Tree damage, allometric relationships, and above-ground net primary production in central Amazon forest

Chambers, Jeffrey Q.; Santos, Joaquim dos; Ribeiro, Ralfh João; Higuchi, Níro

doi:10.1016/s0378-1127(00)00591-0

Cited by 392 publications

(389 citation statements)

References 34 publications

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“…Analysis of a large global dataset, for both temperate and tropical forests, also generally supports the Ϫ2 prediction (17,25). Because stem radii exhibit the predicted scaling with mass, r k ϰ m k 3/8 (26,27), these observations also confirm the predicted scaling of number of stems with mass: f(r) ϰ m Ϫ3/4 (see supporting information in ref. 12).…”

Section: Empirical Results and Theoretical Extensionssupporting

confidence: 71%

Extensions and evaluations of a general quantitative theory of forest structure and dynamics

Enquist

West

Brown

2009

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

247

297

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Here, we present the second part of a quantitative theory for the structure and dynamics of forests under demographic and resource steady state. The theory is based on individual-level allometric scaling relations for how trees use resources, fill space, and grow. These scale up to determine emergent properties of diverse forests, including size-frequency distributions, spacing relations, canopy configurations, mortality rates, population dynamics, successional dynamics, and resource flux rates. The theory uniquely makes quantitative predictions for both stand-level scaling exponents and normalizations. We evaluate these predictions by compiling and analyzing macroecological datasets from several tropical forests. The close match between theoretical predictions and data suggests that forests are organized by a set of very general scaling rules. Our mechanistic theory is based on allometric scaling relations, is complementary to ''demographic theory,'' but is fundamentally different in approach. It provides a quantitative baseline for understanding deviations from predictions due to other factors, including disturbance, variation in branching architecture, asymmetric competition, resource limitation, and other sources of mortality, which are not included in the deliberately simplified theory. The theory should apply to a wide range of forests despite large differences in abiotic environment, species diversity, and taxonomic and functional composition.allometry ͉ mortality rate ͉ plant ecology ͉ size distribution ͉ competitive thinning U nderstanding the key forces that shape the structure, function, and dynamics of ecosystems is a fundamental goal of ecology (1-6). Current approaches to plant communities focus on questions such as what allows for species coexistence (7), why tropical sites have more species than temperate ones (8), and what environmental factors determine the structure, dynamics, and species composition of communities (9). Detailed models have been developed to integrate how species-specific traits ''scale-up'' to inf luence community and ecosystem dynamics (10, 11).Here, we present a complementary but alternative approach. We use a few key principles to show how variation in resource supply together with general cross-taxa patterns of plant architecture and growth give rise to predictable emergent patterns of resource use, spatial structure, and demography. In our previous article (12) we incorporated these principles to derive the first part of a general quantitative theory for the structure and dynamics of a single-species stand. In this article we evaluate these predictions, using data from several tropical forests composed of multiple tree species including: (i) a 20-year record from Costa Rica (13); (ii) a 10-year time series from Panama; (iii) a 40-year survey from a Malaysian forest dataset; (iv) and a successional sequence of Costa Rican forests ranging from recently abandoned pasture to mature uncut forests (14) (for methodology and additional detail, see supporting information (SI) Tex...

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Section: Empirical Results and Theoretical Extensionssupporting

confidence: 71%

Extensions and evaluations of a general quantitative theory of forest structure and dynamics

Enquist

West

Brown

2009

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

247

297

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“…3A derived from a typical run shows total aboveground tree biomass averaged over the entire 100-ha domain, along with five random 1-ha samples. After spinning up to steady state, the average biomass for the 100-ha plot was relatively constant, ranging from 260 to 300 Mg·ha −1 , which compared well with direct biomass estimates in nearby forests (27). In contrast, the single hectare plots were in constant flux, with long stretches of biomass accumulation often punctuated by episodic disturbances, and the time series rarely demonstrating steady-state behavior (Fig.…”

Section: Resultssupporting

confidence: 64%

“…Results from TRECOS estimated the partitioning of tree mortality across all event size classes ( Table 1), demonstrating that 9.1-16.9% of tree mortality was missing from plot-based approaches that poorly sample disturbance events larger than about 8-15 trees per gap. Including this episodic mortality that is generally missing from plot-based estimates would largely offset net biomass accumulation from tree recruitment and growth (27), resulting in approximate landscape carbon balance.…”

Section: Resultsmentioning

confidence: 99%

The steady-state mosaic of disturbance and succession across an old-growth Central Amazon forest landscape

Chambers

Negrón‐Juárez

Marra

et al. 2013

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

Self Cite

208

238

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Old-growth forest ecosystems comprise a mosaic of patches in different successional stages, with the fraction of the landscape in any particular state relatively constant over large temporal and spatial scales. The size distribution and return frequency of disturbance events, and subsequent recovery processes, determine to a large extent the spatial scale over which this old-growth steady state develops. Here, we characterize this mosaic for a Central Amazon forest by integrating field plot data, remote sensing disturbance probability distribution functions, and individual-based simulation modeling. Results demonstrate that a steady state of patches of varying successional age occurs over a relatively large spatial scale, with important implications for detecting temporal trends on plots that sample a small fraction of the landscape. Long highly significant stochastic runs averaging 1.0 Mg biomass·ha −1 ·y −1 were often punctuated by episodic disturbance events, resulting in a sawtooth time series of hectare-scale tree biomass. To maximize the detection of temporal trends for this Central Amazon site (e.g., driven by CO 2 fertilization), plots larger than 10 ha would provide the greatest sensitivity. A model-based analysis of fractional mortality across all gap sizes demonstrated that 9.1-16.9% of tree mortality was missing from plot-based approaches, underscoring the need to combine plot and remote-sensing methods for estimating net landscape carbon balance. Old-growth tropical forests can exhibit complex large-scale structure driven by disturbance and recovery cycles, with ecosystem and community attributes of hectare-scale plots exhibiting continuous dynamic departures from a steady-state condition.biodiversity | community composition | gap dynamics | NEP NEE NBP A common assumption in old-growth forest studies is that, in the absence of a directional forcing, ecosystem characteristics and tree species composition should exhibit some type of steady-state behavior (1). Thus, plot-based studies in old-growth tropical forests that observe changing tree species composition (2), increased liana abundance (3), faster turnover rates (4), and forest biomass accumulation (5, 6), are viewed as surprising departures from an expected steady-state condition. However, disturbance events can create a landscape with patches of varying successional age, and the extent to which forest plots representatively sample this mosaic remains an open question. An important issue is how to distinguish directional trends driven by a warming climate, or rising atmospheric CO 2 concentration, from smaller-scale stochastic patterns driven by disturbance and recovery cycles (7,8).Over long time periods, the disturbance regime of a forested region creates a shifting steady-state mosaic, represented by patches of different successional ages, with the fraction of the landscape in any particular state remaining relatively constant over time (9,10). In many tropical forests, gaps created by the windthrow of canopy trees is a major mode of disturb...

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“…The inclusion of relative wood density in such equations (Baker et al 2004;Chave et al 2003) is, however, a major step forward. A second issue, dealt with in few studies (Chambers et al 2000;Chave et al 2003), accounts for ongoing biomass losses through crown damage and branchfall; depending on the nature of the biomass allometric equation used, failing to correct for such damage can lead to significant overestimates of above-ground biomass increase (Clark et al 2001). Clark, unpublished data).…”

Section: Integrated Forest-level Responses: the Evidence So Farmentioning

confidence: 99%

Sources or sinks? The responses of tropical forests to current and future climate and atmospheric composition

Clark

2004

Phil. Trans. R. Soc. Lond. B

229

184

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How tropical rainforests are responding to the ongoing global changes in atmospheric composition and climate is little studied and poorly understood. Although rising atmospheric carbon dioxide (CO 2 ) could enhance forest productivity, increased temperatures and drought are likely to diminish it. The limited field data have produced conflicting views of the net impacts of these changes so far. One set of studies has seemed to point to enhanced carbon uptake; however, questions have arisen about these findings, and recent experiments with tropical forest trees indicate carbon saturation of canopy leaves and no biomass increase under enhanced CO 2 . Other field observations indicate decreased forest productivity and increased tree mortality in recent years of peak temperatures and drought (strong El Niñ o episodes). To determine current climatic responses of forests around the world tropics will require careful annual monitoring of ecosystem performance in representative forests. To develop the necessary process-level understanding of these responses will require intensified experimentation at the whole-tree and stand levels. Finally, a more complete understanding of tropical rainforest carbon cycling is needed for determining whether these ecosystems are carbon sinks or sources now, and how this status might change during the next century.

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Tree damage, allometric relationships, and above-ground net primary production in central Amazon forest

Cited by 392 publications

References 34 publications

Extensions and evaluations of a general quantitative theory of forest structure and dynamics

Extensions and evaluations of a general quantitative theory of forest structure and dynamics

The steady-state mosaic of disturbance and succession across an old-growth Central Amazon forest landscape

Sources or sinks? The responses of tropical forests to current and future climate and atmospheric composition

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