Treesearch

Mountain pine beetle, Dendroctonus ponderosae Hopkins, is among the most significant forest insect pests, particularly in lodgepole pine, Pinus contorta Dougl. ex Loud., forests in western North America. We established a network of 125, 0.081-ha circular plots in P. contorta forests in Colorado, Idaho, Montana, Utah, and Wyoming to document tree mortality and stand-level responses to D. ponderosae outbreaks. We found notable reductions in several key metrics but also observed significant variability in per-year (0–71%) and cumulative mortality (2–87%). We used this long-term monitoring...

Spanish juniper, Juniperus thurifera L, forests are typically managed as uneven-aged forests in the Iberian range, which requires information about site index (SI) classes and diameter at breast height (dbh) distributions. The objective of this study is to evaluate and compare the performance of remote sensing models using multitemporal airborne laser scanning (ALS) data, Landsat metrics of state and change along with topographic, geographic and climatic predictors for the prediction of SI classes and diameter distributions. The best model for SI classes was a logistic model that showed an...

Western U.S. public forest managers are applying structurally complex treatments not only to restore established mature stands, but to juvenile and reforested stands through practices such as cluster planting. Although studies suggest that structural complexity may negatively impact productivity and ecosystem services throughout stand development, findings are inconsistent. The inconsistencies may reflect a) the structural complexity attributes investigated, b) focusing on tree growth without recruitment or mortality, and/or c) unidentified site quality and stand factors that modulate...

Wildfire extent is growing in the United States (US), a fact attributable to increasingly favorable weather and climatic conditions and the net result of human interventions. US federal land management agencies act upon the wildfire threat by managing hazardous fuels, discouraging human‐caused ignitions, and suppressing active fires. Costs of these actions are rising, so policy makers and wildland managers seek information that can help them understand the trade‐offs of resource allocations. This study generates new information about potential future wildfire and suppression demands by...

It is widely perceived that wildfire activity has increased across the western United States (WUS), with studies generally focusing on large wildfires. This study examines changes in the number of wildfire ignitions and burned area in the WUS using a comprehensive record of more than 750 000 wildfire incidents from 1992 to 2020 across biophysical gradients, seasons, and ignition causes. It further analyzes the environmental conditions associated with elevated fire activity. Our analysis comparing the periods 1992–2006 and 2007–2020 indicates that the annual number of recorded wildfires...

Climate change presents challenges for forest managers in determining strategies and actions to enable forest ecosystems to adapt to rapid and uncertain change. The Adaptive Silviculture for Climate Change (ASCC) Network emerged in direct response to an acute need for experimentally robust and professionally credible examples of climate-adaptive forest management strategies. The ASCC Network advances the field of climate adaptation by applying a replicated resistance–resilience–transition and no-action framework to test coproduced, operational-scale experimental trials that incorporate...

Forest inventory and monitoring is critically important to the long-term success of forest ecosystems, particularly given increasing levels of disturbance from wildfire, insects, disease, and human activity. Since its inception under the McSweeney-McNary Forest Research Act of 1928, and following revisions in the 1998 Agricultural Research, Extension, and Education Reform Act and 2014 Agricultural Act (“Farm Bills”), the U.S. Department of Agriculture (USDA) Forest Service Forest Inventory and Analysis (FIA) program has conducted continuous monitoring of the Nation’s forest resources,...

As attention to valley‐bottom or Stage‐0 restoration increases, direct attempts to evaluate its effects on highly valued salmonid fishes remain rare. We evaluated a valley‐bottom restoration project at Whychus Creek, Oregon, by simulating its effects on the abundance of both resident trout (native Rainbow Trout Oncorhynchus mykiss and introduced Brown Trout Salmo trutta ) that currently occupy the site and anadromous Chinook Salmon O. tshawytscha that historically occupied the site. Specifically, we compared results from a spatially explicit, individual‐based model for pre‐restoration...

Domestic animals represent the largest mammalian biomass on Earth, creating an urgent need to understand their effects on native species. Environmental change may further alter these interactions, particularly for large herbivores that are highly sensitive to climate‐driven resource availability.Interactions among assemblages of large herbivores include interference and exploitation competition, but the grazing optimization hypothesis paradigm suggests that interactions are often facilitative because defoliation from grazing stimulates compensatory regrowth of high‐quality forage that...

Biological nitrogen (N) fixation (BNF) provides the N needed to produce proteins and other biological building blocks, helping feed humanity and mitigate climate change. Due to its high energetic cost compared to other forms of N acquisition, biotic investment in BNF indicates N limitation. Globally gridded BNF flux data provide an opportunity to determine the energetic investment in BNF across ecosystems, which would help reconcile conflicting indicators of N limitation. Here, we use a new BNF synthesis to quantify the relative importance of BNF in different N‐fixing niches, in different...