scholarly journals Canopy Area of Large Trees Explains Aboveground Biomass Variations across Nine Neotropical Forest Landscapes

2018 ◽  
Author(s):  
Victoria Meyer ◽  
Sassan Saatchi ◽  
David B. Clark ◽  
Michael Keller ◽  
Grégoire Vincent ◽  
...  
Keyword(s):  
Forest Structure ◽  
Aboveground Biomass ◽  
Tree Mortality ◽  
Forest Disturbance ◽  
Basal Area ◽  
Selective Logging ◽  
Tree Canopy ◽  
Crown Area ◽  
Large Trees ◽  
Canopy Area

Abstract. Large tropical trees store significant amounts of carbon in woody components and their distribution plays an important role in forest carbon stocks and dynamics. Here, we explore the properties of a new Lidar derived index, large tree canopy area (LCA) defined as the area occupied by canopy above a reference height. We hypothesize that this simple measure of forest structure representing the crown area of large canopy trees could consistently explain the landscape variations of forest volume and aboveground biomass (AGB) across a range of climate and edaphic conditions. To test this hypothesis, we assembled a unique dataset of high-resolution airborne Light Detection and Ranging (Lidar) and ground inventory data in nine undisturbed old growth Neotropical forests. We found that the LCA for trees greater than 27 m (~ 25–30 m) in height and at least 100 m2 crown size in a unit area (1 ha), explains more than 75 % of total forest volume variations, irrespective of the forest biogeographic conditions. When weighted by average wood density of the stand, LCA can be used as an unbiased estimator of AGB across all sites (R2 = 0.78, RMSE = 46.02 Mg ha−1, bias = 0.76 Mg ha−1). Unlike other Lidar derived metrics with complex nonlinear relations to biomass, the relationship between LCA and AGB is linear. A comparison with tree inventories across the study sites indicates that LCA correlates best with the crown area (or basal area) of trees with diameter > 50 cm. The spatial invariance of the LCA–AGB relationship across the Neotropics suggests a remarkable regularity of forest structure across the landscape and a new technique for systematic monitoring of large trees for their contribution to AGB and changes associated with selective logging, tree mortality, and other types of forest disturbance and dynamics.

scholarly journals Canopy area of large trees explains aboveground biomass variations across neotropical forest landscapes

2018 ◽  
Vol 15 (11) ◽  
pp. 3377-3390 ◽  
Author(s):  
Victoria Meyer ◽  
Sassan Saatchi ◽  
David B. Clark ◽  
Michael Keller ◽  
Grégoire Vincent ◽  
...  
Keyword(s):  
Forest Structure ◽  
Aboveground Biomass ◽  
Tree Mortality ◽  
Forest Disturbance ◽  
Basal Area ◽  
Selective Logging ◽  
Tree Canopy ◽  
Crown Area ◽  
Large Trees ◽  
Canopy Area

Abstract. Large tropical trees store significant amounts of carbon in woody components and their distribution plays an important role in forest carbon stocks and dynamics. Here, we explore the properties of a new lidar-derived index, the large tree canopy area (LCA) defined as the area occupied by canopy above a reference height. We hypothesize that this simple measure of forest structure representing the crown area of large canopy trees could consistently explain the landscape variations in forest volume and aboveground biomass (AGB) across a range of climate and edaphic conditions. To test this hypothesis, we assembled a unique dataset of high-resolution airborne light detection and ranging (lidar) and ground inventory data in nine undisturbed old-growth Neotropical forests, of which four had plots large enough (1 ha) to calibrate our model. We found that the LCA for trees greater than 27 m (∼ 25–30 m) in height and at least 100 m2 crown size in a unit area (1 ha), explains more than 75 % of total forest volume variations, irrespective of the forest biogeographic conditions. When weighted by average wood density of the stand, LCA can be used as an unbiased estimator of AGB across sites (R2 = 0.78, RMSE = 46.02 Mg ha−1, bias = −0.63 Mg ha−1). Unlike other lidar-derived metrics with complex nonlinear relations to biomass, the relationship between LCA and AGB is linear and remains unique across forest types. A comparison with tree inventories across the study sites indicates that LCA correlates best with the crown area (or basal area) of trees with diameter greater than 50 cm. The spatial invariance of the LCA–AGB relationship across the Neotropics suggests a remarkable regularity of forest structure across the landscape and a new technique for systematic monitoring of large trees for their contribution to AGB and changes associated with selective logging, tree mortality and other types of tropical forest disturbance and dynamics.

scholarly journals Big trees drive forest structure patterns across a lowland Amazon regrowth gradient

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tassiana Maylla Fontoura Caron ◽  
Victor Juan Ulises Rodriguez Chuma ◽  
Alexander Arévalo Sandi ◽  
Darren Norris
Keyword(s):  
Forest Structure ◽  
Natural Regeneration ◽  
Basal Area ◽  
Significant Decline ◽  
Forest Regrowth ◽  
Large Trees ◽  
Amazonian Forests ◽  
Mammal Diversity ◽  
Structure Patterns ◽  
Plot Type

AbstractDegraded Amazonian forests can take decades to recover and the ecological results of natural regeneration are still uncertain. Here we use field data collected across 15 lowland Amazon smallholder properties to examine the relationships between forest structure, mammal diversity, regrowth type, regrowth age, topography and hydrology. Forest structure was quantified together with mammal diversity in 30 paired regrowth-control plots. Forest regrowth stage was classified into three groups: late second-regrowth, early second-regrowth and abandoned pasture. Basal area in regrowth plots remained less than half that recorded in control plots even after 20–25 years. Although basal area did increase in sequence from pasture, early to late-regrowth plots, there was a significant decline in basal area of late-regrowth control plots associated with a decline in the proportion of large trees. Variation in different forest structure responses was explained by contrasting variables, with the proportion of small trees (DBH < 20 cm) most strongly explained by topography (altitude and slope) whereas the proportion of large trees (DBH > 60 cm) was explained by plot type (control vs. regrowth) and regrowth class. These findings support calls for increased efforts to actively conserve large trees to avoid retrogressive succession around edges of degraded Amazon forests.

Implementation constraints limit benefits of restoration treatments in mixed-conifer forests

2019 ◽  
Vol 28 (7) ◽  
pp. 495 ◽  
Author(s):  
Jamie M. Lydersen ◽  
Brandon M. Collins ◽  
Carolyn T. Hunsaker
Keyword(s):  
Sierra Nevada ◽  
Forest Structure ◽  
Forest Restoration ◽  
Tree Mortality ◽  
Canopy Cover ◽  
Basal Area ◽  
Severe Drought ◽  
Conifer Forest ◽  
Mixed Conifer ◽  
Trade Offs

Forest restoration treatments seek to increase resilience to wildfire and a changing climate while avoiding negative impacts to the ecosystem. The extent and intensity of treatments are often constrained by operational considerations and concerns over uncertainty in the trade-offs of addressing different management goals. The recent (2012–15) extreme drought in California, USA, resulted in widespread tree mortality, particularly in the southern Sierra Nevada, and provided an opportunity to assess the effects of restoration treatments on forest resilience to drought. We assessed changes in mixed-conifer forest structure following thinning and understorey burning at the Kings River Experimental Watersheds in the southern Sierra Nevada, and how treatments, topography and forest structure related to tree mortality in the recent drought. Treatments had negligible effect on basal area, tree density and canopy cover. Following the recent drought, average basal area mortality within the watersheds ranged from 5 to 26% across riparian areas and 12 to 44% across upland areas, with a range of 0 to 95% across all plots. Tree mortality was not significantly influenced by restoration treatments or topography. Our results suggest that the constraints common to many restoration treatments may limit their ability to mitigate the impacts of severe drought.

scholarly journals Supplementary material to "Canopy Area of Large Trees Explains Aboveground Biomass Variations across Nine Neotropical Forest Landscapes"

2018 ◽  
Author(s):  
Victoria Meyer ◽  
Sassan Saatchi ◽  
David B. Clark ◽  
Michael Keller ◽  
Grégoire Vincent ◽  
...  
Keyword(s):  
Aboveground Biomass ◽  
Neotropical Forest ◽  
Large Trees ◽  
Canopy Area ◽  
Supplementary Material

scholarly journals Growth responses of trees and understory plants to nitrogen fertilization in a subtropical forest in China

2017 ◽  
Vol 14 (14) ◽  
pp. 3461-3469 ◽  
Author(s):  
Di Tian ◽  
Peng Li ◽  
Wenjing Fang ◽  
Jun Xu ◽  
Yongkai Luo ◽  
...  
Keyword(s):  
Aboveground Biomass ◽  
Basal Area ◽  
Ground Cover ◽  
N Fertilization ◽  
Subtropical Forest ◽  
Growth Responses ◽  
Understory Plants ◽  
Large Trees ◽  
N Enrichment ◽  
Understory Shrubs

Abstract. Reactive nitrogen (N) increase in the biosphere has been a noteworthy aspect of global change, producing considerable ecological effects on the functioning and dynamics of the terrestrial ecosystems. A number of observational studies have explored responses of plants to experimentally simulated N enrichment in boreal and temperate forests. Here we investigate how the dominant trees and different understory plants respond to experimental N enrichment in a subtropical forest in China. We conducted a 3.4-year N fertilization experiment in an old-aged subtropical evergreen broad-leaved forest in eastern China with three treatment levels applied to nine 20 m  ×  20 m plots and replicated in three blocks. We divided the plants into trees, saplings, shrubs (including tree seedlings), and ground-cover plants (ferns) according to the growth forms, and then measured the absolute and relative basal area increments of trees and saplings and the aboveground biomass of understory shrubs and ferns. We further grouped individuals of the dominant tree species, Castanopsis eyrei, into three size classes to investigate their respective growth responses to the N fertilization. Our results showed that the plot-averaged absolute and relative growth rates of basal area and aboveground biomass of trees were not affected by N fertilization. Across the individuals of C. eyrei, the small trees with a DBH (diameter at breast height) of 5–10 cm declined by 66.4 and 59.5 %, respectively, in N50 (50 kg N ha−1 yr−1) and N100 fertilized plots (100 kg N ha−1 yr−1), while the growth of median and large trees with a DBH of  >  10 cm did not significantly change with the N fertilization. The growth rate of small trees, saplings, and the aboveground biomass of understory shrubs and ground-cover ferns decreased significantly in the N-fertilized plots. Our findings suggested that N might not be a limiting nutrient in this mature subtropical forest, and that the limitation of other nutrients in the forest ecosystem might be aggravated by the enhanced N availability, potentially resulting in an adverse effect on the development of natural subtropical forest.

scholarly journals Recovery of Forest Structure Following Large-Scale Windthrows in the Northwestern Amazon

Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 667
Author(s):  
J. David Urquiza Muñoz ◽  
Daniel Magnabosco Marra ◽  
Robinson I. Negrón-Juarez ◽  
Rodil Tello-Espinoza ◽  
Waldemar Alegría-Muñoz ◽  
...  
Keyword(s):  
Forest Structure ◽  
Large Scale ◽  
Tree Mortality ◽  
Basal Area ◽  
Forest Recovery ◽  
Old Growth ◽  
Study Region ◽  
Central Amazon ◽  
Old Growth Forest ◽  
Study Sites

The dynamics of forest recovery after windthrows (i.e., broken or uprooted trees by wind) are poorly understood in tropical forests. The Northwestern Amazon (NWA) is characterized by a higher occurrence of windthrows, greater rainfall, and higher annual tree mortality rates (~2%) than the Central Amazon (CA). We combined forest inventory data from three sites in the Iquitos region of Peru, with recovery periods spanning 2, 12, and 22 years following windthrow events. Study sites and sampling areas were selected by assessing the windthrow severity using remote sensing. At each site, we recorded all trees with a diameter at breast height (DBH) ≥ 10 cm along transects, capturing the range of windthrow severity from old-growth to highly disturbed (mortality > 60%) forest. Across all damage classes, tree density and basal area recovered to >90% of the old-growth values after 20 years. Aboveground biomass (AGB) in old-growth forest was 380 (±156) Mg ha−1. In extremely disturbed areas, AGB was still reduced to 163 (±68) Mg ha−1 after 2 years and 323 (± 139) Mg ha−1 after 12 years. This recovery rate is ~50% faster than that reported for Central Amazon forests. The faster recovery of forest structure in our study region may be a function of its higher productivity and adaptability to more frequent and severe windthrows. These varying rates of recovery highlight the importance of extreme wind and rainfall on shaping gradients of forest structure in the Amazon, and the different vulnerabilities of these forests to natural disturbances whose severity and frequency are being altered by climate change.

The effects of selective logging on nest-site selection and productivity of hooded warblers (Wilsonia citrina) in Canada

2002 ◽  
Vol 80 (4) ◽  
pp. 644-654 ◽  
Author(s):  
Rebecca M Whittam ◽  
Jon D McCracken ◽  
Charles M Francis ◽  
Mary E Gartshore
Keyword(s):  
Site Selection ◽  
Nest Site ◽  
Basal Area ◽  
Nest Site Selection ◽  
Selective Logging ◽  
Ground Vegetation ◽  
Managed Forest ◽  
Wilsonia Citrina ◽  
Large Trees ◽  
Hooded Warblers

We examined nest-site selection by hooded warblers (Wilsonia citrina) in two forests differing in composition (extensive pine plantation versus largely deciduous) and management (recent selective logging versus minimal logging). We measured habitat at 52 nests and 66 controls in one forest and 57 nests and 41 controls in the second. Nests had denser ground vegetation, fewer tree stems, less basal area due to small trees and greater basal area due to large trees than controls in both forests. In the managed forest with extensive pine plantations, hooded warblers were in coniferous and logged stands more often than expected by chance, nests had more stumps and greater canopy height than controls, and 91% (52/57) of all nests were found in gaps, 84% of which were created by harvest. Gap age was 6.2 ± 0.9 years (mean ± SE) in 1999, and 7.6 ± 0.6 years in 2000. In the managed forest, 52% of 24 nests were parasitized in 1999 and 39% of 33 nests were parasitized in 2000. The daily survival rate was 0.936 ± 0.019 in 1999 and 0.944 ± 0.014 in 2000. Successful nests did not differ from unsuccessful nests in any habitat variable. To benefit hooded warblers, forest managers should mimic natural gap creation by using selective logging to create gaps no larger than 0.05 ha, and should leave a residual basal area of mature trees (>38 cm diameter at breast height) of at least 12 m2/ha.

Comparison of burn severity assessments using Differenced Normalized Burn Ratio and ground data

2005 ◽  
Vol 14 (2) ◽  
pp. 189 ◽  
Author(s):  
Allison E. Cocke ◽  
Peter Z. Fulé ◽  
Joseph E. Crouse
Keyword(s):  
Pinus Ponderosa ◽  
Forest Structure ◽  
Tree Mortality ◽  
Fire Severity ◽  
Basal Area ◽  
Burn Severity ◽  
Burned Areas ◽  
Differenced Normalized Burn Ratio ◽  
Severity Levels ◽  
Normalized Burn Ratio

Burn severity can be mapped using satellite data to detect changes in forest structure and moisture content caused by fires. The 2001 Leroux fire on the Coconino National Forest, Arizona, burned over 18 pre-existing permanent 0.1 ha plots. Plots were re-measured following the fire. Landsat 7 ETM+ imagery and the Differenced Normalized Burn Ratio (ΔNBR) were used to map the fire into four severity levels immediately following the fire (July 2001) and 1 year after the fire (June 2002). Ninety-two Composite Burn Index (CBI) plots were compared to the fire severity maps. Pre- and post-fire plot measurements were also analysed according to their imagery classification. Ground measurements demonstrated differences in forest structure. Areas that were classified as severely burned on the imagery were predominantly Pinus ponderosa stands. Tree density and basal area, snag density and fine fuel accumulation were associated with severity levels. Tree mortality was not greatest in severely burned areas, indicating that the ΔNBR is comprehensive in rating burn severity by incorporating multiple forest strata. While the ΔNBR was less accurate at mapping perimeters, the method was reliable for mapping severely burned areas that may need immediate or long-term post-fire recovery.

Tree canopy displacement and neighborhood interactions

2003 ◽  
Vol 33 (7) ◽  
pp. 1323-1330 ◽  
Author(s):  
Christine C Muth ◽  
F A Bazzaz
Keyword(s):  
Community Dynamics ◽  
Basal Area ◽  
Tree Canopy ◽  
Forest Community ◽  
Spatial Proximity ◽  
Forest Plot ◽  
High Resource ◽  
Canopy Position ◽  
Canopy Area ◽  
Canopy Depth

Competitive interactions among plants are largely determined by spatial proximity. However, despite their sessile nature, plants have the ability to avoid neighbors by growing towards areas with high resource availability and reduced competition. Because of this flexibility, tree canopies are rarely centered directly above their stem bases and are often displaced. We sought to determine how a tree's competitive neighborhood influences its canopy position. In a 0.6-ha temperate forest plot, all trees greater than 10 cm DBH (n = 225) were measured for basal area, height, canopy depth, and trunk position. Canopy extent relative to trunk base was determined in eight subcardinal directions, and this information was used to reconstruct canopy size, shape, and position. We found that trees positioned their canopies away from large neighbors, close neighbors, and shade-tolerant neighbors. Neighbor size, expressed as basal area or canopy area, was the best indication of a neighbor's importance in determining target tree canopy position. As neighborhood asymmetry increased, the magnitude of canopy displacement increased, and the precision with which canopies avoided neighbors increased. Flexibility in canopy shape and position appears to reduce competition between neighbors, thereby influencing forest community dynamics.

scholarly journals Using Model Analysis to Unveil Hidden Patterns in Tropical Forest Structures

2021 ◽  
Vol 9 ◽  
Author(s):  
Nicolas Picard ◽  
Frédéric Mortier ◽  
Pierre Ploton ◽  
Jingjing Liang ◽  
Géraldine Derroire ◽  
...  
Keyword(s):  
Large Scale ◽  
Forest Disturbance ◽  
Null Model ◽  
Basal Area ◽  
Model Analysis ◽  
Tropical Rain Forests ◽  
Model Framework ◽  
Ecological Processes ◽  
Large Trees ◽  
Using Data

When ordinating plots of tropical rain forests using stand-level structural attributes such as biomass, basal area and the number of trees in different size classes, two patterns often emerge: a gradient from poorly to highly stocked plots and high positive correlations between biomass, basal area and the number of large trees. These patterns are inherited from the demographics (growth, mortality and recruitment) and size allometry of trees and tend to obscure other patterns, such as site differences among plots, that would be more informative for inferring ecological processes. Using data from 133 rain forest plots at nine sites for which site differences are known, we aimed to filter out these patterns in forest structural attributes to unveil a hidden pattern. Using a null model framework, we generated the anticipated pattern inherited from individual allometric patterns. We then evaluated deviations between the data (observations) and predictions of the null model. Ordination of the deviations revealed site differences that were not evident in the ordination of observations. These sites differences could be related to different histories of large-scale forest disturbance. By filtering out patterns inherited from individuals, our model analysis provides more information on ecological processes.

Sign in / Sign up

Export Citation Format

Share Document