Land-use characteristics and environmental stewardship programs

Transcription

1 Published March 20, 2017 Documenting Trends in Land-Use Characteristics and Environmental Stewardship Programs on US Golf Courses Wendy D. Gelernter,* Larry J. Stowell, Mark E. Johnson, and Clark D. Brown Abstract Since an initial survey that documented land-use characteristics and environmental stewardship programs for 2005, the acreage for an average 18-hole golf facility has changed little, with a median acreage of 151 acres in 2005 and 150 acres in In contrast, the acreage of maintained turf on 18-hole facilities has decreased significantly during that same period, from 99.2 acres (or 66 of 18-hole facility acreage) to 95.1 acres (or 63 of 18-hole facility). Natural or native vegetation comprises approximately 17 of 18-hole facility acreage, while the remaining acreage is composed of water features (4.2), buildings, (1.5), bunkers (1.6), and parking lots (1.6). The acreage of winter overseeded turf in the Transition, Southwest and Southeast regions has decreased by 49 since Trends in turf-type use have varied only slightly since 2005, with bermudagrass (Cynodon spp.) making up 34 of all US acreage, followed by Kentucky bluegrass (Poa pratensis L.) (23) and annual bluegrass (P annua L.) (11). The observed reductions in golf course facility and maintained turf acreage since 2005 were the result of an interaction between a net decrease in the number of facilities in the United States and voluntary reductions in the size of facility features. The most commonly cited reasons cited for turf reductions included cutting the costs for water and labor, but also for fertilizers, pesticides, and energy. Land-use characteristics and environmental stewardship programs on US golf courses were documented for the first time in a 2006 survey conducted by the Golf Course Superintendents Association of America (GCSAA, Lawrence, KS; Throssell et al., 2009a). Part of a larger effort known as the GCSAA Golf Course Environmental Profile, this survey was one of five national surveys conducted between 2006 and 2009 with the objective of developing a comprehensive environmental profile of golf courses in the United States (Lyman et. al., 2007; Throssell et.al., 2009a, 2009b; Lyman et al., 2012a, 2012b). In 2016, a follow-up survey was conducted through the Environmental Institute for Golf (Lawrence, KS) and was funded by the United States Golf Association (USGA, Far Hills, NJ). The objectives of this second phase were to compare results from the 2016 survey with those generated from the initial 2006 survey in an attempt to characterize and/or quantify trends in land use, turf types, overseeding practices, and environmental stewardship program participation for US golf courses. Applied Turfgrass Science Core Ideas A survey of land-use characteristics and environmental stewardship programs on US golf courses was conducted in 2015 as a follow-up to an initial, 2005, study. There were significant acreage reductions in maintained turf, as well as in overseeded and irrigated turf. Trends in decreased acreage came about primarily through a combination of voluntary reductions in acreage and a net decrease in the number of golf facilities in the USA. Variations in land-use allocations occurred regionally, as well as for public compared with private facilities and 9-hole compared with 18-hole facilities, suggesting that climate, economics, and even real estate values are involved in these decisions. W.D. Gelernter and L.J. Stowell, PACE Turf, 1267 Diamond St., San Diego, CA 92109; M.E. Johnson, Golf Course Superintendents Association of America, 1421 Research Park Dr., Lawrence, KS 66049; C.D. Brown, National Golf Foundation, 1150 US Highway 1, Suite 401, Jupiter, FL *Corresponding author (gelernter@paceturf.org). Received 5 Oct Accepted 29 Jan Abbreviations: 18-HEQ, 18-hole equivalents; GCSAA, Golf Course Superintendents Association of America; NGF, National Golf Foundation; USGA, United States Golf Association. Conversions: For unit conversions relevant to this article, see Table A. Supplemental material is available online for this article. Published in Crop Forage Turfgrass Manage. Volume 3. doi: /cftm American Society of Agronomy and Crop Science Society of America 5585 Guilford Rd., Madison, WI This is an open access article distributed under the CC BY-NC-ND license ( licenses/by-nc-nd/4.0/). crop, forage & turfgrass management 1 of 12

2 Table A. Useful conversions. To convert Column 1 to Column 2, multiply by Column 1 Suggested Unit Column 2 SI Unit foot, ft meter, m yard, yd meter, m acre hectare, ha 5/9 ( F 32) Fahrenheit, F Celsius, C Survey Implementation Of the 15,121 golf facilities in the United States in 2016 (National Golf Foundation [NGF], personal communication, 2016; Supplemental Table S1), 12,951 (85.7 of the national census) courses managed by superintendents with available addresses were identified by integrating the GCSAA and NGF databases. An initial invitation, which included a link to the online survey, was sent to prospective participants in March 2016, followed by three reminders sent in April A total of 1707 completed surveys were received (11.3 of all facilities). This is less than the 18.6 response coverage from the initial survey (Lyman et. al., 2007; Supplemental Table S1), which also included a mail survey campaign. While both surveys targeted the same population, respondents in 2016 were not identical to those in Participation in the survey was encouraged by entering respondents into a drawing for a total of twenty-one $100 gift cards and providing a 0.25 service point to GCSAA members in support of their professional development requirements for certification. Acreage data was provided by survey respondents as estimates. Review of Survey Data Although the survey was implemented in 2016, the data reported by respondents covered management practices for 2015 and earlier. The data reported here on the initial landuse survey (conducted in 2006) covers 2005 and earlier. Full details of the survey process are described by Gelernter et al. (2016). Survey weight factors were calculated as described by Kish (1990) and are shown in Supplemental Table S1. Analysis of National Trends Estimates of national and regional land-use data were projected to the total census of US golf facilities based on survey responses for 2005 and 2015 data, as described in Gelernter et. al., Turfgrass species and overseeding species were reported as a percentage of the total feature acreage. Projections were determined by multiplying the 18-hole facility average (mean) acres per feature in each agronomic region by the number of 18-hole equivalents (18 HEQ) for that feature in the region. To calculate the number of 18 HEQ, a 9-hole facility was assigned HEQ, an 18-hole facility was assigned HEQ, a 27-hole facility was assigned HEQ, etc. This approach was used for analysis of both the 2015 and the 2005 data reported below. A somewhat different method, which relied on the use of the median rather than the mean, was used to calculate projected acreage data reported previously (Lyman et. al., 2007). This method generated 2005 projection data values that are approximately 10 lower than the 2005 data reported below. The use of the median in generating projections was not used for analysis of either the 2005 or 2015 data reported below because it provides less accurate estimates than those based on the mean. To estimate the projected acreage of each turf variety, mixtures of two or more turfgrass species were accounted for as described by Lyman et al. (2007). Analysis of Trends on Individual Golf Facilities In addition to using survey data to project national estimates, land-use patterns at the level of the individual 18-hole golf facility were analyzed by computing the appropriate measure of central tendency for each variable of interest. All 18-hole facilities that provided responses were included in this analysis. A graphical review of the 2005 and 2015 data from both property surveys revealed skewness (>0.6), kurtosis (>3.0), and variance to mean ratios (>6:1) (Supplemental Table S2) well in excess of those expected for a normal distribution for the majority of the acreage data (Supplemental Table S3). In these cases, data were fitted to the Fisk distribution, as described previously (Gelernter et. al., 2016), as the most accurate measure of central tendency. For linear measurements (cart-path length and golf-course length), which displayed a poor fit with the Fisk distribution, the arithmetic median was determined to be the most appropriate measure of central tendency, due to a very high variance to mean ratio but moderate levels of skewness (<1.0). To determine levels of significance among groups, the Wilcoxon rank sum test (Moore et al., 2007), which is appropriate for both normal and non-normal data, was applied. Medians were sorted in increasing order, and pairwise comparisons made starting with the lowest values. Pairwise comparisons that reported a Wilcoxon rank sum test p value > 0.10 were assigned the same letter (a), and significant differences (p < 0.10) were assigned sequentially higher letters in the alphabet. This process was repeated with the lowest significantly different value until all pairwise comparisons were evaluated. The Bonferroni correction was used to provide for multiple tests of significance (Hochberg, 1988). Values were considered 2 of 12 crop, forage & turfgrass management

3 Table 1. Projected and median total acreage for golf facilities in 2005 and Median acreages are for 18- hole facilities only. Total facility projected acres Total facility median acres Change change North Central 629, ,532 44, c 159 c 1.3 Northeast 394, ,877 25, bc 144 ab 3.7 Pacific 90,282 83,144 7, a 127 a* 9.4 Southeast 508, ,079 7, ab 150 bc 4.8 Southwest 198, ,562 13, abc 141 ab 4.6 Transition 447, ,963 21, bc 156 bc 2.9 Upper West/Mountain 152, , bc 149 abc 1.4 United States 2,421,605 2,301, , Within each column, medians followed by the same letter are not significantly different at the 90 confidence level. For each regional comparison, an asterisk indicates that values for 2005 versus 2015 are significantly different at the 90 confidence level. Table 2. Changes in number of facilities and in mean facility size, and the impact on trends in total golf facility projected acreage. Number of facilities (18-hole equivalents) Mean facility size Change in projected total facility acreage due to changes in Change Facility numbers Facility size a c r e s North Central 3,690 3, ,534 7,891 Northeast 2,507 2, ,673 15,697 Pacific ,280 4,858 Southeast 3,303 3, ,691 27,636 Southwest 1,236 1, ,650 8,992 Transition 2,722 2, ,833 4,001 Upper West/Mountain ,583 3,918 United States 14,969 14, ,078 9,719 Values were determined by multiplying the change in 18-hole equivalents between 2005 and 2015 by the average number of acres per 18- hole equivalent per region. Values were determined by multiplying the change in 18-hole equivalents between 2005 and 2015 by the change in average acreage of maintained turf between 2005 and significantly different when p This approach was used for analysis of both the 2015 and the 2005 data sets. Projections and Medians Compared The national (projection) trends reported below illustrate similar, though not identical, trends as those reported for individual golf courses (medians). In the case of the median data reported for individual golf courses, the changes in practices over the past 10 years are documented by providing the average (median) responses for all 18-hole facility respondents within each of the survey s seven agronomic regions for both 2005 and In the case of projections, the analysis was broadened to include the impact of the number of golf facilities in the nation, as well as the average behavior at the individual golf course level. Each type of analysis yields different and equally useful insights, as will be highlighted below. Trends in Total Facility Size Total facility acreage refers to all maintained turf, bunkers, buildings and features, parking lots, water features, and natural, native, or unmowed areas. There was a projected estimate of 2,301,808 acres of golf facilities in the United States in 2015, which represents a 4.9, or 119,797-acre, decrease in total facility acres since 2005 (Table 1). A reduction in the number of golf facilities since 2005 was responsible for almost all of the observed acreage decrease, since the neither median or mean size of golf facilities significantly changed during that time period (Tables 1 and 2). The lower number of facilities is thought to be a market correction in response to the overbuilding of the 1980s and 1990s (NGF, 2016). The median size for an 18-hole facility was 150 acres in 2015, with no significant change from the 151 acres documented in 2005 (Table 1). There was also no significant change in the median facility acreage for 9-hole golf courses, which was 59.0 acres in 2005 and 58.6 acres in 2015 (data not shown). crop, forage & turfgrass management 3 of 12

4 Table 3. Median maintained turf acreage in 2005 and 2015 for 9- and 18-hole golf facilities, and for public and private facilities. Greens Tees Fairways Roughs Practice Nursery Grounds Total Playing length Course type a c r e s yards 9 holes 1.35a 1.38a 1.18a 1.19a 14.2a 13.2a* 17.9a 15.5a 4.02a 3.26a* 0.75a 0.91a 1.33a 1.18a 42.5a 37.6a* 3100a 3105a 18 holes 3.10b* 3.22b 3.08b 3.07b 29.2b 28.1b* 49.4b 47.9b 6.53b 6.00b* 0.91a 0.87a 2.02b 1.70b* 99.2b 95.1b* 6722b* 6800b Public (18-hole) 3.11a* 3.18a 3.21b 3.21b 29.5 b 28.3a* 47.3a 44.4a* 6.72b 6.06a* 0.95b 0.90a 1.84a 1.58a* 97a 92.2a* Private (18-hole) 3.08a* 3.27b 2.91a 2.90a 28.7 a 27.7a* 52.3b 52.8b 6.31 a 5.91a* 0.88a 0.85a 2.27b 1.87b* 101b 98.9b For each facility type/feature combination, an asterisk indicates that the values for 2005 vs are significantly different at the 90 confidence level. Within each column, medians followed by the same letter are not significantly different at the 90 confidence level. Table 4. Projected and median total acreage for maintained turf in 2005 and Maintained turf projected acres Maintained turf median acres Change decrease decrease North Central 411, ,977 42, c c* 4.0 Northeast 241, ,187 25, a 87.7 a 4.5 Pacific 58,509 51,826 6, ab 84.8 a* 9.0 Southeast 315, ,702 17, ab 92.8 ab 0.9 Southwest 128, ,168 15, bc 90.1 a* 11.0 Transition 284, ,887 20, bc bc 1.3 Upper West/Mountain 95,197 94, ab 94.5 ab 4.4 United States 1535, , , * 4.1 Median acreages are for 18-hole facilities only. Within each column, medians followed by the same letter are not significantly different at the 90 confidence level. For each regional comparison, an asterisk indicates that values for 2005 versus 2015 are significantly different at the 90 confidence level. Although median 18-hole facility acreages remained stable on a national level, there was regional variation. The Pacific region demonstrated the greatest deviation from national trends; it was the only area of the country where a significant decrease in facility size was observed from 2005 to This region also had the smallest facility sizes in both 2005 and 2015, as well as the largest percentage decline in facility acreage. The largest facilities occurred in the North Central region (Table 1). The regional range in facility size does not correlate with environmental factors such as rainfall (data not shown) and is probably a reflection of varying real estate values across the United States; the Pacific, Southwest, Southeast, and Northeast regions, which are host to large cities and/or large resorts, tend to have the smallest facility sizes, whereas the North Central, Transition, and Upper West/ Mountain regions have larger facilities. The playing length for 18-hole facilities has increased since 2005, a trend toward longer courses that has been influenced by changes in the design of balls and clubs that allow golfers to hit longer and straighter than in the past (Coleman, 2016). The playing length of 9-hole facilities, however, has not changed significantly since 2005 (Table 3). Trends in Maintained Turf Acreage Maintained turf refers to all greens (including putting and practice greens), tees, fairways, roughs, driving range/ practice areas (excluding putting and practice greens), turf nurseries, and clubhouse grounds (landscaped areas, grass recreational areas) at the golf facility. Maintained turf makes up the largest acreage of all golf course features, comprising a projected estimate of 1,408,412 acres (61 of total facility acreage) in the United States in There has been an 8.3 reduction in maintained turf acreage in the United States since All regions demonstrated a decline, with the Southwest and Pacific regions showing the largest percentage decrease (Table 4). The largest decline in absolute acreage, however, occurred in the North Central region, with a decrease of 42,827 acres of maintained turf since These trends can be understood in the interplay between net reductions since 2005 in the number of golf facilities in each region (Table 5) and reductions in the median acreage of maintained turf features on 18-hole golf courses (Table 4). For example, in the Southwest and Pacific regions, where the number of facilities has declined only slightly since 2005, reductions in the median acreage were the dominant factor in maintained turf acreage reductions. In the North Central region, the decreased number of facilities and the significant median acreage decreases at the individual 4 of 12 crop, forage & turfgrass management

5 Table 5. Changes in number of facilities and in maintained turf acreage in 2005 and 2015 and the impact on trends in total maintained turf projected acreage. Number of facilities (18-hole equivalents) Mean maintained turf Change in projected maintained turf acreage due to changes in Facility Maintained Change numbers turf size a c r e s North Central 3,690 3, ,882 18,944 Northeast 2,507 2, ,922 19,267 Pacific ,478 5,205 Southeast 3,303 3, ,558 4,493 Southwest 1,236 1, ,007 11,998 Transition 2,722 2, ,438 3,616 Upper West/Mountain ,230 2,762 United States 14,969 14, ,056 57,299 Values were determined by multiplying the change in 18-hole equivalents between 2005 and 2015 by the average number of acres per 18- hole equivalent per region. Values were determined by multiplying the change in 18-hole equivalents between 2005 and 2015 by the change in average acreage of maintained turf between 2005 and golf course level both contributed to the downward trend in projected acreage. In the Upper West/Mountain region, there was actually a small increase in the number of facilities, but the increase was more than offset with decreases in the median acreage of maintained turf, producing a net decrease in maintained turf. For 18-hole facilities, the median acreage for maintained turf has been reduced by 4.1 since 2005 (Table 4), which is largely due to the reduction in the median acreage of roughs. The largest declines took place in the Southwest and Pacific regions (Table 6). For individual golf facilities, 35 of survey respondents reported that their acreage of maintained turf had decreased since 2005 (data not shown). This response was reflected in the significant decrease in maintained turf acreage for 9-hole and 18-hole golf courses since However, private courses did not significantly reduce their maintained turf acreage, whereas public facilities did (Table 3). Greens are the only feature for which median acreage has significantly increased during the past 10 years for 18-hole facilities. Median acreage for all other features has remained the same or decreased (Table 6). A possible explanation for this trend on greens are efforts to broaden the audience of golf, as well as to improve the pace of play through installation of larger greens for use by higher handicap golfers (PGA, 2011). The increased size of greens was not observed for 9-hole facilities, however (Table 3). Trends in Irrigated Turf Acreage In 2015, 18-hole facilities irrigated approximately 78 of their maintained turf acreage, though this value varies regionally (Table 7). As documented by Throssell et al. (2009b) and Gelernter et al. (2015), the number of irrigated acres per facility and per region varies, depending on regional climate. Roughs are the least likely to be irrigated of all turf features (Table 7). In addition to climate, the nature of the facility also appeared to have a strong influence on irrigated turf acreage in 2015, with private 18-hole facilities irrigating 85 of their acreage, while public facilities irrigated 72. Likewise, 9-hole facilities irrigated 54 of their turf acreage, while 18-hole facilities irrigated 78 (data not shown). Data on irrigated acres was not solicited in the initial survey, and statistical trends across time are therefore not possible to compute. However, when the national median of 74.0 acres of irrigated turf for 18-hole facilities reported here (Table 7) is compared with the median value of 80.2 acres reported 2 years earlier, using comparable survey methods (Gelernter et. al., 2015), there appears to be a trend toward reduction of irrigated acreage across the country. Trends in Non-turf Acreage Trends in Water Feature Acreage Water features include open water (ponds and lakes), wetlands (areas within the property that receive sufficient water to grow wetland plants), streams and rivers, drainage waterways (areas of conveyance that tie into or connect to a stream or river), and irrigation canals (man-made canals used for irrigation). In 2015, water features made up 6.9 of US facility acreage (Table 8), and 4.2 of the average 18-hole facility acreage, although there was large regional variation for this component of the golf course (Table 9). Arid regions such as the Southwest have the lowest water feature acreage, whereas the rainy Southeast region has the highest. Climate is not the crop, forage & turfgrass management 5 of 12

6 Table 6. Median maintained turf acreage for 18-hole facilities in 2005 and Greens Tees Fairways Roughs North Central 3.25 d* 3.44 b b* 3.15 bc bc 27.0 b c 56.7 d 5.7 North east 3.24 d* 3.43 b a 2.65 a a 24.8 a* ab 45.6 bc 5.0 Pacific 2.90 a 3.01 a bc 2.74 ab d 30.7 cd a 36.3 a* 15.0 Southeast 2.97 ab 3.04 a c 3.24 c d 29.3 cd a 45.1 b 7.4 Southwest 3.03 bc 3.12 a bc 3.07 bc d 30.3 cd* ab 41.9 ab* 11.0 Transition 3.11 cd 3.21 ab c 3.31 c c 28.1 bc b 52.8 cd 1.0 Upper West/Mountain 3.00 bc 3.11 a bc 3.09 bc d 31.0 d* a 44.3 ab 0.2 United States 3.10* * Practice Nursery Clubhouse grounds change North Central 7.37 d 6.37 b* bc 0.91 a bc 1.84 bc* 13.0 North east 5.38 a 5.10 a ab 0.80 a abc 1.73 bc* 16.0 Pacific 5.51 ab 5.11 ab abc 0.81 a a 1.40 abc 9.7 Southeast 6.36 bc 6.13 ab ab 0.82 a c 1.93 c* 19.0 Southwest 6.92 cd 6.20 ab a 0.87 a ab 1.33 ab* 23.0 Transition 6.45 bc 6.19 ab c 0.98 a ab 1.92 c 2.1 Upper West/Mountain 7.51 d 6.33 ab* abc 0.82 a ab 1.14 a* 32.0 United States * * 16.0 change For each comparison of 2005 with 2015, values followed by an asterisk indicate there was a significant difference between the two values at the 90 confidence level. Within each column, values followed by the same letter are not significantly different at the 90 confidence level. Table 7. Median acreage and percentage of irrigated turf on 18-hole facilities in Greens Tees Fairways Roughs Practice Nursery Grounds Total acres acres acres acres acres acres acres acres North Central 3.42 b a b a ab a b b 61.9 Northeast 3.41 b b a a a a ab a 60.3 Pacific 3.00 a c cd a ab a ab c 88.4 Southeast 3.03 a a cd b b a b cd 90.6 Southwest 3.12 a c cd b b a ab d Transition 3.20 a a bc b ab a b c 74.9 Upper West/ Mountain 3.10 a a d b b a a d 96.3 United States Within each column, medians followed by the same letter are not significantly different at the 90 confidence level. only factor, however, determining the size of water features, because the cool and rainy Northeast and Pacific regions also have less acreage devoted to water features (Table 9). It is possible that regional real estate values may contribute to this trend, as discussed previously. Open water makes up by far the largest acreage water feature in all regions of the country. With the exception of the Southwest region, wetlands are the second-largest acreage water feature. In the arid Southwest, however, only a small amount of acreage is devoted to wetlands, and much more is devoted to drainage waterways. Streams and rivers are more common in areas with higher rainfall, such as the North Central, Northeast, and Pacific regions, but those comprise only 7.4 of water feature acreage at the national level. Drainage waterways and irrigation canals each consume less than 5 of the acreage for all water features at the national level (Supplemental Table S4). Trends in the number of linear feet of water features on the typical 18-hole facility have experienced little or no change for streams/rivers and drainage waterways since 2005 (Supplemental Table S5). Since these are relatively fixed features of the landscape and not easily subjected to human manipulations, this trend is not unexpected. 6 of 12 crop, forage & turfgrass management

7 Table 8. Projected acreage for sub-features that make up total facility acreage and percentage of total facility acreage for Bunkers Buildings Parking lots Water features Natural areas Maintained turf of of of of of of acres facility acres facility acres facility acres facility acres facility acres facility North Central 12, , , , , , Northeast 7, , , , , , Pacific 1, , , , , , Southeast 10, , , , , , Southwest 3, , , , , , Transition 7, , , , , , U pper West/ 2, , , , , , Mountain United States 46, , , , , , Table 9. Median acreage for sub-features that make up 18-hole facility acreage for Bunkers Buildings Parking lots Water features Natural areas Maintained turf a c r e s North Central 2.33 a 2.18 a 2.53 a 6.84 b 25.2 a 104 c Northeast 2.29 a 2.26 a 2.57 a 4.82 a 30.7 a 87.7 a Pacific 2.13 a 2.17 a 2.54 a 4.28 a 19.5 a 84.8 a Southeast 2.65 a 2.56 a 2.29 a c 20.3 a 92.8 ab Southwest 2.57 a 1.94 a 2.22 a 4.22 a 29.4 a 90.1 a Transition 2.18 a 2.31 a 2.38 a 5.90 ab 30.7 a 100 bc Upper West/Mountain 2.34 a 2.05 a 2.22 a 5.38 ab 24.6 a 94.5 ab United States Within each column, medians followed by the same letter are not significantly different at the 90 confidence level. Trends in Natural/Native/Unmowed Area Acreage Natural areas refers to the combined total of forests and woodland, and native or undisturbed grasslands (all native grasses and forbs with minimal non-native plants/wildflowers), mixed or improved grasslands (combinations of native and nonnative grasses, forbs, and wildflowers), shrublands (woody plants, with a mix of herbaceous and mostly open canopies), deserts, riparian areas (undisturbed or reestablished vegetation along moving water composed of trees, forbs, and native grasses), buffer strips (grasses transitioning between aquatic and terrestrial communities), beaches, alkaline areas, and garden or landscaped areas. In 2015, natural areas composed 26 of US facility acreage (Table 8) and 17 of the average 18-hole facility acreage. There is only minor regional variation in the acreage devoted to natural areas (Table 9). There is, however, considerable regional variation in the types of vegetation selected for natural areas. In regions with higher rainfall the North Central, Northeast, Pacific, Southeast, and Transition regions forests are the dominant natural areas, whereas in regions with low rainfall the Southwest and Upper West/Mountain regions native and undisturbed grasslands and/or deserts predominate (Supplemental Table S6). In 2015, 46 of all respondents reported that they had increased their natural areas acreage over the past 10 years, whereas only 5 reported a decrease (data not shown). Efforts to increase natural areas acreage, and to convert maintained turf to natural areas, have been promoted as an approach that saves fertilizer, water, labor, fuel, and pesticide inputs, as well as being a method for protecting water resources, improving water conservation, and minimizing soil erosion (Nelson, 1997; Environmental Institute for Golf, 2016). It is possible that at least some of the maintained turf acreage decreases documented in Table 4 have been converted to natural areas during the past 10 years, which would account for the lack of change in total facility size since 2005 (Table 1). Trends in Unlandscaped Acreage Buildings (clubhouse, deck, patio pool, tennis courts, and maintenance buildings) account for approximately 2.3 of total facility acreage (Table 8). The national median acreage for 18-hole facility buildings was 2.24 acres, with no significant differences among regions (Table 9). Parking lots account for approximately 2.0 of total facility acreage (Table 8). The national median acreage for 18-hole facility parking lots was 2.40 acres, with no significant differences among regions (Table 9). crop, forage & turfgrass management 7 of 12

8 Fig. 1. Proportion of each turf type acreage in 2005 and Bunkers account for approximately 2.0 of total facility acreage (Table 8). The national median acreage for 18-hole facility bunkers was 2.36 acres, with no significant differences among regions (Table 9). Cart paths account for approximately 1.6 of total facility acreage (Supplemental Table S7). There were striking regional differences in cart path length, with the Northeast, North Central, Southwest, and Upper West/Mountain regions all well below 15,000 linear feet in 2015, and the Pacific, Southeast, and Transition regions with almost twice as much length devoted to cart paths. The Southwest was the only region with a significant decline in cart path acreage since 2005 (Supplemental Table S7). Trends in the Use of Impervious Surfaces and Runoff Management Hydrologists promote reductions in the acreage of impervious surfaces (paved parking lots, cart paths, sidewalks, and rooftops) in the landscape as a means of reducing urban runoff, water pollution, and negative impacts on aquatic life (Schueler, 2000). On golf courses, 5.1 of the acreage is composed of cart paths, parking lots, and buildings. The majority of this acreage (4.8 of golf course acreage) comprises impervious surfaces, whereas a much smaller acreage (0.3) comprises pervious surfaces. The North Central, Northeast, and Upper West/ Mountain regions had the lowest percentage of impervious surfaces compared with total facility acreage; this trend was due primarily to the low acreage of impervious cart paths in these regions (Supplemental Table S8). Collection of surface runoff can also help reduce water pollution. In 2015, 58 of all survey respondents reported that they collected surface runoff from neighboring properties, and 74 reported collecting runoff for their own property (data not shown). Trends in Turf Type Acreage The turf-type acreages discussed in this section do not include overseeded turf for winter play. Those acreages will be dealt with separately in the Trends in Winter Overseeding section below. Cool-Season Turf Types Kentucky bluegrass (Poa pratensis L.) was by far the most commonly used cool-season turf type, followed by annual bluegrass (Poa annua L.), perennial ryegrass (Lolium perenne L.), creeping bentgrass (Agrostis stolonifera L.), tall fescue [Lolium arundinaceum (Schreb.) Darbysh.], and fine fescue (Festuca spp.) (Fig. 1). There is variation in the distribution of cool-season turf types by region (Table 10) and by turf feature (Supplemental Tables S9 S14). Due at least in part to the net loss of golf facilities (Table 2), the absolute acreage of most turf types has decreased since 2005, with the notable exception of tall fescue, whose acreage has increased by 20 (Table 10). Overall, cool-season turf made up approximately two-thirds of all maintained turf acreage in both 2005 and 2015 (Fig. 2). Warm-Season Turf Types Bermudagrass (Cynodon spp.) made up almost 93 of all warm-season turf in 2015, and with 34 of all maintained turf acreage, it is by far the most used turf type in the nation (Fig. 1, Table 10). There is variation in the distribution of warm-season turf types by region (Table 10) and by turf feature (Supplemental Tables S9 S14). Overall, warm-season turf made up approximately one-third of all maintained turf acreage in both 2005 and 2015 (Fig. 2). Due at least partly to the net loss of golf facilities (Table 2), the absolute acreage of bermudagrass has decreased since 2005 (Table 10). There has been an increase, though, in the acreage of other warm-season turf types such as zoysiagrass (Zoysia spp.) and seashore paspalum (Paspalum vaginatum Sw.). However, they make up only 2 or less of total maintained turf acreage (Fig. 1). 8 of 12 crop, forage & turfgrass management

9 Table 10. Projected total acres for all golf features combined of each grass species in 2005 and 2015 and percentage change since Cool- season grasses Annual bluegrass Creeping bentgrass Fine fescue Kentucky bluegrass Perennial ryegrass Tall fescue North Central 60,983 53, ,284 53, ,013 14, , , ,836 42, ,803 11, North east 48,200 41, ,740 42, ,441 11, ,152 57, ,094 39, ,615 14, Pacific 22,746 21, , ,363 1, ,534 2, ,585 16, , Southeast , NA 3,071 1, Southwest 6,654 5, , ,357 4, ,762 9, ,546 1, Transition 14,574 10, ,479 19, ,270 2, ,502 20, ,881 10, ,534 52, U pper West/ Mountain 14,084 14, , ,691 1, ,328 45, ,438 19, , US 167, , , , ,228 33, , , , , ,565 83, change Warm-season grasses Bermudagrass Zoysiagrass Seashore paspalum Other North Central NA 2, Northeast NA 2, Pacific 2,690 2, NA , Southeast 282, , ,777 4, , Southwest 82,425 71, >100 12, Transition 122, , ,430 20, NA 2, U pper West/ Mountain 4,706 3, NA 0 0 NA United States 495, , ,364 25, , ,517 26, NA, the percentage change was not computed when 10 or fewer acres were reported for either 2005 or change crop, forage & turfgrass management 9 of 12

10 Fig. 2. Ratio of cool-season turf to warm-season turf acreage in 2005 and Table 11. Projected number of overseeded turf acres and the percentage of overseeded acreage for each feature in the Transition, Southeast, and Southwest regions in 2005 and Greens Tees Fairways Roughs acres overseeded acres acres overseeded acres acres overseeded acres acres overseeded acres Southeast , ,822 17, ,734 4, Southwest , ,327 14, ,929 13, Transition , ,264 3, ,053 1, Total , ,413 36, ,716 19, Practice Nursery Total change in overseeded acres acres overseeded acres acres overseeded acres acres overseeded acres Southeast 5, ,212 30, Southwest 4, ,230 34, Transition 1, ,002 6, Total 11, ,444 72, Trends in Winter Overseeding Winter overseeding of warm-season turf with cool-season varieties allows facilities in southerly climates to maintain year-round green turf and golf play. Overseeding has been a common practice in facilities in the Southeast, Southwest, and Transition regions, with 80, 81, and 38, respectively, reporting that they had overseeded at least one feature in Since that time, however, the extra inputs of water, fertilizer, pesticides, energy, and labor required to implement overseeding (O Brien, 2013) have caused many facilities to examine the economic and environmental costs of this practice. As a result, a significant number of facilities have completely stopped overseeding, with the percentage of facilities overseeding declining in 2015 to 53, 55, and 31 in the Southeast, Southwest, and Transition regions, respectively (data not shown). In addition, of those golf courses that still overseed, many have decreased the number of overseeded acres. This is reflected in the 49 decrease in the estimated projected acreage of overseeded turf between 2005 and 2015 (Table 11), compared with the 8.3 decrease in maintained turf acreage (Table 4). This disparity in trends indicates that facilities are cutting back on overseeded acres much more aggressively than they are cutting back on maintained turf acres. The most common reasons cited for decreasing overseeded acreage in were savings in money (86), labor (74), water (66), fuel/energy (62), fertilizer (61), wear and tear on equipment (47), and pesticides (36) (data not shown). In terms of golf facility features, the acreage of overseeded turf was reduced on all golf course features. The biggest decrease in overseeded acreage, however, occurred on fairways. Tees were the most frequently overseeded feature in both 2005 and 2015 (Table 11), and perennial ryegrass was by far the most used turf type for overseeding in both years (Fig. 3). The only feature on which perennial ryegrass did not dominate was greens, where rough bluegrass (Poa trivialis L.) was the most commonly used turf type (Supplemental Tables S15 S20). 10 of 12 crop, forage & turfgrass management

11 Fig. 3. Percentages of various turf types used in winter overseeding in the Transition, Southeast and Southwest regions in 2005 and Trends in Environmental Stewardship Trends in Facility Design for Environmental Protection Since 2005, facilities have focused on irrigation system improvements, recycling, native plantings, and wildlife habitat improvement as means of further fostering environmental compatibility (Table 12). However, recycling was the only activity for which increased participation was reported in 2015 compared with The apparent trend toward less emphasis on environmental improvements at first seems at odds with the efforts at acreage reduction reported above. There are at least two probable explanations. First, several of the activities listed in Table 12 such as installation of petroleum storage tanks, wetland construction, buffer strips, etc. are one-time projects, which, once accomplished do not need to be performed again. An additional possibility is that unlike acreage reductions, which can save large sums of money in the long term, many of the improvements listed in Table 12 are costly. Since the period from 2005 to 2015 encompassed the Great Recession, it is perhaps not surprising that golf facilities deferred non-critical improvements until budgets had been restored to their pre-recession levels. Environmental Stewardship Programs There are a wide variety of publicly and privately administered environmental stewardship programs in which golf courses can voluntarily participate (Supplemental Table S21). Most focus on improving golf course environmental stewardship through education, self-assessment, compliance with environmental laws and regulations, recognition and certification of achievements, and communication among the golf industry, regulatory agencies, and citizen s groups. Table 12. Percentage of all facilities that made improvements in the last 10 yr to help protect the environment making improvement Irrigation system improvement 64 61* Recycling 38* 53 Incorporation of native plantings 50 42* Wildlife habitat improvement 46 41* Chemical storage 52 36* Erosion control 41 34* Installation of buffer strips Waste reduction 26* 30 Chemical mix and load pads 28 21* Stream-bank restoration Composting 24 18* Storm-water retention 21 16* Installation of petroleum storage tank 37 15* Wetland construction/restorations 16 13* Use of alternate water source 15 12* Wild pollinator habitat (not including bee hives/apiaries) NA 10 Capping/closing water wells * Bee hives/apiaries NA 4.9 Installation of rain garden NA 2.3 Equipment washing stations An asterisk indicates that values for 2005 and 2015 are significantly different at the 90 confidence level; NA, question not asked previously. crop, forage & turfgrass management 11 of 12

12 There has been little change in participation in stewardship programs since As in 2005, the Audubon Cooperative Sanctuary Program has had the greatest participation (Supplemental Table S21); however, the majority of golf courses indicate that they are not involved in any of the listed programs. The most commonly cited reasons for lack of participation were lack of funds (41 of respondents), practices already in place before survey (40), or lack of time needed for implementation (39 of respondents) (data not shown). Conclusions and Recommendations Reductions in golf course facility and maintained turf acreage since 2005 were the result of an interaction between a net decrease in the number of facilities in the United States and voluntary reductions in the size of facility features. In the case of total facility acreage, almost all of the observed acreage reductions were the result of facility closures, because the median size of the total facility did not significantly change from 2005 to In contrast, approximately 55 of the observed reduction in maintained turf acreage was due to facility closures, while 45 was due to voluntary reductions. The most commonly cited reasons cited for turf reductions included water and labor savings, but savings in fertilizers, pesticides, and energy are also involved. Additional actions taken since 2005 to reduce environmental impacts include large reductions in the acreage of overseeded turf and apparent reductions in the acreage of irrigated turf. Future reductions in the acreage of impervious surfaces will also decrease environmental impacts if facilities rely on the use of materials such as pervious concrete in the construction or remodeling of cart paths and parking lots and the use of green rooftops on buildings. Variations in land use allocations occurred regionally, as well as for public and private facilities and 9-hole and 18-hole facilities, suggesting that climate, economics, and even real estate values are involved in these decisions. Looking toward the future, the acreage of maintained turf, overseeded turf, and irrigated turf will probably continue to decrease, though probably not at the recession-driven pace documented here. Facility participation in initiatives that seek to educate, motivate, and monitor environmental stewardship on US golf courses will be important tools as the golf industry continues its efforts in this vein. Acknowledgments This study was conducted by GCSAA through its philanthropic organization, the Environmental Institute for Golf, and funded by the United States Golf Association. References Coleman, M Long on design. Grounds Maintenance. grounds-mag.com/construction/grounds_maintenance_long_ design (accessed 29 July 2016). Environmental Institute for Golf BMP performance goals. EIFG-best-management-practice-performance-goals.pdf (accessed 26 Aug. 2016). Gelernter, W.D., L.J. Stowell, M.E. Johnson, C.D. Brown, and J.F. Beditz Documenting trends in water use and conservation practices on U.S. golf courses. Crop, Forage Turfgrass Manage. doi: /cftm Gelernter, W.D., L.J. Stowell, M.E. Johnson, and C.D. Brown Documenting trends in nutrient use and conservation practices on US golf courses. Crop, Forage Turfgrass Manage. doi: /cftm Hochberg, Y A sharper Bonferroni procedure for multiple tests of significance. Biometrika 75: doi: / biomet/ Kish, L Weighting: Why, when and how. In: Proceedings of the Section on Survey Research Methods. Proceedings of the annual meeting of the American Statistical Association, Anaheim, CA. 6 9 August. American Statistical Association, Washington, DC. p Lyman, G.T., M.E. Johnson, G.A. Stacey, and C.D. Brown. 2012a. Golf course environmental profile measures energy use and energy management practices. Appl. Turfgrass Sci. doi: /ats RS Lyman, G.T., M.E. Johnson, G.A. Stacey, and C.D. Brown. 2012b. Golf course environmental profile measures pesticide use practices and trends. Appl. Turfgrass Sci. doi: /ats rs Lyman, G.T., C.S. Throssell, M.E. Johnson, G.A. Stacey, and C.D. Brown Golf course profile describes turfgrass, landscape and environmental stewardship features. Appl.Turfgrass Sci. doi: /ats rs Moore, D.S., G.P. McCabe, and B. Craig Introduction to the practice of statistics. 6th ed. W.H. Freeman and Company. New York. Nelson, M., Natural areas. USGA Green Section Record (November/December): National Golf Foundation (NGF) NGF Update: Golf facilities in the U.S report released. NGF Dashboard &t= (accessed 5 Jan. 2017). O Brien, P Let s make a deal: Overseed or no overseed? USGA Green Section Record 51(6). Professional Golfers Association (PGA) Tee it forward. (accessed 24 July 2016). Schueler, T.R The importance of imperviousness. In: T.R. Schueler and H.K. Holland, editors. The practice of watershed protection. Center for Watershed Protection, Ellicott City. MD. p Throssell, C.S., G.T. Lyman, M.E. Johnson, G.A. Stacey, and C.D. Brown. 2009a. Golf course environmental profile measures nutrient use and management and fertilizer restrictions, storage and equipment calibration. Appl. Turfgrass Sci. doi: / ATS RS Throssell, C.S., G.T. Lyman, M.E. Johnson, G.A. Stacey, and C.D. Brown. 2009b. Golf course environmental profile measures water use, source, cost, quality, and management and conservation strategies. Appl. Turfgrass Sci. doi: /ats rs 12 of 12 crop, forage & turfgrass management