Temporal Development and Regeneration Dynamics of Restored Urban Forests

Mapping Intimacies ◽

10.26686/wgtn.17143823 ◽

2021 ◽

Author(s):

◽

Katherine De Silva

Keyword(s):

New Zealand ◽

Urban Forest ◽

Urban Forests ◽

Basal Area ◽

Light Transmittance ◽

Permanent Plots ◽

Seedling Regeneration ◽

Temporal Shift ◽

Forest Development ◽

Seedling Community

<p>Urban forest restoration programmes are a key tool used to initiate, re-create or accelerate the succession of forest species; improving ecosystem services, function, resilience and biodiversity. Succession is a temporal shift in species dominance driven by abiotic and biotic influences, but over decadal timescales the trajectory and success of restoration plantings in degraded urban environments can be hindered. To facilitate the successful reconstruction of forest ecosystems from scratch, an understanding of the temporal patterns in planted forest development, dynamics of seedling regeneration and dominant drivers of seedling diversity is required. Using a chronosequence approach, permanent plots were established at 44 restored urban forests aged 5 to 59 years since initial plantings took place, across five New Zealand cities between Wellington and Invercargill. Vegetation surveys were undertaken and data on micro-climate were collected. This study examined the 1) temporal dynamics of restored urban forest development and seedling regeneration and 2) dominant drivers of seedling regeneration. Data were analysed using linear regression models, breakpoint analysis and mixed-effects modelling. Early forest development (<20 years) exhibited the most changes in canopy composition and structure, forest floor dynamics, seedling community and microclimate. This period saw significant increases in canopy stem abundance, height, basal area and leaf litter cover. Significant declines occurred for light transmittance, herbaceous cover and daily soil and air temperature range within the same timeframe. Dominant traits amongst the seedling community included early successional species, tree species, shade and drought tolerant species, insect-pollinated species and frugivory dispersed species. Seedlings with these traits had higher species richness levels across the whole chronosequence. Collectively, five biotic drivers representing forest composition, structure and landscape factors strongly influenced seedling diversity. Seedling diversity increased with the proportion of surrounding natural landcover, sapling diversity, basal area, canopy diversity and herbaceous cover. The influence of these predictors of seedling diversity, was more significant when modelled as a set, than when viewed independently. Geographic location (city) was indicated as a stronger predictor for similarities in canopy and seedling community composition than the age of the restoration planting. This was shown by stronger clustering of sites according to their city, more so than forest planting age, in a non-metric multidimensional scaling analysis. Our results provide valuable insight to restoration practitioners on the outcomes of urban restoration programmes implemented across much of New Zealand and helps close the gap between the science of restoration ecology and the practice of ecological restoration.</p>

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Temporal Development and Regeneration Dynamics of Restored Urban Forests

10.26686/wgtn.17143823.v1 ◽

2021 ◽

Author(s):

◽

Katherine De Silva

Keyword(s):

New Zealand ◽

Urban Forest ◽

Urban Forests ◽

Basal Area ◽

Light Transmittance ◽

Permanent Plots ◽

Seedling Regeneration ◽

Temporal Shift ◽

Forest Development ◽

Seedling Community

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New Silvicultural Treatments for Conifer Peri-Urban Forests Having Broadleaves in the Understory - The First Application in the Peri-Urban of Xanthi in Northeastern Greece

South-east European forestry ◽

10.15177/seefor.19-16 ◽

2019 ◽

Vol 10 (2) ◽

pp. 107-116 ◽

Cited By ~ 2

Author(s):

Elias Milios ◽

Kyriaki Kitikidou ◽

Kalliopi Radoglou

Keyword(s):

Urban Forest ◽

Urban Forests ◽

Basal Area ◽

Conifer Forests ◽

Research Hypothesis ◽

Silvicultural Treatments ◽

Dead Trees ◽

Selective Approach ◽

Conifer Trees ◽

Cutting Intensity

Background and Purpose: In Greece, forest practice did not develop special silvicultural treatments for planted conifer peri-urban forests where broadleaf trees appear as natural regeneration in the understory. The aims of this study are: a) to analyze the new proposed selective silvicultural treatments for the planted peri-urban forest of Xanthi and for analogous planted conifer forests, where broadleaf trees are naturally established in the understory b) to check the research hypothesis that the new selective silvicultural treatments exhibited higher intensity in terms of the basal area of cut trees, compared to that of traditional treatments in the studied peri-urban forest. Materials and Methods: In the traditional treatments, in the pine overstory cuttings, apart from the dead trees, mainly the malformed, damaged, suppressed and intermediate trees were cut. In the lower stories, the goal of the thinning was the more or less uniform distribution of broadleaf trees. In the proposed selective treatments, the main aim of pine cuttings is to release the broadleaf formations growing in the lower stories, while the treatments of the broadleaf trees will be a form of “positive selection” thinning. Plots were established in areas where the two types of treatments were going to be applied. In each plot, tree measurements and a classification of living trees into crown classes took place. After the application of the treatments the characteristics of cut trees were recorded. Results: In the established plots, before the cuttings (and thinning), total basal area was not statistically significantly different between the two types of treatments. In selective treatments, the basal area of all cut trees was statistically significantly higher than that of the results of traditional treatments. In the broadleaf cut trees there were statistical differences in the ratios of dominant, intermediate and suppressed trees between the two silvicultural approaches. Conclusions: The research hypothesis was verified. The intensity of treatments in terms of the basal area of cut trees was higher in the selective approach, compared to the traditional treatments in the Xanthi peri-urban forest. However, the overstory cutting intensity of the selective treatments depends on the spatial distributions and densities of broadleaved and conifer trees. In the broadleaf trees, the different objectives of the two types of treatments resulted in thinning with different qualitative characteristics. The proposed silvicultural treatments will accelerate the conversion of peri-urban conifer forests having an understory of broadleaf trees into broadleaved forests, or into mixed forests of conifers and broadleaf trees.

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Survival of Mount Eden Bush, an urban forest remnant in Auckland, New Zealand

Pacific Conservation Biology ◽

10.1071/pc990083 ◽

1999 ◽

Vol 5 (2) ◽

pp. 83 ◽

Cited By ~ 13

Author(s):

M. C. Smale ◽

R. O. Gardner

Keyword(s):

New Zealand ◽

Urban Forest ◽

Basal Area ◽

Ground Layer ◽

Indigenous Species ◽

Basaltic Lava ◽

Vascular Flora ◽

Ligustrum Lucidum ◽

Seed Sources ◽

Forest Remnant

Mount Eden Bush is the only reserved fragment of primary broadleaved forest on basaltic lava on the Auckland isthmus in northern New Zealand. An edaphic variant of northern coastal short forest, the reserved forest of 0.7 ha is approximately 1-2% of the estimated original <50 ha tract and contains 84% of the vascular species recorded in it. The canopy is dominated by Griselinia lucida, Litsea calicaris, and Pseudopanax lessonii, the subcanopy by Melicytus ramiflorus, and the understorey by Coprosma macrocarpa and Macropiper excelsum. A depauperate vascular flora compared with other basaltic lava forests in the district may result from long isolation of the original tract in a deforested landscape remote from seed sources. Low tree density, low basal area, and a strongly rupestral/xerophytic ground layer reflect the drought-prone lava substrate (mean boulder cover 38%). It has probably been dominated by the adventive trailing herb Tradescantia fluminensis for >60 years (mean cover 38%), which reduces abundance of woody native seedlings and cover of native ground layer herbaceous species. Over two-fifths of the vascular flora is now alien native (all planted) or adventive, the latter almost all garden escapes from the surrounding suburban matrix and including many of the most threatening weeds of urban Auckland. Despite widespread T. fluminensis, currently important canopy/subcanopy and understorey dominants appear to be replacing themselves. In the absence of intervention, however, indigenous species are likely to become less important in the canopy and adventive Ligustrum lucidum and Prunus serrulata more important; the latter two species are respectively the second and third commonest canopyforming species regenerating in gaps. Future extinction of some indigenous species with critically small populations cannot be ruled out.

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Quantifying Tree Cover Loss in Urban Forests within Nairobi City Metropolitan Area from Earth Observation Data

Environmental Sciences Proceedings ◽

10.3390/iecf2020-07952 ◽

2020 ◽

Vol 3 (1) ◽

pp. 78

Author(s):

Francis Oloo ◽

Godwin Murithi ◽

Charlynne Jepkosgei

Keyword(s):

Land Cover ◽

Metropolitan Area ◽

Land Surface ◽

Urban Forest ◽

Urban Forests ◽

Earth Observation ◽

Tree Cover ◽

Observation Data ◽

Vegetation Health ◽

Earth Observation Data

Urban forests contribute significantly to the ecological integrity of urban areas and the quality of life of urban dwellers through air quality control, energy conservation, improving urban hydrology, and regulation of land surface temperatures (LST). However, urban forests are under threat due to human activities, natural calamities, and bioinvasion continually decimating forest cover. Few studies have used fine-scaled Earth observation data to understand the dynamics of tree cover loss in urban forests and the sustainability of such forests in the face of increasing urban population. The aim of this work was to quantify the spatial and temporal changes in urban forest characteristics and to assess the potential drivers of such changes. We used data on tree cover, normalized difference vegetation index (NDVI), and land cover change to quantify tree cover loss and changes in vegetation health in urban forests within the Nairobi metropolitan area in Kenya. We also used land cover data to visualize the potential link between tree cover loss and changes in land use characteristics. From approximately 6600 hectares (ha) of forest land, 720 ha have been lost between 2000 and 2019, representing about 11% loss in 20 years. In six of the urban forests, the trend of loss was positive, indicating a continuing disturbance of urban forests around Nairobi. Conversely, there was a negative trend in the annual mean NDVI values for each of the forests, indicating a potential deterioration of the vegetation health in the forests. A preliminary, visual inspection of high-resolution imagery in sample areas of tree cover loss showed that the main drivers of loss are the conversion of forest lands to residential areas and farmlands, implementation of big infrastructure projects that pass through the forests, and extraction of timber and other resources to support urban developments. The outcome of this study reveals the value of Earth observation data in monitoring urban forest resources.

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Assessing the Ecological Value of an Urban Forest Park: A Case Study of Sinhua Forest Park in Taiwan

Forests ◽

10.3390/f12060806 ◽

2021 ◽

Vol 12 (6) ◽

pp. 806

Author(s):

Wan-Yu Liu ◽

Yo-Zheng Lin ◽

Chi-Ming Hsieh

Keyword(s):

Urban Forest ◽

Contingent Valuation Method ◽

Urban Forests ◽

Green Spaces ◽

Socioeconomic Background ◽

Tobit Regression ◽

Ecological Value ◽

Forest Park ◽

Study Results ◽

Ecological Conservation

Urban forests offer multiple functions: they can balance negative effects from the environment and provide the public with a place for leisure and recreation. Hence, urban forests are crucial to urban ecology and have been widely studied. In addition, relevant study results were applied for policymaking in urban development and forest park management. This study evaluated the ecological value of the Sinhua Forest Park and examined whether the socioeconomic background of participants influences their willingness to pay (WTP) for ecological conservation. Questionnaires were distributed to visitors in the Sinhua Forest Park in Tainan, Taiwan, and the payment card format of the contingent valuation method was employed to evaluate the ecological value. The results showed that the visitors had an annual WTP of $22.01 per person. However, when samples with protest responses were excluded, the WTP rose to $24.58. By considering the total number of visitors of a year, the total ecological value was $1,426,964.14/year and reached $1,593,257.31/year after excluding the protest samples. This study also analyzed participants’ within-variable socioeconomic background (e.g., gender and education) and discovered that male participants who are aged 60 years or older, with an education level of senior/vocational high school, and those who visited green spaces two to three times per week presented a high WTP score on average. A Tobit regression model was employed for examination, and the results indicated that participants’ education and frequency of visiting green spaces significantly influenced their WTP for the ecological conservation of the Sinhua Forest Park.

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Effects of Urban Forest Types and Traits on Soil Organic Carbon Stock in Beijing

Forests ◽

10.3390/f12040394 ◽

2021 ◽

Vol 12 (4) ◽

pp. 394

Author(s):

Xinhui Xu ◽

Zhenkai Sun ◽

Zezhou Hao ◽

Qi Bian ◽

Kaiyue Wei ◽

...

Keyword(s):

Organic Carbon ◽

Soil Organic Carbon ◽

Carbon Stock ◽

Urban Forest ◽

Coniferous Forest ◽

Predictor Variable ◽

Urban Forests ◽

Least Squares Regression ◽

Forest Types ◽

Organic Carbon Stock

Forests can affect soil organic carbon (SOC) quality and distribution through forest types and traits. However, much less is known about the influence of urban forests on SOC, especially in the effects of different forest types, such as coniferous and broadleaved forests. Our objectives were to assess the effects of urban forest types on the variability of SOC content (SOC concentration (SOCC) and SOC density (SOCD)) and determine the key forest traits influencing SOC. Data from 168 urban forest plots of coniferous or broadleaved forests located in the Beijing urban area were used to predict the effects of forest types and traits on SOC in three different soil layers, 0–10 cm, 10–20 cm, and 20–30 cm. The analysis of variance and multiple comparisons were used to test the differences in SOC between forest types or layers. Partial least squares regression (PLSR) was used to explain the influence of forest traits on SOC and select the significant predictors. Our results showed that in urban forests, the SOCC and SOCD values of the coniferous forest group were both significantly higher than those of the broadleaved group. The SOCC of the surface soil was significantly higher than those of the following two deep layers. In PLSR models, 42.07% of the SOCC variance and 35.83% of the SOCD variance were explained by forest traits. Diameter at breast height was selected as the best predictor variable by comparing variable importance in projection (VIP) scores in the models. The results suggest that forest types and traits could be used as an optional approach to assess the organic carbon stock in urban forest soils. This study found substantial effects of urban forest types and traits on soil organic carbon sequestration, which provides important data support for urban forest planning and management.

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Beijing Resident’s Preferences of Ecosystem Services of Urban Forests

Forests ◽

10.3390/f12010014 ◽

2020 ◽

Vol 12 (1) ◽

pp. 14

Author(s):

Han Zhi-Ying ◽

Youn Yeo-Chang

Keyword(s):

Ecosystem Services ◽

Air Quality ◽

Fresh Water ◽

Urban Forest ◽

Urban Forestry ◽

Urban Forests ◽

Wildlife Habitat ◽

Quality Regulation ◽

Water Provision ◽

Air Quality Regulation

This paper aims to investigate the Beijing resident’s preferences over various options of urban forest management strategies. The literature investigation and expert Delphi method were conducted to classify the ecosystem services of urban forests into six categories: (1) fresh water provision, (2) noise reduction, (3) moderation of extreme events, (4) air quality regulation, (5) species diversity and wildlife habitat, and (6) recreation and spiritual experience. To elicit the relative preferences to ecosystem service (hereafter referred to as ES) of Beijing residents, we employed the choice experiment method. The data were collected by interviews with questionnaires conducted in October 2017, and a total of 483 valid questionnaires were analyzed. The subjects of this experiment were residents older than 19 years old who have lived in Beijing for more than 1 year and have visited any one of the urban forests located in Beijing more than once during 2016. The results were as follows: Firstly, the air quality regulation ES was considered as the most important service for Beijing residents in terms of their choices of urban forest. In addition, Beijing residents regarded the fresh water provision ES as the second most important ES. Beijing residents were willing to pay up to 1.84% of the average monthly income of Chinese households annually to expand urban forest ecosystems in order to improve air quality. Secondly, apartment owners were willing to pay more municipality tax for forest ESs than residents who did not own an apartment. Thirdly, residents were more willing to pay for urban forest ESs as their income increases. The results indicated that Beijing residents were willing to pay more tax in support of urban forestry for air quality improvement. This research suggests that urban environmental policy makers in Beijing should pay more attention to the regulation function of forests (especially improving air quality) when designing and managing urban forests.

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Spatio-Temporal Changes of Urban Forests and Planning Evolution in a Highly Dynamical Urban Area: The Case Study of Wrocław, Poland

Forests ◽

10.3390/f11010017 ◽

2019 ◽

Vol 11 (1) ◽

pp. 17 ◽

Cited By ~ 3

Author(s):

Justyna Jaworek-Jakubska ◽

Maciej Filipiak ◽

Adam Michalski ◽

Anna Napierała-Filipiak

Keyword(s):

World War Ii ◽

Urban Forest ◽

Urban Forests ◽

Spatial Dimension ◽

Temporal Changes ◽

City Centre ◽

Socialist Economy ◽

Urban Green Spaces ◽

Spatio Temporal ◽

The City

Knowledge about urban forests in Poland is still limited, as it is primarily based on aggregate, formal data relating to the general area, ignoring the spatial dimension and informal green areas. This article describes and analyses spatio-temporal changes in the actual urban forest resources in Wrocław in 1944–2017, which covers the first period of the city’s rebuilding after its destruction during World War II and its development during the nationalised, centrally-planned socialist economy, as well as the second period of intensive and only partly controlled growth under conditions of market economy. The study is based on current and historical orthophotomaps, which were confronted with cartographic data, as well as planning documents. We found that between 1944 and 2017, the percentage contribution of informal woodlands increased tenfold (from 0.5 to 4.9% of the present total area of the city). The area occupied by such forests has grown particularly during the most recent years of the city’s intensive development. However, the forests have been increasingly fragmented. During the first period, new forest areas were also created in the immediate vicinity of the city centre, while during the second one, only in its peripheral sections. The post-war plans regarding the urban green spaces (UGS), including the current plan, are very conservative in nature. On the one hand, this means no interference with the oldest, biggest, and most valuable forest complexes, but on the other hand, insufficient consideration of the intensive built-up area expansion on former agriculture areas. Only to a limited extent did the above-mentioned plans take into account the informal woodlands, which provide an opportunity for strengthening the functional connectivity of landscape.

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