Faculty Research Publications (College of Forestry & Oregon Forest Research Laboratory)

Abundance of natural regeneration and growth comparisons with planted seedlings 10–13 years after commercial thinning in 50-year-old Douglas-fir, Douglas-fir/western hemlock, Oregon Coast Range

2013-05-21T19:57:42Z

Abundance of natural regeneration and growth comparisons with planted seedlings 10–13 years after commercial thinning in 50-year-old Douglas-fir, Douglas-fir/western hemlock, Oregon Coast Range Nabel, Mark R.; Newton, Michael; Cole, Elizabeth C. Post-thinning natural regeneration in the Pacific Northwest of USA was evaluated 13 years after thinning 50-year-old Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco var. menziesii) stands on a drier, interior Coast Range site (McDonald) and 10 years after thinning 50- to 55-year-old Douglas-fir/western hemlock (Tsuga heterophylla [Raf.] Sarg.) stands on a moister, coastal site (Blodgett) as part of a long-term study of late-seral habitats following commercial thinning. At each site, thinning varied in residual stand density (ranging from 17 to 34 m²/ha) and pattern (uniform thinning or thinning with the incorporation of 0.06- and 0.1-ha gaps). Effects of understory vegetation control were also evaluated. McDonald had minor components of grand fir (Abies grandis [Dougl. ex D. Don.] Lindl.); Blodgett had substantial overstory stocking of western hemlock. Natural seedling densities and heights of natural and underplanted seedlings were recorded where stands had been thinned to four (McDonald) and three (Blodgett) residual densities. Densities of natural Douglas-fir seedlings ranged from 55 to 980/ha at McDonald (13 years after thinning) and from 887 to 1566/ha at Blodgett (10 years after thinning). Douglas-fir abundance was inversely related to overstory density at McDonald after thinning and was greater at both sites where understory had been chemically controlled. Natural regeneration of grand fir at McDonald was limited by proximity to seed source, but more abundant than Douglas-fir where it occurred. Regeneration of western hemlock 10 years after thinning at Blodgett averaged 44,058–56,845/ha and did not vary across overstory densities or with vegetation control. Heights of hemlock and Douglas-fir regeneration were greatest where overstories were least dense. Hemlock was consistently taller than Douglas-fir at the site (Blodgett) where regeneration of both species occurred. However, Douglas-fir was preferentially browsed, which limited height growth. Canopy gaps did not consistently increase density or height of natural regeneration at either site, but many of the tallest seedlings recorded were found within gaps. Heights and recent height growth rates for western hemlock at Blodgett were similar between natural and planted seedlings. Natural Douglas- fir were shorter than planted Douglas-fir at both sites. Reliance on natural Douglas-fir regeneration in thinned stands provided variable stocking, with uncertain futures where post-thinning overstory basal area exceeded 28 m²/ha in 50-year-old stands. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Elsevier and can be found at: http://www.elsevier.com/.

Prediction of Wood Fiber Attributes from LiDAR-Derived Forest Canopy Indicators

2013-05-23T00:01:04Z

Prediction of Wood Fiber Attributes from LiDAR-Derived Forest Canopy Indicators Hilker, Thomas; Frazer, Gordon W.; Coops, Nicholas C.; Wulder, Michael A.; Newnham, Glenn J.; Stewart, James D.; van Leeuwen, Martin; Culvenor, Darius S. We investigated the potential use of airborne light detection and ranging (LiDAR) data to predict key wood fiber properties from extrinsic indicators in lodgepole pine leading forest stands located in the foothills of central Alberta, Canada. Six wood fiber attributes (wood density, cell perimeter, cell coarseness, mature fiber length, microfibril angle, and modulus of elasticity) were measured at 21 plots, and with use of data reduction techniques, two components of wood properties were derived: wood strength, stiffness, and fiber yield and fiber strength and smoothness. These wood fiber components were then compared with extrinsic indicators of wood characteristic-derived LiDAR-estimated topographic morphology, tree height, and canopy light metrics. The first principal component indicating wood strength and stiffness was significantly correlated to the depth of different canopy zones (or light regimes; r² = 0.55, P < 0.05). The second component, related to fiber strength and smoothness, was significantly correlated to the height of the canopy and canopy thickness (r² = 0.65, P < 0.05). The results indicate that airborne LiDAR attributes can explain about half of the observed variance in intrinsic wood fiber attributes, which is approximately 5-10% less than that explained by growth-related field-measured variables such as diameter increment and height. This reduction in explained variance can be balanced by the opportunities for much broader spatial characterizations of wood quantity and quality at the stand and landscape levels. FOR. SCI. 59(2):231-242. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Society of American Foresters and can be found at: http://www.safnet.org/.

Farmers’ Strategies for Adapting to and Mitigating Climate Variability and Change through Agroforestry in Ethiopia and Kenya

2013-05-15T20:44:10Z

Farmers’ Strategies for Adapting to and Mitigating Climate Variability and Change through Agroforestry in Ethiopia and Kenya Bishaw, Badege; Neufeldt, Henry; Mowo, Jeremias; Abdelkadir, Abdu; Muriuki, Jonathan; Dalle, Gemedo; Assefa, Tewodros; Guillozet, Kathleen; Kassa, Habtemariam; Dawson, Ian K.; Luedeling, Eike; Mbow, Cheikh

Do network relationships matter? Comparing network and instream habitat variables to explain densities of juvenile coho salmon (Oncorhynchus kisutch) in mid-coastal Oregon, USA

2013-04-24T01:02:51Z

Do network relationships matter? Comparing network and instream habitat variables to explain densities of juvenile coho salmon (Oncorhynchus kisutch) in mid-coastal Oregon, USA Flitcroft, Rebecca L.; Burnett, Kelly M.; Reeves, Gordon H.; Ganio, Lisa M. 1. Aquatic ecologists are working to develop theory and techniques for analysis of dynamic stream processes and communities of organisms. Such work is critical for the development of conservation plans that are relevant at the scale of entire ecosystems. The stream network is the foundation upon which stream systems are organized. Natural and human disturbances in streams alter the configuration of stream habitats such as pools, riffles, and glides across seasons, decades, or centuries. Thus, native aquatic species have developed mechanisms for adapting to the dynamic configuration of habitats in stream networks. 2. At different spatial scales, stream network structure informs habitat connectivity for aquatic–obligate species. The movement of aquatic species both upstream and downstream is limited by stream channels and may be modified by the downstream flow of water, nutrients, and physical materials such as wood and substrate. Analysing streams as networks offers a realistic and holistic perspective for assessing movement and distribution by freshwater aquatic species in response to life-history needs and environmental conditions. 3. In this study, network analysis was facilitated by automating, in a Geographic Information System, the calculation of network distances and variables that represent spatial configuration. A comparison between traditional instream habitat variables and network variables for juvenile coho salmon (Oncorhynchus kisutch) in seven sub-basins of Oregon's mid-coast over a 5-year period revealed that network variables perform better at explaining juvenile coho salmon density than instream habitat variables. Moreover, analysis of network distances among seasonal habitats indicates that juvenile coho salmon density may be higher where the distance between critical seasonal habitats is short. This work furthers aquatic conservation, management, and restoration by including analysis of the proximity and connectivity among aquatic freshwater habitats. Published in 2012. This article is a US Government work and is in the public domain in the USA. This is a scanned version of a published article. The original can be found at: http://onlinelibrary.wiley.com/journal/10.1002/%28ISSN%291099-0755. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work.