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Fire is known to structure tree populations, but the role of broad-scale climate variability is less clear. For example, the influence of climatic ?teleconnections? (the relationship between oceanic?atmospheric fluctuations and anomalous weather patterns across broad scales) on forest age structure is relatively unexplored. We sampled semiarid pi�on?juniper (Pinus edulis?Juniperus osteosperma) woodlands in western Colorado, USA, to test the hypothesis that woodland age structures are shaped by climate, including links to oceanic?atmospheric fluctuations, and by past fires and livestock grazing. Low-severity surface fire was lacking, as fire scars were absent, and did not influence woodland densities, but stand-replacing...
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We analyzed very-high-resolution imagery to assess status of Metrosideros polymorpha forests across an 83,603 hectare study area that experienced extensive canopy dieback in the 1970s on the eastern side of the island of Hawaii. Using GIS we generated 1170 virtual vegetation plots with a 100 m radius; 541 plots in areas mapped in 1977 with trees dead or mostly defoliated (dieback), and 629 plots in adjacent wet forest habitat, previously mapped as non-dieback condition. In each plot we estimated the percent of M. polymorpha trees dead or mostly defoliated, and percent of trees with healthy crowns. These results were combined with habitat data to produce a spatial model depicting probability of canopy dieback within...
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Several previously published reports and geographic information system (GIS) data layers were used to code information on site attributes for each assessment plot using the spatial join tool in ArcMap. This information was used for an analysis of dieback and non-dieback habitat characteristics. The results of this analysis are presented in this table which depicts the probability of heavy to severe canopy dieback occurring at some time at a particular 30 x 30 m pixel location within the study area.
Fire is known to structure tree populations, but the role of broad-scale climate variability is less clear. For example, the influence of climatic ?teleconnections? (the relationship between oceanic?atmospheric fluctuations and anomalous weather patterns across broad scales) on forest age structure is relatively unexplored. We sampled semiarid pi�on?juniper (Pinus edulis?Juniperus osteosperma) woodlands in western Colorado, USA, to test the hypothesis that woodland age structures are shaped by climate, including links to oceanic?atmospheric fluctuations, and by past fires and livestock grazing. Low-severity surface fire was lacking, as fire scars were absent, and did not influence woodland densities, but stand-replacing...
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These NetCDF data were compiled to investigate how two complementary models can contribute to our understanding of contemporary and future big sagebrush regeneration across the historical and potential future sagebrush region. Objective of our study was to apply both models to address three specific objectives: (i) examine the geographic patterns of big sagebrush regeneration probabilities that the two different models project under historical conditions and future climate scenarios; (ii) quantify the robustness of model projections, e.g., the consistency among climate models in projected changes in regeneration for future time periods; and (iii) identify how model predictions for regeneration potential relate to...
Due to a gap in information on regeneration of hard-mast trees in the floodplain, interpretation was completed of existing 8“/pixel aerial imagery delineating a detailed hardwood forest spatial dataset within the floodplain forest of the Fish and Wildlife Upper Mississippi National Wildlife & Fish Refuge, McGregor District. The detailed map of bottomland hardwoods will allow for the identification of existing habitat and assess bottomland hardwood tree patterns to enable management of these areas.
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This dataset describes the boundary of the study area used to analyze regeneration and change in status of native ohia forests in the wet habitat on the eastern side of the island of Hawaii. This area includes forests that were heavily impacted by landscape-level canopy dieback in the 1970s as well as forests that were not affected with tree canopy death or defoliation.
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Abstract Ecological factors favoring either resprouting or obligate seeding in plants have received considerable attention recently. Three ecological models have been proposed to explain patterns of these two life history types. In this study we test these three models using data from California chaparral. We take an innovative approach to testing these models by not testing community or landscape patterns, but instead, investigating environmental patterns characteristic of pairs of either resprouting or obligate seeding subspecies of Arctostaphylos (Ericaceae), a dominant and diverse shrub genus in chaparral. Four species were investigated that contain both a resprouting and an obligate seeding subspecies. Data...
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Fire is known to structure tree populations, but the role of broad-scale climate variability is less clear. For example, the influence of climatic “teleconnections” (the relationship between oceanic–atmospheric fluctuations and anomalous weather patterns across broad scales) on forest age structure is relatively unexplored. We sampled semiarid piñon–juniper (Pinus edulis–Juniperus osteosperma) woodlands in western Colorado, USA, to test the hypothesis that woodland age structures are shaped by climate, including links to oceanic–atmospheric fluctuations, and by past fires and livestock grazing. Low-severity surface fire was lacking, as fire scars were absent, and did not influence woodland densities, but stand-replacing...
Juniperus woodlands are widely distributed in western North America. Few studies of seedling emergence, long-term survival, growth or mortality of the dominant Juniperus spp. in these woodlands have been carried out. Consequently, regeneration dynamics in these woodlands are poorly understood. Juniperus ashei is the dominant woody plant in the majority of woodland and savanna communities of the Edwards Plateau region in central Texas. We examined the emergence, mortality and growth of various spatial and temporal cohorts of J. ashei seedlings over an eight or nine-year period. Greatest emergence was found during the cool, mostly winter months and under the canopy of mature J. ashei trees. Emergence was significantly...
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We analyzed very-high-resolution imagery to assess status of Metrosideros polymorpha forests across an 83,603-hectare study area that experienced extensive canopy dieback in the 1970s on the eastern side of the island of Hawaii. Using GIS we generated 1,170 virtual vegetation plots with a 100-m radius; 541 plots in areas mapped in 1977 with trees dead or mostly defoliated (dieback), and 629 plots in adjacent wet forest habitat, previously mapped as non-dieback condition. In each plot we estimated the percent of M. polymorpha trees dead or mostly defoliated, and percent of trees with healthy crowns. These results were combined with habitat data to produce a spatial model depicting probability of canopy dieback within...
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This data set includes an accuracy assessment of the repeatability of identifying heavy to severe tree canopy dieback in virtual plots located within the Ohia Dieback 83,603 hectare study area.
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This data set provides the locations of the ground-based vegetation plots that have been used to assess the status of the ohia forests on the eastern side of the island of Hawaii following a landscape-level canopy dieback event that occurred in this area in the 1970s. These plots have been resurveyed several times and the results summarized by Boehmer et al. 2013.
These NetCDF data were compiled to investigate how rangelands in the western U.S. are limited by access to water. As a result, these ecosystems may be especially vulnerable to changes in water availability and drought as a result of climate change. This project utilized an ecosystem water balance model to quantify spatial and temporal patterns of rangeland ecological drought conditions under historical and future climate conditions. Water balance results were used to estimate several metrics that describe the seasonal timing and amount of moisture available for plant utilization in western rangelands. These data represent different aspects of water availability and drought. They are based on 1/16-degree gridded...
    map background search result map search result map Historical fire and multidecadal drought as context for piñon–juniper woodland restoration in western Colorado Arctostaphylos Occurrence and Historical Fires Table Upper Mississippi National Wildlife and Fish Refuge: McGregor District Mast Hardwood Floodplain Forest Community Hawaii Island Regeneration of Metrosideros polymorpha forests since landscape-level canopy dieback in the 1970s Map of study area for canopy status assessment in 2015 Ohia Dieback Study - 1977 Ground Survey Plot Locations Ohia Dieback Study - Canopy Status Accuracy Assessment Ohia Dieback Study - Hawaii Island Canopy Status Assessment Table, 1977 - 2015 Ohia Dieback Study - Dieback Model Results Table Regeneration trends along climate gradients in Taxodium distichum forest of the southeastern United States, 2007-2019 Simulated rangewide big sagebrush regeneration estimates and relationships with abiotic variables as function of soils under historical and future climate projections Historical and future ecological drought conditions for rangelands of the western U.S. Map of study area for canopy status assessment in 2015 Upper Mississippi National Wildlife and Fish Refuge: McGregor District Mast Hardwood Floodplain Forest Community Hawaii Island Regeneration of Metrosideros polymorpha forests since landscape-level canopy dieback in the 1970s Ohia Dieback Study - 1977 Ground Survey Plot Locations Ohia Dieback Study - Canopy Status Accuracy Assessment Ohia Dieback Study - Hawaii Island Canopy Status Assessment Table, 1977 - 2015 Ohia Dieback Study - Dieback Model Results Table Historical fire and multidecadal drought as context for piñon–juniper woodland restoration in western Colorado Regeneration trends along climate gradients in Taxodium distichum forest of the southeastern United States, 2007-2019 Arctostaphylos Occurrence and Historical Fires Table Simulated rangewide big sagebrush regeneration estimates and relationships with abiotic variables as function of soils under historical and future climate projections Historical and future ecological drought conditions for rangelands of the western U.S.