5 research outputs found
Wildlife linkages: volumes and values of residual timber in riparian zones in eastern Texas
In regenerating southern pine, maintenance of riparian zones (RZs) is a major land concession for soil and water protection and wildlife habitat enhancement. However, there are few data quantifying the volume and value of residual timber in such areas. We inventoried merchantable timber in nine RZs of three widths in sapling-class East Texas pine plantations. Present, discounted, and projected volumes and values of residual timber were determined. Average per-acre volumes of narrow, medium, and wide RZs were 337, 1438, and 2542 board feet (Doyle log rule) and 4.6, 8.2, and 7.2 cords, respectively. At US 57.00 per thousand board feet for pine and hardwood saw timber, respectively, and US 5.00 per cord for pine and hardwood pulpwood, respectively, average present per-acre values were US 209.93 and US 4.52, US 34.38, respectively. Stumpage values at the time of harvest projected at 7% compound interest for 30 years ranged US 3547.54 per acre and for 80 years ranged US 104 499.95 per acre. The impact of these results on wildlife is discusse
The PMIP4 contribution to CMIP6 – Part 3:the last millennium, scientific objective, and experimental design for the PMIP4 past1000 simulations
Abstract
The pre-industrial millennium is among the periods selected by the Paleoclimate Model Intercomparison Project (PMIP) for experiments contributing to the sixth phase of the Coupled Model Intercomparison Project (CMIP6) and the fourth phase of the PMIP (PMIP4). The past1000 transient simulations serve to investigate the response to (mainly) natural forcing under background conditions not too different from today, and to discriminate between forced and internally generated variability on interannual to centennial timescales. This paper describes the motivation and the experimental set-ups for the PMIP4-CMIP6 past1000 simulations, and discusses the forcing agents orbital, solar, volcanic, and land use/land cover changes, and variations in greenhouse gas concentrations. The past1000 simulations covering the pre-industrial millennium from 850 Common Era (CE) to 1849 CE have to be complemented by historical simulations (1850 to 2014 CE) following the CMIP6 protocol. The external forcings for the past1000 experiments have been adapted to provide a seamless transition across these time periods. Protocols for the past1000 simulations have been divided into three tiers. A default forcing data set has been defined for the Tier 1 (the CMIP6 past1000) experiment. However, the PMIP community has maintained the flexibility to conduct coordinated sensitivity experiments to explore uncertainty in forcing reconstructions as well as parameter uncertainty in dedicated Tier 2 simulations. Additional experiments (Tier 3) are defined to foster collaborative model experiments focusing on the early instrumental period and to extend the temporal range and the scope of the simulations. This paper outlines current and future research foci and common analyses for collaborative work between the PMIP and the observational communities (reconstructions, instrumental data)