Mountain pine beetle emergence from lodgepole pine at different elevations near Fraser, CO

Abstract

The concepts and a procedure for evaluating plant community change using the squared Euclidean distance (SED) resemblance function are described. Analyses are based on the concept that Euclidean distances constitute a sample from a population of distances between sampling units (SUs) for a specific number of times and SUs. With different times, the distances will be intracluster or intercluster. Intercluster distances represent a control treatment. If the communities differ between times, the population will contain clusters (regions of high density with short distances between SUs) that are separated by regions of low density (great distances between SUs). Within-and between-years mean squares from analyses of variance for each species (sp) in the data matrix can be used to compute the intracluster and intercluster mean distances. A multivariate ANOV A gives a test of the hypothesis that the intracluster mean distance is equal to the intercluster mean distance at an overall error rate approximately equal to ex. The statistical distribution of SEDs is the distribution of a linear combination of independent Chi-square random variables. Knowledge of this distribution and use of the usual approximations make the estimation of approximate confidence intervals for the mean intercluster and intracluster distances and their difference possible and reliable. The confidence intervals may be examined and a decision made regarding any indicated change in the community. A simple example is provided to permit study of computational methods.

Tree regeneration and future stand development after bark beetle infestation and harvesting in Colorado lodgepole pine stands

“…Mountain pine beetle began to cause widespread overstory pine mortality at the FEF in 2002 (Tishmack et al, 2004) (USDA, 2008). Project planning stipulated that harvesting conducted on the Fraser Experimental Forest facilitate long-term research; this allowed us to retain uncut stands adjacent to harvest units.…”

Mountain Pine Beetle Develops an Unprecedented Summer Generation in Response to Climate Warming

“…Historical documentation of MPB flight patterns in Colorado are rare, but U.S. Forest Service reports indicate that the MPB flight season in ponderosa pine forests of Colorado lasted for approximately 7 weeks, with peak flights during the second and third weeks of August (McCambridge 1964). Historical records of MPB flight timing and duration for Colorado lodgepole pine forests are unavailable (Tishmack et al 2005), but a recent study in a forest at similar elevation 30 km southwest of our study site reported similar results, with infrequent emergences in July, large numbers of MPBs flying between August 5 and 19 and a flight season of approximately 50 days (Tishmack et al 2005).…”

Snagfall the first decade after severe bark beetle infestation of high‐elevation forests in Colorado, USA

“…Bark beetles were detected at FEF in 2003 in lodgepole pine trees attacked in 2002 and epidemic levels of beetle emergence were measured in various locations across the research area the following year (Tishmack et al. ). Beetle activity and tree mortality peaked around 2006 both at FEF and elsewhere in northern Colorado (Collins et al.…”

“…Mixed-species conifer forests occupy valley bottom and north-facing slopes and extend to treeline (3,300-3,500 m); fir and spruce dominance increases with elevation and stand age. Bark beetles were detected at FEF in 2003 in lodgepole pine trees attacked in 2002 and epidemic levels of beetle emergence were measured in various locations across the research area the following year (Tishmack et al 2004). Beetle activity and tree mortality peaked around 2006 both at FEF and elsewhere in northern Colorado (Collins et al 2011, Diskin et al 2011, Chapman et al 2012, Meddens and Hicke 2014.…”