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There are many ancient Zelkova schneideriana trees that are over one hundred years old in Hunan Province, China, which have cultural and ecological values. However, the distribution, growth status and determinants of these Z. schneideriana remain to be explored. We collected data on the location and growth status of Z. schneideriana from the Information Management System of Ancient and Precious Trees in Hunan Province. Then, Average Nearest Neighbor and kernel density analysis were applied to investigate the distribution patterns and characteristics of Z. schneideriana. The potential distribution area and habitat suitability of Z. schneideriana were studied using the MaxEnt model. Finally, the factors affecting the distribution and growth status of Z. schneideriana were analyzed. The results showed that there were 501 Z. schneideriana in Hunan Province, distributed in 34 counties of 10 prefecture-level cities. The spatial distribution of these Z. schneideriana was clustered, with Chengbu Miao Autonomous County and Xinhuang Dong Autonomous County being high-density distribution areas. More than 60% of Z. schneideriana occurs at altitudes between 400 and 800 m. The most important factor influencing its population distribution is solar radiation in May (Srad5), followed by precipitation in the driest month (Bio14), with the total contribution of 82.63%. Specifically, when Srad5 > 15,544 (KJ/ (m2 × day)) and Bio14 < 24 mm, the area is not suitable (LOV < 0.2) for the growth of Z. schneideriana. In various habitats, Z. schneideriana exhibits differences in growth conditions and tree characteristics. The highest number of Z. schneideriana (68.66%) are found along rural roadsides, but they grow in poorer conditions, are negatively impacted by road construction, and have lower tree height and crown width than that in other habitats. The size of Z. schneideriana is influenced by intraspecific competition, with scattered Z. schneideriana being taller and larger. These results can provide guidance for the conservation, management and tourism development of Z. schneideriana. [ABSTRACT FROM AUTHOR]

Introduction: Heritage trees have special historical, cultural, and landscape value in cities and are keystone ecological structures for urban areas. However, these trees are threatened by rapid urbanization. To facilitate the conservation and management of such trees, our study investigated ancient trees in Chengdu, which is one of the hotspot of biodiversity and Historical and Cultural cities in Southwest of China. Methods: The floristic diversity, Shannon-Wiener index (H), spatial pattern, characteristics, dimension, age, and health status of the trees were estimated by using ecological indexes and mathematical statistics. Results: A total of 9383 heritage trees belonging to 119 species in 20 districts of Chengdu were surveyed. Dujiangyan (DJY) had the largest Shannon-Weiner index (H) (2.63), species count (76), and tree count (1842) and is therefore the most important district for preserving ancient trees. In contrast, Qingyang (QY) had the largest density of trees (120 trees/10 km²) among the 20 studied districts. In terms of important species, Phoebe zhennan (2351) was the dominant species, followed by Cupressus funebris, Ginkgo biloba, and Ficus virens. Akaike information criterion weights and standard deviation ellipse analysis showed that mean annual rainfall is a critical predictor for species distribution and age. Discussion: Findings from this study suggest that reducing water stress environments will improve the management and conservation of heritage trees in the future. [ABSTRACT FROM AUTHOR]

Protecting rare and endangered species from habitat loss caused by climate and land use changes is crucial for stopping unprecedented biodiversity loss. Data on species' future range shifts is crucial in protected area management planning to establish proper refuges. This study focused on identifying the suitable habitat, vulnerabilities, and conservation gaps of Vatica guangxiensis—a canopy tree species endemic to the subtropical forests of southwest China and listed as Endangered in the IUCN Red List— through Maxent species distribution modeling using current and future climate data. Results showed that the predicted suitable habitats for V. guangxiensis under current climate were more extensive than its known range, encompassing parts of China, northern Laos, northern Vietnam, and eastern Myanmar. They are most likely to be in wetter regions with acidic soils. However, these habitats were predicted to decrease by 90% and shift to lower latitudes and higher elevations by 2081–2100 due to climate change, which leads to habitat loss for five out of twelve current wild populations, as well as severe fragmentation and reduced protected area coverage. Our findings demonstrate the potential for new field discoveries of V. guangxiensis based on its predicted distribution under current climate, but also show the vulnerability of its habitats under future climate change. We present a dire outlook for V. guangxiensis and highlight the need for field discovery of new populations and the establishment of ex situ populations that are explicitly guided by suitable habitat predictions. Furthermore, this study can contribute to the expansion of climate-informed protected areas in the Indochina region, to support the flagship '30 × 30' target for protected areas under the Kunming-Montreal Global Biodiversity Framework. Lastly, our findings elucidate the importance of transboundary conservation efforts, such as the Lancang-Mekong Cooperation Five-Year Action Plan, in preserving biodiversity and achieving global conservation goals. [ABSTRACT FROM AUTHOR]

Societal Impact Statement Conserving trees is fundamental to maintaining forests, which are home to about half of the global biodiversity and provide unmeasurable benefits to people. Colombia has 5868 known species of trees, 1148 of which are endemic to the country. Unfortunately, 45% of the endemic trees of Colombia are threatened with extinction, and therefore, the ecosystem services they provide might be in jeopardy. This study represents an important contribution to conservation planning for the endemic trees of a megadiverse country and highlights critical considerations for their conservation. Summary Colombia has a very rich tree flora and high levels of tree endemism. As a contribution to the “Global Tree Assessment”, we assessed 860 species to complete the Red List of the 1148 endemic trees of the country. The information is being used to support spatial conservation planning as Key Biodiversity Areas identification. To categorize the species according to the International Union for the Conservation of Nature (IUCN) Red List guidelines, we used geographic occurrences obtained from herbarium specimens. We carried out detailed analysis of habitat quantity and quality (using forest cover and human footprint maps) and documented anthropogenic threats and conservation actions. Almost half (45%) of the endemic trees were categorized as threatened. Most species had small distributions (with an extent of occurrence of less than 40,000 km2). Endemic tree occurrences were more common in the Andes and Magdalena regions, which have very high human footprint and consequently a large proportion of threatened species. The major threat to endemic trees was habitat destruction, due mainly to deforestation for livestock and crops. Many endemic trees were present in protected areas (65%), but threatened and non‐threatened species had low coverage with habitat protection, and many of their populations persist in disturbed habitats. Colombia has hundreds of threatened endemic trees, most of them in global biodiversity hotspots, with very few proactive conservation actions. It is urgent to increase the coverage of endemic tree populations in area‐based conservation strategies and to complement this with ex situ and other conservation actions.

Societal Impact Statement Trees play vital roles in many of the world's ecosystems while providing many benefits to people. New evidence indicates that a third of tree species are threatened with extinction, representing a tree extinction crisis. Here we demonstrate how tree species extinction will lead to the loss of many other plants and animals and significantly alter the world's ecosystems. We also show how tree extinction will negatively affect billions of people through loss of livelihoods and benefits. We highlight a series of urgent actions needed to avert an ecological, cultural and socio‐economic catastrophe caused by widespread extinction of tree species. Summary Trees are of exceptional ecological importance, playing a major functional role in the world's ecosystems, while also supporting many other plants, animals and fungi. Many tree species are also of direct value to people, providing a wide range of socio‐economic benefits. Loss of tree diversity could lead to abrupt declines in biodiversity, ecosystem functions and services and ultimately ecosystem collapse. Here we provide an overview of the current knowledge regarding the number of tree species that are threatened with extinction, and the threats that affect them, based on results of the Global Tree Assessment. This evidence suggests that a third of the world's tree species are currently threatened with extinction, which represents a major ecological crisis. We then examine the potential implications of tree extinctions, in terms of the functioning of the biosphere and impacts on human well‐being. Large‐scale extinction of tree species will lead to major biodiversity losses in other species groups and substantially alter the cycling of carbon, water and nutrients in the world's ecosystems. Tree extinction will also undermine the livelihoods of the billions of people who currently depend on trees and the benefits they provide. This warning to humanity aims to raise awareness of the tree extinction crisis, which is a major environmental issue that requires urgent global attention. We also identify some priority actions that need to be taken to reduce the extinction risk of tree species and to avert the ecological and socio‐economic catastrophe that will result from large‐scale extinction of tree species.

Societal Impact Statement: India is credited with 2603 tree species, and the Global Tree Assessment confirmed that 469 of these species are threatened with extinction. Urgent restoration and conservation efforts are required to prevent the loss of tree diversity. The present study is the first published attempt to reintroduce Buchanania barberi, a Critically Endangered tree endemic to the south Western Ghats (UNESCO World Heritage Site) of Kerala, India, which has only two surviving mature individuals. The techniques and approaches applied here may provide guidance for implementing translocation programmes for this rare species and also for other International Union for Conservation of Nature (IUCN) Red Listed species of the genus globally. [ABSTRACT FROM AUTHOR]

Societal Impact Statement: Understanding the current state of trees within the United States is imperative for protecting those species, their habitats, and the countless communities they support, as well as the ecosystem services they provide. We present an updated checklist of all tree species native to the contiguous United States, their state distribution, extinction risk, and most common threats. Knowledge of national threat "hotspots" and conservation priorities facilitates efficient conservation efforts and the allocation of resources to safeguard the 11–16% of US tree species that are threatened. These results lay the groundwork for tree and ecosystem conservation efforts in the United States that contribute to achieving critical international conservation goals, including the United Nations Decade for Ecosystem Restoration and the Global Tree Assessment. Summary: The Global Tree Assessment aims to complete threat assessments for all the world's ~60,000 tree species, but most species native to the continental United States had either never been assessed or were outdated on the two most widely used threat assessment platforms in the United States, International Union for the Conservation of Nature (IUCN) Red List and NatureServe. There was also no coordinated mechanism for sharing data between these platforms, resulting in missing, duplicated, or outdated information.We (1) created an updated checklist of all tree species native to the contiguous United States based on the standardized Global Tree Assessment tree definition, (2) created over 700 new or updated IUCN Red List assessments and NatureServe Global Ranks, and (3) developed a replicable assessment data sharing process.We present an updated checklist of native US trees that includes 881 species from 269 genera, with Quercus and Crataegus as the most species‐rich tree genera. We present the first country‐wide analysis of tree extinction risk, patterns of geographic and taxonomic diversity, and leading threats. An estimated 11–16% of US tree species are threatened with extinction, with the most common threat being invasive and problematic pests and diseases. We introduce a "crosswalk" process for efficient, large‐scale data sharing between the IUCN Red List and NatureServe, using IUCN Red List Species Information Service (SIS) Connect, which can be applied to other taxonomic groups in North America.The checklist, threat assessments, and crosswalk methodology represent a significant advancement in prioritizing conservation action for at‐risk tree species and restoration of forests in the United States, supporting the global goals of the United Nations Decade for Ecosystem Restoration and the Global Tree Assessment effort. [ABSTRACT FROM AUTHOR]

Tilia (Malvaceae) is a genus of deciduous trees widespread in the northern hemisphere. Tilia species native to Japan include three endemic species, T. japonica, T. maximowicziana, and T. kiusiana, as well as the more widespread T. mandshurica. Other species were also introduced, the most important being T. miqueliana, brought to Japan with the arrival of Buddhism and planted on temple grounds as Bodaiju. Both historically and at present, Tilia trees are valuable to the people in Japan. Some Tilia trees are considered sacred in both Buddhism and Shinto. They are also prominent ornamental and park trees, albeit less popular in Japan than in Europe. Japanese Tilia spp. are used in the manufacturing of honey, cosmetics, lumber (especially plywood and veneers), and traditional bast cloth. Many Tilia trees are significant hubs in pollinator and mycorrhizal networks, but research on Japanese Tilia ecology is scarce. Despite their importance, Japanese Tilia trees have received less scientific attention in comparison with European Tilia species. The most striking example is T. kiusiana, with virtually no scientific literature regarding the species (save for a series of publications studying its secondary metabolites and potential medical uses). Furthermore, most published resources concerning Tilia in Japan are available only in Japanese, restricting their accessibility. This review seeks to translate, collect, and organize the information available on Japanese Tilia species. By doing so, areas are highlighted where new studies are necessary. A better understanding of these important trees would also be instrumental in their conservation. [ABSTRACT FROM AUTHOR]

Copyright of Plants, People, Planet is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Plants, People, Planet is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This article describes the radiocarbon analysis of the large Indian banyan (Ficus benghalensis) at Narora, Uttar Pradesh (UP). It was discovered during floristic surveys in the Upper Ganga Ramsar site in UP and ranks as the tenth largest banyan tree in the world with its 4069 sq. m crown spread. The tree has a unique architecture, with just four prop roots supporting the main stem. The oldest sample was found to be 346 ± 40 years BP, which corresponds to a calibrated age of 430 ± 35 cal years. The radiocarbon dating results indicate an age of 450 ± 50 years for the Indian banyan at Narora. This age represents the oldest accurate dating result for the species. Several protection measures are included to ensure the long-term survival of this archaic tree. [ABSTRACT FROM AUTHOR]

The objectives of this study were to reconstruct the design process of the Japanese pavilion in Venice Biennale, Italy (1956) designed by Takamasa Yoshizaka and to reveal the architect's formal manipulations and underlying strategic design thinking. The study materials are the original design sketches held in the National Archives of Modern Architecture, Tokyo, Japan. Initially, the chronological order of the design sketches was established by inspecting their dates and analyzing their formal similarities. The transformability (variations or changes of architectural form presented in a certain state of design) was analyzed and interpreted through a series of "studies" (partial problem‐solving processes). Finally, the architect's formal manipulations were reconstructed and presented and his relevant design intentions were revealed. [ABSTRACT FROM AUTHOR]

Societal Impact Statement Trees are the backbone of many terrestrial ecosystems and provide essential benefits for people and the planet. This unique life form requires specific horticultural, management, and conservation expertise to grow and thrive. ArbNet—the global, interactive community of arboreta—was established in 2011 to identify arboreta, define industry standards for arboreta, raise professionalism, support tree planting and proper care, facilitate collaborations, and advance tree research and conservation. Over the past 10 years, ArbNet has been instrumental in helping establish, grow, and network arboreta around the world and bring awareness to the importance of trees. This report presents ArbNet's flagship programs and resources and outlines opportunities for engagement at the individual or institutional level, to further strengthen the global network of arboreta and tree‐focused professionals and to ensure healthy trees for the future of people and the planet.

Abstract The objectives of this study were to reconstruct the design process of the Japanese pavilion in Venice Biennale, Italy (1956) designed by Takamasa Yoshizaka and to reveal the architect's formal manipulations and underlying strategic design thinking. The study materials are the original design sketches held in the National Archives of Modern Architecture, Tokyo, Japan. Initially, the chronological order of the design sketches was established by inspecting their dates and analyzing their formal similarities. The transformability (variations or changes of architectural form presented in a certain state of design) was analyzed and interpreted through a series of “studies” (partial problem‐solving processes). Finally, the architect's formal manipulations were reconstructed and presented and his relevant design intentions were revealed.

Venerable trees are important natural resources and cultural heritage, offering historical, ecological, social and economic value. However, global warming and anthropogenic activities have threatened their welfare and survival. A comprehensive understanding of their current and future spatial patterns, vis-á-vis environmental conditions, can inform the co-management of sustainable resource use and conservation. We employed the existing spatial occurrence data and environmental variables (bioclimate and elevation) to simulate the optimal habitats for venerable trees in China's Sichuan Province. We evaluated the current and future climate scenarios of 2100 with double CO2 concentration. The BIOCLIM and QGIS spatial analyses assessed the primary factors of geographical distribution. The results identified 10,720 venerable trees from 123 species, 81 genera and 42 families. Cupressus funebris dominated, with the maximum importance value, followed by Ginkgo biloba, Ficus virens var. sublanceolata, and Phoebe zhennan. The elevation distribution of tree abundance and species richness demonstrated a unimodal pattern, skewing to the low-elevation end, with a concentration in the 600–1500 m low-medium altitude. The majority of trees and excellent habitats were found in eastern Sichuan with a less harsh terrain and climate. The bio3 (isothermality) and bio7 (temperature annual range) factors significantly influenced tree occurrence. Temperature imposed a greater effect on distribution than moisture under the current climate scenario. For the future climate-change scenario, the suitable habitats were predicted to maintain an overall stable pattern, with largely contiguous expansions of better habitats. However, climate warming would shrink the excellent habitats on the plains. The findings can inform strategies and guidelines for venerable-tree conservation in Sichuan. Furthermore, vulnerable areas could be identified. The future range expansion sites could be enlisted to cultivate new trees to replenish the venerable-tree pool. Habitat patches that remain sustainable could provide refugia with the potential for protected-area designation. [ABSTRACT FROM AUTHOR]

The interlinked biodiversity crisis and challenge of global climate change cannot be addressed without the management of tree species. It is crucial that we use the information now available as a result of the Global Tree Assessment to manage, conserve and restore threatened tree species and tree diversity. With over 17,500 tree species now known to be threatened with extinction, well-planned actions need to be urgently identified and implemented that target multiple species. In this review, we highlight approaches that coordinate and mobilise multi-species conservation at the taxonomic, national, regional and global levels. Only through a considerable scaling up of planning and action will we prevent the extinction of both trees and the associated plants, animals and fungi that depend on them, sustain livelihoods and ensure the ecological health of the planet. [ABSTRACT FROM AUTHOR]

Aim: Range shifts are a key process that determine species distributions and genetic patterns. A previous investigation reported that Juglans cinerea (butternut) has lower genetic diversity at higher latitudes, hypothesized to be the result of range shifts following the last glacial period. However, genetic patterns can also be impacted by modern ecogeographical conditions. Therefore, we re‐investigate the genetic patterns of butternut with additional northern population sampling, hindcasted species distribution models and fossil pollen records to clarify the impact of glaciation on butternut. Location: Eastern North America. Taxon: Juglans cinerea (L., Juglandaceae) (butternut). Methods: Using 11 microsatellites, we examined range‐wide spatial patterns of genetic diversity (allelic richness, heterozygosity, FST) for 1004 previously studied butternut individuals and an additional 757 samples. We constructed hindcast species distribution models and mapped fossil pollen records to evaluate habitat suitability and evidence of species' presence throughout space and time. Results: Contrary to previous work on butternut, we found that genetic diversity increased with distance to range edge, and previously observed latitudinal clines in diversity were likely due to a few outlier populations. Populations in New Brunswick, Canada were genetically distinct from other populations. At the Last Glacial Maximum, pollen records demonstrate butternut likely persisted near the glacial margin, and hindcast species distribution models identified suitable habitat in the southern United States and near Nova Scotia. Main conclusions: Genetic patterns in butternut may be shaped by both glaciation and modern environmental conditions. Pollen records and hindcast species distribution models combined with genetic distinctiveness in New Brunswick suggest that butternut may have persisted in cryptic northern refugia. We suggest that thorough sampling across a species range and evaluating multiple lines of evidence are essential to understanding past species movements. [ABSTRACT FROM AUTHOR]

Understanding the genetic basis of how species respond to changing environments is essential to the conservation of species. However, the molecular mechanisms of adaptation remain largely unknown for long-lived tree species which always have large population sizes, long generation time, and extensive gene flow. Recent advances in landscape genomics can reveal the signals of adaptive selection linking genetic variations and landscape characteristics and therefore have created novel insights into tree conservation strategies. In this review article, we first summarized the methods of landscape genomics used in tree conservation and elucidated the advantages and disadvantages of these methods. We then highlighted the newly developed method "Risk of Non-adaptedness," which can predict the genetic offset or genomic vulnerability of species via allele frequency change under multiple scenarios of climate change. Finally, we provided prospects concerning how our introduced approaches of landscape genomics can assist policymaking and improve the existing conservation strategies for tree species under the ongoing global changes. [ABSTRACT FROM AUTHOR]

Understanding the genetic basis of how species respond to changing environments is essential to the conservation of species. However, the molecular mechanisms of adaptation remain largely unknown for long-lived tree species which always have large population sizes, long generation time, and extensive gene flow. Recent advances in landscape genomics can reveal the signals of adaptive selection linking genetic variations and landscape characteristics and therefore have created novel insights into tree conservation strategies. In this review article, we first summarized the methods of landscape genomics used in tree conservation and elucidated the advantages and disadvantages of these methods. We then highlighted the newly developed method “Risk of Non-adaptedness,” which can predict the genetic offset or genomic vulnerability of species via allele frequency change under multiple scenarios of climate change. Finally, we provided prospects concerning how our introduced approaches of landscape genomics can assist policymaking and improve the existing conservation strategies for tree species under the ongoing global changes.

Societal Impact Statement Trees are the backbone of many terrestrial ecosystems and provide essential benefits for people and the planet. This unique life form requires specific horticultural, management, and conservation expertise to grow and thrive. ArbNet—the global, interactive community of arboreta—was established in 2011 to identify arboreta, define industry standards for arboreta, raise professionalism, support tree planting and proper care, facilitate collaborations, and advance tree research and conservation. Over the past 10 years, ArbNet has been instrumental in helping establish, grow, and network arboreta around the world and bring awareness to the importance of trees. This report presents ArbNet's flagship programs and resources and outlines opportunities for engagement at the individual or institutional level, to further strengthen the global network of arboreta and tree‐focused professionals and to ensure healthy trees for the future of people and the planet. [ABSTRACT FROM AUTHOR]

'Peasant populations in tropical areas use Traditional Home Gardens (THG) as a key resource for their homes. THG supports significant plant biodiversity, most directly related to asset production, including locally rare species related to food, fuelwood, cultural, ornamental, shade, and wind barriers. Previous studies have considered factors driving tree diversity in THG; however, few have evaluated the biological, environmental, and management factors that shape tree diversity. Our objective in the present study was to identify the drivers of the tree community in THG across a precipitation gradient, evaluating biological, environmental and management factors. We visited forty-eight THG distributed across the precipitation gradient spanning around 300 km The tropical Mayan Forest in the Yucatan Peninsula, Mexico., where tree inventory and identification were obtained from specimens with a diameter at breast height > 5 cm. Interviews were conducted with owners about the history of THG. Metadata were captured and analyzed for 19 putative determinants of tree population structure. Differences in tree diversity by individual THG and region were determined statistically. Modeled interaction networks were determined based on a co-occurrence matrix. THG tree abundances are mainly explained by the relative abundance of not deliberately established individuals, the organic carbon content in the soil, and surrounding forest integrity. Management history of THG by peasants, including factors such as irrigation, TGH area, and fertilization, showed smaller but significant differences. Tree distribution is at a lower degree influenced by the precipitation gradient in the Yucatan Peninsula, which shows different abundances even for species established by THG owners. Our results suggest that biological and environmental factors may shape tree abundance and distribution over anthropic activities in THG. We identified rare, region-specific, and indicator species by region and modeled interaction networks that show coincidences with the empirical knowledge of THG owners. [Display omitted] • Tree diversity was determined for 48 Traditional Home Gardens (THG) distributed in six suburban localities in the Yucatan Peninsula, Mexico. • Our analysis shows a high proportion of region–exclusive species, especially in the South region. • The putative factors explaining THG tree diversity, precipitation, forest integrity index, voluntary index, Nitrogen-fixing Fabaceae, organic Carbon, fertilization, and irrigation. • Our data demonstrate that tree–tree competition is present in 59 % of THG. • Some cases of predicted tree–tree interactions match peasant knowledge. [ABSTRACT FROM AUTHOR]

Venerable trees are important natural resources and cultural heritage, offering historical, ecological, social and economic value. However, global warming and anthropogenic activities have threatened their welfare and survival. A comprehensive understanding of their current and future spatial patterns, vis-á-vis environmental conditions, can inform the co-management of sustainable resource use and conservation. We employed the existing spatial occurrence data and environmental variables (bioclimate and elevation) to simulate the optimal habitats for venerable trees in China’s Sichuan Province. We evaluated the current and future climate scenarios of 2100 with double CO2 concentration. The BIOCLIM and QGIS spatial analyses assessed the primary factors of geographical distribution. The results identified 10,720 venerable trees from 123 species, 81 genera and 42 families. Cupressus funebris dominated, with the maximum importance value, followed by Ginkgo biloba, Ficus virens var. sublanceolata, and Phoebe zhennan. The elevation distribution of tree abundance and species richness demonstrated a unimodal pattern, skewing to the low-elevation end, with a concentration in the 600–1500 m low-medium altitude. The majority of trees and excellent habitats were found in eastern Sichuan with a less harsh terrain and climate. The bio3 (isothermality) and bio7 (temperature annual range) factors significantly influenced tree occurrence. Temperature imposed a greater effect on distribution than moisture under the current climate scenario. For the future climate-change scenario, the suitable habitats were predicted to maintain an overall stable pattern, with largely contiguous expansions of better habitats. However, climate warming would shrink the excellent habitats on the plains. The findings can inform strategies and guidelines for venerable-tree conservation in Sichuan. Furthermore, vulnerable areas could be identified. The future range expansion sites could be enlisted to cultivate new trees to replenish the venerable-tree pool. Habitat patches that remain sustainable could provide refugia with the potential for protected-area designation.

During recent field surveys, a new Ceylon iron wood (Manilkara hexandra) population was discovered in the Upper Ganga Ramsar Site, Uttar Pradesh (UP), India. The largest specimen located at Van Khandeshwar partially collapsed in 2012, which led to a canopy impairment. The rupture enabled direct extraction of samples close to the pith of the main stem. The radiocarbon date of the oldest sample was 361 ± 23 BP, which corresponds to a calibrated age of 525 ± 25 cal yr. The results indicate the Ceylon iron wood of Narora, UP is the oldest dated extant M. hexandra with a calculated age of 550 ± 50 yr. Several protection measures are presented and urgent action is required to prevent the total collapse of this ancient tree. [ABSTRACT FROM AUTHOR]

Venerable trees are precious natural-cum-cultural heritage and an important component of regional biodiversity, with significant social, cultural and ecological values. A thorough understanding of their spatial patterns in relation to environmental factors can foster co-management for conservation and sustainable resource use. The Jianfengling National Forest Park in tropical China is a unique and rare primary tropical forest protected area with exceptionally high biodiversity and a rich endowment of venerable trees. This study evaluated the venerable tree stock regarding botanical makeup and factors shaping spatial patterns. We collected detailed tree data (species, age, dimensions, location, etc.) and environmental variables (elevation, slope and soil). The environmental variations were analyzed concerning tree abundance, species richness and tree age. The results identified 2134 venerable trees from 72 species, 55 genera and 30 families. Lithocarpus fenzelianus dominated with maximum importance value, followed by Cyclobalanopsis patelliformis , Madhuca hainanensis , Altingia obovata and Castanopsis tonkinensis. The top-ranking species were predominantly Fagaceae members. The age pattern demonstrated an inverted J-shape, with mainly 100–299 years trees and a few > 500 years. DBH, tree height, and crown width displayed an approximately normal distribution. Spatial distributions by age tiers were uneven, with more in the northeast part. The altitudinal gradient significantly influenced the spatial patterns of tree abundance and species richness. The unimodal distribution marked tree and species concentration at circa 600 m mid-elevation. The findings have implications for venerable-tree conservation and management in tropical protected areas with similar threatened and remnant-tree status. [ABSTRACT FROM AUTHOR]

Highlights • Synoptic heritage-tree conditions in mainland China was reviewed via >300 articles. • We studied remnant heritage trees in the large new city of Shenzhen in south China. • Tree density and diversity are notably higher in the oldest and youngest districts. • Village and forest habitats are more amenable to tree conservation in urban areas. • Policies for town-plan layout and urban tree management determine tree conservation. Abstract In China, heritage trees are actively surveyed and reported. Over 300 relevant published articles were reviewed to assess the contents, trends and geographical distributions of the investigations. The majority of the heritage trees studies in China were found in the eastern provinces and published within 2010–2014. Most studies reported surveys on all old trees. For studies focused on single species, Ginkgo (Ginkgo biloba) and Chinese Yew (Taxus chinensis) was most frequently reported. Unlike the champion tree registry in the US and other countries, the tree registry in China emphasized more on the tree age than the size. We then have studied the heritage trees in the rapidly-developed municipality of Shenzhen in South China in details. The species composition, diversity and spatial distribution were investigated using ecological indices and statistical techniques. Most trees were native with domination by Ficus microcarpa. Heritage-tree density was not correlated with land area, population density, green cover, or district development year. The oldest and youngest districts have relatively higher species diversity and tree density. It indicated the preservation of an old town plan and the creation of a new town plan conducive to accommodating pre-urbanization heritage trees. Village and forest habitats with rich tree endowments can be targeted for conservation in new urban areas. The importance of adopting a nature-friendly town plan, and the associated policies that can facilitate it, are instrumental in heritage-tree nurturing and protection. The findings can inform tree preservation and urban green infrastructure provision in fast developing cities in China and beyond. [ABSTRACT FROM AUTHOR]

The Authors report the results of a study conducted with the purpose of increasing the knowledge about the insects and fungi living on Zelkova sicula Di Pasquale, Garfì & Quézel, 1992 (Rosales, Ulmaceae). The plant is a very rare relict of the Tertiary period, belonging to a genus of trees extinct in continental Europe. Only two small populations are known living in a restricted woodland in the province of Syracuse, Sicily. The results concern both the insects picked up during surveys that were carried out in 2014 and 2015, and the species of fungi and insects already known on Zelkova sicula from literature. As a result of surveys, two species of Buprestidae, two species of Cerambycidae, and two of Lepidoptera have been recognized. From literature, seven species of phytophagous insects are reported on Zelkova sicula, they belong to Hemiptera: Aphididae (1 sp.), Diaspididae (1 sp.), Coccidae (1 sp.); Coleoptera: Buprestidae (1 sp.), Cerambycidae (2 spp.); and Lepidoptera: Lasiocampidae (1 sp.). Five species of fungi are known from literature and they belong to: Botryosphaeriales (3 spp.), Pleosporales (1 sp.), and Diaporthales (1 sp.). [ABSTRACT FROM AUTHOR]

Background. Greenery resources in small towns are not protected adequately due to insufficient data on their quality and quantity. The aim of the study was to identify valuable foreign tree species in the town of Bolków to protect the natural and cultural heritage. Material and methods. The study area was the historical part of the town of Bolków, which was identified upon available archival materials. In 2016 trees of foreign origin were inventoried in that area. The analysis of historical materials, measurements of the trunk perimeter, the list of forms of nature conservation provided by the Regional Directorate for Environmental Protection in Lower Silesia and assessment of the health status were used as the criteria taken into consideration to assess the possibility of legal protection of rare and valuable trees, which could receive the status of natural monuments. Results. 21 rare trees of 14 taxa were identified in Bolków. Most of the trees were found in the garden of former coeducational college established in 1886. All the trees are mostly located near non-historical objects. The trunk perimeter of most of the trees met the minimum limit for natural monuments in Lower Silesia. The following rare taxa were identified: horse chestnut (Aesculus hippocastanum L.) 'Laciniata', European ash (Fraxinus excelsior L.) 'Pendula Wentworthii' and Rocky Mountain ponderosa pine (Pinus ponderosa P. Lawson & C. Lawson var. scopulorum Engelm.). Conclusions. The lack of natural monuments should not be interpreted as the lack of valuable trees in small towns. The case study of Bolków shows that valuable tree taxa do not usually grow in parks or squares. The qualitative research presented the history of greenery and horticulture of small towns in Lower Silesia. [ABSTRACT FROM AUTHOR]

The world’s fast pace of urbanization has exerted profound pressure on urban trees. With over 400 years of urban history, Macau has developed an exceptionally high population density and ultra-compact mode, yet it permits survival of interesting and diverse heritage trees. These outstanding living remnants connote special values in history, ecology and botany. In conjunction with commemorative importance, they have been designated as Old and Precious Trees (OPT). This study evaluated the OPT with reference to: (a) species diversity and evenness; (b) spatial distribution; (c) tree dimensions, age and health; and (d) spatial differentiation of tree attributes by four districts and eight tree-habitats. Heritage trees in Macau were compared with those in Hong Kong and Guangzhou. The 793 OPT belong to 63 species. The exotic Ficus rumphii is overwhelmingly dominant, followed by F. microcarpa , Cinnamomum camphora and Dimocarpus longan . Species composition, age distribution and health conditions are associated with tree-habitat. Roadside has the largest number of OPT but the least species richness. Public parks and gardens has the highest diversity and largest tree dimensions. The oldest trees are clustered in urban parks and religious places. Tree health is poorer at roadsides, and private residential and commercial properties. The patterns suggest close relationship between tree traits and physical fabric of the city. However, the variety rather than duration of geographical contacts is a key determinant of urban tree diversity. The findings offer insights for heritage-tree conservation and management strategies in compact cities with similar urban structure and history. [ABSTRACT FROM AUTHOR]

Keywords: changing environment; genotype-environment associations (GEAs); landscape genomics; local adaptation; tree conservation EN changing environment genotype-environment associations (GEAs) landscape genomics local adaptation tree conservation 1 2 2 05/02/22 20220428 NES 220428 In the original article, there was a mistake in the legend for Figure 1 titled as B The general framework of landscape genomics for tree conservation b as published. The citation has now been inserted in the legend of Figure 1 and should read: The general framework of landscape genomics for tree conservation. The plots of cluster, I F i SB ST sb outlier test and RONA are modified from Du et al. ([1]) and Feng et al. ([2]), respectively. [Extracted from the article]

As an increasing proportion of the global human population resides in urban areas, urban forests are becoming both more important and more threatened. In many cities urban tree cover conflicts with strategies for urban intensification, and is being reduced due to inadequate protection. Here, we assess the effectiveness of one type of tree protection policy used by a number of cities worldwide: the case-by-case protection of specific individual trees. We use Auckland, New Zealand as a case study, where the main form of urban tree protection is now through Auckland Council's Schedule of Notable Trees. We investigated: (1) the species composition of the listed trees, and (2) the relative contribution of geographical variables (suburb age, dwelling density, socio-economic deprivation, and tree cover) in explaining spatial variation in listed-tree density. Tree cover (>8 m) in central Auckland was 6% of the land area, 63.2% of which was on private land. Of these trees, approximately 15% were protected. The tree species protected reflected cultural heritage; popular species were protected in large numbers, whilst only a single individual of a threatened native species was protected. The highest numbers of listed trees were in older suburbs, those with higher density housing, and those with lower levels of socio-economic deprivation. A low correlation between vegetation cover and listed-tree density shows that the proportion of trees protected varies substantially in different areas. We conclude that this case-by-case tree protection strategy provides insufficient protection for Auckland's urban biodiversity, but better implementation would improve biodiversity and social outcomes. [ABSTRACT FROM AUTHOR]

With 10% of trees (> 8,000 species) threatened with extinction there is an urgent need for botanical gardens to protect threatened trees in dedicated conservation collections. Species conservation is mentioned in the mission statements of most major botanical gardens, yet the actual conservation value of existing ex situ tree collections is low. We conducted interviews with members of the botanical garden community and organized a symposium at the 5th Global Botanic Gardens Congress to identify challenges and collect recommendations to improve living ex situ tree collections. We summarize and evaluate this information to facilitate gardens becoming more effective agents for global tree conservation. Experts agree that gardens offer valuable strengths and assets for tree conservation. Some challenges exist, however, including a lack of strategic conservation focus, collection management limitations, gaps in fundamental biological information for trees, and a lack of global coordination. Solutions are offered to facilitate gardens and arboreta of all sizes to participate more effectively in tree conservation. Prioritizing genetically diverse tree collections, participating in conservation networks, developing tree-specific conservation models and guidelines, and strengthening tree science research efforts are a few examples. Most importantly, a more coordinated global effort is needed to fill knowledge gaps, share information, and build conservation capacity in biodiversity hotspots to prevent the loss of tree species. [ABSTRACT FROM PUBLISHER]

Road traffic emits a cocktail of pollutants that can influence the vegetation and plant diversity in neighboring areas. However, the recovery potential of bryophytes after traffic abandonment is still little explored. In addition, the effects of the main pollutants of road verges, such as metals and salinity, on moss flora need to be investigated. In our study, we compared the moss richness and diversity in two closely related veteran tree allees of high conservation importance. The allees in Gryżów and Lubrza, Poland, were chosen because of their similarity in age, geographical location, type of surrounding areas, and tree species. The only difference was that the trees in Gryżów had not been exposed to direct road pollution for almost 30 years. The moss richness and diversity differed significantly between the sites. Altogether, 20 moss species were recorded on 229 trees, 17 species in Gryżów (abandoned road), and 13 in Lubrza (busy road). We found considerable differences between moss cover on the road-facing and opposite sides of tree trunks. In Lubrza, mosses on the road-facing side were very scarce. The moss cover in Gryżów was highly balanced between trunk sides as well as among trunk heights. Typical epiphytic species such as Bryum moravicum, Dicranoweisia cirrata, Leskea polycarpa, and Orthodicranum tauricum preferred the Gryżów tree stands, where they were present in numbers almost twice as high as that at Lubrza. The study shows that constructing a bypass road could be an effective conservation measure for veteran tree protection with their epiphytic moss flora. [ABSTRACT FROM AUTHOR]

Abstract: Public housing estates (PHEs) in Hong Kong, accommodating 3.3 million of the 7-million population, have generous landscape planting in their grounds. The independent tree management regime generates a tree stock that deviates from the general urban-tree population. This study evaluated species composition, floristic diversity, importance value, and spatial distribution of trees in 102 PHEs (half of the total) occupying 8.31km2 (territory land area of 1104km2), assessed their contribution to urban biodiversity, and developed a species selection strategy to enrich urban biodiversity. 48,823 trees belonged to 232 species, 151 genera and 59 families. Natives contributed 69 species and 10,837 trees. Species profile was skewed toward exotic species and trees. The species were divided into six frequency groups. The signature group had 45 species each with >200 trees. The dominant, common and occasional groups had 20, 26 and 48 species, respectively. 59 species in the rare group and 34 in the solitary group denoted changing and diverse species selections, respectively. Nonmetric Multidimensional Scaling (NMDS) found that species distribution in PHEs was strongly associated with species diversity, estate area and estate age. However, district and region were not correlated with NMDS. Some 98 species were significantly correlated (Spearman) with one or both NMDS axes. Species groups were analyzed to inform a species selection strategy to improve future planting program and enrich urban biodiversity. The methods and findings could be applied to south-China and other cities to rationalize urban-forest programs with the help of objective research data. [Copyright &y& Elsevier]

Abstract: Heritage trees in a city, echoing factors conducive to outstanding performance, deserve special care and conservation. To understand their structural and health conditions in urban Hong Kong, 30 defect-disorder (DD) symptoms (physical and physiological) subsumed under four tree-position groups (soil-root, trunk, branching, and crown-foliage) and tree hazard rating were evaluated. The surveyed 352 trees included 70 species; 14 species with 233 trees were native. More trees had medium height (10–15m), medium DBH (1–1.5m) and large crown (>15m). In ten habitats, public park and garden (PPG) accommodated the most trees, and roadside traffic island (RTI) and public housing estate (PH) had the least. Tree dimensions and tree habitats were significantly associated. The associations between the 2831 DD and tree-position groups, tree habitats and tree hazard rating were analyzed. Fourteen trees from Ficus microcarpa, Ficus virens and Gleditsia fera had high hazard rating, 179 trees from 22 species moderate rating, and 159 trees from 55 species low rating. RTI, roadside tree strip (RTS), roadside tree pit (RTP), roadside planter (RP) and stone wall (SW) had more moderate hazard rating, and PPG, roadside slope (RS) and government, institutional and community land (GIC) more low rating. Redundancy analysis showed that DD were positively correlated with RTS, RTP, RP and SW, but negatively correlated with PPG, RS and GIC (p <0.05). The DD significantly increased tree hazard rating and failure potential. Future management implications for heritage-tree conservation and enhancement focusing squarely on critical tree defect-disorder in urban Hong Kong were explored, with application to other compact cities. [Copyright &y& Elsevier]

Abstract: Heritage trees play special ecological, historical and landscape roles in cities. The officially designated old-valuable trees (OVTs) in Hong Kong, threatened by urban intensification and improper care, demand deep understanding to inform management and conservation. This study evaluated their floristic diversity, biomass structure and importance value, and spatial pattern and differentiation by districts and tree-habitats. Data analysis was assisted by detrended correspondence analysis (DCA), similarity percentage analysis (SIMPER) and other statistical tests. New indices, namely district dissimilarity index (DDI), district heterogeneity index (DHI), habitat dissimilarity index (HDI) and habitat heterogeneity index (HHI) helped to assess spatial differentiation. The 352 OVTs belonged to 70 species, 56 genera and 36 families. Ficus microcarpa dominated with maximum importance value, accompanied by only three common species. Some 22 rare and 44 solitary species denote diverse origins due to inheritance and cultivation. Moraceae and Ficus were the dominant family and genus. The oldest districts accommodated more species, trees, and unique species, whereas newer districts had notably less. DCA showed higher floristic fidelity in old districts, and three common Ficus species were ubiquitous in districts. SIMPER results showed the highest DDI and lowest DHI in the newer district. Public park and garden (PPG) habitat harbours most species, trees, and botanical uniqueness. Three Ficus species were also ubiquitous in habitats. Public housing and PPG had the highest HDI. District and habitat dissimilarities were mainly contributed by dominant and common species. Management implications with reference to preservation and enhancement of OVTs were explored, with applications for other cities. [Copyright &y& Elsevier]

In southern Bahia, Brazil, cabrucas are the traditional agroforests in which cacao trees are planted under thinned-out native forests. To analyze the role of cabrucas in tree species conservation, we inventoried the non-cocoa trees in 1.0 ha plots of cabruca in 16 cocoa farms and compared our results with a similar survey undertaken in the early 1960s in the same region to analyze the long term changes. We also interviewed 160 cocoa farmers to investigate their preferences for species and the main practices used in managing shade trees. The cabrucas showed high levels of tree diversity for an agroforestry system (Shannon index ranging from 2.21 to 3.52) and also high variation in structure and composition among the different farms. Forest specialist trees accounted for most species (63.9%) in the survey and were among the species most preferred by the farmers, although we found evidence that some of these trees are gradually being replaced by other species. Our results indicate that cabrucas are poor substitutes for undisturbed forests in terms of tree species richness, but their presence in human-altered landscapes is of utmost importance to the conservation of forest tree species as they increase overall heterogeneity and may serve as ecological corridors, additional habitats, and buffer zones. [ABSTRACT FROM AUTHOR]

La Sepultura Biosphere Reserve-created in 1995 in Chiapas, Mexico-is well known for its biodiversity. Its buffer zone, harboring the upper ''Tablón'' river basin, has been intensively managed by peasants for 48 years. We carried out interviews with cattle producers at the Los Ángeles ejido, coupled with field surveys of vegetation presence, to determine the nature and allocation of different vegetation associations and their relation to indicators of tree regeneration (sapling presence). Our data showed that 96% of the producers surveyed owned areas with open pastures, and 83% owned at least 1 patch of forested pastures where cattle browse. For oak-forested pastures, the results suggest a trend of high sapling presence with high tree cover. In contrast, for deciduous pastures, the results suggest a trend of high sapling presence with intermediate tree cover. These results are consistent with the hypothesis that woody vegetation within grazing areas may facilitate natural tree recruitment around reserves. Furthermore, these vegetation cover results suggest that within the pasturelands found today in the Los Ángeles ejido, some ranchers may be inadvertently conducting practices that are consistent with agro-silvo-pastoral systems. [ABSTRACT FROM AUTHOR]

Gomortega keule (Molina) Baillon is a rare Chilean species classified as endangered and currently under conservation. Currently, conservation of this species is carried out by private companies and government agencies, but is done so based more on pragmatic criteria than scientifically based strategies. In this context, information concerning the genetic variability of the species among the different populations over its entire distribution range is incomplete, making it difficult to coordinate management and conservation strategies. Here we report a study to evaluate the genetic variability and population structure of G. keule over its entire distribution in Chile. Twenty-five ISSR primers for 223 individuals from 11 geographical populations were tested to evaluate genetic variability. Results showed a high level of genetic diversity for the species. A high level of genetic differentiation among populations was found, while genetic structure of the geographic populations was also shown by using STRUCTURE 2.1 software. Despite the fact that this species has been highly affected by human intervention and habitat destruction, a high level of genetic diversity was present. A likely explanation for this is that it reflects the previous distribution of this long-lived species and the current lack of sexual regeneration. Genetic diversity data must be considered in the development of a management strategy for further developing the protected areas, for identifying isolated small populations for conservation, and using larger populations with higher genetic diversity as seed sources for ex situ propagation and replanting. [ABSTRACT FROM AUTHOR]

Cambodia forms part of the Indo-Burma hotspot. Its extent of biodiversity, however, is subject to considerable uncertainty, as there has been little systematic collection of flora and fauna. During the Khmer Rouge regime institutions were banned, academics were prosecuted and written documentation systematically destroyed. Compared with neighbouring countries Cambodia has a low population density and relatively large natural areas that are still intact. However, deforestation is expanding rapidly and a significant but un-estimated area of forest has been degraded by development of agro-industries, encroachment, illegal logging, over-harvesting and forest fire as well as the use of chemicals during war. The purpose of the paper is to: (i) apply reserve selection methods to design more robust conservation networks when knowledge of species occurrence is incomplete and habitat is threatened, and (ii) evaluate the usefulness of systematic conservation planning in a developing country where data are limited and institutions for implementation are weak. This study investigates the performance of four non-probabilistic strategies: (i) a so-called ‘rule of thumb’, (ii) hotspot, (iii) minimum cost representation, and (iv) maximum coverage; and one probabilistic design strategy, i.e. maximum expected coverage. The maximum expected coverage approach is between 15% and 24% more efficient than the non-probabilistic strategies. Finally, the relevance of such tools to real-world conservation planning in Cambodia is investigated. By incorporating experts in the generation of data, running the models and setting up premises, they acknowledge that it is possible to contribute to more systematic conservation planning in developing countries. [Copyright &y& Elsevier]

Abstract: Heritage trees (HTs) play pertinent ecological-landscaping roles in cities, yet the few known studies are mainly descriptive or resource inventories. This paper explores the intertwined natural and cultural spatial associations between trees (species, dimensions and age) and city (landscape impact, urban fabric, district history and landuse), assessing the integrated city–tree complex at the macro-scale. The study area includes eight main built-up districts (covering 116 km2) of Guangzhou, a compact and major city in South China. A survey of historical and inventory records identified 348 HTs which encompass the city’s officially recognized HTs. Principal component analysis (PCA), Jaccard Index of Similarity (JIS), and other statistical tests helped to unravel spatial associations. The 25 HT species, compared to 254 species in the city’s entire urban forest, are dominated by four common species. The number of HTs increases with district age of 25–2500 years. The more stressful and cramped roadside habitat accommodates more HTs, followed by spacious park, and intra-lot interstitial spaces in education, government-institution, and religious sites. The HTs are dominated by the 100–200-year age bracket, with few older trees, indicating a generation gap and the inability of old districts to preserve older trees. Park and religious sites accommodate more of the oldest and largest trees. Roadside contains more wide-crown trees mainly due to effective protection from motor vehicles by the inner bicycle lane. District is indicated by JIS as the major determinant of species variations, with landuse playing a secondary role. Large trees polarise into normal and degraded tree forms due to physical site constraints. Tall-wide and short-wide tree forms with high landscape impact contribution dominate landscape impacts. PCA extracted three factors that explained 71.9% of the variations, namely age–dimension, potential growth, and district history. Increasing compactness and the present management regime may fail to sustain the HT stock and deprive the city of HT precursors. The concept of ecological brinkmanship and transgenerational arboriculture are proposed to enhance HT conservation. [Copyright &y& Elsevier]

Recent rapid urbanization of Guangzhou in south China has degraded its rich urban-tree endowment, scattered in roadside, park, and public and semi-public grounds. Based mainly on age, 384 outstanding trees of 25 species were officially designated as heritage specimens. They were evaluated in the field for tree dimensions and habitat types to establish landscape-ecological impacts and spatial differentiation by districts and landuses. To aid the analysis, new quantitative indices were developed, namely landscape-ecological value (LEV), biomass–landscape congruence (BLC), and species spatial differentiation (SSD), respectively, for species presence, abundance, fidelity and clustering. Cultivated natives and five common species dominated heritage trees, accompanied by 11 rare and 9 single ones. Comparisons between the urban- and the heritage-tree populations, and between the LEV of individual species, indicated the uniqueness of heritage species composition and relative landscape-ecological contributions of species groups. Tree count, LEV and species diversity increased markedly with district age, culminating in the second oldest district and then declined somewhat in the oldest; species richness peaked in the mature district and dropped in the old and oldest. Older districts had a narrow range of similarly stressful habitats accommodating mainly inherited old trees; mature districts had more diversified habitats and a dual provenance of inheritance plus recent recruits; young districts had few of both types. Stressful roadside landuse was dominated by tree count, but it was poor in species diversity and richness, and had a rather monotonous native-foliage character. Park provided ample opportunities for a complex species cohort of disparate geographical origin, dimension, age, and amenity function, but its species diversity fell short of expectations. The public and semi-public grounds harboured mainly common species except religious grounds which had higher species diversity and some notably large and unique trees. BLC and SSD results echoed the differential operation of environmental and human influences on tree biomass, configuration and landscape impacts, resulting in notable variations between districts and landuses. The management implications of the results and prognosis for the future of urban heritage trees were explored with reference to Guangzhou and other cities. [Copyright &y& Elsevier]

The recent fast pace of urbanization in China and other developing countries has exerted pressure on urban trees, which constitute a key urban environmental asset. The most outstanding trees should be treated as natural-cum-cultural heritage. Guangzhou City’s growth has threatened its rich urban-tree endowment, a diversified assemblage of 200,000 trees represented by 254 species and located in three major habitats: roadside, park, and institutional grounds. Mainly based on age and performance, 348 trees were officially designated as heritage specimens. They were evaluated in the field for tree dimensions, habitat, performance, and landscape contribution, to establish enhanced conservation and management strategies. With only 25 species, heritage trees were dominated by five cultivated natives and encompass some of the city’s rare species; some common urban-forest species were not represented. Older districts and roadside habitats, despite their compact town plan and limited growing space, had the largest tree dimensions and largest share of heritage trees. Many heritage trees were large with long life expectancy and the potential for biomass expansion, and had pivotal cityscape impacts where they occur. Old neighborhoods, traditional haven for the arborescent treasure, are being changed by construction activities and periodic typhoon and windstorm damages. Increasing development density could degrade the heritage trees and their growing space, and reduce tree quality and life span. Upgrading the statutory-administrative systems and arboricultural care can enhance long-term survival of the precious natural-cum-cultural heritage. The experience of Guangzhou in identifying and preserving its high-quality urban trees can provide management strategies for other cities. [ABSTRACT FROM AUTHOR]