scholarly journals Landscape-scale changes in forest structure and functional traits along an Andes-to-Amazon elevation gradient

2013 ◽  
Vol 10 (9) ◽  
pp. 15415-15454 ◽  
Author(s):  
G. P. Asner ◽  
C. Anderson ◽  
R. E. Martin ◽  
D. E. Knapp ◽  
R. Tupayachi ◽  
...  
Keyword(s):  
Functional Traits ◽  
Forest Structure ◽  
Structural Information ◽  
Plant Cover ◽  
Elevation Gradient ◽  
Imaging Spectroscopy ◽  
Landscape Scale ◽  
Elevation Gradients ◽  
Peruvian Andes ◽  
Environmental Controls

Abstract. Elevation gradients provide opportunities to explore environmental controls on forest structure and functioning, but plot-based studies have proven highly variable due to limited geographic scope. We used airborne imaging spectroscopy and LiDAR (light detection and ranging) to quantify changes in three-dimensional forest structure and canopy functional traits in a series of 25 ha landscapes distributed along a 3300 m elevation gradient from lowland Amazonia to treeline in the Peruvian Andes. Canopy greenness, photosynthetic fractional cover and exposed non-photosynthetic vegetation varied as much across lowland forests (100–200 m) as they did from the lowlands to the Andean treeline (3400 m). Elevation was positively correlated with canopy gap density and understory vegetation cover, and negatively related to canopy height and vertical profile. Increases in gap density were tightly linked to increases in understory plant cover, and larger gaps (20–200 m2 produced 25–30 times the response in understory cover than did smaller gaps (< 5 m2. Scaling of gap size to gap frequency was, however, relatively constant along the elevation gradient, which when combined with other canopy structural information, indicates equilibrium turnover patterns from the lowlands to treeline. Our results provide a first landscape-scale quantification of forest structure and canopy functional traits with changing elevation, thereby improving our understanding of disturbance, demography and ecosystem processes in the Andes-to-Amazon corridor.

scholarly journals Landscape-scale changes in forest structure and functional traits along an Andes-to-Amazon elevation gradient

2014 ◽  
Vol 11 (3) ◽  
pp. 843-856 ◽  
Author(s):  
G. P. Asner ◽  
C. B. Anderson ◽  
R. E. Martin ◽  
D. E. Knapp ◽  
R. Tupayachi ◽  
...  
Keyword(s):  
Functional Traits ◽  
Forest Structure ◽  
Plant Cover ◽  
Elevation Gradient ◽  
Landscape Scale ◽  
Canopy Gap ◽  
Turnover Rates ◽  
Elevation Gradients ◽  
Peruvian Andes ◽  
Environmental Controls

Abstract. Elevation gradients provide opportunities to explore environmental controls on forest structure and functioning. We used airborne imaging spectroscopy and lidar (light detection and ranging) to quantify changes in three-dimensional forest structure and canopy functional traits in twenty 25 ha landscapes distributed along a 3300 m elevation gradient from lowland Amazonia to treeline in the Peruvian Andes. Elevation was positively correlated with lidar-estimated canopy gap density and understory vegetation cover, and negatively related to canopy height and the vertical partitioning of vegetation in canopies. Increases in canopy gap density were tightly linked to increases in understory plant cover, and larger gaps (20–200 m2) produced 25–30 times the response in understory cover than did smaller gaps (< 5 m2). Vegetation NDVI and photosynthetic fractional cover decreased, while exposed non-photosynthetic vegetation and bare soil increased, with elevation. Scaling of gap size to gap frequency (λ) was, however, nearly constant along the elevation gradient. When combined with other canopy structural and functional trait information, this suggests near-constant canopy turnover rates from the lowlands to treeline, which occurs independent of decreasing biomass or productivity with increasing elevation. Our results provide the first landscape-scale quantification of forest structure and canopy functional traits with changing elevation, thereby improving our understanding of disturbance, demography and ecosystem processes in the Andes-to-Amazon corridor.

Large variation in branch and branch-tip hydraulic functional traits in Douglas-fir (Pseudotsuga menziesii) approaching lower treeline

2019 ◽  
Vol 39 (8) ◽  
pp. 1461-1472
Author(s):  
Theresa K Condo ◽  
Keith Reinhardt
Keyword(s):  
Functional Traits ◽  
Pseudotsuga Menziesii ◽  
Elevation Gradient ◽  
Douglas Fir ◽  
Elevation Gradients ◽  
Trade Offs ◽  
Hydraulic Vulnerability ◽  
Maximum Conductivity ◽  
Negative Impacts ◽  
Water Limitations

Abstract Few studies have quantified intraspecific variation of hydraulic functional traits in conifers across elevation gradients that include range boundaries. In the Intermountain West, USA, the lower elevational limit of forests (lower treeline) is generally assumed to be caused by water limitations to growth and water relations, yet few studies directly show this. To test this assumption, we measured changes in a suite of traits that characterize drought tolerance such as drought-induced hydraulic vulnerability, hydraulic transport capacity and morphological traits in branch tips and branches of Douglas-fir (Pseudotsuga menziesii var. glauca (Mirb.) Franco) along a 400-m elevation gradient in southeastern Idaho that included lower treeline. As elevation decreased, vulnerability to hydraulic dysfunction and maximum conductivity both decreased in branches; some hydraulic safety–efficiency trade-offs were evident. In branch tips, the water potential at the turgor loss point decreased, while maximum conductance increased with decreasing elevation, highlighting that branch-tip-level responses to less moisture availability accompanied by warmer temperatures might not be coordinated with branch responses. As the range boundary was approached, we did not observe non-linear changes in parameters among sites or increased variance within sites, which current ecological hypotheses on range limits suggest. Our results indicate that there is substantial plasticity in hydraulic functional traits in branch tips and branches of Douglas-fir, although the direction of the trends along the elevation gradient sometimes differed between organs. Such plasticity may mitigate the negative impacts of future drought on Douglas-fir productivity, slowing shifts in its range that are expected to occur with climate change.

scholarly journals Evolutionary Diversity Peaks at Mid-Elevations Along an Amazon-to-Andes Elevation Gradient

2021 ◽  
Vol 9 ◽  
Author(s):  
Andy R. Griffiths ◽  
Miles R. Silman ◽  
William Farfan-Rios ◽  
Kenneth J. Feeley ◽  
Karina García Cabrera ◽  
...  
Keyword(s):  
Census Data ◽  
Elevation Gradient ◽  
Taxonomic Diversity ◽  
Elevation Gradients ◽  
Peruvian Andes ◽  
Diversity Patterns ◽  
Representing Tree ◽  
Tree Ferns ◽  
Diversity Gradients ◽  
Amazonian Lowlands

Elevation gradients present enigmatic diversity patterns, with trends often dependent on the dimension of diversity considered. However, focus is often on patterns of taxonomic diversity and interactions between diversity gradients and evolutionary factors, such as lineage age, are poorly understood. We combine forest census data with a genus level phylogeny representing tree ferns, gymnosperms, angiosperms, and an evolutionary depth of 382 million years, to investigate taxonomic and evolutionary diversity patterns across a long tropical montane forest elevation gradient on the Amazonian flank of the Peruvian Andes. We find that evolutionary diversity peaks at mid-elevations and contrasts with taxonomic richness, which is invariant from low to mid-elevation, but then decreases with elevation. We suggest that this trend interacts with variation in the evolutionary ages of lineages across elevation, with contrasting distribution trends between younger and older lineages. For example, while 53% of young lineages (originated by 10 million years ago) occur only below ∼1,750 m asl, just 13% of old lineages (originated by 110 million years ago) are restricted to below ∼1,750 m asl. Overall our results support an Environmental Crossroads hypothesis, whereby a mid-gradient mingling of distinct floras creates an evolutionary diversity in mid-elevation Andean forests that rivals that of the Amazonian lowlands.

scholarly journals TomoSAR Mapping of 3D Forest Structure: Contributions of L-Band Configurations

2021 ◽  
Vol 13 (12) ◽  
pp. 2255
Author(s):  
Matteo Pardini ◽  
Victor Cazcarra-Bes ◽  
Konstantinos Papathanassiou
Keyword(s):  
Information Content ◽  
Forest Structure ◽  
Structural Information ◽  
3D Structure ◽  
Physical Structure ◽  
Structure Mapping ◽  
Structure Information ◽  
Forest Sites ◽  
L Band ◽  
Structure Indices

Synthetic Aperture Radar (SAR) measurements are unique for mapping forest 3D structure and its changes in time. Tomographic SAR (TomoSAR) configurations exploit this potential by reconstructing the 3D radar reflectivity. The frequency of the SAR measurements is one of the main parameters determining the information content of the reconstructed reflectivity in terms of penetration and sensitivity to the individual vegetation elements. This paper attempts to review and characterize the structural information content of L-band TomoSAR reflectivity reconstructions, and their potential to forest structure mapping. First, the challenges in the accurate TomoSAR reflectivity reconstruction of volume scatterers (which are expected to dominate at L-band) and to extract physical structure information from the reconstructed reflectivity is addressed. Then, the L-band penetration capability is directly evaluated by means of the estimation performance of the sub-canopy ground topography. The information content of the reconstructed reflectivity is then evaluated in terms of complementary structure indices. Finally, the dependency of the TomoSAR reconstruction and of its structural information to both the TomoSAR acquisition geometry and the temporal change of the reflectivity that may occur in the time between the TomoSAR measurements in repeat-pass or bistatic configurations is evaluated. The analysis is supported by experimental results obtained by processing airborne acquisitions performed over temperate forest sites close to the city of Traunstein in the south of Germany.

scholarly journals Multi-Year NDVI Values as Indicator of the Relationship between Spatiotemporal Vegetation Dynamics and Environmental Factors in the Qaidam Basin, China

2021 ◽  
Vol 13 (7) ◽  
pp. 1240
Author(s):  
Junpeng Lou ◽  
Guoyin Xu ◽  
Zhongjing Wang ◽  
Zhigang Yang ◽  
Sanchuan Ni
Keyword(s):  
Environmental Factors ◽  
Vegetation Dynamics ◽  
Vegetation Index ◽  
Qaidam Basin ◽  
Elevation Gradient ◽  
Practical Significance ◽  
Elevation Gradients ◽  
Relative Contribution ◽  
Significant Difference ◽  
Different Altitudes

The Qaidam Basin is a unique and complex ecosystem, wherein elevation gradients lead to high spatial heterogeneity in vegetation dynamics and responses to environmental factors. Based on the remote sensing data of Moderate Resolution Imaging Spectroradiometer (MODIS), Tropical Rainfall Measuring Mission (TRMM) and Global Land Data Assimilation System (GLDAS), we analyzed the spatiotemporal variations of vegetation dynamics and responses to precipitation, accumulative temperature (AT) and soil moisture (SM) in the Qaidam Basin from 2001 to 2016. Moreover, the contribution of those factors to vegetation dynamics at different altitudes was analyzed via an artificial neural network (ANN) model. The results indicated that the Normalized Difference Vegetation Index (NDVI) values in the growing season showed an overall upward trend, with an increased rate of 0.001/year. The values of NDVI in low-altitude areas were higher than that in high-altitude areas, and the peak values of NDVI appeared along the elevation gradient at 4400–4600 m. Thanks to the use of ANN, we were able to detect the relative contribution of various environmental factors; the relative contribution rate of AT to the NDVI dynamic was the most significant (35.17%) in the low-elevation region (< 2900 m). In the mid-elevation area (2900–3900 m), precipitation contributed 44.76% of the NDVI dynamics. When the altitude was higher than 3900 m, the relative contribution rates of AT (39.50%) and SM (38.53%) had no significant difference but were significantly higher than that of precipitation (21.97%). The results highlight that the different environmental factors have various contributions to vegetation dynamics at different altitudes, which has important theoretical and practical significance for regulating ecological processes.

Landscape-scale effects of fire severity on mixed-conifer and red fir forest structure in Yosemite National Park

2013 ◽  
Vol 287 ◽  
pp. 17-31 ◽  
Author(s):  
Van R. Kane ◽  
James A. Lutz ◽  
Susan L. Roberts ◽  
Douglas F. Smith ◽  
Robert J. McGaughey ◽  
...  
Keyword(s):  
Forest Structure ◽  
National Park ◽  
Scale Effects ◽  
Fire Severity ◽  
Landscape Scale ◽  
Yosemite National Park ◽  
Mixed Conifer

Beyond mean functional traits: Influence of functional trait profiles on forest structure, production, and mortality across the eastern US

2014 ◽  
Vol 328 ◽  
pp. 1-9 ◽  
Author(s):  
Matthew B. Russell ◽  
Christopher W. Woodall ◽  
Anthony W. D’Amato ◽  
Grant M. Domke ◽  
Sassan S. Saatchi
Keyword(s):  
Functional Traits ◽  
Forest Structure ◽  
Functional Trait

The shrinkage of a forest: Landscape-scale deforestation leading to overall changes in local forest structure

2016 ◽  
Vol 196 ◽  
pp. 1-9 ◽  
Author(s):  
Larissa Rocha-Santos ◽  
Michaele S. Pessoa ◽  
Camila R. Cassano ◽  
Daniela C. Talora ◽  
Rodrigo L.L. Orihuela ◽  
...  
Keyword(s):  
Forest Structure ◽  
Landscape Scale ◽  
Forest Landscape

scholarly journals Advances in the Derivation of Northeast Siberian Forest Metrics Using High-Resolution UAV-Based Photogrammetric Point Clouds

2019 ◽  
Vol 11 (12) ◽  
pp. 1447 ◽  
Author(s):  
Frederic Brieger ◽  
Ulrike Herzschuh ◽  
Luidmila A. Pestryakova ◽  
Bodo Bookhagen ◽  
Evgenii S. Zakharov ◽  
...  
Keyword(s):  
High Resolution ◽  
Forest Structure ◽  
Stand Structure ◽  
Structural Information ◽  
Carbon Sink ◽  
Local Maximum ◽  
Window Size ◽  
Point Clouds ◽  
Percentage Error ◽  
Individual Tree

Forest structure is a crucial component in the assessment of whether a forest is likely to act as a carbon sink under changing climate. Detailed 3D structural information about the tundra–taiga ecotone of Siberia is mostly missing and still underrepresented in current research due to the remoteness and restricted accessibility. Field based, high-resolution remote sensing can provide important knowledge for the understanding of vegetation properties and dynamics. In this study, we test the applicability of consumer-grade Unmanned Aerial Vehicles (UAVs) for rapid calculation of stand metrics in treeline forests. We reconstructed high-resolution photogrammetric point clouds and derived canopy height models for 10 study sites from NE Chukotka and SW Yakutia. Subsequently, we detected individual tree tops using a variable-window size local maximum filter and applied a marker-controlled watershed segmentation for the delineation of tree crowns. With this, we successfully detected 67.1% of the validation individuals. Simple linear regressions of observed and detected metrics show a better correlation (R2) and lower relative root mean square percentage error (RMSE%) for tree heights (mean R2 = 0.77, mean RMSE% = 18.46%) than for crown diameters (mean R2 = 0.46, mean RMSE% = 24.9%). The comparison between detected and observed tree height distributions revealed that our tree detection method was unable to representatively identify trees <2 m. Our results show that plot sizes for vegetation surveys in the tundra–taiga ecotone should be adapted to the forest structure and have a radius of >15–20 m to capture homogeneous and representative forest stands. Additionally, we identify sources of omission and commission errors and give recommendations for their mitigation. In summary, the efficiency of the used method depends on the complexity of the forest’s stand structure.

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