Homebuilder Practices and Perceptions of Construction on the Wooded Lot: A Quarter Century Later Follow-Up Assessment

Perceptions

The results from this study found that building homes in wooded lots continued to be common in central Wisconsin, with all builders responding to this study doing such. An average of about half of the trees were removed from the lot, and no builder responded that the site was ever totally denuded of trees. In the study area, builders primarily construct custom homes (pers. observation). Developing several homes at a time on speculation (e.g., home built in anticipation of a buyer) was less common in the study area, even in subdivisions considered large for the area. This prevalence of custom homes may explain why about two-thirds of builders indicated they do not receive complaints at all from clients regarding trees. Clients who pay for custom-built homes putatively visit the site before and during construction to add their input, which conceivably results in few surprises.

Most builders gave no preference to the size of trees they remove, but those that did tended to leave large trees standing, which was consistent with the desire of the majority of homebuyers. Despot and Gerhold (2003) found that an overwhelming majority of builders agreed that clients will pay extra for large trees to be preserved on-site. Similarly, removing about half of the trees on the lot was consistent with homebuyers’ overwhelming desire for a finished lot that was both partially landscaped and partially natural. These findings are also consistent with Schroeder and Green (1985) and Yang et al. (2009), who found large trees and moderately dense (park-like) environments are visually attractive and highly rated. The preference for what a site looks like did vary by the person’s age, education level, occupation, and personal level of interest in a natural environment (Brush 2000; Bjerke et al. 2006; Nassauer et al. 2009; Miller et al. 2015).

Knowledge

The results confirm that most builders did not consult a tree preservation expert (78%), such as an arborist or forester, and they ranked ‘consulting with tree preservation experts’ as the very least important activity when preserving trees on wooded lots (index 2.58). Similarly, Olsen et al. (2014) found that 77% of construction professionals in Alabama, U.S., seldom (41%) or never (26%) work with a certified arborist before beginning construction on a project with trees to be preserved. The remaining 33% seldom worked with certified arborists and no one said they always or almost always do such. The use of certified arborists to review construction plans for tree protection and preservation was also uncommon in the Alabama study, with 100% saying they sometimes (37%), seldom (9%), or never (54%) consult with this credentialed expert. This exemplifies why it is so important that homeowners become educated and begin requesting proper tree preservation practices and the involvement of those that have the necessary skills and knowledge (Fite and Smiley 2008a). Olsen et al. (2014) found that the primary barrier to implementing tree preservation on a project was that clients do not request it, with over 90% sometimes (52%) and seldom or never (41%) requesting tree protection. If clients requested that proper tree preservation practices be followed, builders could presumably find a way to comply.

Many mechanisms exist to educate homeowners and builders through outreach programs, including local municipal foresters, extension personnel, university educators, professional organizations, non-profit groups, private companies, and others (Nichnadowicz 2007; Hauer and Johnson 2008; Miller et al. 2015). Builders themselves could develop knowledge of best management practices for construction practices in wooded environments, but interest in a workshop was limited. This could change if homeowners began requesting those practices more frequently, since builders are motivated by market demand (Tinker et al. 2006).

A regulation through local ordinance or state statute is another way to force adherence to tree preservation standards (Abbey 1998; Galvin et al. 2010; Miller et al. 2015). Woodland protection ordinances have become more common. Duerksen and Richman (1993) reported that 100 tree protection ordinances existed in the entire United States in the early 1980s. By the end of that decade, over 80 such ordinances existed in the state of California alone. Today, nearly 50% of communities (n ≈ 650) that responded to a national municipal tree management survey indicated they have an ordinance that details some level of tree preservation during development on public and/or private land (Hauer and Peterson 2015). Schmied and Pillman (2003) found 74% of 34 contacted cities in Europe had tree protection legislation for public and/or private areas. Elmendorf et al. (2003) found in Pennsylvania, U.S., that most shade tree commission respondents had the attitude that tree preservation ordinances (81%) and preserving trees in development (87%) was important. In practice, however, approximately 20% had a tree preservation or landscape ordinance, and 20% practiced approaches to preserve trees in construction.

In this study area, no local ordinances or state laws regulate construction near trees. One possible reason for a lack of tree preservation regulations is that the study area has much residual forested area that has not been developed, and any visual impact of tree loss from either removal or later construction-induced mortality is minimal. There is an example of one covenant from the study area that regulates tree removal and requires at least 25% of the lot trees be preserved or 25% of the lot be planted with trees (City of Stevens Point, undated).

Builders, however, perceive regulatory approaches as moderately effective with tree preservation compared to arborists and designers who viewed them as a useful part of promoting tree preservation (Despot and Gerhold 2003). Janse and Konijnendijk (2007) found that in order to develop effective public policy and regulatory approaches, decision making is best developed by a stepwise process that uses socially inclusive planning by first informing public constituents in an alluring way to determine public opinion and directly involving people in a fully participatory process. Regardless of whether local ordinances or state laws regulate trees during construction, the ANSI A300 Part 5 provides standards for developing specifications for managing trees and shrubs in development areas (Fite and Smiley 2008a; TCIA 2012). For example, the standard specifies an arborist or other qualified person should be involved with site assessments. An arborist should further be involved with the implementation of on-site recommendations during the construction phase. Thus, even without local regulations, a national standard provides a basis that qualified people (e.g., an arborist) should be involved with tree conservation and preservation objectives that involve trees during construction (Fite and Smiley 2008a). As found in this study in Wisconsin and in the study in Alabama by Olsen et al. (2014), this consultation occurs infrequently. Or the consultation occurs too late in the development process to prevent some construction damage to trees (Despot and Gerhold 2003).

When compared to the 1980 study, builder knowledge of soils increased. Despot and Gerhold (2003) found 58% of builders strongly agreed or agreed they knew enough about the effects of soil properties in tree survival and growth to adequately specify or use tree preservation methods. All builders in this study correctly arranged three soil textures according to air and water movement through the soil, an important concept for construction activities in general and for understanding trees’ susceptibility to construction impacts. However, few could arrange soil textures according to susceptibility to compaction, which is also important in construction practices. The wording of these two arrangement-type questions may have biased these results. The words “susceptibility to” were omitted in both studies and the respondents were asked to arrange soil textures “according to the degree of compaction.” The importance of tree root growth and limitations imposed by negative soil changes (e.g., compaction, saturation, oxygen limitation) are well-reviewed by Day et al. (2010b). Compaction on construction sites, if not prevented, can increase soil bulk density levels to those that impede root growth and lead to tree death (Alberty et al. 1984; Randrup 1997; Scharenbroch et al. 2005; Tirado-Corbalá and Slater 2010).

Unlike questions concerning soils, knowledge of tree–understory relationships was relatively the same and reflects the interest of clients. Builders indicated that homebuyers express no preference for small trees to be left on-site, which could be interpreted by builders as ‘no undergrowth.’ Thirty percent of builders indicated that the removal of native undergrowth vegetation and leaf litter would actually be beneficial to tree health. It seems that undergrowth and leaf litter were generally ignored or removed as a nuisance by builders because clients usually express no preference for them.

Builders showed a significant increase in their understanding of the negative effects caused by heavy equipment and soil storage near the base of the tree. Preventing soil compaction can be done by either not using equipment in a tree protection zone or placing materials (e.g., mulch, gravel, plywood) over the root system to minimize compaction (Lichter and Lindsey 1994). Over half of builders in Pennsylvania said the use of wood chips was beneficial to reduce soil compaction, but only 0.1% actually used this practice (Despot and Gerhold 2003). This study likewise found few builders regularly (4%) or occasionally (15%) used mulch or boards. Nearly all builders in this study and over 80% in a study by Despot and Gerhold (2003) knew keeping fill outside the root area was best. Yet in both studies storage of fill within the root area up to the tree stem regularly occurred.

The percentage of builders responding that it was wise to treat root loss with compensatory crown pruning was 30%, and statistically similar to the 50% in 1980. The correct answer in 1980 was that compensatory pruning was a practice to counteract damage to tree root systems; however, the literature since that time has moved away from a clear consensus on this topic (Watson 1998; Watson et al. 2014b). Builder understanding of the structure of tree root systems was generally poor with only 11% believing that tree roots generally extend away laterally from the tree beyond the dripline, which could have dangerous implications for trees on construction sites. This knowledge was inconsistent with Day et al. (2010a), who found that tree roots can extend several times the height of a tree away from the stem. Even though tree height is commonly used to provide a lateral extent of tree root systems, tree diameter appears to be a better predictor (Day et al. 2010a). There was a significant decrease in the number of builders believing that application of nitrogen was helpful to tree recovery from root loss. Fertilization during and at least one year after construction should be modest at most, unless a nutrient deficiency exists (Harris et al. 2004).

Activities

Despite some minor improvement in their knowledge, builders in this study still commonly engaged in activities potentially detrimental to the successful preservation of trees on construction sites, such as storing building materials near the base of trees, using heavy equipment near the base of trees, placing sidewalks within 3 m of trees, and trenching for utilities. Other detrimental activities, such as bringing in fill soil to raise the grade of a site and storing soil near the base of trees, have both increased significantly since 1980. This was all despite scoring very highly on questions regarding soils, making improvements since 1980 on questions regarding damage to root systems, and rating the avoidance of excessive fill soil over tree root systems as the second most important tree preservation decision (index 4.04).

Raising the grade of a site could be done for a variety of reasons, such as to facilitate a walkout basement. It could also be done to facilitate raising the grade above a seasonal flooding issue. In the study area, much of the development occurs in well-drained outwash sand plains and moraines, which were both artifacts of glacial activity that ended approximately 10,000 years ago (Clayton et al. 2006). The western part of the study area has older soils that were untouched by the last glacial period, have greater clay content, and drain more poorly, which can result in seasonal flooding. In this situation, raising the grade during development could account for a change in the builder response to this question. However, development in the well-drained sites was as common in this study as it was in 1980.

Excavation within the critical root zone can lead to declining and dead trees (Fite and Smiley 2008a). Very few builders (7%) in 2008 reported placing foundations within 3 m of trees. In 1980, over 60% did such. This significant reduction (P < 0.000) with few builders excavating soil within 3 m of trees could be the result of selective placement of buildings or the preemptive removal of trees deemed too close for survival. This result might also apply to placement of driveways and sidewalks. But it was not known if this was because driveways and sidewalks are moved during the planning stage or if the trees were simply removed more often. Smiley (2008) found that trenching cuts made closer than three times the stem diameter away from willow oak (Quercus phellos L.) took less force for tree failure. Thus, the recommendation with trenching is to stay at least three times the diameter or more away from the stem. Thus, if builders from this study stayed at least 3 m away with root severing, then assuming a similar outcome as with willow oak, tree stability would likely be insignificant for trees up to 100 cm in diameter. If root disruption does occur on one side of the tree and a distance of 3 m or more away is maintained, an effect of greater tree death or reduced tree health was less likely (Hauer et al. 1994; Koeser et al. 2014).

It is possible that the lack of painting of wounds of oak trees by over 60% of the builders is an artifact of messages since the 1970s and 1980s that say painting tree wounds is not beneficial and can exacerbate tree decay (Shigo and Shortle 1983). Applying a wound dressing and proper pruning using the cut promoted by Shigo reduced the chance of oak wilt when a tree is pruned or wounded (Camilli et al. 2007). In the Midwest, many educational approaches (e.g., billboards, public service announcements, brochures, newspaper articles, workshops) exist to educate professionals and laypeople about oak wilt management (Miller et al. 2015). Avoiding wounding of oak trees, and if wounding occurs covering the wound immediately (paint is often suggested), are two main points.

Builders are either not motivated to change their activities, have little financial incentive, and/or lack training on alternative construction methods conducive to the effective preservation of trees. Despot and Gerhold (2003) found the Building with Trees seminar, hosted by The Arbor Day Foundation, to be effective in increasing knowledge of construction practices in wooded areas. University extension agencies and state departments of forestry have produced comprehensive guides available for free, such as those in Minnesota (Johnson 1999), Pennsylvania (Elmendorf 2005), Oregon (Ries et al. 2009), and other locations. The information and training was and still is available if builders are motivated to pursue it.