Vegetation Cover Data for 1953-1966, 1970 for USFS Study FSRM 1706-12

The file contains perennial grass basal cover and shrub foliar cover data collected for USFS Study FSRM 1706-12. A copy of the Study Plan may be downloaded from the web site.

Measurements were taken on 20 randomly located permanent 100-ft. line transects in each of five pastures.

The pastures had been grazed yearlong by cow-calf herds since 1915; utilization ranged from 47-60%. Two changes in grazing management were instituted at the start of the study period: 1) The utilization objective was lowered to 40%, and 2) Summer deferment (July-Sept) in alternate years began in 1958 in two pastures and in 1959 in the other two. Pasture 9 continued to be grazed yearlong and was measured in 1958 and 1963-1966 for comparative purposes. Data from pasture 9 were not included in published analyses.

Mesquites (Prosopis velutina) in pastures 1 and 7 were killed with diesel oil between 1954 and 1957. Mesquites in pastures 8, 9, and 10 were left untreated.

Cover was measured annually in late summer from 1957-1966 (except 1960) in units of 0.01 ft. Perennial grass was recorded as basal intercept; i.e., length of live root crown portion of tuft at ground level. Shrub cover was recorded as the entire live crown intercept excluding conspicuous openings or areas of dead crown.

Taxa were recorded separately to the species level in most cases and sometimes to the genus level only. The OTHERPG code refers to unidentified perennial grass species; OTHSHRUB to unidentified shrub species.

Sources of data were the original field data sheets except: Sources for pasture 1 in 1961-1966 were handwritten summaries that had been compiled from the field data sheets.

A value of -9999 in a field means that no data were available because a reading was not made for that date.

本数据集包含美国林务局（United States Forest Service, USFS）FSRM 1706-12研究项目采集的多年生草本基盖度与灌木叶盖度数据。研究方案副本可从该网站下载。
研究在5个牧场中各设置20条随机布设的永久性100英尺样线样带开展测定。
这5个牧场自1915年起便由母牛-犊牛群全年放牧，放牧利用率介于47%至60%之间。研究启动时，牧场放牧管理做出两项调整：其一，将放牧利用率目标下调至40%；其二，2个牧场自1958年起实施隔年夏季休牧（7月至9月），其余2个牧场则于1959年开始该项休牧措施。为开展对照研究，9号牧场保持全年放牧，并分别于1958年及1963年至1966年进行了测定，但9号牧场的数据未纳入已发表的分析结果。
1954年至1957年间，研究人员使用柴油杀灭了1号和7号牧场中的细叶牧豆树（*Prosopis velutina*），而8号、9号及10号牧场的牧豆树未做处理。
盖度测定于每年夏末开展，测定周期为1957年至1966年（1960年除外），测定单位为0.01英尺。多年生草本盖度以基株截距记录，即地面处丛状草本活根颈部分的长度；灌木盖度则以整个活冠截距记录，需剔除明显的空隙或枯冠区域。
多数情况下，分类单元记录至物种水平，少数情况下仅记录至属水平。代码OTHERPG指代未鉴定的多年生草本物种，OTHSHRUB指代未鉴定的灌木物种。
本数据集的原始数据来源为原始野外记录表，但1961年至1966年的1号牧场数据除外——该时段的数据为根据野外记录表整理的手写汇总材料。
数据字段中取值为-9999，表示该日期未开展测定，无对应数据。