Investigating Contemporary Evolution via Size-Selective Harvest

2009 ◽  
Vol 71 (3) ◽  
pp. 151-155 ◽  
Author(s):  
Joseph H. Allen ◽  
Jill Wold
1995 ◽  
Vol 22 (1) ◽  
pp. 57-79 ◽  
Author(s):  
A.J. Cataldo

The Revenue Reconciliation Act of 1993 (RRA93) significantly expanded the earned income credit (EIC), which was changed to include low-income taxpayers without dependents. Evolving, most directly, from the “workfare” plan (1972) proposed by Senate Finance Committee Chairman, Russel B. Long, and in response to President Nixon's Family Assistance Program (FAP), the post-1974 EIC was not the first of its kind. It had two predecessors. The EIC of 1923 through 1931 benefitted taxpayers with or without dependents and excluded any “workfare” feature. A second EIC, in name only, was in effect for the 1934 through 1943 tax years. This paper develops a historical framework for study of the post-1974 EIC. This framework necessarily precedes any investigation of contemporary issues relating to the twenty-year history of the post-1974 EIC which, unlike its first predecessor, appears destined to continue as a permanent, expanding mechanism for the delivery of basic subsistence to the “working poor.” The resolution of these contemporary issues will determine whether the post-1974 EIC is destined to replace or continue to co-exist with a (presumably) more costly welfare delivery system.


2009 ◽  
Vol 20 (1) ◽  
pp. 79-90 ◽  
Author(s):  
A.J. Sánchez Meador ◽  
M.M. Moore ◽  
J.D. Bakker ◽  
P.F. Parysow

2020 ◽  
Vol 41 (2) ◽  
pp. 243-249
Author(s):  
Oscar Manuel de Jesús Vera Cabral ◽  
Eduardo da Silva Lopes ◽  
Carla Krulikowski Rodrigues ◽  
Afonso Figueiredo Filho

Demand for higher value-added wood products stimulates research for new, mainly mechanized, thinning operations in order to increase productivity and reduce production costs. In this context, the aim of this study was to evaluate the impact of distance between strip roads on forwarder productivity and costs of thinning operations in Pinus taeda stands. The study was carried out in 10-year-old Pinus taeda stands located in Parana State, Brazil. Two thinning methods were evaluated: (1) TH5: systematic harvest in every fifth tree row and selective harvest in adjacent rows; and (2) TH7: systematic harvest in every seventh tree row and selective harvest in adjacent rows. Working cycle times, productivity and costs were determined through a time-motion study of the forwarder. The additional variables evaluated were wood assortments (industrial wood and energy wood) and extraction distances (50, 100, 150 and 200 m), and mean values were compared between thinning methods using t tests for independent samples (α=0.05). Loading and unloading elements consumed the most time in the working cycle, with lower participation time in TH7 due to greater availability of logs along the strip roads (higher pile volumes), influencing total cycle time up to the mean distance of 150 m for both assortments. TH7 consequently showed 6% higher productivity, its energy yield was 5.3% lower and its production cost was 3.0% lower.


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