Changes in landscape patterns and associated forest succession on the western slope of the Rocky Mountains, Colorado
Using repeat photography, we conducted a qualitative and quantitative analysis of changes in forest cover on the western slope of the Rocky Mountains in Colorado. For the quantitative analysis, both images in a pair were classified using remote sensing and geographic information system (GIS) technologies. Comparisons were made using three landscape metrics: total relative cover, mean relative patch size, and number of patches per major vegetation type. We noted several important changes in the pattern of the landscape and the structure of the forests. The relative area covered by interspersed, nonforested rangelands has decreased significantly, and the total forest cover across these landscapes has increased. Statistical analyses (ANOVA) of other landscape characteristics (patch number and patch size distribution) did not detect changes. However, nonstatistical observation of the trends in these data revealed that in many cases, there has been important, observable change in the configuration of the landscape at many of these locations. Furthermore, our field data show that 96% of the sampled forests have a conifer component in the overstory, understory, or both.
Aspen seedlings in recently burned areas of Grand Teton and Yellowstone National Parks
l l l hough lspen tPopu lur tn :nu lo i , l t s \ p rodu | . ! r iub l . scds nron lea fs . n {d l ins esr rb l i shmo, r h ls se ldonr been repor red in the tsearer (lreel lftr nr (;'erd letor \ational I'arL, the greatest corcernations ocLrured at the Lottorn ofLettles or other tqrgraphic depres-.ior-. (here densitie-. ranged from 925 ro 2.7Oilrh! nr 1989. In fellorlsrone National lark. aspen seedlirgs Nere $ide1r dislibuted orer the atea burned br the l9ilil lililfires on the northenr rarge but the greatest concenlr.lions occurred ni riparian zones thot had been burned down to bare rnineral soil. ln those locutions rLspen seedLing densities rs high as 11.5 r l0",ha tere recorded and areraged l.l2.6,15lha oD permanent plots established ni 1989. OD permanenr plots in the Bearer Creel Bun. the arerage aspen seedlirg densir nrcreased br lrry0 from 1989 ro l99l i{hile on permanent plots in Yellorstone Park, aspen seedhrg densities declined ;8r10 ihuirg the some interral. tr hile an ubunduce o{ n.turallr occurrnrg aspen seedlings hos not beer reportecl be lo re . e r ence sugFes ls lho l these seer l ings mal no t le l l to the guL lh o l mature t rees or the dere lopr ren t o f aspen c lones .
A device for uranium series leaching from glass fiber in HEPA filter
For the disposal of a high efficiency particulate air (HEPA) glass filter into the environment, the glass fiber should be leached to lower its radioactive concentration to the clearance level. To derive an optimum method for the removal of uranium series from a HEPA glass fiber, five methods were applied in this study. That is, chemical leaching by a 4.0 M HNO3–0.1 M Ce(IV) solution, chemical leaching by a 5 wt% NaOH solution, chemical leaching by a 0.5 M H2O2–1.0 M Na2CO3 solution, chemical consecutive chemical leaching by a 4.0 M HNO3 solution, and repeated chemical leaching by a 4.0 M HNO3 solution were used to remove the uranium series. The residual radioactivity concentrations of 238U, 235U, 226Ra, and 234Th in glass after leaching for 5 h by the 4.0 M HNO3–0.1 M Ce(IV) solution were 2.1, 0.3, 1.1, and 1.2 Bq/g. The residual radioactivity concentrations of 238U, 235U, 226Ra, and 234Th in glass after leaching for 36 h by 4.0 M HNO3–0.1 M Ce(IV) solution were 76.9, 3.4, 63.7, and 71.9 Bq/g. The residual radioactivity concentrations of 238U, 235U, 226Ra, and 234Th in glass after leaching for 8 h by a 0.5 M H2O2–1.0 M Na2CO3 solution were 8.9, 0.0, 1.91, and 6.4 Bq/g. The residual radioactivity concentrations of 238U, 235U, 226Ra, and 234Th in glass after consecutive leaching for 8 h by the 4.0 M HNO3 solution were 2.08, 0.12, 1.55, and 2.0 Bq/g. The residual radioactivity concentrations of 238U, 235U, 226Ra, and 234Th in glass after three repetitions of leaching for 3 h by the 4.0 M HNO3 solution were 0.02, 0.02, 0.29, and 0.26 Bq/g. Meanwhile, the removal efficiencies of 238U, 235U, 226Ra, and 234Th from the waste solution after its precipitation–filtration treatment with NaOH and alum for reuse of the 4.0 M HNO3 waste solution were 100, 100, 93.3, and 100%.