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We used measurements from airborne imaging spectroscopy and LiDAR to quantify the biophysical structure and composition of vegetation on a dryland substrate age gradient in Hawaii. Both vertical stature and species composition changed during primary succession, and reveal a progressive increase in vertical stature on younger substrates followed by a collapse on Pleistocene-aged flows. Tall-stature Metrosideros polymorpha woodlands dominated on the youngest substrates (hundreds of years), and were replaced by the tall-stature endemic tree species Myoporum sandwicense and Sophora chrysophylla on intermediate-aged flows (thousands of years). The oldest substrates (tens of thousands of years) were dominated by the short-stature native shrub Dodonaea viscosa and endemic grass Eragrostis atropioides. We excavated 18 macroscopic charcoal fragments from Pleistocene-aged substrates. Mean radiocarbon age was 2,002 years and ranged from < 200 to 7,730. Genus identities from four fragments indicate that Osteomeles spp. or M. polymorpha once occupied the Pleistocene-aged substrates, but neither of these species is found there today. These findings indicate the existence of fires before humans are known to have occupied the Hawaiian archipelago, and demonstrate that a collapse in vertical stature is prevalent on the oldest substrates. This work contributes to our understanding of prehistoric fires in shaping the trajectory of primary succession in Hawaiian drylands.

Abstract Background High fidelity carbon mapping has the potential to greatly advance national resource management and to encourage international action toward climate change mitigation. However, carbon inventories based on field plots alone cannot capture the heterogeneity of carbon stocks, and thus remote sensing-assisted approaches are critically important to carbon mapping at regional to global scales. We advanced a high-resolution, national-scale carbon mapping approach applied to the Republic of Panama – one of the first UN REDD + partner countries. Results Integrating measurements of vegetation structure collected by airborne Light Detection and Ranging (LiDAR) with field inventory plots, we report LiDAR-estimated aboveground carbon stock errors of ~10% on any 1-ha land parcel across a wide range of ecological conditions. Critically, this shows that LiDAR provides a highly reliable replacement for inventory plots in areas lacking field data, both in humid tropical forests and among drier tropical vegetation types. We then scale up a systematically aligned LiDAR sampling of Panama using satellite data on topography, rainfall, and vegetation cover to model carbon stocks at 1-ha resolution with estimated average pixel-level uncertainty of 20.5 Mg C ha-1 nationwide. Conclusions The national carbon map revealed strong abiotic and human controls over Panamanian carbon stocks, and the new level of detail with estimated uncertainties for every individual hectare in the country sets Panama at the forefront in high-resolution ecosystem management. With this repeatable approach, carbon resource decision-making can be made on a geospatially explicit basis, enhancing human welfare and environmental protection.

We used aerial photography from 1954 and airborne LiDAR and imaging spectroscopy from 2008 to infer changes in extent and location of tallstature woody vegetation in 127 [km.sup.2] of subalpine dry forest on the island of Hawai'i (Pohakuloa Training Area), and to identify 25.8 [km.sup.2] of intact woody vegetation for restoration and management. Total cover of woody vegetation was 54.7 [km.sup.2] in 1954 and 58.6 [km.sup.2] in 2008. Approximately 28.9 [km.sup.2] underwent woody vegetation change (22.7%) between 1954 and 2008. Increases in woody vegetation cover occurred in 16.4 [km.sup.2], and 12.5 [km.sup.2] represented reduction of woody vegetation cover (12.9% and 9.8% of the 127 [km.sup.2] study area, respectively). Our findings suggest that 3.9 [km.sup.2] (3.0%) experienced a net increase in woody vegetation cover between 1954 and 2008. Spatial patterns suggest that fires may be the primary driver of reductions in woody vegetation cover. Increases could be due to regeneration of dry forest trees or measurement errors associated with historical imagery. Areas remaining in woody vegetation cover over the 53-yr study interval can be targeted for restoration and management. We discuss challenges to integrating historical photography with contemporary conservation and management in Hawai'i and the Pacific and we outline additional studies that would help to improve estimates. The methods and analysis are general and could be applied to other dryland ecosystems with complex volcanic substrates in Hawai'i and the Pacific., A challenge to conservation and restoration projects is defining management objectives in the context of historical impacts. Whether current patterns represent natural or modified conditions is usually unknown in the [...]

Biological invasions contribute to global environmental change, but the dynamics and consequences of most invasions are difficult to assess at regional scales. We deployed an airborne remote sensing system that mapped the location and impacts of five highly invasive plant species across 221,875 ha of Hawaiian ecosystems, identifying four distinct ways that these species transform the three-dimensional (3D) structure of native rain forests. In lowland to montane forests, three invasive tree species replace native midcanopy and understory plants, whereas one understory invader excludes native species at the ground level. A fifth invasive nitrogen-fixing tree, in combination with a midcanopy alien tree, replaces native plants at all canopy levels in lowland forests. We conclude that this diverse array of alien plant species, each representing a different growth form or functional type, is changing the fundamental 3D structure of native Hawaiian rain forests. Our work also demonstrates how an airborne mapping strategy can identify and track the spread of certain invasive plant species, determine ecological consequences of their proliferation, and provide detailed geographic information to conservation and management efforts. biological invasion | Hawaii | imaging spectroscopy | LiDAR | tropical forest

The two-hole high Tc rf-Superconducting Quantum Interference Device (SQUID) is a good non-destructive testing field device as it has good sensitivity, portability, resolution and penetration depth. SQUID can measure low frequency signals and is employed to examine cracks inside electrical conductors. SQUID functions at liquid nitrogen temperatures.