Surface Soil Changes Following Selective Logging in an Eastern Amazon Forest

Olander, Lydia; Bustamante, Mercedes Maria da Cunha; Asner, Gregory P.; Telles, Everaldo De Carvalho ConceiçÃ. £O.; Prado, Z. A.; Camargo, Plínio Barbosa de

doi:10.1175/ei135.1

Cited by 42 publications

(39 citation statements)

References 43 publications

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“…Therefore, a disproportionate increase in larger gaps can be expected to slow overall forest recovery rates and thus will have long-lasting effects on a wide range of ecological processes from carbon cycling to faunal dynamics (16,30,31). These results also highlight the value of reduced-impact logging operations that tend to minimize initial canopy damage levels and thus are more conducive to an expeditious reestablishment of ecosystem functions (15,27,32). Low-impact or low-volume logging also leaves the forest with fewer and smaller canopy gaps, which significantly reduces the risk of fire (26).…”

Section: Resultsmentioning

confidence: 99%

Condition and fate of logged forests in the Brazilian Amazon

Asner

Broadbent

Oliveira

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

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The long-term viability of a forest industry in the Amazon region of Brazil depends on the maintenance of adequate timber volume and growth in healthy forests. Using extensive high-resolution satellite analyses, we studied the forest damage caused by recent logging operations and the likelihood that logged forests would be cleared within 4 years after timber harvest. Across 2,030,637 km 2 of the Brazilian Amazon from 1999 to 2004, at least 76% of all harvest practices resulted in high levels of canopy damage sufficient to leave forests susceptible to drought and fire. We found that 16 ؎ 1% of selectively logged areas were deforested within 1 year of logging, with a subsequent annual deforestation rate of 5.4% for 4 years after timber harvests. Nearly all logging occurred within 25 km of main roads, and within that area, the probability of deforestation for a logged forest was up to four times greater than for unlogged forests. In combination, our results show that logging in the Brazilian Amazon is dominated by highly damaging operations, often followed rapidly by deforestation decades before forests can recover sufficiently to produce timber for a second harvest. Under the management regimes in effect at the time of our study in the Brazilian Amazon, selective logging would not be sustained.Brazil ͉ forest disturbance ͉ remote sensing ͉ selective logging ͉ tropical forest S atellite observations show that deforestation, defined here as clear-cutting of forests for pasture, agricultural, urban, and other uses, is a major force of ecological change throughout tropical regions (1). The pattern and process of deforestation have thus received considerable attention in ecological, socioeconomic, and policy studies (2, 3). Other human-caused forest disturbances, such as from selective timber harvesting and fire, are also common in tropical forests (4-7).Selective logging is an economically important land use that results in less forest damage than deforestation, but the amount of canopy damage associated with logging can leave tropical forests highly susceptible to drought and fire (5,(8)(9)(10)(11). If canopy damage levels are low, then selective logging has relatively small immediate and long-term impacts on forest resources (12, 13). If damage levels are high, however, then fundamental ecological processes (e.g., regeneration and succession) can be radically altered (14-18). Moreover, deforestation has long been associated with logging according to the theory of ''invasive forest mobility'' (19), whereby logging roads permit settler access into forests (3). However, neither the amount of forest disturbance caused by selective logging nor the amount of logged forest converted to cleared land has been directly quantified over large regions of tropical forest.Selective logging is a diffuse but ubiquitous forest disturbance that occurs throughout the Brazilian Amazon. Using the Carnegie Landsat Analysis System (CLAS; see Supporting Text, which is published as supporting information on the PNAS web site), we have shown ...

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Section: Resultsmentioning

confidence: 99%

Condition and fate of logged forests in the Brazilian Amazon

Asner

Broadbent

Oliveira

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

307

216

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“…That these trees perform better, when old, far from logging gaps may be link to a greater sensitivity to environmental changes in logging gaps. For example, it has been suggested that logging gaps dry out and have lower humidity due to the direct sunlight (Olander et al. 2005), although we did not measure these environmental factors in our study.…”

Section: Discussionmentioning

confidence: 99%

Growth responses of neotropical trees to logging gaps

Hérault

Ouallet

Blanc

et al. 2010

Journal of Applied Ecology

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Summary1. Modelling growth strategies among tropical trees is an important objective in predicting the response of tree dynamics to selective logging and in gaining insights into the ecological processes that structure tree communities in managed tropical forests. 2. We developed a disturbance index to model the effects of distance to and area of logging gaps on stem radial growth rates. This index was tested using census data of 43 neotropical tree species, representing a variety of life-history strategies and developmental stages, from a selectively logged forest at Paracou, French Guiana. Growth strategies were analyzed in light of two indicators: the inherent species growth rate (when disturbance index is null) and the species reaction (change in growth rate) to logging gaps. 3. Across species, the predicted inherent growth rates in unlogged forest ranged from 0AE25 to 6AE47 mm year . Ontogenetic shifts in inherent growth rate were found in 26 of the 43 species. 4. Species growth response to logging gaps varied widely among species but was significantly positive for 27 species. The effect of ontogeny on growth response to logging was retained for 14 species, and species with inherent fast growth rate (5 mm year ) responded less to logging gap disturbances than did species with slow inherent growth (1 mm year )1 ). 5. Functional traits explained 19-42% of the variation in the inherent growth rate and in species' response across all developmental stages. Whereas maximum diameters and seed mass were strong predictors of inherent growth rate, maximum height, wood density, mode of germination and stem architecture were additionally involved in tree growth response. 6. Synthesis and applications: This study provides a necessary framework for developing predictive post-logging growth models for the thousands of species comprising tropical forests and is sufficiently general to apply to a broad range of managed tropical forests.

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“…For example, total P in the Costa Rican Ultisols is approximately twice that at Tapajo´s, and plant-available P fractions are also ;25% higher in the Costa Rican sites (Silver et al 2000, Olander et al 2005. For example, at the site-specific scale, foliar P is significantly higher (F ¼ 6.2, df ¼ 1, 4, P , 0.01), and foliar N:P significantly lower (F ¼ 5.6, df ¼ 1, 4, P , 0.01), across all species common to both the Costa Rican Mollisols and the neighboring Ultisols.…”

Section: Environmental Controls Over Foliar N:p Ratiosmentioning

confidence: 99%

Controls Over Foliar N:p Ratios in Tropical Rain Forests

Townsend

Cleveland

Asner

et al. 2007

Ecology

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386

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Correlations between foliar nutrient concentrations and soil nutrient availability have been found in multiple ecosystems. These relationships have led to the use of foliar nutrients as an index of nutrient status and to the prediction of broadscale patterns in ecosystem processes. More recently, a growing interest in ecological stoichiometry has fueled multiple analyses of foliar nitrogen:phosphorus (N:P) ratios within and across ecosystems. These studies have observed that N:P values are generally elevated in tropical forests when compared to higher latitude ecosystems, adding weight to a common belief that tropical forests are generally N rich and P poor. However, while these broad generalizations may have merit, their simplicity masks the enormous environmental heterogeneity that exists within the tropics; such variation includes large ranges in soil fertility and climate, as well as the highest plant species diversity of any biome. Here we present original data on foliar N and P concentrations from 150 mature canopy tree species in Costa Rica and Brazil, and combine those data with a comprehensive new literature synthesis to explore the major sources of variation in foliar N:P values within the tropics. We found no relationship between N:P ratios and either latitude or mean annual precipitation within the tropics alone. There is, however, evidence of seasonal controls; in our Costa Rica sites, foliar N:P values differed by 25% between wet and dry seasons. The N:P ratios do vary with soil P availability and/or soil order, but there is substantial overlap across coarse divisions in soil type, and perhaps the most striking feature of the data set is variation at the species level. Taken as a whole, our results imply that the dominant influence on foliar N:P ratios in the tropics is species variability and that, unlike marine systems and perhaps many other terrestrial biomes, the N:P stoichiometry of tropical forests is not well constrained. Thus any use of N:P ratios in the tropics to infer larger-scale ecosystem processes must comprehensively account for the diversity of any given site and recognize the broad range in nutrient requirements, even at the local scale.

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Surface Soil Changes Following Selective Logging in an Eastern Amazon Forest

Cited by 42 publications

References 43 publications

Condition and fate of logged forests in the Brazilian Amazon

Condition and fate of logged forests in the Brazilian Amazon

Growth responses of neotropical trees to logging gaps

Controls Over Foliar N:p Ratios in Tropical Rain Forests

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