Proper management of uneven-aged interior Douglas-fir (Pseudotsuga menziesii var. glauca) stands is …
Proper management of uneven-aged interior Douglas-fir (Pseudotsuga menziesii var. glauca) stands is important for British Columbia’s central and southern interior. These stands constitute one of main components of the operable forest land in these areas, with easy access from main roads and towns. This study focused on the growth of uneven-aged Douglas-fir stands after pre-commercial thinning (spacing), with an impetus to improve upon current management practices. Data were collected from 24 permanent sample plots which were established near Williams Lake, British Columbia in 1989; thinning took place between 1990 and 1991. Three measurements have been made post-treatment: 1993, 1997 and 2004. The plot data were used to analyze different growth responses among three different spacing regimes (standard, 3 m clumped and 5 m clumped spacing) and a control. Analyses were performed at both the stand and tree level. The growth of basal area per ha, quadratic mean dbh, volume per ha and Lorey’s height were used for stand level analyses. At the tree level, dbh, height, basal area and volume were the variables of interest. At the stand level, mortality increased (7.1 to 107.1 stems/ha) and ingrowth decreased (2.4 to 8.6 stems/ha) for the second growth period (1997-2003), compared to the first growth period (5.8 to 107.1 stems/ha and 5.0 to 12.4 stems/ha, respectively). No significant differences in annual growth of quadratic mean dbh, basal area and volume per ha and Lorey’s height were noted between the different spacing regimes and the control. At the individual tree level, the 5 m clumped spacing regime usually had the highest dbh, basal area and volume growth for both growth periods. The one exception was for height growth, when analyzed using mixed-effects modeling, where no significant differences were found. Trees on the other two spacing regimes also had higher growth in dbh, basal area, and volume than trees on the control plots. The positive growth response to the spacing treatments at the single tree level was obtained without a reduction in growth at the stand level. This growth increase will result in the residual trees reaching larger sizes more quickly than they would have with no treatment, leading to improved mule deer winter range habitat and higher timber values.
This article, part of Biodiversity Counts, examines how to responsibly collect and …
This article, part of Biodiversity Counts, examines how to responsibly collect and keep specimens. The article discusses the reasons why collecting specimens is important and the behaviors and attitudes that define responsible collecting for both scientists and students.
This video segment from Kentucky Life describes how scientists control pollination of …
This video segment from Kentucky Life describes how scientists control pollination of one of the few remaining American chestnut trees to develop blight resistant trees.
Cretaceous and Tertiary strata exposed in northern Alaska record clastic sediment deposition …
Cretaceous and Tertiary strata exposed in northern Alaska record clastic sediment deposition within a foreland basin adjacent to the ancestral Brooks Range, and form part of an important petroleum play. The goal of this U.S. Geological Survey report is to synthesize the complex stratigraphy of this area into a more simplified scheme. It discusses the regional geology of northern Alaska and the stratigraphy of the Colville Basin in detail. Maps, cross sections, correlation charts, and numerous outcrop photos with detailed captions accompany the text.
Students build on their understanding and feel for flow rates, as gained …
Students build on their understanding and feel for flow rates, as gained from the associated Faucet Flow Rate activity, to estimate the flow rate of a local river. The objective is to be able to relate laboratory experiment results to the environment. They use the U.S. Geological Survey website (http://waterdata.usgs.gov/nwis/rt) to determine the actual flow rate data for their river, and compare their estimates to the actual flow rate. For this activity to be successful, choose a nearby river and take a field trip or show a video so students gain a visual feel for the flow of the nearby river.
In this video segment adapted from Northwest Indian College, Lummi Elders explain …
In this video segment adapted from Northwest Indian College, Lummi Elders explain how a decline in the availability of salmon reflects a threatened environment that must in some way be protected.
This informational text introduces students to the life cycle and migration of …
This informational text introduces students to the life cycle and migration of the sanderling, a bird that winters on beaches in the Southern United States and South America but breeds in the Arctic during the summer months. The text is written at a grade two through grade three reading level. This version is a full-color PDF that can be printed, cut and folded to form a book. Each book contains color photographs and illustrations.
This article, part of Biodiversity Counts, examines site preservation, focusing on a …
This article, part of Biodiversity Counts, examines site preservation, focusing on a new national park in El Salvador. The article discusses the questions faced as part of the decision-making process, the formation of an advisory committee in the early 1990s to study the park and make recommendations for how it should be managed, the committee's recommendations, and a description of those changes that are in the works, such as opening a portion of the park to the public.
This performance assessment aligns with NGSS Performance Expectation 5.LS2.1 and is intended …
This performance assessment aligns with NGSS Performance Expectation 5.LS2.1 and is intended to be used as an interim assessment. These assessments can either be used summatively, as an end of learning activity, or formatively, utilizing student responses to identify next instructional steps.
A database of and access to journal articles and book chapters found …
A database of and access to journal articles and book chapters found useful by college and university science students; built from student work at Grinnell College, Grinnell, IA, USA. Used in science courses (especially Biology and Psychology courses) at Grinnell College.
This website was created by the GMO working group in the UConn …
This website was created by the GMO working group in the UConn College of Agriculture, Health and Natural Resources. We offer clear descriptions and explanations of a variety of issues related to genetically modified organisms, or GMOs. We hope you find the information useful, and we welcome your feedback. We thank Purdue Agriculture for inspiration, the format and assistance in building this site.
In this video segment adapted from the College of Menominee Nation, tribal …
In this video segment adapted from the College of Menominee Nation, tribal members share examples of how seasons are changing, and how these changes are affecting local plants.
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