scholarly journals On the Management of Large-Diameter Trees in China’s Forests

Forests ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 111 ◽  
Author(s):  
Chuping Wu ◽  
Bo Jiang ◽  
Weigao Yuan ◽  
Aihua Shen ◽  
Shuzhen Yang ◽  
...  
Keyword(s):  
Biodiversity Conservation ◽  
Forest Cover ◽  
Large Diameter ◽  
Management Strategies ◽  
Ecosystem Functions ◽  
Secondary Forests ◽  
Critical Question ◽  
Old Growth ◽  
Plantation Forests ◽  
Old Growth Forests

Large-diameter trees have mainly been used for timber production in forestry practices. Recently, their critical roles played in biodiversity conservation and maintenance of ecosystem functions have been recognized. However, current forestry policy on the management of large-diameter trees is weak. As China is the biggest consumer of large-diameter timbers, how to maintain sustainable large-diameter timber resources as well as maximize ecological functions of the forests is a critical question to address. Here we summarize historical uses, distribution patterns, and management strategies of large-diameter trees in China. We found that large-diameter trees are mainly distributed in old-growth forests. Although China’s forest cover has increased rapidly in the past decades, large-diameter trees are rarely found in plantation forests and secondary forests. We suggest that knowledge of large-diameter trees should be widely disseminated in local forestry departments, especially their irreplaceable value in terms of biodiversity conservation and ecosystem functions. Protection of large-diameter trees, especially those in old-growth forests, is critical for sustainable forestry. To meet the increasing demand of large-diameter timbers, plantation forests and secondary forests should apply forest density management with thinning to cultivate more large-diameter trees.

scholarly journals Recovery of Functional Diversity Following Shifting Cultivation in Tropical Monsoon Forests

Forests ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 506 ◽  
Author(s):  
Fuying Deng ◽  
Yunling He ◽  
Runguo Zang
Keyword(s):  
Functional Diversity ◽  
Functional Traits ◽  
Shifting Cultivation ◽  
Forest Ecosystems ◽  
Recovery Process ◽  
Secondary Forests ◽  
Old Growth ◽  
Old Growth Forests ◽  
Tropical Monsoon ◽  
Monsoon Forests

The relationship between biodiversity and ecosystem functioning is an important issue in ecology. Plant functional traits and their diversity are key determinants of ecosystem function in changing environments. Understanding the successional dynamics of functional features in forest ecosystems is a first step to their sustainable management. In this study, we tested the changes in functional community composition with succession in tropical monsoon forests in Xishuangbanna, China. We sampled 33 plots at three successional stages—~40-year-old secondary forests, ~60-year-old secondary forests, and old growth forests—following the abandonment of the shifting cultivation land. Community-level functional traits were calculated based on measurements of nine functional traits for 135 woody plant species. The results show that the community structures and species composition of the old-growth forests were significantly different to those of the secondary stands. The species diversity, including species richness (S), the Shannon–Weaver index (H), and Pielou’s evenness (J), significantly increased during the recovery process after shifting cultivation. The seven studied leaf functional traits (deciduousness, specific leaf area, leaf dry matter content, leaf nitrogen content, leaf phosphorus content, leaf potassium content and leaf carbon content) changed from conservative to acquisitive syndromes during the recovery process, whereas wood density showed the opposite pattern, and seed mass showed no significant change, suggesting that leaf traits are more sensitive to environmental changes than wood or seed traits. The functional richness increased during the recovery process, whereas the functional evenness and divergence had the highest values in the 60-year-old secondary communities. Soil nutrients significantly influenced functional traits, but their effects on functional diversity were less obvious during the secondary succession after shifting cultivation. Our study indicates that the recovery of tropical monsoon forests is rather slow; secondary stands recover far less than the old growth stands in terms of community structure and species and functional diversity, even after about half a century of recovery, highlighting the importance of the conservation of old growth tropical monsoon forest ecosystems.

scholarly journals Understanding Land Cover Change in a Fragmented Forest Landscape in a Biodiversity Hotspot of Coastal Ecuador

2018 ◽  
Vol 10 (12) ◽  
pp. 1980 ◽  
Author(s):  
Xavier Haro-Carrión ◽  
Jane Southworth
Keyword(s):  
Land Cover ◽  
Forest Cover ◽  
Secondary Forest ◽  
Dry Forest ◽  
Training Data ◽  
Forest Types ◽  
Landsat Images ◽  
Old Growth ◽  
Plantation Forests ◽  
Forest Regrowth

Understanding forest cover changes is especially important in highly threatened and understudied tropical dry forest landscapes. This research uses Landsat images and a Random Forest classifier (RF) to map old-growth, secondary, and plantation forests and to evaluate changes in their coverage in Ecuador. We used 46 Landsat-derived predictors from the dry and wet seasons to map these forest types and to evaluate the importance of having seasonal variables in classifications. Initial RF models grouped old-growth and secondary forest as a single class because of a lack of secondary forest training data. The model accuracy was improved slightly from 92.8% for the wet season and 94.6% for the dry season to 95% overall by including variables from both seasons. Derived land cover maps indicate that the remaining forest in the landscape occurs mostly along the coastline in a matrix of pastureland, with less than 10% of the landscape covered by plantation forests. To obtain secondary forest training data and evaluate changes in forest cover, we conducted a change analysis between the 1990 and 2015 images. The results indicated that half of the forests present in 1990 were cleared during the 25-year study period and highlighted areas of forest regrowth. We used these areas to extract secondary forest training data and then re-classified the landscape with secondary forest as a class. Classification accuracies decreased with more forest classes, but having data from both seasons resulted in higher accuracy (87.9%) compared to having data from only the wet (85.8%) or dry (82.9%) seasons. The produced cover maps classified the majority of previously identified forest areas as secondary, but these areas likely correspond to forest regrowth and to degraded forests that structurally resemble secondary forests. Among the few areas classified as old-growth forests are known reserves. This research provides evidence of the importance of using bi-seasonal Landsat data to classify forest types and contributes to understanding changes in forest cover of tropical dry forests.

Evidence for arrested succession within a tropical forest fragment in Singapore

2011 ◽  
Vol 27 (03) ◽  
pp. 323-326 ◽  
Author(s):  
Gregory R. Goldsmith ◽  
Liza S. Comita ◽  
Siew Chin Chua
Keyword(s):  
Ecosystem Services ◽  
Tropical Forest ◽  
Tropical Forests ◽  
Secondary Forests ◽  
Forest Fragment ◽  
Landscape Mosaic ◽  
Old Growth ◽  
Arrested Succession ◽  
Old Growth Forests ◽  
Tropical Landscape

Secondary forests occupy a growing portion of the tropical landscape mosaic due to regeneration on abandoned pastures and other disturbed sites (Asneret al. 2009). Tropical secondary forests and degraded old-growth forests now account for more than half of the world's tropical forests (Chazdon 2003), and provide critical ecosystem services (Brown & Lugo 1990, Guariguata & Ostertag 2001).

scholarly journals Large carbon sink potential of Amazonian Secondary Forests to mitigate climate change

2020 ◽  
Author(s):  
Viola Heinrich ◽  
Ricardo Dalagnol ◽  
Henrique Cassol ◽  
Thais Rosan ◽  
Catherine Torres de Almeida ◽  
...  
Keyword(s):  
Carbon Sequestration ◽  
Spatial Patterns ◽  
Environmental Variability ◽  
Carbon Sink ◽  
Climate Mitigation ◽  
Secondary Forests ◽  
Old Growth ◽  
Mitigation Potential ◽  
Old Growth Forests ◽  
Mitigate Climate Change

Abstract Secondary forests (SF) have a large climate mitigation potential, given their ability to sequester carbon up to 20 times faster than old-growth forests. Environmental variability and anthropogenic disturbances lead to uncertainties in estimating spatial patterns of SF carbon sequestration rates. Here we quantify the influence of environmental and disturbance drivers on the rate and spatial patterns of regrowth in the Brazilian Amazon, by integrating a 33-year land cover timeseries with a 2017 Aboveground Biomass dataset. Carbon sequestration rates of young Amazonian SF (<20 years old) are at least twice as high in the west (3.0±1.0 MgC ha-1 yr-1) than in the east (1.3±0.3 MgC ha-1 yr-1). Disturbances reduce SF regrowth rates by 8–50% (0.6 – 1.3 MgC ha-1 yr-1). We estimate the 2017 SF carbon stock to be 294 TgC, which could be 8% higher by avoiding fires and repeated deforestation. Maintaining the 2017 SF area has the potential to accumulate ~15 TgC yr-1 until 2030, contributing ~5% to Brazil’s 2030 net emissions reduction target. Supporting SF and old-growth forests conservation alongside the expansion of SF in deforested areas is therefore a viable nature-based climate mitigation solution.

scholarly journals Forest structural parameters and aboveground biomass in old-growth and secondary forests along an elevational gradient in Mexico

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Martina Alrutz ◽  
Jorge Antonio Gómez Díaz ◽  
Ulf Schneidewind ◽  
Thorsten Krömer ◽  
Holger Kreft
Keyword(s):  
Climate Change ◽  
Forest Structure ◽  
Aboveground Biomass ◽  
Basal Area ◽  
Elevational Gradient ◽  
Stem Density ◽  
Secondary Forests ◽  
Old Growth ◽  
Old Growth Forest ◽  
Old Growth Forests

Background: Tropical montane forests are important reservoirs of carbon and biodiversity but are threatened by deforestation and climate change. It is important to understand how forest structure and aboveground biomass change along gradients of elevation and succession. Questions: What are the interactive effect of elevation and two stages of succession on forest structure parameters? Studied species: Tree communities. Study site and dates: Cofre de Perote, Veracruz, Mexico. August to December 2015. Methods: We studied four sites along an elevational gradient (500, 1,500, 2,500, and 3,500 m). At each elevation and each forest type, we established five 20 × 20 m plots (n = 40 plots). Within each plot, we measured stem density, mean diameter at breast height (dbh), and tree height and derived basal area and aboveground biomass (AGB). Results: AGB peaked at 2,500 m and was significantly related to elevation and succession, with higher values in old-growth forests than in secondary forests at higher altitudes. Lower values of mean dbh and basal area were found at higher elevations. At the lowest elevation, both successional stages had the same values of stem density and AGB. At both lower elevations, secondary forests had higher values of dbh and basal area. There were high biomass stocks in the old-growth forest at 2,500 and 3,500 m. Conclusions: Old-growth forests at higher elevations are threatened by deforestation, consequently these remaining fragments must be preserved because of their storage capacity for biomass and their ability to mitigate climate change.

scholarly journals Smallholder agriculture results in stable forest cover in riverine Amazonia

2021 ◽  
Author(s):  
Oliver T. Coomes ◽  
Margaret Kalacska ◽  
Yoshito Takasaki ◽  
Christian Abizaid ◽  
Tristan Grupp
Keyword(s):  
Satellite Imagery ◽  
Shifting Cultivation ◽  
Forest Cover ◽  
Secondary Forest ◽  
Forest Disturbance ◽  
Secondary Forests ◽  
Smallholder Agriculture ◽  
Peruvian Amazon ◽  
Terra Firme ◽  
Old Growth

Abstract Recent studies point to a rapid increase in small-scale deforestation in Amazonia. Where people live along the rivers of the basin, customary shifting cultivation creates a zone of secondary forest, orchards and crop fields around communities in what was once was old-growth terra firme forest. Visible from satellite imagery as a narrow but extensive band of forest disturbance along rivers, this zone is often considered as having been deforested. In this paper we assess forest disturbance and the dynamics of secondary forests around 275 communities along a 725 km transect on the Napo and Amazon rivers in the Peruvian Amazon. We used high-resolution satellite imagery to define the ‘working area’ around each community, based on the spatial distribution of forest/field patches and the visible boundary between old-growth and secondary forests. Land cover change was assessed between ca. 1989 and 2015 using CLASliteTM image classification. Statistical analyses using community and household-level data from the Peruvian Amazon Rural Livelihoods and Poverty (PARLAP) Project identified the predictors of the extent of forest disturbance and the dynamics of secondary forests around communities. Although shifting cultivation is the primary driver of old-growth forest loss, we find that secondary forest cover which replaces old-growth forests is stable through time, and that both the area and rate of expansion into old-growth forests are modest when compared to forest conversion in Peru for colonization and plantation development. Our findings challenge the notion that smallholder agriculture along rivers is an important threat to terra firme forests in Amazonia and point to the importance of protecting forests on community lands from loggers, colonists and other outsiders.

scholarly journals Die Suche nach altem Wald in der Schweiz

2015 ◽  
Vol 166 (2) ◽  
pp. 67-74 ◽  
Author(s):  
Rita Bütler ◽  
Markus Bolliger ◽  
Brigitte Commarmot
Keyword(s):  
Forest Cover ◽  
Dead Wood ◽  
Stand Structure ◽  
National Forest Inventory ◽  
Old Growth ◽  
Forest Patches ◽  
Natural Processes ◽  
Old Growth Forest ◽  
Veteran Trees ◽  
Old Growth Forests

The search for old-growth forests in Switzerland Old-growth forests and stands have multiple values, such as biological, scientific, socioeconomic, aesthetic, spiritual and cultural ones, but they are very rare in central Europe. Currently, an overview about the existence and size of old-growth forest patches in Switzerland is missing. We propose a definition for old-growth forests worth preserving based on ten criteria: 1) presence of veteran trees, 2) significant biomass, 3) heterogeneous stand structure including senescent and decaying stages, 4) presence of natural processes and disturbances, 5) high dead wood volume (at least 30 m3/ha) and a large diversity of dimensions and decay stages of dead wood pieces, 6) autochthonous tree species, 7) diverse and natural species assemblages, 8) only extensive or no harvesting for the last 50 years, 9) long continuity of forest cover, 10) minimal area of 30 ha for old-growth forests and 1 ha for old-growth stands. When searching for old-growth forests and stands worth preserving, quantitative criteria from the National Forest Inventory and other sources should also be used. We call on all forest specialists to identify old-growth patches, to inform the population and decision makers about their high value, and to protect them in an adequate manner as a unique natural heritage.

Old-growth forests in the temperate deciduous zone of Quebec: Identification and evaluation for conservation and research purposes

2003 ◽  
Vol 79 (3) ◽  
pp. 559-569 ◽  
Author(s):  
Normand Villeneuve ◽  
Jacques Brisson
Keyword(s):  
Acer Saccharum ◽  
Sugar Maple ◽  
Forest Cover ◽  
Deciduous Forest ◽  
Control Site ◽  
Old Growth ◽  
Forest Zone ◽  
Dead Trees ◽  
Old Growth Forests ◽  
Shade Tolerant Species

The Quebec Department of Natural Resources (Ministère des ressources naturelles du Québec) is working to identify and protect old-growth forests in the deciduous forest zone of the province. A total of 88 sites was visited and a multivariate analysis of the main attributes of old growth allowed the development of quantitative definitions and criteria for identifying old-growth sugar maple (Acer saccharum), eastern hemlock (Tsuga canadensis), eastern white pine (Pinus strobus), eastern white-cedar (Thuja occidentalis), and red spruce (Picea rubens) stands. Life expectancy of various species according to environment was determined through a statistical analysis of 21 500 study trees taken from the province's forest inventory. Four different identification criteria for old-growth forests were developed that include a number of indicators for old growth. Along with advanced age of forest cover, the criteria that best reflected the nature of old-growth forests were the presence of large dead trees, low cutting intensity, and the importance of shade-tolerant species. Old-growth forests identified during this validation work occupy roughly 60 km2 in Quebec's deciduous forest zone. Among other things, old-growth sugar maple stands of over 400 years old were discovered, containing stems with a diameter at breast height of 140 cm and a height of over 38 m. The very great potential of many of these exceptional forests for scientific research and biodiversity conservation is illustrated by the work carried out in the Boisé des Muir. Despite its small size, this sugar maple stand, which is over 300 years old, has advanced knowledge in fields as varied as forest dynamics, biodiversity, and climate studies, and has also served as a control site for various scientific studies. Key words: old-growth forests, definitions, criteria, indicators, inventory, Quebec, conservation, scientific value

Continued loss of temperate old-growth forests in the Romanian Carpathians despite an increasing protected area network

2012 ◽  
Vol 40 (2) ◽  
pp. 182-193 ◽  
Author(s):  
JAN KNORN ◽  
TOBIAS KUEMMERLE ◽  
VOLKER C. RADELOFF ◽  
WILLIAM S. KEETON ◽  
VLADIMIR GANCZ ◽  
...  
Keyword(s):  
Protected Areas ◽  
Protected Area ◽  
Management Practices ◽  
Forest Cover ◽  
Satellite Image ◽  
Area Network ◽  
Old Growth ◽  
Protected Area Network ◽  
Old Growth Forest ◽  
Old Growth Forests

SUMMARYOld-growth forests around the world are vanishing rapidly and have been lost almost completely from the European temperate forest region. Poor management practices, often triggered by socioeconomic and institutional change, are the main causes of loss. Recent trends in old-growth forest cover in Romania, where some of the last remaining tracts of these forests within Europe are located, are revealed by satellite image analysis. Forest cover declined by 1.3 % from 2000 to 2010. Romania's protected area network has been expanded substantially since the country's accession to the European Union in 2007, and most of the remaining old-growth forests now are located within protected areas. Surprisingly though, 72% of the old-growth forest disturbances are found within protected areas, highlighting the threats still facing these forests. It appears that logging in old-growth forests is, at least in part, related to institutional reforms, insufficient protection and ownership changes since the collapse of communism in 1989. The majority of harvesting activities in old-growth forest areas are in accordance with the law. Without improvements to their governance, the future of Romania's old-growth forests and the important ecosystem services they provide remains uncertain.

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