scholarly journals Urbanization and Decline of Old Growth Windbreak Trees on Private Homesteads: A Case Study in Ryukyu Island Villages, Japan

Forests ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 990
Author(s):  
Bixia Chen
Keyword(s):  
Spatial Distribution ◽  
Tree Height ◽  
Urban Trees ◽  
Historical Change ◽  
Urban Setting ◽  
Tree Age ◽  
Ryukyu Island ◽  
Ryukyu Archipelago ◽  
Old Growth ◽  
Minimum Diameter

Urban trees are under unprecedented pressure and competition worldwide with other land uses. Homestead windbreaks in urban areas are an important part of urban forests because of their proximity to settlements. To aid in the conservation of old-growth homestead trees in the urban setting on Ryukyu Archipelago, Japan, this article surveys the dimensions and spatial distribution of century-old trees planted as windbreaks along homestead borderlines on Ishigaki Island in the Ryukyu Archipelago and the historical change caused by urban sprawl. The homesteads studied in this article do not match the scale of a traditional Western context and usually consist of an area of less than 200 square meters on Okinawa. A combined approach consisting of field surveys and the study of aerial photos was applied to identify changes in spatial distribution of tree lines surrounding the houses in 1945, 1972 and the present. We measured the dimensions of 1659 Fukugi trees with a minimum diameter at breast height (DBH) of 5 cm. The mean tree height, mean DBH and mean estimated tree age were 7.3 m, 26.9 cm and 107.5 years, respectively. Homestead trees are not only useful as windbreaks, timber sources and musical instruments, but have also been historically resilient in the face of strong typhoons and catastrophic tsunamis in the region. Over 60% of the surveyed trees were planted on the east and north sides of homesteads as protection from typhoons and monsoonal winds in the winter. In addition to G. subelliptica, other tree species, namely Podocarpus macrophyllus and Diospyros egbert-walkeri, have been commonly used as homestead windbreaks. However, homestead windbreaks in highly urbanized regions are generally declining and have experienced fragmentation, lower tree density and shorter tree height than those in rural areas. Because of the small number of trees older than 200 years, we assume that high urbanization has jeopardized old-growth trees. The demand for settlement land dramatically increases as the population increases and household-size decreases, creating more households. Therefore, a conservation project involving multiple stakeholders must be developed to conserve old-growth trees in urban settings.

scholarly journals Differentiating mature and old-growth forests in the Upper Foothills and Subalpine Subregions of west-central Alberta

2003 ◽  
Vol 79 (3) ◽  
pp. 602-612 ◽  
Author(s):  
Luigi E Morgantini ◽  
John L Kansas
Keyword(s):  
Forest Management ◽  
Growth Index ◽  
Tree Height ◽  
Tree Age ◽  
Old Growth ◽  
West Central ◽  
Decay Class ◽  
Management Area ◽  
Growth Attributes ◽  
Live Tree

Weyerhaeuser Company Ltd. is developing harvest strategies that will maintain appropriate levels of late to very late seral stages ("old growth") in its Drayton Valley Forest Management Area. This management area encompasses 490 570 ha in the Foothills and Rocky Mountain Natural Regions of west-central Alberta. In planning for future forest landscapes, Weyerhaeuser intends to maintain a range of age structures consistent with the ecological processes characteristic of each natural region and subregion. The absence of a discrete point separating mature forest from old growth means that the age at which a stand is currently identified as "old growth" and subject to special management practices is arbitrary. In a research study initiated in the summer of 2000, we seek to understand the differences in structure and composition between forests of various ages and topographic site conditions (elevation, aspect, and slope angle). Using 95 sampling plots in a 123-km2 study area in the Upper Foothills and Subalpine Natural Subregions, we quantified vegetation structure and composition for stands ranging in age from 70 to 300 years. Variables measured and analysed included live-tree height and diameter, snag density, diameter and decay class, downed woody material volume, diameter and decay class, vascular plant species richness, sapling and regeneration density, and duff depth. An old-growth index was developed for each sampled stand that took into account multiple attributes. Preliminary results indicate that specific attributes (snag basal area and density, decay stage and density of downed woody material, variation in live-tree age, and variation in live-tree height and age) separate a younger forest from a more mature one and hence may describe "old-growth" conditions. The age of onset of these old-growth attributes is variable but appears to occur between 160 and 180 years. Key factors other than stand age that contribute to or modify the development of old-growth attributes (as measured by the old-growth index) are elevation and moisture regime (as modified by site position). Further investigation is required to more accurately assess the effect of site factors on old-growth attributes. These results are now used by Weyerhaeuser to address retention of late seral stages in long-term forest planning. Key words: old growth, mature forests, old growth protection, forest management, Alberta, Weyerhaeuser, Rocky Mountains foothills

scholarly journals Mutual Influences of Urban Microclimate and Urban Trees: An Investigation of Phenology and Cooling Capacity

Forests ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 533
Author(s):  
Celina H. Stanley ◽  
Carola Helletsgruber ◽  
Angela Hof
Keyword(s):  
Species Differences ◽  
Tree Height ◽  
Growing Season ◽  
Cooling Capacity ◽  
Urban Trees ◽  
Tree Age ◽  
Surface Cooling ◽  
Urban Heat ◽  
Old Trees ◽  
Suitable Measure

This paper presents an empirical study on urban tree growth and regulating ecosystem services along an urban heat island (UHI) intensity gradient. The UHI effect on the length of the growing season and the association of cooling and shading with species, age, and size of trees was studied in Salzburg, Austria. Results show that areas with a low UHI intensity differed from areas with a medium or high UHI intensity significantly in three points: their bud break began later, the leaf discoloration took longer, and the growing season was shorter. After leaves have developed, trees cool the surface throughout the whole growing season by casting shadows. On average, the surfaces in the crown shade were 12.2 °C cooler than those in the sun. The tree characteristics had different effects on the cooling performance. In addition to tree height and trunk circumference, age was especially closely related to surface cooling. If a tree’s cooling capacity is to be estimated, tree age is the most suitable measure, also with respect to its assessment effort. Practitioners are advised to consider the different UHI intensities when maintaining or enhancing public greenery. The cooling capacity of tall, old trees is needed especially in areas with a high UHI intensity. In the future, species differences should be examined to determine the best adapted species for the different UHI intensities. The present results can be the basis for modeling future mutual influences of microclimate and urban trees.

Impact of different sub-tropical trees on outdoor thermal comfort in an Indian city – A microclimatic modelling approach

2021 ◽  
Author(s):  
Sana Javaid ◽  
Kameswara Yashaswini Sista ◽  
Stephan Pauleit
Keyword(s):  
Thermal Comfort ◽  
Tree Species ◽  
Tree Height ◽  
Urban Trees ◽  
Urban Setting ◽  
Outdoor Thermal Comfort ◽  
Climatic Zones ◽  
Urban Settings ◽  
Modelling Approach

<p>Indians cities are facing incessant urbanization with lack of adequate green spaces exposing inhabitants to heat stress and increased mortality. Reduction of heat stress or optimization of outdoor thermal comfort (OTC) has been recognized as one of the multiple benefits of urban green infrastructure across different climatic zones. However, there is dearth of such studies in humid-subtropical (Cwa) context, especially India. ‘Urban trees’ are most preferred vegetation type concerning OTC, whereas, ‘parks, streets and gardens’ are most preferred urban green settings in a residential neighbourhood, as indicated by social survey results of another part of this study. But role of urban trees in enhancing OTC in different urban settings remains underexplored. In particular, it needs to be better understood how different morphological characteristics of trees influence their thermal benefits. Hence, we investigated nine sub-tropical tree species in these urban settings of a typical residential neighbourhood in the mid-sized, humid-subtropical city of Dehradun in north India. A sizeable world population inhabits humid-subtropical climates and almost 1/3rd of Indians reside in mid-size cities, making this study widely relevant.</p><p>We used a modelling approach enabling comparison of different trees in similar urban settings which is not possible through on-ground studies. 70 tree species were identified through field surveys and further filtered based on frequency, canopy density, morphology and growth habit. Finally, nine species were selected, three for each urban setting and modelled using Albero, a plugin of the 3D microclimatic simulation software, ENVI-met. Parameters such as tree height, trunk height, canopy shape and density, leaf area density, root spread and diameter etc. were considered for tree modelling. Modelling was validated using the field measurements and indicated a high correlation of 90%. Total nine scenarios were created using ENVI-met for each tree species in the respective urban setting maintaining canopy cover area. Their performance was evaluated by air temperature, relative humidity and mean radiant temperature at 15:00 and 19:00 hours of a peak summer day (2nd July 2019). Thermal comfort was also evaluated using PET (Physiologically Equivalent Temperature) between 9:00-20:00 hours. </p><p>Our results indicate that Mangifera Indica, Azadirachta Indica and Alstonia Scholaris perform best on an average for all parameters in gardens, park and streets respectively. These three trees had dense canopy i.e. high leaf area density (LAD) values and an average tree height between 11-15m. It should be noted that we did not have trees bigger than 15m on our site so results need to be further verified for taller trees. It can, however, be inferred that LAD value and tree height influenced cooling benefits more than trunk height or canopy shape in all urban settings. These results will be used to explore most suitable plantation arrangement in these urban settings. We acknowledge limitation of tree modelling using a software, however, forthcoming ENVI-Met 2021 release will enable detailed tree modelling and further improvise the study. Our results can be used in green space planning in humid subtropical climatic zones with similar urban settings or for further exploration of role of urban tree species. </p>

scholarly journals A comparison of forest structure among old-growth, variable retention harvested, and clearcut peatland black spruce (Picea mariana) forests in boreal northeastern Ontario

2003 ◽  
Vol 79 (3) ◽  
pp. 579-589 ◽  
Author(s):  
Aaron M Deans ◽  
Jay R Malcolm ◽  
Sandy M Smith ◽  
Terance J Carleton
Keyword(s):  
Forest Structure ◽  
Black Spruce ◽  
Basal Area ◽  
Structural Features ◽  
Tree Age ◽  
Old Growth ◽  
Minimum Diameter ◽  
Advance Regeneration ◽  
Ecological Features ◽  
Wide Range

Harvesting techniques that retain structural elements of the original forest may help to preserve the characteristic ecological features and biological diversity of old-growth forests. Harvesting with advance regeneration protection (HARP) is one such technique practised in the Lake Abitibi Model Forest of northeastern Ontario on peatland sites. In this system, winter harvesting operations clear trees in strips about 5–7 m wide and using a minimum diameter limit cut extract trees from the adjacent residual forest rows, 5–9 m wide. In order to assess the effectiveness of HARP in retaining forest structure, we quantified forest and understorey structural features in 24 1.65-ha plots spanning a wide range of forest retention, including clearcuts, three levels of HARP, and the edge and interior of unharvested forest (logging had occurred 2.5–3.5 years before the study). Mean tree age, diameter, and height in HARP forests in all cases exceeded 68% of the mean values found in unharvested forest, which was strikingly higher than the percent retention of basal area (20–43%). Also, unlike clearcuts, HARP forests retained the inverse-J curves between stem density and size class observed in unharvested forests, although stem densities in all size classes were lower. The percentage of black spruce regeneration originating from seed versus vegetative layering was directly related to the amount of forest basal area retained, averaging 2–5% in unharvested forests, 9–38% in HARP forests, and 67% in clearcuts. Many understorey characteristics closely followed the harvest intensity gradient, with amounts of moss, lichen, and Ledum highest at the unharvested end of the gradient and amounts of decaying moss, coarse and fine downed woody debris, exposed soil, and sedge highest at the clearcut end of the gradient. When the structural features were combined into a single composite variable using Principal Components Analysis (PCA) and the scores plotted against basal area, the relationship was curvilinear, with HARP treatments retaining greater amounts of structural characteristics than expected based solely on the basal area of wood harvested. This research suggests that the retention and redevelopment of old-growth features in peatland black spruce forests will be better under a HARP system than under a traditional clearcut system. Longer-term research, specifically on the edge habitats created by the HARP system, is required. Key words: boreal, peatland, black spruce, alternative harvesting methods, forest ecology

scholarly journals Spring Freeze Damage of Pecan Bloom: A Review

Horticulturae ◽  
2020 ◽  
Vol 6 (4) ◽  
pp. 82
Author(s):  
Amandeep Kaur ◽  
Louise Ferguson ◽  
Niels Maness ◽  
Becky Carroll ◽  
William Reid ◽  
...  
Keyword(s):  
Tree Height ◽  
The United States ◽  
Reproductive Organs ◽  
Tree Age ◽  
The Us ◽  
Nut Production ◽  
Freeze Damage ◽  
Terminal Buds ◽  
And Function ◽  
The Impact

Pecan is native to the United States. The US is the world’s largest pecan producer with an average yearly production of 250 to 300 million pounds; 80 percent of the world’s supply. Georgia, New Mexico, Texas, Arizona, Oklahoma, California, Louisiana, and Florida are the major US pecan producing states. Pecan trees frequently suffer from spring freeze at bud break and bloom as the buds are quite sensitive to freeze damage. This leads to poor flower and nut production. This review focuses on the impact of spring freeze during bud differentiation and flower development. Spring freeze kills the primary terminal buds, the pecan tree has a second chance for growth and flowering through secondary buds. Unfortunately, secondary buds have less bloom potential than primary buds and nut yield is reduced. Spring freeze damage depends on severity of the freeze, bud growth stage, cultivar type and tree age, tree height and tree vigor. This review discusses the impact of temperature on structure and function of male and female reproductive organs. It also summarizes carbohydrate relations as another factor that may play an important role in spring growth and transition of primary and secondary buds to flowers.

Incidence of main stem infections of lodgepole pine by western gall rust decreases with tree age

2005 ◽  
Vol 35 (6) ◽  
pp. 1314-1318 ◽  
Author(s):  
Peter V Blenis ◽  
Wuhan Li
Keyword(s):  
Pinus Contorta ◽  
Lodgepole Pine ◽  
Stem Elongation ◽  
Tree Height ◽  
Shoot Elongation ◽  
Main Stem ◽  
Tree Age ◽  
Precommercial Thinning ◽  
Two Factors ◽  
Artificial Inoculations

Infection of lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) by western gall rust has been shown to decrease with tree height and age, but the effects of those two factors have not been separated. Five replicate artificial inoculations were done on a total of 327 trees of different ages in two height classes. Temperature and percentage of spore germination at the height of inoculation, shoot development (stem elongation at the time of inoculation as a proportion of final shoot elongation), main stem leader length at the time of inoculation, tree height, and tree age were measured. Modeled percentages of infected trees and the number of galls per 10 cm of shoot length decreased by 85% and 88%, respectively, as tree age increased between 2 and 10 years, indicating the undesirability of early, aggressive precommercial thinning of lodgepole pine stands in areas where western gall rust is common. By controlling and (or) statistically accounting for inoculum, microclimate, and phenological factors, it was possible to demonstrate that changes in susceptibility with tree age are sufficient to account for the reduction in infection with tree height.

The epiphyte vegetation of the palm Socratea exorrhiza - correlations with tree size, tree age and bryophyte cover

2003 ◽  
Vol 19 (1) ◽  
pp. 81-90 ◽  
Author(s):  
Gerhard Zotz ◽  
Birgit Vollrath
Keyword(s):  
Attachment Site ◽  
Tree Height ◽  
Vertical Axis ◽  
Tree Size ◽  
Tree Age ◽  
Species Trees ◽  
Lowland Rain Forest ◽  
Vascular Epiphytes ◽  
Palm Trees ◽  
Socratea Exorrhiza

We conducted a survey of the epiphyte flora growing on the stilt palm Socratea exorrhiza in a primary lowland rain forest in Panama by means of a canopy crane. For each palm in a 0.9-ha plot, we determined diameter at breast height, tree height, per cent bryophyte cover and the number, identity and attachment site of all vascular epiphytes. The 118 palm trees hosted a total of 701 epiphytes and hemi-epiphytes, belonging to 66 species. Trees were estimated to be c. 20 y old before colonization with vascular epiphytes began. Epiphyte species were highly clumped and segregated along the vertical axis of the trunk. Sequential colonization led to an increased number of species and individuals as the tree grows. Epiphytes were associated with bryophyte patches much more than expected by chance, but no species seemed to depend upon them for establishment. The influence of tree size, age and bryophyte cover on the composition of the epiphyte community are discussed.

scholarly journals Approach to Urban Environmental Justice Using Exploratory Spatial Data Analysis. The Case of Valencia’s Monumental Trees

2020 ◽  
Vol 12 (18) ◽  
pp. 7760
Author(s):  
Alfonso Gallego-Valadés ◽  
Francisco Ródenas-Rigla ◽  
Jorge Garcés-Ferrer
Keyword(s):  
Spatial Distribution ◽  
Data Analysis ◽  
Environmental Justice ◽  
Spatial Data ◽  
Urban Trees ◽  
Spatial Data Analysis ◽  
Exploratory Spatial Data Analysis ◽  
The Public ◽  
Object Of Study ◽  
The City

Environmental justice has been a relevant object of analysis in recent decades. The generation of patterns in the spatial distribution of urban trees has been a widely addressed issue in the literature. However, the spatial distribution of monumental trees still constitutes an unknown object of study. The aim of this paper was to analyse the spatial distribution of the monumental-tree heritage in the city of Valencia, using Exploratory Spatial Data Analysis (ESDA) methods, in relation to different population groups and to discuss some implications in terms of environmental justice, from the public-policy perspective. The results show that monumental trees are spatially concentrated in high-income neighbourhoods, and this fact represents an indicator of environmental inequality. This diagnosis can provide support for decision-making on this matter.

Importance of boreal forested wetlands for epiphytic macrolichen communities

2020 ◽  
Vol 50 (12) ◽  
pp. 1333-1339
Author(s):  
Tegan Padgett ◽  
Yolanda F. Wiersma
Keyword(s):  
Community Composition ◽  
Abies Balsamea ◽  
Canopy Cover ◽  
Tree Height ◽  
Forested Wetlands ◽  
Tree Age ◽  
Forested Wetland ◽  
Forest Types ◽  
Significant Difference ◽  
Face Threats

Forested wetlands provide ecosystem services and often support elevated levels of biodiversity and rare species. However, forested wetlands are understudied and face threats such as logging and land conversion. Epiphytic lichens are abundant in forested wetlands and may be useful to help delineate microhabitats across wetland–upland gradients. We investigated epiphytic macrolichen richness, diversity, and community composition in 15 sites in the Avalon Forest Ecoregion, Newfoundland, Canada. Within each site, we set up three parallel 40 m transects in (i) the forested wetland, (ii) the ecotone, and (iii) the upland forest. Along each transect, we selected five balsam fir (Abies balsamea (L.) Mill.) trees 10 m apart and surveyed for macrolichens on the lower bole. We collected data on tree height and tree diameter at breast height, which differed significantly among forest types. We also collected data on tree age and canopy cover, which did not differ significantly among forest types. Contrary to hypotheses suggesting that biodiversity is highest in ecotones, we found that mean macrolichen richness was significantly higher in wetlands, lower in the ecotones, and lowest in upland forests, and macrolichen diversity followed a similar pattern but with no significant difference among groups. Macrolichen community composition significantly differed among wetlands, ecotones, and upland forests. A lichen of conservation concern, Erioderma pedicellatum (Hue) P.M. Jørg., was detected primarily in forested wetlands, highlighting wetlands as key habitats for rare epiphytic macrolichens.

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