Estimating snag and large tree densities and distributions on a landscape for wildlife management.

Abstract

We provide efficient and accurate methods for sampling snags and large trees on a landscape to conduct compliance and effectiveness monitoring for wildlife in relation to the habitat standards and guidelines on National Forests. Included online are the necessary spreadsheets, macros, and instructions to conduct all surveys and analyses pertaining to estimation of snag and large tree densities and distributions at the subwatershed scale. The methods focus on optimizing sampling effort by choosing a plot size appropriate for the specific forest conditions encountered. Two methods are available for density analysis. Method one requires sampling until a desired precision level is obtained for a density estimate. Method two is intended for use in areas that have low snag densities compared to Forest plan targeted densities. After taking a minimum of 60 samples, one may test for a significant difference between the estimated and targeted densities. In addition, data can be used to calculate a distribution index. The value obtained from the distribution index indicates whether the current distribution of target snags and large trees across a subwatershed is adequate to meet the habitat needs of territorial cavity-nesters and other wildlife species. Wildlife use also may be evaluated.Keywords: Density, distribution, foraging, nesting, monitoring, sampling technique, snag, large tree, woodpecker, wildlife management, wildlife use.

Sustaining Cavity-Using Species: Patterns of Cavity Use and Implications to Forest Management

“…Likewise, there was no difference in nesting levels between clustered and scattered snags that had been created by topping, suggesting that some natural phenomenon was acting [315]. Trees, snags, and down wood typically occur in clumps [348]. It is unclear whether primary excavators seek dense patches of nest trees for some associated value or if it merely re�ects the patchy way in which trees are killed by insects or disease.…”

Spruce snag quantification by coupling colour infrared aerial photos and a GIS

“…Dead wood inventories for research and monitoring purposes are currently generally carried out using labour-intensive and expensive field methods (Stierlin et al, 1994;Harmon and Sexton, 1996;Anonymous, 1998;Buckland et al, 1998;Davis, 1998;Hurlburt et al, 1998;Bate et al, 1999;Ganey, 1999). The data is collected using sample plots, strips or transects.…”

Snag characteristics and cavity-nesting birds in the unmanaged post-fire northeastern Canadian boreal forest

“…black-backed woodpecker; Bate et al 1999, Drapeau et al 2002, Saint-Germain et al 2004, Hutto 2006. They are used by a wealth of invertebrate, vertebrate, and plant species.…”