Growth-Climate Relationships and Long-Term Growth Trends of the Tropical Forest Tree Choerospondias axillaris (Anacardiaceous) in East-Central Thailand

Tropical forests play important roles in global carbon cycling. Tree-ring analysis can provide important information for understanding long-term trends in carbon-fixation capacity under climate change. However, tree-ring studies in tropical regions are limited. We carried out a tree-ring analysis to investigate the dendrochronological potential of the tropical forest tree Choerospondias axillaris (Anacardiaceae) in east-central Thailand. Our study focused on growth-climate relationships and long-term growth trends. A chronology was constructed covering the period from 1932 to 2019. The tree-ring width index of C.axillaris was positively correlated with precipitation in June, July, and October. Furthermore, growth of C.axillaris was positively correlated with the Standardized Precipitation-Evapotranspiration Index (SPEI) from July to October, indicating that growth of C.axillaris is mainly limited by moisture availability in the late monsoon season. Moving correlation analysis further revealed the consistency and temporal stability of the relationship of tree growth with monsoon season precipitation and SPEI during the period under study. There was a significant increasing trend in long-term growth from 1932 to 2002 (slope = 0.017, p < 0.001); however, long-term growth decreased from 2003 to 2019 (slope = −0.014, p < 0.001). Our study provides important insight into the growth-climate correlations of a broad-leaved tree species in a dry evergreen forest in tropical Asia.

Climatically Driven Holocene Glacier Advances in the Russian Altai Based on Radiocarbon and OSL Dating and Tree Ring Analysis

Analysis of new chronological data, including 55 radiocarbon, 1 OSL, and 8 dendrochronological dates, obtained in the upper reaches of trough valleys within the Katun, North Chuya, South Chuya, and Chikhachev ranges, together with the 55 previously published ones, specifies climatically driven glacier dynamic in the Russian Altai. Available data refute the traditional concept of the Russian Altai Holocene glaciations as a consecutive retreat of the Late Pleistocene glaciation. Considerable and prolonged warming in the Early Holocene started no later than 11.3–11.4 cal kBP. It caused significant shrinking or even complete degradation of alpine glaciers and regeneration of forest vegetation 300–400 m above the modern upper timber limit. Stadial advances occurred in the middle of the Holocene (4.9–4.2 cal kBP), during the Historical (2.3–1.7 cal kBP), and the Aktru (LIA thirteenth–nineteenth century) stages. New radiocarbon ages of fossil soils limited glaciers expansion in the Middle Holocene by the size of the Historical moraine. Lesser glacial activity between 5 and 4 cal kBP is also supported by rapid reforestation in the heads of trough valleys. Glaciers advance within the Russian Altai, accompanied by accumulation of the Akkem moraine, could have occurred at the end of the Late Pleistocene.

Characterizing Urban Expansion Combining Concentric-Ring and Grid-Based Analysis for Latin American Cities

Spatio-temporal characterization of urban expansion is the first step towards understanding how cities grow in space. We summarize two approaches used in urban expansion measurement, namely, concentric-ring analysis and grid-based analysis. Concentric-ring analysis divides urban areas into a series of rings, which is used to quantify the distance decay of urban elements from city centers. Grid-based analysis partitions a city into regular grids that are used to interpret local dynamics of urban growth. We combined these two approaches to characterize the urban expansion between 2000–2014 for five large Latin American cities (São Paulo, Brazil; Mexico City, Mexico; Buenos Aires, Argentina; Bogotá, Columbia; Santiago, Chile). Results show that the urban land (built-up area) density in concentric rings decreases from city centers to urban fringe, which can be well fitted by an inverse S curve. Parameters of fitting curves reflect disparities of urban extents and urban form among these five cities over time. Grid-based analysis presents the transformation of population from central to suburban areas, where new urban land mostly expands. In the global context, urban expansion in Latin America is far less rapid than countries or regions that are experiencing fast urbanization, such as Asia and Africa. Urban form of Latin American cities is particularly compact because of their rugged topographies with natural limitations.

Comparative Analysis of Rare and Endangered Plants of Hirkan Dendroflora

In the research work has been comparatively analyzed the Hirkan dendroflora and have been collected herbariums of rare and endangered trees and shrubs. There are identified 26 families, 40 genera, 60 species of rare and endangered trees and shrubs naturally spreading areas, distribution of individuals in populations, have been performed tree-ring analysis on old samples. As a result of the observations have been determined, that in the Hirkan flora the majority of species in the areas have been diminished and decreased compared to previous years, many species are in danger of being disappeared. From this point of view by the monitorings of the area were studied threat criteria, the reasons of decline in plant varieties, those plants have been identified based on version of IUCN 3.1. In the research work have been processed out the protection measures, the biological features of species, the causes of change in natural resources.

Dendrogeomorphology of Different Landslide Types: A Review

The dating of past landslide events is one of the most crucial aspects of landslide research, leading to a better understanding of past landslide activity. Landslides can be extremely dangerous natural hazards, and thus, solving the relationships between their activity and climate variations is of high importance. For these purposes, data about past landslide activity are fundamental for such analyses. Various methods of landslide absolute dating exist, but the most precise approach that dates back several centuries is based on tree-ring analysis (dendrogeomorphology). Landslide movements can affect the growth of trees in response to specific growth disturbances. Although dendrogeomorphic methods are successfully used for dating other geomorphic processes, their use in landslide research is actually the most frequent. Dendrogeomorphic research on landslides is strongly influenced by general approaches of landslide signal extraction from tree-ring series of disturbed trees and by the type of landslide (varying by morphology, material and mechanism of movement). This study provides an overview of basic aspects of dendrogeomorphic research on landslides, and more specifically, it reviews basic tree-ring-based approaches of landslide dating. Presented review focuses on various landslide types and their effect on dendrogeomorphic dating. This review is built from the extensive database of all accessible dendrogeomorphic studies of landslides from 1893 to 2020. Moreover, recommendations for specific sampling and approach choice in individual landslide types are presented. Finally, limits of tree-ring-based approaches are presented, including provided proposals for further research.

Tree-Ring Analysis of Intermediate Hawthorn (Crataegus media Bechst.) in NW Poland

Intermediate hawthorn (Crataegus × media Bechst.) is broadly distributed in Europe but very rarely examined by dendrochronologists. In NW Poland, it is one of three naturally occurring hawthorn species, growing mainly at forest margins, along roads, in mid-field woodlots, and on uncultivated land. Biocenotically, it is a very valuable species. This study aimed to determine the age of trees, tree-ring dynamics, and growth–climate relationship for intermediate hawthorn. Signature years were also determined. Samples for analysis were collected from 22 trees growing in a typical agricultural landscape in a monospecific mid-field woodlot comprised of several hundred specimens of various ages and forms (shrubs and trees). Using classic methods of dendrochronological dating, a 40-year long chronology spanning 1981–2020 was constructed. The radial growth rate of intermediate hawthorn is comparable to other tree species forming stands in NW Poland and equals 2.41 mm/year. Considerable intersubject variability is noted, from 1.48 to 4.44 mm/year. The chronology was also used for dendroclimatological analyses, including correlation and response function and signature years. Of the meteorological parameters analyzed, annual incremental growth in hawthorn is the most strongly shaped by precipitation totals from May to August of the current vegetation year: high rainfall favors the formation of wide tree-rings. Statistically significant growth–climate relationships were also obtained for winter months (December of the preceding vegetation year, January and February), for which period negative correlation and regression values are noted for air temperature and insolation. Furthermore, high precipitation, low-temperature and low insolation late in the preceding vegetation year (especially in August) make a positive influence on the condition of trees in the upcoming growing season. Signature year analysis clearly pointed to precipitation as the dominant factor in shaping tree-rings in the studied hawthorn population. As there are no dendrochronological papers concerning indigenous hawthorn species, future studies should be expanded to include diverse geographic locations and habitat conditions and should include all three species of hawthorn occurring in Poland.

Reconstruction of Resin Collection History of Pine Forests in Korea from Tree-Ring Dating

Resin is one of the traditional non-timber forest products in the Republic of Korea. In order to investigate the chronological activity of resin collection, the wounds/cuts on red pines (Pinus densiflora) were dated using a tree-ring analysis technique. Additionally, the size of the trees in the resin collection years and the present conditions of the trees were investigated to verify the tree conditions and the size of wounds. Eighty-eight red pines distributed over nine sites in the Republic of Korea were selected to extract increment cores and investigate the wound size. Through the tree-ring analysis, the trees with big wounds (24.7 × 104.7 cm) made via panel hacksaw method were dated in the range 1938–1952, whereas small wounds (40.2 × 20.9 cm) made via the conventional chisel method were dated between 1956 and 1973. Moreover, the red pines thicker than 20.0 cm were the ones that were used for resin collection. Furthermore, the wounds created by the conventional chisel were healed with time, whereas the ones formed via the panel hacksaw method still required long times for healing. The large wounds had the advantage of supplying a large amount of resin, but this was temporary. On the other hand, the smaller wounds formed via the traditional chisel method could generate resin for a longer time and heal faster.