The demography of range boundaries versus range cores in eastern US tree species

Regional species–climate correlations are well documented, but little is known about the ecological processes responsible for generating these patterns. Using the data from over 690 000 individual trees I estimated five demographic rates—canopy growth, understorey growth, canopy lifespan, understorey lifespan and per capita reproduction—for 19 common eastern US tree species, within the core and the northern and southern boundaries, of the species range. Most species showed statistically significant boundary versus core differences in most rates at both boundary types. Differences in canopy and understorey growth were relatively small in magnitude but consistent among species, being lower at the northern (average −17%) and higher at the southern (average +12%) boundaries. Differences in lifespan were larger in magnitude but highly variable among species, except for a marked trend for reduced canopy lifespan at the northern boundary (average −49%). Differences in per capita reproduction were large and statistically significant for some species, but highly variable among species. The rate estimates were combined to calculate two performance indices: R0 (a measure of lifetime fitness in the absence of competition) was consistently lower at the northern boundary (average −86%) whereas Z* (a measure of competitive ability in closed forest) showed no sign of a consistent boundary–core difference at either boundary

On the NASA GEDI and ESA CCI biomass maps: aligning for uptake in the UNFCCC global stocktake

Earth Observation data are uniquely positioned to estimate forest aboveground biomass density (AGBD) in accordance with the United Nations Framework Convention on Climate Change (UNFCCC) principles of 'transparency, accuracy, completeness, consistency and comparability'. However, the use of space-based AGBD maps for national-level reporting to the UNFCCC is nearly non-existent as of 2023, the end of the first global stocktake (GST). We conduct an evidence-based comparison of AGBD estimates from the NASA Global Ecosystem Dynamics Investigation and ESA Climate Change Initiative, describing differences between the products and National Forest Inventories (NFIs), and suggesting how science teams must align efforts to inform the next GST. Between the products, in the tropics, the largest differences in estimated AGBD are primarily in the Congolese lowlands and east/southeast Asia. Where NFI data were acquired (Peru, Mexico, Lao PDR and 30 regions of Spain), both products show strong correlation to NFI-estimated AGBD, with no systematic deviations. The AGBD-richest stratum of these, the Peruvian Amazon, is accurately estimated in both. These results are remarkably promising, and to support the operational use of AGB map products for policy reporting, we describe targeted ways to align products with Intergovernmental Panel on Climate Change (IPCC) guidelines. We recommend moving towards consistent statistical terminology, and aligning on a rigorous framework for uncertainty estimation, supported by the provision of open-science codes for large-area assessments that comprehensively report uncertainty. Further, we suggest the provision of objective and open-source guidance to integrate NFIs with multiple AGBD products, aiming to enhance the precision of national estimates. Finally, we describe and encourage the release of user-friendly product documentation, with tools that produce AGBD estimates directly applicable to the IPCC guideline methodologies. With these steps, space agencies can convey a comparable, reliable and consistent message on global biomass estimates to have actionable policy impact

Annual forest inventories for the north central region of the United States

The primary objective in developing procedures for annual forest inventories for the north central region of the United States is to establish the capability of producing standard forest inventory and analysis estimates on an annual basis. The inventory system developed to accomplish this objective features several primary functions, including (1) an annual sample of measured field plots, (2) satellite-based remote sensing for stratification into land use and land use change classifications, (3) a database of current and past plot and tree infomation, and (4) models for predicting the growth and survival of trees not measured in the current year. The discussion focuses on specific features and options for each functio

Actualización de los volúmenes proporcionados por los Inventarios Forestales Nacionales

Para monitorizar el estado y los cambios en los recursos forestales, organizaciones internacionales, tales como FAO o UNFCCC, solicitan información a los distintos países. Entre los parámetros solicitados uno de los más habituales es el volumen forestal. Para dar respuesta a los requerimientos la mayoría de los países utilizan los datos de sus Inventarios Forestales Nacionales (IFN). Sin embargo, dada la creciente frecuencia en la demanda de información, que en algunos casos llega a ser anual, existen discrepancias temporales entre las fechas de los IFN y de los datos requeridos. Para solventar dichas diferencias algunos países recurren a modificar los protocolos de medición para contar con datos anuales a nivel nacional, mientras otros recurren a la actualización de los datos mediante modelos. En cualquiera de los casos es necesaria una metodología específica para proporcionar estimaciones adecuadas con un error aceptable. En este trabajo se presentan dos metodologías diferentes. La primera de ellas es la utilizada en Estados Unidos donde se toman datos anualmente en todo el país. La segunda metodología permite actualizar los volúmenes medidos en el IFN español, con periodo de remedición de 10 años. Se hace especial hincapié en describir la metodología española, la cual se basa en la modelización del balance anual del volumen en las parcelas del IFN, y en la estimación de valores medios y la incertidumbre asociada (intervalos de confianza) mediante técnicas de inferencia híbrida. Se destacan en todos los casos la importancia del uso de imágenes provenientes de sensores remotos como información auxiliar