Quantifying the sampling error in tree census measurements by volunteers and its effect on carbon stock estimates

Butt, Nathalie; Slade, Eleanor M.; Thompson, Jill; Malhi, Yadvinder; Riutta, Terhi

doi:10.1890/11-2059.1

Cited by 60 publications

(45 citation statements)

References 31 publications

(48 reference statements)

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“…The initial diameter of each tree and the diameter of lianas in each census in each plot were varied at random using a normal distribution with a SE of 5% (42). In subsequent censuses, tree diameters were calculated by adding a randomly selected value of dendrometer growth from a normal distribution with an SE of 3% (44) to the initial tree diameter. The resulting diameters for each census were then used to calculate tree height and subsequently biomass for each tree and each plot.…”

Section: Methodsmentioning

confidence: 99%

Lianas reduce carbon accumulation and storage in tropical forests

Heijden

Powers

Schnitzer

2015

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

154

136

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Tropical forests store vast quantities of carbon, account for onethird of the carbon fixed by photosynthesis, and are a major sink in the global carbon cycle. Recent evidence suggests that competition between lianas (woody vines) and trees may reduce forest-wide carbon uptake; however, estimates of the impact of lianas on carbon dynamics of tropical forests are crucially lacking. Here we used a large-scale liana removal experiment and found that, at 3 y after liana removal, lianas reduced net above-ground carbon uptake (growth and recruitment minus mortality) by ∼76% per year, mostly by reducing tree growth. The loss of carbon uptake due to lianainduced mortality was four times greater in the control plots in which lianas were present, but high variation among plots prevented a significant difference among the treatments. Lianas altered how aboveground carbon was stored. In forests where lianas were present, the partitioning of forest aboveground net primary production was dominated by leaves (53.2%, compared with 39.2% in liana-free forests) at the expense of woody stems (from 28.9%, compared with 43.9%), resulting in a more rapid return of fixed carbon to the atmosphere. After 3 y of experimental liana removal, our results clearly demonstrate large differences in carbon cycling between forests with and without lianas. Combined with the recently reported increases in liana abundance, these results indicate that lianas are an important and increasing agent of change in the carbon dynamics of tropical forests.L ianas (woody vines) are a key component of lowland tropical forests, commonly contributing more than 25% of the woody stems and species and competing intensely with trees. By relying on the structural investment of trees for support, lianas are able to allocate a higher proportion of biomass than trees into the production of foliage rather than carbon-dense stems (1). Thus, lianas themselves contribute relatively little to forest-level biomass (1, 2). The ecological effects of lianas may be more extensive than their relatively modest contribution to biomass suggests, however. Liana-tree competition can be far more intense than tree-tree competition (3), substantially reducing tree growth (2, 4), fecundity (5, 6), and survival (4, 7). Furthermore, lianas may constrain net above-ground forest primary productivity, i.e., the total amount of carbon fixed into both canopy material (leaves, flowers, fruits, and seeds) and woody stems (8), by failing to compensate for the biomass that they displace in trees (1, 2).Recent evidence indicates that lianas are now increasing in abundance and biomass in tropical forests, possibly being driven by a combination of increased atmospheric CO 2 concentration, changing climatic conditions, and seasonal droughts, as well as increased natural and anthropogenic disturbances (9, 10). The increase in lianas, combined with the observations that lianas can reduce individual tree growth by up to 84% (11) and increase tree mortality risk twofold to threefold (4, 7), has made it pertin...

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Section: Methodsmentioning

confidence: 99%

Lianas reduce carbon accumulation and storage in tropical forests

Heijden

Powers

Schnitzer

2015

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

154

136

View full text Add to dashboard Cite

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“…Abd-Elrahman et al [42] used geo-referenced data gathered by volunteers to augment forest inventory data. Butt et al [43] showed that volunteers can provide accurate tree height and tree diameter measurements in relation to carbon stock estimates. Pratihast et al [22] used mobile devices for community-based REDD+ monitoring in Vietnam and showed that local communities can provide data with comparable accuracy to expert measurements for estimating tree counts and forest disturbance.…”

Section: Introductionmentioning

confidence: 99%

Relasphone—Mobile and Participative In Situ Forest Biomass Measurements Supporting Satellite Image Mapping

et al. 2016

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Due to the high cost of traditional forest plot measurements, the availability of up-to-date in situ forest inventory data has been a bottleneck for remote sensing image analysis in support of the important global forest biomass mapping. Capitalizing on the proliferation of smartphones, citizen science is a promising approach to increase spatial and temporal coverages of in situ forest observations in a cost-effective way. Digital cameras can be used as a relascope device to measure basal area, a forest density variable that is closely related to biomass. In this paper, we present the Relasphone mobile application with extensive accuracy assessment in two mixed forest sites from different biomes. Basal area measurements in Finland (boreal zone) were in good agreement with reference forest inventory plot data on pine (R 2 = 0.75, RMSE = 5.33 m 2 /ha), spruce (R 2 = 0.75, RMSE = 6.73 m 2 /ha) and birch (R 2 = 0.71, RMSE = 4.98 m 2 /ha), with total relative RMSE(%) = 29.66%. In Durango, Mexico (temperate zone), Relasphone stem volume measurements were best for pine (R 2 = 0.88, RMSE = 32.46 m 3 /ha) and total stem volume (R 2 = 0.87, RMSE = 35.21 m 3 /ha). Relasphone data were then successfully utilized as the only reference data in combination with optical satellite images to produce biomass maps. The Relasphone concept has been validated for future use by citizens in other locations.

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“…Figure 5 shows a sample topic composition for one (Butt et al 2013) of the two publications that matched both the search term "citizen science" and "forest monitoring". This example illustrates that only a small number of topics are active in this document.…”

Section: Resultsmentioning

confidence: 99%

“…The increase of the citizen science material since 2005 is rather dramatic. Only two articles (Roman et al 2013;Butt et al 2013), both published in 2013, contained both search terms; for our analysis we assigned Roman et al (2013) to the "forest monitoring" and Butt et al (2013) to the "citizen science" document set.…”

Section: Datamentioning

confidence: 99%

“…The algorithm was run for 2000 iterations Figure 2 Informal explanation of the intuition behind topic modelling (adapted from (Blei 2012)). An excerpt of a sample abstract (Butt et al 2013) is quoted for illustration purposes. A document is assumed to be the result of an iterative process that selects topics from a document-specific probabilistic topic distribution and words from a topic-specific probabilistic word distribution.…”

Section: Lda Configuration -Choosing the Number Of Topicsmentioning

confidence: 99%

See 1 more Smart Citation

Assessing citizen science opportunities in forest monitoring using probabilistic topic modelling

2014

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Background: With mounting global environmental, social and economic pressures the resilience and stability of forests and thus the provisioning of vital ecosystem services is increasingly threatened. Intensified monitoring can help to detect ecological threats and changes earlier, but monitoring resources are limited. Participatory forest monitoring with the help of "citizen scientists" can provide additional resources for forest monitoring and at the same time help to communicate with stakeholders and the general public. Examples for citizen science projects in the forestry domain can be found but a solid, applicable larger framework to utilise public participation in the area of forest monitoring seems to be lacking. We propose that a better understanding of shared and related topics in citizen science and forest monitoring might be a first step towards such a framework.

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Quantifying the sampling error in tree census measurements by volunteers and its effect on carbon stock estimates

Cited by 60 publications

References 31 publications

Lianas reduce carbon accumulation and storage in tropical forests

Lianas reduce carbon accumulation and storage in tropical forests

Relasphone—Mobile and Participative In Situ Forest Biomass Measurements Supporting Satellite Image Mapping

Assessing citizen science opportunities in forest monitoring using probabilistic topic modelling

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