Bewirtschaftung von tropischen Sekundärwäldern

2002 ◽  
Vol 46 (1) ◽  
Author(s):  
Dietrich Schmidt-Vogt

AbstractManagement of secondary tropical forests: a new perspective for sustainable use of forests in Asia. The decline of primary forests in the tropics is leading to a reassessment of the role secondary forests might play within the context of tropical forest management. Recent research has shown that secondary forests in the tropics can be both rich in species and complex in terms of stand structure. There is, moreover, a growing recognition of the importance of secondary forests for traditional subsistence economies in the tropics and of their economic potential for land use systems in the future. Management of secondary forests in Asia as an alternative to the extraction of timber from primary forests but also as one among other options to intensify traditional land use systems has a potential for the future especially because of the existence of vast tracts of valuable secondary forest cover, and because of the store of traditional knowledge that can still be found in tropical Asia.

2010 ◽  
Vol 14 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Arlete Silva de Almeida ◽  
Thomas A. Stone ◽  
Ima Célia G. Vieira ◽  
Eric A. Davidson

Abstract While interest in Amazonian deforestation mostly focuses on frontier areas, the amount of forest cover in areas already dominated by human settlement is also changing. Secondary forests play an increasingly important role for maintaining genetic diversity, hydrological functioning, and greenhouse gas emissions of altered landscapes, but secondary forests are also being converted to more intensive agricultural uses. Five dates of Landsat imagery from 1984 to 2002 were analyzed, covering 8000 km2 of the Zona Bragantina of the eastern part of the Brazilian state of Pará, which underwent its most intensive wave of deforestation several decades ago. However, even in this area of relatively long-term human occupation, ongoing decreases of forest cover were found, both in the small remaining areas of mature forest and in the more widespread areas of secondary forests, as human population increased and land use intensified. Although there was an initial increase in the area of secondary forest from 1984 to 1994, there has been a steady decline since then, from 75% secondary forest cover in 1994 to 54% in 2002. The amount of pasture was relatively stable from 1984 to 1994 but more recently has shown a steady increase, reaching 37% cover in 2002. The average rate of carbon loss over the 18-yr study period was 0.9 Mg C ha−1 yr−1 for the 8000 km2 study area. Forests in this long-settled region of eastern Amazonia continue to be degraded, resulting in the loss of ecosystem services and carbon stocks due to continued land-use change.


1990 ◽  
Vol 6 (1) ◽  
pp. 1-32 ◽  
Author(s):  
Sandra Brown ◽  
Ariel E. Lugo

ABSTRACTThe literature on tropical secondary forests, defined as those resulting from human disturbance (e.g. logged forests and forest fallows), is reviewed to address questions related to their extent, rates of formation, ecological characteristics, values and uses to humans, and potential for management. Secondary forests are extensive in the tropics, accounting for about 40% of the total forest area and their rates of formation are about 9 million ha yr−1. Geographical differences in the extent, rates of formation and types of forest being converted exist.Secondary forests appear to accumulate woody plant species at a relatively rapid rate but the mechanisms involved are complex and no clear pattern emerged. Compared to mature forests, the structure of secondary forest vegetation is simple, although age, climate and soil type are modifying factors. Biomass accumulates rapidly in secondary forests, up to 100 t ha−1 during the first 15 yr or so, but history of disturbance may modify this trend. Like biomass, high rates of litter production are established relatively quickly, up to 12–13 t ha−1 yr−1 by age 12–15 yr. And, in younger secondary forests (< 20 yr), litter production is a higher fraction of the net primary productivity than stemwood biomass production. More organic matter is pro duced and transferred to the soil in younger secondary forests than is stored in above-ground vegetation. The impact of this on soil organic matter is significant and explains why the recovery of organic matter in the soil under secondary forests is relatively fast (50 yr or so). Nutrients are accumulated rapidly in secondary vegetation, and are returned quickly by litterfall and decomposition for uptake by roots.We propose a model of the gains and losses, yields and costs, and benefits and tradeoffs to people from the current land-use changes occurring in the tropics. When the conversion of forest lands to secondary forests and agriculture is too fast or land-use stages are skipped, society loses goods and services. To avoid such a loss, we advocate management of tropical forest lands within a landscape perspective, a possibility in the tropics because land tenures and development projects are often large.


Land ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 817
Author(s):  
Marina Palmero-Iniesta ◽  
Josep Maria Espelta ◽  
Mario Padial-Iglesias ◽  
Òscar Gonzàlez-Guerrero ◽  
Lluís Pesquer ◽  
...  

Farmland abandonment has been a widespread land-use change in the Iberian Peninsula since the second half of the 20th century, leading to the establishment of secondary forests across the region. In this study, we aimed to address changes in the recent (1985–2014) emergence patterns of these forests and examine how environmental factors affected their growth by considering differences in leaf-habit types. We used a combination of Landsat-derived land-cover maps and aboveground biomass (AGB) maps from the European Space Agency to assess the secondary forest establishment and growth, respectively, in the study region. We also obtained a set of topographic, climatic and landscape variables from diverse GIS layers and used them for determining changes over time in the environmental drivers of forest establishment and AGB using general linear models. The results highlight that secondary forest cover was still increasing in the Iberian Peninsula at a rate above the European average. Yet, they also indicate a directional change in the emergence of secondary forests towards lower and less steep regions with higher water availability (mean rainfall and SPEI) and less forest cover but are subjected to greater drought events. In addition, these environmental factors differentially affect the growth of forests with different leaf-habit types: i.e., needleleaf secondary forests being less favoured by high temperature and precipitation, and broadleaf deciduous forests being most negatively affected by drought. Finally, these spatial patterns of forest emergence and the contrasting responses of forest leaf-habits to environmental factors explained the major development of broadleaf evergreen compared to broadleaf deciduous forests and, especially, needleleaf secondary forests. These results will improve the knowledge of forest dynamics that have occurred in the Iberian Peninsula in recent decades and provide an essential tool for understanding the potential effects of climate warming on secondary forest growth.


2021 ◽  
Author(s):  
Madelon Lohbeck ◽  
Ben DeVries ◽  
Frans Bongers ◽  
Miguel Martinez-Ramos ◽  
Armando Navarrete-Segueda ◽  
...  

Forest regrowth is key to achieve restoration commitments, but we need to better understand under what circumstances it takes place and how long secondary forests persist. We studied a recently colonized agricultural frontier in southern Mexico. We quantified the spatiotemporal dynamics of forest loss and regrowth and tested how temporal variation in climate, and spatial variation in land availability, land quality and accessibility affect forest disturbance, regrowth and secondary forest persistence. Marqués de Comillas consistently exhibits more forest loss than regrowth, resulting in a net decrease of 30% forest cover (1991-2016). Secondary forest cover remained relatively constant while secondary forest persistence increased, suggesting that farmers are moving away from shifting cultivation. Temporal variation in disturbance and regrowth were explained by the annual variation in the Oceanic El Niño index combined with dry season rainfall and key policy and market interventions.Across communities the availability of high-quality soil overrules the effects of land availability and accessibility, but that at the pixel-level all three factors contributed to explaining forest conservation and restoration. Communities with more high-quality soils were able to spare land for forest conservation, and had less secondary forest that persisted for longer. Old forest and secondary forests were better represented on low-quality lands and on communal land. Both old and secondary forest were less common close to the main road, where secondary forests were also less persistent. Forest conservation and restoration can be explained by a complex interplay of biophysical and social drivers across time, space and scale. We warrant that stimulating private land ownership may cause remaining forest patches to be lost and that conservation initiatives should benefit the whole community. Forest regrowth and secondary forest persistence competes with agricultural production and ensuring farmers can access restoration benefits is key to success.


2008 ◽  
Vol 38 (12) ◽  
pp. 3033-3046 ◽  
Author(s):  
Thomas Knoke ◽  
Patrick Hildebrandt ◽  
Daniel Klein ◽  
Rodrigo Mujica ◽  
Martin Moog ◽  
...  

The expected opportunity costs of conserving a specific land use are usually considered adequate as financial compensation. However, a “conservation premium” is sometimes proposed as an added incentive, i.e., compensation greater than the expected opportunity costs. This paper discusses various methodological opportunities for deriving effective compensation under uncertainty. Based on cumulative distribution functions of possible opportunity costs (a Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco) plantation was considered the alternative to conserving a Chilean secondary forest), generated through Monte Carlo simulations, we derived an inclusive range of possible compensations from 77 up to 375 US$·ha–1·year–1. If we assumed that the two land-use alternatives were mutually exclusive and independent from other risky investments, a compensation of 375 US$·ha–1·year–1 was necessary to convince every decision maker to maintain the secondary forest. However, only 77 US$·ha–1·year–1 was enough for a risk-averse decision maker (given average opportunity costs of 113 US$·ha–1·year–1). Yet, it turned out that the greatest possible opportunity costs would already be compensated for with 199 US$·ha–1·year–1, given an error probability of 0.05. Compensating for the last 5% of possible opportunity costs would thus require an additional 176 US$·ha–1·year–1. Our approach had two main limitations, namely we did not consider portfolio effects, which would allow diversifying away unsystematic risks, and we did not take into account the different systematic risks of the compared alternatives. These limitations may have led to an overestimation of effective compensation.


Oryx ◽  
2010 ◽  
Vol 44 (3) ◽  
pp. 352-357 ◽  
Author(s):  
Jörn P. W. Scharlemann ◽  
Valerie Kapos ◽  
Alison Campbell ◽  
Igor Lysenko ◽  
Neil D. Burgess ◽  
...  

AbstractForest loss and degradation in the tropics contribute 6–17% of all greenhouse gas emissions. Protected areas cover 217.2 million ha (19.6%) of the world’s humid tropical forests and contain c. 70.3 petagrams of carbon (Pg C) in biomass and soil to 1 m depth. Between 2000 and 2005, we estimate that 1.75 million ha of forest were lost from protected areas in humid tropical forests, causing the emission of 0.25–0.33 Pg C. Protected areas lost about half as much carbon as the same area of unprotected forest. We estimate that the reduction of these carbon emissions from ongoing deforestation in protected sites in humid tropical forests could be valued at USD 6,200–7,400 million depending on the land use after clearance. This is > 1.5 times the estimated spending on protected area management in these regions. Improving management of protected areas to retain forest cover better may be an important, although certainly not sufficient, component of an overall strategy for reducing emissions from deforestation and forest degradation (REDD).


2021 ◽  
Vol 22 (10) ◽  
Author(s):  
Karmini Karmini ◽  
Karyati Karyati ◽  
Kusno Yuli Widiati

Abstract. Karmini, Karyati, Widiati KY. 2021. The ecological and economic values of a 50 years old secondary forest in East Kalimantan, Indonesia. Biodiversitas 22: 4597-4607. Secondary forests in the tropics are often ignored since they are assumed to have low ecological functions while on the other hand the economic values have been reduced. This study aimed to analyze the ecological and economic values of a 50-year secondary forest in East Kalimantan that experienced several various land-use changes. The ecological aspects analyzed were stand structure, floristic composition, and species diversity. Economic aspects include log prices, logging costs, profit margins, and stumpage values. A vegetation survey of woody trees with a diameter at breast height of more than 5 cm was carried out on ten plots measuring 20 m × 20 m each. A total of 437 trees belonging to 38 species, 30 genera, and 19 families were recorded with Moraceae and Euphorbiaceae were the most dominant families with Family Important Value (FIV) of 86.79. The three most dominant species were Macaranga motleyana (IVi of 50.95), Artocarpus elasticus (IVi of 34.41), and Symplocos fasciculata (IVi of 31.46). The trees in the study plot have a diversity index of 1.33, dominance index of 0.07, evenness index of 0.37, and species richness of 6.09. The average logging cost, logs price, lumber price, profit margin, and stumpage value at secondary forest were USD69.43 m-3, USD44.63 m-3, USD100.03 m-3, USD10.30 m-3, and USD28.73 ha-1, respectively. The 50 years old secondary forests in East Kalimantan have biodiversity, especially trees that have economic value, therefore their existence needs to be preserved and their use is carried out by maintaining and increasing biodiversity.


2017 ◽  
Author(s):  
Wei Li ◽  
Philippe Ciais ◽  
Chao Yue ◽  
Thomas Gasser ◽  
Shushi Peng ◽  
...  

Abstract. Bookkeeping models are used to estimate land-use change (LUC) carbon fluxes (ELUC). These models combine time series of areas subject to different LUC types with response curves of carbon pools in ecosystems and harvested products after a unit change of land use. The level of detail of bookkeeping models depends on the number of response curves used for different regions, the carbon pools they represent, and the diversity of LUC types considered. The uncertainty of bookkeeping models arises from data used to define response curves (usually local data) and their representativeness of large regions. Here, we compare biomass recovery curves derived from a recent synthesis of secondary forest plots data by Poorter et al. (2016) with the curves used in bookkeeping models from Houghton (1999) and Hansis et al. (2015) in Latin America. We find that both Houghton (1999) and Hansis et al. (2015) overestimate the long-term (100 years) biomass carbon density of secondary forest, by about 25 %. We also show the importance of considering gross forest area change in addition to the net forest area change for estimating regional ELUC. To do so, simulations are constructed with a bookkeeping model calibrated with three different sets of response curves (linear, exponential and logarithmic) to study ELUC created by a pulse of net forest area change, with different gross-to-net forest area change ratios (γAnetAgross). Following the initial pulse of forest area change, ELUC is subsequently calculated over 100 years. Considering a region subject to a net gain in forest area during one year, different values of gross forest area changes that sum up to this initial net gain can change the magnitude and even the sign of ELUC with a given time horizon after the initial forest area change. In other words, in the case of a net gain in forest area composed of a large gross loss and a large gross gain, the initial gross loss has an important legacy effect that the system can be a net source of CO2 to the atmosphere. We show the existence of a critical value of γAnetAgross above which ELUC switches from CO2 sink to source with a given time horizon after the initial forest area change. This critical ratio derived from the structure of the bookkeeping model is compared against real-world high resolution Landsat TM observations of gross forest area change in the Amazon to distinguish areas where current forest land turnover will legate LUC carbon emissions or sinks in 20 years, 50 years and 100 years in the future.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Katie M. McGee ◽  
Teresita M. Porter ◽  
Michael Wright ◽  
Mehrdad Hajibabaei

Abstract Tropical forests are fundamental ecosystems, essential for providing terrestrial primary productivity, global nutrient cycling, and biodiversity. Despite their importance, tropical forests are currently threatened by deforestation and associated activities. Moreover, tropical regions are now mostly represented by secondary forest regrowth, with half of the remaining tropical forests as secondary forest. Soil invertebrates are an important component to the functioning and biodiversity of these soil ecosystems. However, it remains unclear how these past land-use activities and subsequent secondary forest developments have altered the soil invertebrate communities and any potential ecological consequences associated with this. DNA metabarcoding offers an effective approach to rapidly monitor soil invertebrate communities under different land-use practices and within secondary forests. In this study, we used DNA metabarcoding to detect community-based patterns of soil invertebrate composition across a primary forest, a 23-year-old secondary forest, and a 33-year-old secondary forest and the associated soil environmental drivers of the soil invertebrate community structure in the Maquenque National Wildlife Refuge of Costa Rica (MNWR). We also used a species contribution analysis (SIMPER) to determine which soil invertebrate groups may be an indication of these soils reaching a pre-disturbed state such as a primary forest. We found that the soil invertebrate community composition at class, order, family, and ESV level were mostly significantly different across that habitats. We also found that the primary forest had a greater richness of soil invertebrates compared to the 23-year-old and 33-year-old secondary forest. Moreover, a redundancy analysis indicated that soil moisture influenced soil invertebrate community structure and explained up to 22% of the total variation observed in the community composition across the habitats; whereas soil invertebrate richness was structured by soil microbial biomass carbon (C) (Cmic) and explained up to 52% of the invertebrate richness across the primary and secondary forests. Lastly, the SIMPER analysis revealed that Naididae, Entomobryidae, and Elateridae could be important indicators of soil and forest recuperation in the MNWR. This study adds to the increasing evidence that soil invertebrates are intimately linked with the soil microbial biomass carbon (Cmic) and that even after 33 years of natural regrowth of a forest, these land use activities can still have persisting effects on the overall composition and richness of the soil invertebrate communities.


2021 ◽  
Vol 9 (2) ◽  
pp. 405
Author(s):  
Basuki Rahman ◽  
Abdi Fithria ◽  
Basir Achmad ◽  
Danang Biyatmoko

Artain is a village located opposite the Riam Kanan reservoir in Aranio District, Banjar Regency, South Kalimantan Province. There are various types of habitat in the Village, from the edge of a reservoir to primary forest which is thought to be home to various birds species, which over time has the potential to degrade or change due to human activity which then reduces its quality and function as habitat for many birds species. It is necessary to research the diversity and evenness of birds in each habitat type in Artain, so that the existence of various bird species can be known. The research was conducted from May to June 2020, the method used in the study was the cruising circumference point, which is determining the observation point and its radius and then making observations by exploring the observation path continue. The results showed that there were 9 types of bird's habitat in Artain, they are Settlements, Periphery Reservoirs, Shrubs, Mixed Gardens, Rubber Gardens, Reeds, Fields, Secondary Forests, and Primary Forests. The lowest diversity value (H' = 1.25) was identified in field habitats and the highest (H' = 3.17) in scrub habitats, meaning that the level of diversity in all habitats was classified as moderate. The lowest evenness value in secondary forest habitats (E = 0.80) and the highest is mixed garden habitats and rubber gardens (E = 0.97), which means that evenness in each habitat is in the high category.


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