Treesearch

This study examined the effects of two types of parent material, sandstone and limestone, on the response of vegetation growth after the 1990 Dude Fire in central Arizona. The operating hypothesis of the study was that, given the right conditions, severe wildfire can trigger vegetation type conversion. Overall, three patterns emerged: (1) oak density increased by 413% from unburned sites to burned sites, with the highest densities occurring on sandstone soils; (2) weeping lovegrass (Eragrostis curvula Nees), a very aggressive non-native grass species seeded after the fire, now makes up 81%...

In the quest to develop renewable energy sources, woody and agricultural crops are being viewed as an important source of low environmental impact feedstocks for electrical generation and biofuels production (Hall and Scrase 1998, Eriksson et al. 2002, Somerville et al. 2010, Berndes and Smith 2013). In countries like the USA, the bioenergy feedstock potential is dominated by agriculture (73%) (Perlack et al. 2005). In others like Finland the largest potential comes from forest resources. Forest bioenergy operational activities encompass activities of a continuing and cyclical nature such...

The on-going public debate on sustainability of bioenergy began in 2007 and 2008 after a couple of papers were published questioning the reported N2O emissions caused by cultivation of agricultural crops (Crutzen et al., 2007) and the carbon neutrality of biomass use (Searchinger et al., 2008) due to direct and indirect land use change as well as change of carbon stocks. Since these initial papers, many others have been published mainly questioning the positive climate impact of bioenergy. The impact of these papers changed the attitude towards use of bioenergy in the public and political...

Pile burning is a common means of disposing the woody residues of logging and for post-harvest site preparation operations, in spite of the practice’s potential negative effects. To examine the long-term implications of this practice we established a 50-year sequence of pile burns within recovering clear cuts in lodgepole pine forests. We compared tree, shrub and herbaceous plant abundance and documented indicators of soil degradation in openings where logging residue was piled and burned as part of post-harvest site preparation and the adjacent forests regenerating after clear cutting. We...

The response of dynamic and static modulus of elasticity (MOEdyn and MOEsta) of red pine small clear wood (25.4 × 25.4 × 407 mm3) within the temperature range -40 to 40°C has been investigated. The moisture content (MC) of the specimens ranged from 0 to 118%. The MOEdyn was calculated based on measured ultrasonic velocity (V) and wood density. The MOEsta was measured by static bending tests in a climate chamber between -40 and 40°C. The results indicate that both MOEdyn and MOEsta were affected by temperature and the MC. Above freezing point, MOE decreased linearly at a slow rate with...

To improve wood utilization efficiency, oriented strandboard (OSB) was developed; 80% of the wood removed from the forest can now be processed into marketable products. This manuscript describes the history of developing this most profitable wood product, OSB, and the early FPL contribution in development.

A recent publication and an article in Wetland Science & Practice (Lichvar and Gillrich 2014b, 2014a) discuss two metrics for determining if vegetation is hydrophytic for purposes of U.S. wetland delineations, the Prevalence Index (PI) and a proposed Hydrophytic Cover Index (HCI). Based on Wentworth et al. (1988), the PI is a weighted average of ordinal scores (1-5) for species in five wetland-indicator categories (defined in Table 1). 􀀐 􀁌􀁑􀁇􀁌􀁆􀁄􀁗􀁒􀁕􀀃􀁆􀁄􀁗􀁈􀁊􀁒􀁕􀁌􀁈􀁖􀀃􀀋􀁇􀁈􀂿􀁑􀁈􀁇􀀃􀁌􀁑􀀃􀀷􀁄􀁅􀁏􀁈􀀃􀀔􀀌􀀑􀀃􀀶􀁆􀁒􀁕􀁈􀁖􀀃􀁒􀁉􀀃􀀔􀂱􀀖􀀃

The final phase in the development of an artificial diet that contains no ash host material and the phenology of the emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Bupresidae) on that diet are documented. A diet containing powdered ash phloem exists, but host material introduces potential variability and contamination, and the cost and effort needed to collect and process it can be high. The post-embryonic development of A. planipennis was evaluated on four artificial diets lacking host material, and effects of variations in diet layer thickness and moisture content were...

Exotic earthworms are invading forests in North America where native earthworms have been absent since the last glaciation. These earthworms bioturbate soils and may enhance physical interactions between minerals and organic matter (OM), thus affecting mineral sorption of carbon (C) which may affect C cycling. We quantitatively show how OM-mineral sorption and soil C inventories respond to exotic earthworms along an earthworm invasion chronosequence in a sugar maple forest in northern Minnesota. We hypothesized that mineral surface area in A horizons would increase as burrowing earthworms...

Season affects many characteristics of populations and, as a result, the interpretations of surveys conducted at different seasons. We explored seasonal variation in occupancy using data from four studies on the Pacific marten Martes caurina. Detection surveys were conducted during winter and summer using either cameras or track stations. We conducted a 'multiple location, paired season' analysis using data from all four study areas and a 'multiple season' analysis using seasonally replicated occupancy data collected at one of the areas. In the former analysis, summer occupancy estimates...