Above- and below-ground biomass accumulation, production, and distribution of sweetgum and loblolly pine grown with irrigation and fertilization.

Abstract: Increased forest productivity has been obtained by improving resource availability through water and nutrient amendments. However, more stress-tolerant species that have robust site requirements do not respond consistently to irrigation. An important factor contributing to robust site requirements may be the distribution of biomass belowground, yet available information is limited. We examined the accumulation and distribution of above- and below-ground biomass in sweetgum (Liqrridambar sfyrac$lua L.) and loblolly pine (Pinus taeda L.) stands receiving irrigation and fertilization. Mean annual aboveground production after 4 years ranged from 2.4 to 5.1 ~g.ha-'.year' for sweetgum and from 5.0 to 6.9 ~g.ha-l.year-l for pine. Sweetgum responded positively to irrigation and fertilization with an additive response to irrigation + fertilization. Pine only responded to fertilization. Sweetgum root mass fraction (RME)in creased with fertilization at 2 years and decreased with fertilization at 4 years. There were no detectable treatment differences in loblolly pine RMF. Development explained from 67% to 98% of variation in shoot versus root allometry for ephemeral and perennial tissues, fertilization explained no more than 5% of the variation in for either species, and irrigation did not explain any. We conclude that shifts in allocation from roots to shoots do not explain nutrient-induced growth stimulations

Trait Response and Change in Genetic Variation upon Selection for Spike Number in Salina Wildrye

Salina wildrye (Leymus salinus [M.E. Jones] Á. Löve) is a perennial cool-season grass that potentially could become an important restoration species in the Colorado Plateau. However, its seed production has never been commercially viable due to sparse heading. We compared a 4x ssp. salmonis population, Lakeside C3, to an 8x ssp. salinus population, 9043501, for seed production − related traits and measured the response of 9043501 to 2 cycles of selection for increased spike number over a 4-yr period at Millville, Utah. Seed yield of Lakeside and 9043501 was similar (P > 0.10) in 2013, but seed yield of 9043501 was 81% greater (P 0.10) in 2014 and 2015. Seeds per spike of 9043501 were 71% (P 0.10). Selection did not change (P > 0.10) seeds per spike or individual seed mass. Consequently, seed yield increased (P 0.10) in 2014 or 2015. Dry matter per plant across the 4 yr increased (P < 0.01) 10.3 g per plant per cycle (9.3%), and canopy height increased (P < 0.01) 3.9 cm per cycle (6.6%) in 2013. AFLP DNA primers detected a 1.7% loss of genetic variation per cycle, presumably due to a combination of selection and genetic drift, but no plant traits were diminished as a result.The Rangeland Ecology & Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information

The Steering Group as Policy Advice Instrument: A Case of “Consultocracyâ€\x9D in Stadium Subsidy Deliberations

This study considers the use of steering groups and private consultants as sources of policy advice to local governments. More particularly, our research addresses the combined role of a government-appointed working party and consulting firm in the deliberation process precipitating from proposals to renovate/re-build a sports stadium. Through this New Zealand-based case, we explore the political tensions arising from the Working Party's mandates to consult and its role as vehicle to market policy solutions. Data is gleaned from interviews with working party members (and their consultants), observations of public consultations and analysis of documents (e.g., background papers, reports, and press releases). Implications of this institutional arrangement are discussed in light of recurring logics, tensions and paradoxes. We first consider the Carisbrook Working Party as an instrument of policy advice and distinguish its founding logic from other forms such as task forces or commissions of inquiry. We further discuss the paradoxes of the Working Party's procedural and political imperatives including its roles as facilitators of the process, advocates of the “problem,â€\x9Dand as authoritative proclaimers of certainty. Copyright Springer Science+Business Media B.V. 2006