Treesearch

Reference evapotranspiration (ETo) is an important hydrometeorological term widely used in understanding and projecting the hydrological effects of future climate and land use change. We conducted a case study in the Qinhuai River Basin that is dominated by a humid subtropical climate and mixed land uses in southern China. Long-term (1961–2012) meteorological data were used to estimate ETo by the FAO-56 Penman–Monteith model. The individual contribution from each meteorological variable to the trend of ETo was quantified. We found basin-wide annual ETo decreased significantly (p < 0.05) by...

Forest densification, wildfires, and disease can reduce the growth and survival of hardwood trees that are important for biological and cultural diversity within the Pacific Northwest of USA. Large, full-crowned hardwoods that produce fruit and that form large cavities used by wildlife were sustained by frequent, low-severity fires prior to Euro-American colonization. Shifts in fire regimes and other threats could be causing declines in, large hardwood trees. To better understand whether and where such declines might be occurring, we evaluated recent trends in Forest Inventory and Analysis...

Reviewing: William J. Matthews and Edie Marsh-Matthews, Stream Fish Community Dynamics: A Critical Synthesis, 2017 Johns Hopkins University Press, 330 pp. Community dynamics are often difficult relationships to describe because they encompass multiple taxa involved in numerous types of interactions of varying strengths, all of which may shift over space and time. Gaining insights from a suite of several long-term projects is difficult logistically and can be difficult to sustain. However, in their book Stream Fish Community Dynamics: A Critical Synthesis, Matthews and Marsh-Matthews offer...

We explore the underlying motivations of NYC community gardeners in order to gain greater insight into how these valued public resources support individual and community well-being. Semi-structured interviews were used to capture a range of enduring gardener motivations over time. We find that the underlying motivations of NYC community gardeners are both personal and collective. For many, community gardens provide a space for reflection and for profound connection to the natural world. Gardening was reported to be restorative, and to help to strengthen an individual’s connection to a...

The ongoing emission of greenhouse gases (GHGs) is triggering changes in many climate hazards that can impact humanity. We found traceable evidence for 467 pathways by which human health, water, food, economy, infrastructure and security have been recently impacted by climate hazards such as warming, heatwaves, precipitation, drought, floods, fires, storms, sea-level rise and changes in natural land cover and ocean chemistry. By 2100, the world’s population will be exposed concurrently to the equivalent of the largest magnitude in one of these hazards if emmisions are aggressively reduced,...

Wildfire is a natural phenomenon that began with the development of terrestrial vegetation in a lightning-filled atmosphere of the Carboniferous Period (307-359 million years before the present). Sediment deposits from that era contain evidence of charcoal from post-fire ash slurry flows. As human populations developed in the Pleistocene and Holocene epochs, mankind transformed fire into one of its oldest tools. Human and naturally ignited fires from lightning altered and steered the trajectories of ecosystem development in most parts of the world. Humans are now the primary source of...

The unprecedented number of devastating disasters recently experienced in the United States is a clarion call to revisit how we understand our vulnerability in the face of global change, and what we are prepared to do about it. We focus on the case of Hurricane María’s impact in Puerto Rico to underscore five critical concerns in addressing vulnerability and adaptation planning: (i) vulnerability as a product of flows; (ii) how our beliefs about the capacities of ourselves and others affect local vulnerability; (iii) the role uncertainty, politics, and information access play in amplifying...

Future vegetation shifts under changing climate are uncertain for forests with infrequent stand-replacing disturbance regimes. These high-inertia forests may have long persistence even with climate change because disturbance-free periods can span centuries, broadscale regeneration opportunities are fewer relative to frequent-fire systems, and mature tree species are long-lived with relatively high tolerance for sub-optimal growing conditions. Here, we used a combination of empirical and process-based modeling approaches to examine vegetation projections across high-inertia forests of...

Background: Volume and taper equations are essential for obtaining estimates of total and merchantable stem volume. Taper functions provide advantages to merchantable volume equations because they estimate diameter inside or outside bark at specific heights on the stem, enabling the estimation of total and merchantable stem volume, volume of individual logs, and a height at a given diameter. Methods: Using data collected from 1218 trees (1093 Douglas-fir (Pseudotsuga menziesii (Mirbel) Franco) and 125 western hemlock (Tsuga heterophylla)), we evaluated the performance of one simple...

Rainfall thresholds for streamflow generation are commonly mentioned in the literature, but studies rarely include methods for quantifying and comparing thresholds. This paper quantifies thresholds in ephemeral streams and evaluates how they are affected by rainfall and watershed properties. The study sites are in southern Arizona, USA; one is hyperarid and the other is semiarid. At both sites rainfall and streamflow were monitored in watersheds ranging from 10−3 to 102km2. Streams flowed an average of 0–5 times per year in hyperarid watersheds and 3–11 times per year in semiarid watersheds...