Long-term ecosystem responses from the Coram woody biomass and residue utilization study

This data publication includes long-term ecosystem datasets generated from the Forest Residues Utilization Research and Development Program's study at the Coram Experimental Forest, which is nested within the Flathead National Forest in northwest Montana. This multi-disciplinary study was developed in 1973 and implemented in 1974 by scientists in the Forest Service Rocky Mountain Research Station (then, Intermountain Forest and Range Experiment Station) in the cool, western larch-mixed conifer forest of the northern Rocky Mountains ecoregion. Four utilization treatment levels (a combination of biomass utilization level and residue burning treatment) were applied within each of three silvicultural harvests (clearcut, shelterwood, and group selection) with 2 replications. In addition to conventional timber removal, the four utilization levels were specified to (1) cut understory, remove residue, and broadcast burn; (2) cut understory, leave residue, and broadcast burn; (3) cut understory, remove residue, and do not burn; and (4) do not cut understory, remove residue, and do not burn. These experimental harvests and prescribed burning took place in 1974-1975, and data were collected between 1973 and 2013. There are four core sets of data included in this publication: tree, shrub, plantation, and forest floor. A suite of tree (including natural and planted) measurements were taken in 2012 such as height, diameter at breast height, live crown base height, species, and seedling counts. In 1973, 1976, and 1978 non-tree woody vegetation (shrub) data such as crown diameter, height, density, and species were measured. In 2012 shrub basal diameter (of root crown) was also recorded. Plantation data such as vigor, crown position, tree height, diameter at breast height, crown length and width, etc. were recorded up to 10 times between 1977 and 2013. In 2013, forest floor depth and mineral soil materials were also measured.
As identified in the project's 1973 study design, a major problem that has been confronting forestry is how to more efficiently harvest and utilize timber without creating unacceptable impacts on the forest environment. This study was designed to address two related needs. The first was to improve recovery and utilization of the total wood resource, leaving less material as residue. Experts in the 1970s predicted substantial increases in demand for wood and wood fiber-based products, especially softwood housing construction materials. Today, these predictions still stand and include demand for renewable woody residues for power and heat generation or recalcitrant carbon storage. Harvesting practices that facilitate more complete utilization of the available wood resource in the northern Rocky Mountains can contribute significantly to meeting this demand. The second need was to reduce the adverse aesthetic and environmental impacts of timber harvesting and other on-site activities. Utilization standards and logging practices may leave large amounts of residue (small trees, cull and broken logs, tops, and dead timber) on the ground following harvesting operations. These residues can contribute to the forest's nutrient reservoir, reduce erosion, protect seedlings, and provide wildlife cover. In the quantities that frequently occur, however, they create a fire hazard, inhibit regeneration, detract from area esthetic values, and represent waste of a scarce fiber resource. Harvesting practices that improve the economic feasibility of using more of this material can remedy a major source of undesirable impacts on the area. The project addressed a need for silvicultural prescriptions and skyline harvesting systems that can be combined to achieve improved utilization within realistic environmental economic, and management constraints. These data were collected to test the long-term effects of various silvicultural alternatives in the western larch-mixed conifer forest type, especially as they pertain to forest regeneration and dynamics, ecosystem structure and composition, and forest productivity and nutrient loss.
These data have been used to summarize short-term effects of forest utilization treatments in 1980-1981 (see Forest Service General Technical Reports listed as cross-references below) as well as to investigate the long term ecosystem effects in the context of the 21st century forest management (see Jang and others between 2015 and 2018, listed as cross-references).