator, we recommend finer resolution and more inclusive natural cover mapping. In addition, we recommend monitoring to be complemented with field-based data to improve interpretability of the effective mesh size values and better understand the impact of fragmentation on the ecology of natural systems.
Assessing the Introduction and Age of the Acer platanoides (Norway Maple) invasion within Wilket Creek ravine in Toronto, Ontario.
(2021-01-15) Postma, Madison; Puric-Mladenovic, Danijela; Baird, Katherine
After over a century of disturbance the property that encompasses the Toronto Botanical Garden and the Wilket Creek ravine in Toronto, Ontario has fallen victim to the invasive Norway maple (Acer platanoides). The objectives of this study were to improve the overall knowledge of Norway maple invasions within the Wilket Creek ravine, to determine when and where Norway maples were introduced in the study area, and to improve the overall understanding of Norway maple age dynamics within the property. The results show that Norway maple was introduced into the Wilket Creek ravine in the 1940s and 50% of the sampled Norway maple within the study were established between 1980s and 2000s (18 and 40 years old). The results also show that Norway maple regeneration is present in almost all wooded areas. To control Norway maple, it is recommended to implement an intensive management plan that includes mechanical and chemical control methods, strict invasive species policy, and the development of public education and outreach programs to halt the regeneration and growth of the invasive tree species.
Assessing the Success of Group Openings in Recruiting Mid/In-Tolerant Deciduous Tree Species in Haliburton Forest
(2023-01) Guppy, Callum; James, Patrick
Current silvicultural and forest management practices in the northern hardwood forests of eastern North America tend to create closed canopy environments that favour shade-tolerant species and suppress shade mid-tolerant and intolerant tree species. Reduced regeneration of mid/intolerant tree species has greatly reduced overall diversity and availability of mast in these forest ecosystems. In particular, mast-producing yellow birch (Betula alleghaniensis Britt), black cherry (Prunus serotina Ehrh.), and red oak (Quercus rubra L.) are underrepresented in the Great Lakes St Lawrence forests relative to their historical abundance. These three tree species represent potentially valuable substitutes for the rapidly declining high-protein beech mast and it has therefore become an objective of forest practitioners to create favorable conditions for their growth during harvests. Group openings (GO) are one such harvesting regime that is thought to promote the regeneration of mid/intolerant tree species by allowing more light to reach the forest floor compared to Single Tree Selection (STS). Higher light conditions in GO is also thought to reduce beech recruitment which is considered to be a desirable outcome due to the species’ foreseeable decline in the value and its tendency to suppress more desirable regeneration. To develop a better understanding of this silvicultural regime’s applicability to this problem, I investigated the effects of GO treatments on the regeneration of mid/intolerant tree species, target species (yellow birch, black cherry, and red oak) and beech in yellow birch, black cherry, and red oak seed tree stands in Haliburton Forest and Wild Life Reserve. I also examined the effects of GO on oak regeneration during different seasons of harvest. In most cases, GO treatments increased the regeneration of mid/intolerant tree species compared to control or Single Tree Selection plots. Among target species, only yellow birch regeneration significantly increased in GO treatments. Contrary to expectation, beech regeneration was not reduced by GO treatments. Season of harvest also did not affect oak regeneration in response to harvest type; however, oak regeneration was greater in winter-harvested stands in both GO and control plots. We conclude that GO treatments have the potential to increase the regeneration of mid/intolerant tree species, with limited success on target species regeneration. GO was not found to be an effective tool to reduce beech regeneration, but lack of treatment differences could be due to rhizomic regeneration. In addition, the effects of GO treatments on oak regeneration were not affected by the season of harvest.
Assessing the Viability of Skipping Tree Marking for Shelterwood System: A Comparative Study in Haliburton Forest
(2025-01-06) Zhang, Mengyuxin; Yousefpour, Rasoul
This study investigates the feasibility of eliminating tree marking in shelterwood systems by comparing marked and unmarked treatments in Haliburton Forest, Ontario. Key stand parameters, including residual basal area, seed tree basal area, and harvested volume, were assessed to evaluate silvicultural outcomes. Simulations using SORTIE-ND modeled the long-term impacts of tree selection practices over a 20-year period. The results revealed no statistically significant differences in any aspects of harvest outcome between marked and unmarked treatments. Although both failed to meet target residual basal area objectives, the unmarked treatment came closer to achieving these targets than the marked treatment. The results challenged the assumption that tree markers are inherently more reliable and highlighted the potential for replacing tree markers with loggers. Furthermore, advancements in technology, such as harvest algorithms and remote sensing, may provide viable alternatives to traditional tree selection methods in the future. This study also emphasizes the importance of establishing a network of marteloscopes in North America to enhance training, research, and collaboration, ensuring more consistent and informed decision-making in forest management practices.
Assessing Understory Vegetation Communities as Indicators of Ecological Integrity in the Toronto Ravine System
(2018-01-22) Kabigting, Jose Mari; Thomas, Sean
Urbanization has resulted in the disturbance and loss of ecosystems around the globe. As this trend is unlikely to stop, it is essential for urban planning to adopt ecological concepts in order to increase the sustainability of urban centres. One of the first steps required for this to happen is the implementation of ecological monitoring within urban areas – this would allow a better understanding of the current ecological state of urban environments, from which future studies and management recommendations can be based on. The concept of ecological integrity, which aims to quantify the wholeness of an ecosystem’s structure, composition, and function, can be used as a guiding principle for such monitoring schemes. In this study, the ecological integrity of the urban ravine system in Toronto, Ontario is quantified using understory vegetation communities as an indicator group. Vegetation sampling sites were established in three ravines located in downtown Toronto, with plot selection based on a 1977 study of the same ravines. Each plot was then ranked as having low, medium, or high ecological integrity based on the proportion of native versus non-native ground cover in each plot. Additionally, two possible drivers of these patterns in ecological integrity were tested – the role of plot position along a slope, and the effect of non-native ground cover abundance. It was found that while invasive species dominated most plots, pockets of native vegetation were persisting within the ravines. Additionally, the majority of invasive ground cover appeared to be “leaking” down from residential areas at the tops of ravines, indicating the role of “garden escapes” as propagules for invasive establishment. Management recommendations include the implementation of citizen science programs to monitor the state of these vegetation communities, as well as using the information gathered to target their efforts.

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