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

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).

2003 ◽  
Vol 79 (3) ◽  
pp. 645-651 ◽  
Author(s):  
Ole Hendrickson

How much old growth is there? How much was there? Is remaining old growth disappearing? If so, how fast and why? Is any more old growth being created? How fragmented are old-growth forests? What other forest types and land uses surround them? Scientists see these as challenging questions, never to be fully resolved. Policy makers see information gaps and want answers. They assume that because the public values old-growth forests, their continuing availability must be assured. Forest managers need to be convinced that old-growth forests provide unique values before taking costly measures to conserve them. The relative stability of old-growth forests is interesting from a management perspective. Are old-growth forests more resistant to high-intensity disturbances, such as crown fires and violent storms? Do they resist insect outbreaks? A related issue is the quality of ecosystem services provided by old-growth forests. Do they have an exceptional ability to provide clean water, to stabilize hydrologic regimes, and to moderate local climates? Can they be used to test hypotheses about complexity, stability, resilience, and ecosystem change? These questions provide a strong rationale for developing working definitions of old-growth forests, for retaining areas of old-growth forest, and for replicating old-growth features in landscapes managed for timber production. Old-growth forests are desirable sites for monitoring, serving as benchmarks for adaptive management. Knowledge about old-growth forests has already had a considerable impact on policy and management, particularly in coastal regions. Current research and monitoring systems may not be adequate for the task of identifying and describing the biological complexity and diversity inherent in old-growth forests. New investments in collecting and managing data from old-growth (and secondary) forests are needed, and will pay manifold dividends to future generations of Canadians. This paper suggests that the central role of old-growth forests in developing sustainable forest management should create an incentive for the forest science, policy, and management communities to unite in support of their conservation. Key words: biodiversity, gene conservation, resilience, ecosystem approach, information management, ecosystem services


2009 ◽  
Vol 6 (4) ◽  
pp. 7565-7597 ◽  
Author(s):  
J. Chave ◽  
D. Navarrete ◽  
S. Almeida ◽  
E. Álvarez ◽  
L. E. O. C. Aragão ◽  
...  

Abstract. The production of aboveground soft tissue represents an important share of total net primary production in tropical rain forests. Here we draw from a large number of published and unpublished datasets (n=81 sites) to assess the determinants of litterfall variation across South American tropical forests. We show that across old-growth tropical rainforests, litterfall averages 8.61±1.91Mg/ha/yr. Secondary forests have a lower annual litterfall than old-growth tropical forests with a mean of 8.01±3.41 Mg/ha/yr. Annual litterfall shows no significant variation with total annual rainfall, either globally or within forest types. It does not vary consistently with soil type, except in the poorest soils (white sand soils), where litterfall is significantly lower than in other soil types (5.42±1.91Mg/ha/yr). Litterfall declines significantly with increasing N:P. We also study the determinants of litterfall seasonality, and find that it does not depend on annual rainfall or on soil type. However, litterfall seasonality is significantly positively correlated with rainfall seasonality. Finally, we assess how much carbon is stored in reproductive organs relative to photosynthetic organs. Mean leaf fall is 5.74±1.83 Mg/ha/yr (71% of total litterfall). Mean allocation into reproductive organs is 0.69±0.40Mg/ha/yr (9% of total litterfall). The investment into reproductive organs divided by leaf litterfall is negatively related to the N:P ratio, suggesting that on poor soils, the allocation to photosynthetic organs is prioritized over that to reproduction. Finally, we discuss the ecological and biogeochemical implications of these results.


Forests ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 442 ◽  
Author(s):  
Paúl Eguiguren ◽  
Richard Fischer ◽  
Sven Günter

Anthropogenic activities such as logging or forest conversion into agricultural lands are affecting Ecuadorian Amazon forests. To foster private and communal conservation activities an economic incentive-based conservation program (IFC) called Socio Bosque was established. Existing analyses related to conservation strategies are mainly focused on deforestation; while degradation and the role of IFC to safeguard ecosystem services are still scarce. Further on, there is a lack of landscape-level studies taking into account potential side effects of IFC on different forest types. Therefore we assessed ecosystem services (carbon stocks, timber volume) and species richness in landscapes with and without IFC. Additionally, we evaluated potential side-effects of IFC in adjacent forest types; hypothesizing potential leakage effects of IFC. Finally, we tested if deforestation rates decreased after IFC implementation. Forest inventories were conducted in 72 plots across eight landscapes in the Ecuadorian Central Amazon with and without IFC. Plots were randomly selected within three forest types (old-growth, logged and successional forests). In each plot all individuals with a diameter at breast height greater than 10 cm were measured. Old-growth forests in general showed higher carbon stocks, timber volume and species richness, and no significant differences between old-growth forests in IFC and non-IFC landscapes were found. Logged forests had 32% less above-ground carbon (AGC) and timber volume in comparison to old-growth forests. Surprisingly, logged forests near IFC presented higher AGC stocks than logged forests in non-IFC landscapes, indicating positive side-effects of IFC. Successional forests contain 56% to 64% of AGC, total carbon and timber volume, in comparison to old-growth forests, and 82% to 87% in comparison to logged forests. Therefore, successional forests could play an important role for restoration and should receive more attention in national climate change policies. Finally, after IFC implementation deforestation rate decreased on parish level. Our study presents scientific evidence of IFC contribution to conserving ecosystem services and species richness. In addition IFC could help indirectly to reduce degradation effects attributed to logging, indicating potential compatibility of conservation aims with forest activities at a landscape level.


Forests ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 506 ◽  
Author(s):  
Fuying Deng ◽  
Yunling He ◽  
Runguo Zang

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.


Forests ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 111 ◽  
Author(s):  
Chuping Wu ◽  
Bo Jiang ◽  
Weigao Yuan ◽  
Aihua Shen ◽  
Shuzhen Yang ◽  
...  

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.


Author(s):  
Carlos Eduardo Frickmann Young

Tropical forests are among the most biodiverse areas on Earth. They contribute to ecosystem functions, including regulating water flow and maintaining one of the most important carbon sinks on the planet, and provide resources for important economic activities, such as timber and nontimber products and fish and other food. Rainforests are not empty of human population and are sites of ethnically and culturally diverse cultures that are responsible for many human languages and dialects. They also provide resources for important economic activities, such as timber and nontimber products. However, tropical deforestation caused by the expansion of agricultural activities and unsustainable logging continues at very high levels. The causes of forest loss vary by region. Livestock is the main driver in the Amazon, but commercial plantations (soybeans, sugar cane, and other tradable crops) also have an impact on deforestation, in many cases associated with violent conflicts over land tenure. In Southeast Asia, logging motivated by the tropical timber trade plays an important role, although palm oil plantations are an increasing cause of deforestation. In Africa, large-scale agricultural and industrial activities are less important, and the most critical factor is the expansion of subsistence and small-scale agriculture. However, trade-oriented activities, such as cocoa and coffee plantations in West Africa and logging in Central Africa, are becoming increasingly important. Public policies have a strong influence on these changes in land use, from traditional community-based livelihood practices to for-profit livestock, cultivation, and timber extraction. Investments in infrastructure, tax and credit incentives, and institutional structures to stimulate migration and deforestation represent economic incentives that lead to deforestation. Poor governance and a lack of resources and political will to protect the traditional rights of the population and environmental resources are another cause of the continuous reduction of tropical forests. Consequently, deforestation prevents the expansion of economic activities that could be established without threats to the remnants of native forest. There are also negative social consequences for the local population, which suffers from the degradation of the natural resources on which their production is based, and is hampered by air pollution caused by forest fires. In some situations, a vicious cycle is created between poverty and deforestation, since the expansion of the agricultural frontier reduces the forest areas where traditional communities once operated, but without generating job opportunities. New approaches are required to reverse this paradigm and to lay the foundation for a sustainable economy based on the provision of ecosystem services provided by tropical forests. These include (a) better governance and public management capacity, (b) incentives for economic activities compatible with the preservation of the tropical forest, and (c) large-scale adoption of economic instruments to support biodiversity and ecosystem services. Public policies are necessary to correct market failures and incorporate the values of ecosystem services in the land use decision process. In addition to penalties for predatory actions, incentives are needed for activities that support forest preservation, so the forest is worth retaining rather than clearing. Improving governance capacity, combining advanced science and technology with traditional knowledge, and improving the management of existing activities can also help to ensure sustainable development in tropical forest regions.


2020 ◽  
Author(s):  
Viola Heinrich ◽  
Ricardo Dalagnol ◽  
Henrique Cassol ◽  
Thais Rosan ◽  
Catherine Torres de Almeida ◽  
...  

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.


2010 ◽  
Vol 7 (1) ◽  
pp. 43-55 ◽  
Author(s):  
J. Chave ◽  
D. Navarrete ◽  
S. Almeida ◽  
E. Álvarez ◽  
L. E. O. C. Aragão ◽  
...  

Abstract. The production of aboveground soft tissue represents an important share of total net primary production in tropical rain forests. Here we draw from a large number of published and unpublished datasets (n=81 sites) to assess the determinants of litterfall variation across South American tropical forests. We show that across old-growth tropical rainforests, litterfall averages 8.61±1.91 Mg ha−1 yr−1 (mean ± standard deviation, in dry mass units). Secondary forests have a lower annual litterfall than old-growth tropical forests with a mean of 8.01±3.41 Mg ha−1 yr−1. Annual litterfall shows no significant variation with total annual rainfall, either globally or within forest types. It does not vary consistently with soil type, except in the poorest soils (white sand soils), where litterfall is significantly lower than in other soil types (5.42±1.91 Mg ha−1 yr−1). We also study the determinants of litterfall seasonality, and find that it does not depend on annual rainfall or on soil type. However, litterfall seasonality is significantly positively correlated with rainfall seasonality. Finally, we assess how much carbon is stored in reproductive organs relative to photosynthetic organs. Mean leaf fall is 5.74±1.83 Mg ha−1 yr−1 (71% of total litterfall). Mean allocation into reproductive organs is 0.69±0.40 Mg ha−1 yr−1 (9% of total litterfall). The investment into reproductive organs divided by leaf litterfall increases with soil fertility, suggesting that on poor soils, the allocation to photosynthetic organs is prioritized over that to reproduction. Finally, we discuss the ecological and biogeochemical implications of these results.


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