Effect of management activities on forest soil properties in the Rocky Mountains: II. Tree, stump, and downed woody debris data

Site preparation when applied (hand or mechanical methods) in the western United States often has two objectives: 1) modify the soil, litter, or surface vegetation to create microclimates that favor the establishment and growth of desired tree species and 2) to remove excess surface fuel to decrease the fire hazard. Between 1989 and 1992, data were collected from 11 national forests across the Rocky Mountains (Idaho, Montana, and Arizona) in moist and dry mixed-conifer and ponderosa pine forests. Depending on the forest, stands were treated with the following prescriptions over the five-year period (listed by treatment code): 1 = bole removed followed by broadcast burn, 2 = bole removed followed by dozer or grapple pile, 3 = control (undispersed), 4 = whole tree removal (only in 1990 Helena/Deerlodge Forest), and 9 = burned only. Not every treatment was used in each forest. Each harvested stand was also paired with an adjacent untreated stand on a similar aspect, slope, and habitat type. For each stand in the study, the variable radius plots were used to collect characteristics on trees > 5 inches diameter at breast height (DBH) and to measure and tally stumps. The information gathered from the variable radius plot included tree species, diameter, and height. Brown’s transects (Brown 1971, 1974) were used to collect data on downed woody debris (dwd) and tree and stump density. The information gathered from the Brown’s transects included size and distribution of the sound and rotten wood currently laying on the ground and estimates of the total weights of sound and rotten wood. These data were intended to provide the general characteristics of live and dead wood for each stand after treatment. The original intent of the study was to summarize the data to an individual stand so returning to each stand for additional sampling in subsequent years was not planned and plot locations were not permanently marked. However, written or diagrammed descriptions of the location of each sample site exist on the sample forms. These descriptions are included with these archived data in case there is a future need to return to the sample areas.
The overall purpose of this study was to determine how management practices, such as burning, machine piling, scarifying, and scalping, change the character of the organic-rich surface soil layer; and how this change affects seed sprouting, seed-growth performance, and mycorrhizal development that maintain vegetation in these Rocky Mountain forests. The specific purpose of the tree, stump, and downed woody debris study was to describe whether the growth of trees, and the amount of stumps or dead woody materials varied significantly on a site if it was dozer piled, prescribe burned, or in an unharvested area. Data collection for this portion of the study included measurements on tree and stump size and basal area for all tree species on the plot. It also included measurements in tons per acre of the downed woody debris (fine and coarse), and of the amount of sound and rotten woody debris laying on the ground.
There are six separate data publications containing the data collected to examine the effect of management activities on forest soil properties in the Rocky Mountains: I. understory vegetation; II. tree, stump, and downed woody debris data (variable plots and transects); III. soil core data; IV. soil chemistry data; V. burn and soil surface conditions; and VI. microsite data. Data were originally published on 08/04/2021. Minor metadata updates were made on 09/27/2021.