Treesearch

Tree mortality is a natural process in all forest ecosystems. High mortality can be an indicator of forest health problems. On a regional scale, high mortality levels may indicate widespread insect or disease impacts or stress from large-scale regional weather events, such as severe droughts. High mortality may also occur if a large proportion of the forest in a particular region is made up of older, senescent stands. The approach presented here seeks to detect mortality patterns that might reflect changes to ecosystem processes at large scales. In many cases, the proximate cause of...

Coarse woody materials (CWM) are often defined as dead wood of a certain minimum size in forest ecosystems.

The U.S. Department of Agriculture Forest Inventory and Analysis (FIA) program collects data describing the condition and change of forest ecosystems across all lands in the United States (Smith 2002, USDA Forest Service 2019b). The extraordinary size of the spatial domain and breadth of forest variables sampled by the FIA program make it a unique and powerful resource for determining the extent and severity of undesirable changes in forest health across large spatial domains in the United States. Due to a lack of flexible, userfriendly tools for estimation of forest variables (Tinkham and...

Heterobasidion root disease (Heterobasidion irregulare; HRD) causes substantial pine (Pinus spp.) mortality in North America and other regions of the Northern Hemisphere. It first appeared in Wisconsin in 1993 and has since been documented in 28 counties. It was first documented in Michigan in 1963, and recent survey work found it was present in 19 counties. New infestations mainly occur when spores carried by wind land on freshly cut pine and spruce (Picea spp.) stumps. Expanding mortality gaps develop as the fungus spreads along interconnected roots. Treating cut conifer stumps with a...

We conducted three separate studies, described below, to assess ash mortality and effects of EAB in riparian forests.

Our objectives were to (1) quantify MPB-caused mortality within the past 10 years in stands where RM bristlecone and limber pines co-occur, (2) evaluate in the field if MPB is capable of successful brood production in RM bristlecone pine, and (3) quantify the timing and concentration of constitutive and induced SM defenses, and morphological defenses, in RM bristlecone and limber pine growing in the same stands across the range of RM bristlecone pine.

The 2012–2016 drought and associated bark beetle outbreaks in California resulted in extensive tree mortality and provided a unique opportunity to examine questions of why some trees die while others survive these co-occurring disturbances and to increase understanding of how subsequent bark beetle-caused tree mortality alters fuel profiles and forest flammability over time. Our study objectives were to: (1) identify factors relating to conifer tree mortality and monitor changes in vegetation after mortality and (2) determine temporal changes in fuel loading and hazard due to bark beetle-...

The overall goal of our Evaluation Monitoring project (EM-18-WC) funded by the Forest Service, Forest Health Monitoring program was to provide a rigorous assessment of ADS and eDaRT products and outline recommendations for complementary use by land managers. To meet this goal, our specific objectives were to (1) develop and execute a ground-based sampling strategy to compare ADS and eDaRT to reference validation data, and (2) make recommendations for appropriate use of data in varied applications.

Forest insects and diseases have widespread ecological and economic impacts on the forests of the United States and may represent the most serious threats to the Nation’s forests (Logan and others 2003, Lovett and others 2016, Tobin 2015). U.S. law therefore authorizes the U.S. Department of Agriculture Forest Service to “conduct surveys to detect and appraise insect infestations and disease conditions and man-made stresses affecting trees and establish a monitoring system throughout the forests of the United States to determine detrimental changes or improvements that occur over time, and...

As a pervasive disturbance agent operating at many spatial and temporal scales, wildland fire is a key abiotic factor affecting forest health both positively and negatively. In some ecosystems, for example, wildland fires have been essential for regulating processes that maintain forest health (Lundquist and others 2011). Wildland fire is an important ecological mechanism that shapes the distributions of species, maintains the structure and function of fire-prone communities, and acts as a significant evolutionary force (Bond and Keeley 2005). At the same time, wildland fires have created...